Big-HP, insane build IDEAS thread - turn the 818 into a super car killer

[Matty_STi]

The purpose of this thread is to toss around ideas related to doing a high HP 818 build but not JUST big hp numbers but suspension, aero, braking, tires, etc.. Something that will rival a caparo, ultima, slc, atom v8, etc. etc.

Okay on to the nitty gritty. I am going to build an 818 using VMAN7's vantage body style (adapted with the aero bits I deem necessary by simulation and testing), using a 3MI Racing destroked big bore EJ series (Micah is also working on my STi motor). Goal will be about 650-750whp (yes there is a lot of variability here but that is because depending on how aero, brakes, tires, suspension and chassis handle it will determine how high the wick gets turns). Turbo will be a borgwarner efr 8374 (79lb) or 9180(95lb) my STi build will be the test bed for which turbo I will use, and be running similar HP figures at the crank. ECU will be the same as my STi a Syvecs S8. As you can tell lessons learned from my STi will be applied to my 818 build. Details about my engine build will be forth coming in my build thread in the built motor subforum on NASIOC (motor is still in the planning stages with Micah over at 3MI). Oh and sticky wide R compound rubber.

As for ideas, here is a few. I am going to use per gear boost control, traction control, active aero devices (with input from TPS, brake pedal position, and vehicle speed), brake rotor cooling vanes to separate the boundary layer, air water intercooler integrated into an intake manifold (an idea I am currently working on and will deploy on my STi), I am working on some anti-lag designs based around the prodrive rocket antilag used in the subaru wrc cars (may also look into variable openings for the turbo manifold). Transmission will be one the newer porsche transaxles, have been spoken with a few porsche and subaru transmission guys about my choice of tranny for my build, more details about this to follow.

My STi will be a test bed for lots of these ideas and refined there. My 818 will be my track car and go fast car and scare myself car. This is going to be a lightweight rocket ship designed to scare the crap out of people and really push the boundary's.

I will be going into much more details about all this stuff to generate discussions and to get some facts going for those thinking about how they would go about a high hp 818 build.. There will be guys who want to do them and so this thread will be here for them to toss ideas around and discuss what could work and what won't. Also how to setup an 818 to deal with extreme hp. High hp 818's will be built but hopefully we can figure out ways to properly manage and build them without it becoming like what is currently happening with supra's that just have massive turbos tonnes of boost huge hp numbers lag up the butt and impossible to drive... My car will be quick but also easy to handle and not a lag monster that tries to kill me.

So lets get the ideas flowing and see what you all think!

-Matt


*I spend my time mostly in the built motor forum on NASIOC and there are threads of mine there.

*** Oh and keep the flaming to a minimum, my wants and desires for my build are not the same as yours, discussion is great but lets keep this positive. I have put lots of thought into this and I have lots of track experience with some serious cars and done some serious builds as well. If you have criticisms keep them constructive so that others can get something out of this discussion.

[Flamshackle]

*I spend my time mostly in the built motor forum on NASIOC and there are threads of mine there.

*** Oh and keep the flaming to a minimum, my wants and desires for my build are not the same as yours, discussion is great but lets keep this positive. I have put lots of thought into this and I have lots of track experience with some serious cars and done some serious builds as well. If you have criticisms keep them constructive so that others can get something out of this discussion.

This isn't Nasioc, you wont get flamed here... Love that about the FFR community.

All sounds amazing cant wait to see the development of your idea as the kits roll out! :D

[Matty_STi]

I only added thy because when I first raised this point about a high hp build it turned a bit ugly. Lol

[metalmaker12]

With all that goes into 500-600whp+, the right modified gearing, suspension, aero and a weight of 1600-1700 or less the 818 could be a ultima contender, or better. If you realize this build you might show this possibility. I am interested in what you come up with.

[Benji]

1. You won't need 650-750whp to beat an Ultima GTR.

2. Even 400whp is going to be a handful, all the time.

Invest in this:

http://www.racelogic.co.uk/index.php/en/other-products/traction-control

[Matty_STi]

This thread isn't just for me either but for anyone who wants to think about a big HP build.

Not just comparing to ultima's but all those light crazy track oriented cars, bac mono, ariel atom v8, and so on. 818 will only be able to get so light. (btw a 1000+hp ultima could weigh in around 950 kilos, to get comparable power to weight I would need 650-750 whp in an 818)

Syvecs has traction control and being the ecu I can integrate more sensors into how that control is dished out and have much more fine control.

**note** with a true motorsports quality ecu like a pectel or motec or bosch or syvecs you can have many different maps and switch on the fly, i could have 200whp for putzing around town and then go to the track and turn it up to 750whp with the turn of a knob.

With aero, suspension, ecu control, tires and brakes this won't have to be a handle just a scary fast car. It's all about finding the balance of how big can I go before it's uncontrollable. I believe i can get upwards of 1000lbs of downforce with some good tires and a proper suspension setup 700+whp should be more than manageable. can-am, turbo f1 era, group b, and group c wec cars all were equally or even more over powered than this project would ever be with much much less technology available.

I am excited for when kits start rolling out! lets see some more ideas! This will be a great discussion I think! :)

-Matt

[fateo66]

I like where your heads at Matty! My only $.02 is to keep in mind that the 818 is half the weight of an STI and it will be much harder to build boost. I'm sure you have driven up a hill while doing a pull and felt how powerful and responsive your car feels because of it!

I plan on doing a fairly big build too but not quite that insane.

Power:
Sleeved 2.5L block
Cosworth pistions
Cosworth bearings
Eagle rods
11mm oil pump
Accusump
Z25 SOHC heads
custom valve springs
228/220 duration .458" lift SOHC cams
Two part 2.5I intake manifold
Pressurized by a special 58 lb/min turbo with a 55mm turbine exducer in a small 6cm housing for instant spool!
Bosch EV14 injectors tuned on speed density

Suspension:
04 STI caster adding front lower control arms
Old skool spherical bearing Perrin PSRS
Custom roll center and bumpsteer kit (if needed)
Adjustable rear trailing arms
Adjustable rear control arms
Poly bushings on all hubs and sway bar mounts
Front and rear sway bars
Koni adjustable coilovers
14.8:1 steering rack (still looking into this)

Brakes:
1 1/6" master cylinder
Line locks
327mm two part rotors Wilwood 6 piston front brakes
310mm two part rotors Wilwood 4 piston rear brakes
Hawk HP+ pads all around

Drivetrain:
AP suretrac front LSD
4.11 Subaru 5mt (Thinking of going to a built auto though)

Interior:
Sparco steering wheel
Momo corse seats
STI gauge cluster


But that's just what I have laying around right now, things might change a little bit in the next 5 months.

[philly15]

this might be my next project after a year or two of the 818, twin turbo H6 might not go twin but definitely turbo h6

http://i981.photobucket.com/albums/ae293/philly1515/h6.jpg

[shinn497]

How do you plan on doing your aero simulation. I'm learning CFD and trying to find a good vehicle simulation program....I'm heavily interested in active aerodynamics and active suspensions and want to learn as much as possible. If I can't find anything, I'd just write my own, but i don't know where to get test data from...

[SkiRideDrive]

I am not aware of any good vehicle simulation programs that are even remotely affordable. Plus simulation programs and models are only as good as the tire data used to populate them, which is hard data to come by. The best simulations are run by race teams, who are very secretive about their tire data and their simulations. Having a simulation program take all variables into account is a large order and I recommend attacking each element in turn, while trying to account for the effect of one system on another, aero on the kinematics for example. An affordable suspension simulation program is offered by Optimum G, which I found to be helpful. You can also use a CAD program like solidworks and use its motion functions coupled with spreadsheets to create your own models, determining how the chassis motion will effect the kinematics of the vehicle. Optimum G's software simplifies these calculations by doing them for you, allowing you to input sweeps of chassis orientation (corner entry for example accounting for changes in pitch and roll) and outputting data such as camber, toe, and roll center location, both lateral and vertical. A program which will account for all of these calculations, and helping you optimize kinematics via tying together the tires orientation and normal load to tire models, and do it accurately, is tough to come by.

[Matty_STi]

How do you plan on doing your aero simulation. I'm learning CFD and trying to find a good vehicle simulation program....I'm heavily interested in active aerodynamics and active suspensions and want to learn as much as possible. If I can't find anything, I'd just write my own, but i don't know where to get test data from...

I run autodesk inventor along with the CFD sim add-on package. I also run openfoam. Lots of guys run the solid works cfd stand alone, there are tonnes of great tools out there. Ansys, etc. The problem though is cost. These are big money simulation applications (except things like openfoam), and the hardware requirements are pretty substantial.

Check out this forum and ask the guys there about what programs they like or would suggest. http://www.f1technical.net/forum/viewforum.php?f=6 some serious serious aero knowledge can be found here, and in general all their subforums are filled with so much info it will make your mind melt. lol

As an aside active suspension isn't something I quite want to tackle yet. But I would love to see peoples ideas about it and how homebrew solutions could be implemented or hacking a system to make it work for the needs of a high hp 818!

-Matt

[rjh2pd]

Star ccm is a great flow simulator. I'm not sure how expensive it is, but our formula sae team uses it and are self taught on it. When do you plan on starting this, cause I can't wait.

[Desertrunner]

Fateo66 & Matt
A couple of things to keep in mind,
You need to give the brakes a bit more thought as rear engine car mostly have the same brakes front and rear and just change the force directed to the front and back. The reason is that the back of the car has a lot more grip, the brake sizing you outlined is more for a front engine car. I am sure there are plenty of guys that have more experiance then me on this.
Second point if you really want your 818 to handle you have to dump the poly bushes and go with spherical plain bearings. The poly bushes have a habit of flexing just that little bit and making it harder to hold the line in a tight corner.
You mentioned increasing the oil pump size but you really need to increase the suction size from the sump. The 3.3l engine has the bigger pump standard and the suction pipe is a lot larger. Didn't see anyone mention dry sump, given the G forces this car could hit not sure if the engine won't have oil issues with air. remember the heads hold a hell of a lot of oil in a hard corner. Rough guess the total volume of the sump is pump out in less then 10 seconds so you need good flow.

Of course these are just suggestions to consider keep up the good work.

Can't wait to see what people do with there 818's.
Tony

[longislandwrx]

**note** with a true motorsports quality ecu like a pectel or motec or bosch or syvecs you can have many different maps and switch on the fly, i could have 200whp for putzing around town and then go to the track and turn it up to 750whp with the turn of a knob.
-Matt

In my humble opinion I don't think a car with injectors, head flow and cams sized for 750 whp 900? at the crank would be very drivable tuned to 200, although looking at dyno runs of big motor cars with those turbos, it may not be too awful, but why spend 100k on an 818 only to drive it around with 200whp.

If you are going with vmans design with such a big mouth maybe an active grill?

http://www.youtube.com/watch?v=D6gNk0nOeXw

What's the timeline to get the ball rolling on your STI? Do you have the car yet and if so what year is it?

[fateo66]

Fateo66 & Matt
A couple of things to keep in mind,
You need to give the brakes a bit more thought as rear engine car mostly have the same brakes front and rear and just change the force directed to the front and back. The reason is that the back of the car has a lot more grip, the brake sizing you outlined is more for a front engine car. I am sure there are plenty of guys that have more experiance then me on this.
Second point if you really want your 818 to handle you have to dump the poly bushes and go with spherical plain bearings. The poly bushes have a habit of flexing just that little bit and making it harder to hold the line in a tight corner.
You mentioned increasing the oil pump size but you really need to increase the suction size from the sump. The 3.3l engine has the bigger pump standard and the suction pipe is a lot larger. Didn't see anyone mention dry sump, given the G forces this car could hit not sure if the engine won't have oil issues with air. remember the heads hold a hell of a lot of oil in a hard corner. Rough guess the total volume of the sump is pump out in less then 10 seconds so you need good flow.

Of course these are just suggestions to consider keep up the good work.

Can't wait to see what people do with there 818's.
Tony

Like I said at the end of my list, that is just the parts that I currently have laying around.

I fully agree on the polly bushing thing, on all my car any bushing I could replace with a solid metal joint I have, which is why I love my old Perrin PSRS's, solid endlinks, solid trailing arms and solid lateral links so much. But to my knowledge no one makes spherical bearings for the rear hub assembly.

As for the rear brakes the Wilwood kit has nearly a 2" bigger rotor, do you not think that will be enough?

[Wayne Presley]

In my humble opinion I don't think a car with injectors, head flow and cams sized for 750 whp 900? at the crank would be very drivable tuned to 200.




Why would you say that? It's simply a matter of backing off the boost although it's going to be lazy off boost due to the low CR. Running staged injectors, it's no problem to have it idle just fine.

[longislandwrx]

You caught me mid edit. On big displacement Subaru engines, those two turbos don't really hit boost until 4500 rpm plus. On a destroked motor, maybe even later. Just seems real laggy to poke around town with, but like I said maybe not THAT bad.

staged injectors would help, but also mean another added expense and additional tuning requirement.

[FFR-ADV]

I won't be doing this, but imagine 65 PSI of boost....1000 HP...


http://www.youtube.com/watch?feature=player_detailpage&v=7SoGzbrxKuw

uses a closed deck from S&R Performance:

http://www.sandrperformance.com/SR-STi-25L-Closed-Deck-Short-Block--Stage-2-Plus_p_926.html

Looks interesting...

Cheers!

[FFR-ADV]

Here is a video showing the deck machining:


https://www.youtube.com/watch?feature=player_detailpage&v=J1Cr6GpSukA

Looks interesting.

Cheers!

[Matty_STi]

Why would you say that? It's simply a matter of backing off the boost although it's going to be lazy off boost due to the low CR. Running staged injectors, it's no problem to have it idle just fine.

compression ratio for my build will be fairly close to stock which already isn't all that high.

as for lowering the wick, you don't need much of anything while putzing around town, and this won't be my "putzing car". lol. I doubt very much I would be running under 400whp really ever, but a limp map and a low low boost map will be created.

Brakes will be built up accordingly but size isn't the only factor and really not the most important one. Heat transfer, heat management and balance are the big things. Bias adjusters are easy to create, I am planning on using a tilton pedal box assembly master cylinders and bias adjuster. Fluid flow and management is a specialty of mine and thermal management is something I am well versed in. I will be posting a lot of stuff about how to properly deal with heat built up in brake assemblies, air flow for cooling of brake assemblies and more later on. Have some diagrams I need to draw up and run some sims in autocad to verify their validity. I'm trying to decide between alcon, ap and a brembo track oriented caliper and rotor assembly. Carbotech brake pads will be my go too A) really high quality B) tonnes of pad compound choices to suit different track and road conditions C) you don't need to grind the rotors and rebed the pads when you change them as the transfer layer built up on the rotor from any of the pad range is more than adequate to deal with the other pads (YAY!)

I am looking at dry sump but right now Killer B pickup pan and baffle assembly is my current go to but we shall see what 3MI would have to say as he has far more motorsports experience than myself.

Building boost/turbo lag - Rocket style antilag test, variable vane (may play around with the variable vane holsets), variable opening housing - this has recently popped up on NASIOC again but i've been thinking about something similar to the current thread for a while (depends on how my rocket tests go), super short post turbo piping to my unified intercooler/manifold (which will be an AWIC so even less flow restriction) with as straight of piping as possible.

Not sure what I will do about bushing material or design something I will need to think about but in general I thus far haven't thought a lot about suspension design. I figure getting the chassis in front of me will allow me a better chance to really get a feel for what I need to change for my specific needs. - Good that suspension talk has been brought up. This will become a big big focus I think for anyone wanting to do a high HP 818 build due to how light and stiff this chassis can/will be.

I don't know if an H6 would be the best motor for this particular car. Lots of extra weight being stuff way at the back of the chassis. Sounds like a recipe for vicious snap oversteer (think old school 911's). lol but maybe would be a cool mile car!!

Staged injectors is what I am playing on doing, say ID1000s and ID2000s, easy to manage with an S8. Don't want to go with too big of injectors, things just get unruly at a certain point.

Active grill won't be used by me, I want the air flow over the rads and coolers and it's also going to be used for generating downforce through louvering and directed flow.

Closed deck I don't really see as beneficial for me, besides I can get stronger sleeves put in and get the sleeves pinned like JR has done if I really need that stability but in all honesty sleeving I see as a better option when done right. Besides if 3MI, MPS and others are sleeving versus closed decking I think they must know better than I.. lol

I will post some links up later. I'm feeling a bit too lazy for that right now. lol

I have a 2012 Sti that I use as my Daily right now, still working out the motor build details with 3MI, that should be sorted out soon I think and by the end of the summer/early fall i'm doing break in and getting everything in place for lots of fun for summer 2014. (I like to give as much project time as possible. lol)


-Matt

[Desertrunner]

If you guys go to stage injectors what ECU will you use?

[Wayne Presley]

Lots will support staged injection, Electromotive, MoTec, MSpro, Syvecs to name a few

[Matty_STi]

Add pectel, hydra, aem, life racing, link, ecutek, haltech, gems, autronic to that list. but those are all standalones. lol

-Matt

[Desertrunner]

Any preference on ECU,
Tony

[bromikl]

Matty, you mentioned suspension earlier. While I didn't understand half of what you said, do you have any knowledge/experience with hydraulic roll dampening? I'm hoping someone here takes it on. It looks promising, but few people have the skills or budget to try it.

[Wayne Presley]

Any preference on ECU,
Tony

I have tuned Electromotive, FAST, MegaSquirt, Accel, MoTec, Redline, Apexi, GReddy, Adaptonics, Hondata, Hydra, Haltech, SCT, Diablosport, HPtuners, Big Stuff, Cobb, AEM, GM, Ford, Dodge, and all but the Apexi did what they were advertised to do. The MoTec is really expensive but will do everything from traction control to telemetry. Electromotive has tons of features for the money and really works well. The Adaptronics is really nice, I have them on the Lotus' we race. FAST, Accel, Big Stuff are overpriced for the features you get. Best bang for the buck is the MegaSquirt Pro, $1199, will do everything you need. I'm a dealer for Electromotive, FAST, Redline, Cobb, HPTuners, Adaptronics, AEM, SCT so I can supply you with what you need, even for your daily driver.

[BS]

Curious about the Porsche transaxle mentioned in the first post. 930 type? How would you adapt it to the H6 motor- is there an adaptor currently available or would this be a one-off piece?
How about the size and length of the Porsche transaxle? Will it physically fit in the space in the 818 or will body revisions need to be made? Will the Porsche transaxle require the use of custom axles and/or spindles to fit everything together and handle the extra horsepower? (which would probably also mean custom control arms and trailing links)
Sounds like some modification to the chassis may be in order to make everything fit and work as described. I'm really interested in seeing this come together. Hopefully there will be lots of pics and descriptions of what you are doing so we can follow along and possibly adapt ideas to other builds.

Bob

[Matty_STi]

Desertrunner - Syvecs or Motec would be my preference. The level of control with this class of ecu is much greater than lower end ecu's with all the control, data logging, sensor management and feature sets that come with them.. ECU preference though should really boil down not to price but the feature sets you require. I chose a Syvecs because the features are perfect for me, the control level is fantastic, data logging is great, the syvecs guys work with subies and know them well, and most of all the quality of the ECU is top drawer. But then again a motec or syvecs are the sort of ECU I require. There is a reason that this level of ECU exists and for a high revving high output high strung subie motor that also will be using the ECU for a variety of different control schemes than I honestly think the money should be spent on a computer that will control it to the greatest degree possible with the best possible component quality. You get what you pay for. lol tldr; Research ECU's and pick the one with the best features for you, that your tuner know best, fits your budget and is of the highest quality.



Bromikl - No direct experience with hydraulic roll dampening but I have read up on it. Something to look into for sure. I will do some more reading and see what sort of costs, materials research, vendor support, etc. cool idea to look into.

BS - There are a couple guys that have swapped subie motors into porsches and used the porsche transaxles. There are adapter plates that have been made, I am going to look into this further, if lots of people are interested then maybe one of the vendors would be interested in a run of adapter plates for those of us that don't want to run the glass trans and want an extra gear. I am looking at the g96 or g97 transaxle btw. Also I am using an EJ257 4 cylinder block not the 6, I think the H6 is added weight without much gain for the 818 application, especially considering guys are running their EJ series H4's to 1000+ crank hp!!! :O For a heavier application where more torque would be required the H6 would be fantastic! I will be doing custom axles to keep that from being a weak point as well. The chassis may need to be modded slightly but I will know better with a transaxle and the chassis in front and how I best want to mount it.


-Matt



Any preference on ECU,
Tony


Matty, you mentioned suspension earlier. While I didn't understand half of what you said, do you have any knowledge/experience with hydraulic roll dampening? I'm hoping someone here takes it on. It looks promising, but few people have the skills or budget to try it.


Curious about the Porsche transaxle mentioned in the first post. 930 type? How would you adapt it to the H6 motor- is there an adaptor currently available or would this be a one-off piece?
How about the size and length of the Porsche transaxle? Will it physically fit in the space in the 818 or will body revisions need to be made? Will the Porsche transaxle require the use of custom axles and/or spindles to fit everything together and handle the extra horsepower? (which would probably also mean custom control arms and trailing links)
Sounds like some modification to the chassis may be in order to make everything fit and work as described. I'm really interested in seeing this come together. Hopefully there will be lots of pics and descriptions of what you are doing so we can follow along and possibly adapt ideas to other builds.

Bob

[Wayne Presley]

I personally would like to do a compound supercharger/turbo set up like on my cobra. Has great low end driveability, solid midrange and top end rush.

[Desertrunner]

Guy you are all talking about the big Hp and yet I haven't seen one of you mention the engine cooling. Am I to take it that its not a issue?
Given my experiance with Subaru I think it will be a problem.
Tony

[JeromeS13]

Kent Porter of Precision Chassis works has done a few Boxster/Subaru swaps. The Porsche transaxle doesn't look much longer, but it does look to be a good bit 'fatter'. Looking at the development pictures, though, it looks like being 'fat' won't really be an issue...

http://www.precisionchassisworks.com/boxstersubaru-engine-conversion.html

16317

[Matty_STi]

Guy you are all talking about the big Hp and yet I haven't seen one of you mention the engine cooling. Am I to take it that its not a issue?
Given my experiance with Subaru I think it will be a problem.
Tony

Upgraded radiator with proper air flow, oil cooler for track use with thermostat to keep oil from getting too cold, trans cooler with thermostat as well. Running water wetter is a good idea too or RMI25. Brake ducting is important as well. There are also heat emitter coatings that can be applied to radiators, coolers, heat exchangers, intercoolers, brake calipers, engine blocks, heads, etc. to increase their efficiency. Make sure you keep exhaust mani and turbine scroll housing coated/wrapped/heat shielded to keep that radiant heat out of the engine bay. Stagnant air in the engine bay should be vented. Protective heat wrap on all wires, fluid lines and piping. Isolate the intake mani with heat shielding and use composite tgv deletes or phenolic style spacers to keep conductive heat out it as well. Keep the heat where it needs to be and prevent it from getting to the parts where it doesn't. Nothing too fancy in all honesty.

If you wrap your headers, up-pipe, down-pipe, exhuast, make sure to use some sort of aluminum foil tape or something to keep engine fluids off the wrap to prevent fires, this will also protect the wrap from road debris and from being scratched up and getting messy and generally losing it's effectiveness and increases it's life span. If you've ever wrapped a header you'll know that the less often you re-wrap the better.

Subies aren't really too bad for coolant issues, sure if you are in a hot climate that can be a problem but as long as you have a properly sized rad and good air flow and your intercooler meets the flow requirements there shouldn't be any problem.

Proper oil pump is important (lots of threads on NASIOC about this, make sure when getting your engine built you don't just go to the biggest pump you can get consult your builder or a known expert.). When a 10mm pump is all that's needed and you use a 12mm you could be aerating oil left and right and effectively create a situation where you kill your motor. -> This is pretty important and lots of motors have died because of this. Oiling is more important to a subie engine than the coolant stuff. There are guys running big numbers on an essentially stock coolant system with no issues. Conversely there are bearings being spun left and right, engines being chewed to crap because they don't have their oiling setup - setup properly.

- Matt

[07FIREBLADE]

The one thing we have to worry about is the transmission mounts and will the axles line up with where the wheels nees to go. So basiclly who is gonna do a boxster transmission swap instead of the wrx. This is going a very interesting aspect for some who are looking for big hp to consider.

[BipDBo]

We know that there are plans to eventually adapt the 818 to get a donor engine other than a subaru boxer. Talk of the high mpg 818 spoke of a VW TDi straight 4 mounted in the transverse. An insane HP build may best be started with a non-subaru engine mounted in the transverse, perhaps a V6 or V8 with more displacement. One disadvantage, though to transverse vs the Subaru boxer would be a higher CG.

[longislandwrx]

I have a 2012 Sti that I use as my Daily right now, still working out the motor build details with 3MI, that should be sorted out soon I think and by the end of the summer/early fall i'm doing break in and getting everything in place for lots of fun for summer 2014. -Matt

What are you planning to DD once you turn this bad boy into a monster? Have you done a budget yet for the STI/818? I'm wondering what a build of this caliber would cost if I decide to go this route.

I have two other cars and the wife has a third, so not worried about the 818 being broken down all the time.

[Matty_STi]

I'll mostly DD my sti. I also have a 2005 ford focus that my gf and sister trade using when they need to take longer drives and not put tonnes of miles on their cars. I also am thinking about getting an SUV to better handle crazy winter driving, and my many excursions to the mountains for camping, backpacking and fly fishing. Don't think that killing my sti on logging roads is the greatest idea. I also have my amc javelin still kicking and I try to car pool with my gf as much as possible occasionally we use her tiburon. Also got the farm truck lol. My other project cars have all been sold off. :(

Sti budget is north of $50k though I'm still working out hard numbers. 818 will probably be at minimum a 70k build not including the 818 itself.

-Matt

[longislandwrx]

Got it.

That will be impressive if you can hit all your stated targets for 70 grand. 900 hp at the flywheel is going to eat up a bunch of that budget. I'm thinking $25k-30k for your long block with all the parts/machining you're going to need, and another 20 for your Syvecs ecu and everything else you'll need to get it running. Add that to the built G50 with custom axles for 15k and you don't have much left for your ambitious aero/handing goals.

Although help from sponsors might bring the costs down, i've learned most sponsors are not willing to shell out parts and money until you start winning races, regardless of your ambition.

[Matty_STi]

Syvecs will likely only be about 7-10k possibly 15k being handy with electronics is a big help here as I can design and program most things. Active aero will be hopefully a lot cheaper by being able to design and implement everything myself. I would conceive of it being possible to do my aero stuff for under $10k if I really focus on what I know works and not get too creative and start experimenting. If I were to go tried and true on everything I could get in under $70k but I expect my minimum of 70 to be exceeded. Possibly up to 90 hopefully no more than $100k. All depends on how the project proceeds. Nothing is set in stone. Lol.

Oh and I'm not looking for sponsors. Vendors that help me with knowledge and info is really all I'm after. If I get a deal here and there great but not something I have any desire for. Plus I don't really plan on racing this. I don't know if there is a race series I could run in!! Lol

[longislandwrx]

and another 20 for your Syvecs ecu and everything else you'll need to get it running.

Sorry, unclear. "It" being the motor, meaning the Syvecs, injectors, coils, turbo, exhaust, intercooler setup, custom intake manifold for dual stage injectors, bigger TB etc. 100k is a lot of money to put into a race car and not race it, but I understand what you are doing.

[Matty_STi]

Ah lol, that makes sense.

This is a bit of a "******* stepchild" sort of car/pseudo race car. lol

[Desertrunner]

Hi Matt,
Not sure why you wouldn't stick with the Subaru gearbox these guys have parts that will make any Subaru box stand what ever you can throw at it.
http://www.ppgearbox.com.au/

Tony

[StatGSR]

^ Tony is right, not sure what ratios they offer but im sure they would work with you on that.

[Matty_STi]

As does Modena, par, kaps and others. But the 5mt transmission is a compromised design that was never intended to deal with these sorts of torque figures or shock loads. There's plenty of anecdotal and test evidence to show that spindle flex due to case flex and other issues cause gear separation. Combine that with having to modify it to drive two wheels versus 4 and the design is further compromised. I could stick the burliest gears on the planet (ppg though very good wouldn't be at the absolute top of that list) and still have issues as the entire design of the 5mt never had this use in mind the G96 and G97 boxes were designed for cars using mid engine rear wheel drive with huge grip and potential torque figures north of 700lb-ft. These are a seriously robust gear box. Ask the gtm and gt-40 kits and ultima guys who are putting down north of 1000 hp with LS series small blocks. Plus 6 gears versus 5 and with a 10,000 rpm fuel cut potentially that gives me loads of shift options to get right where I need to be.

Also - because race car!! ;)

*** should note I've spent a butt load of time researching transmission options for my sti. And spoken with every major vendor and many different race teams (drag, time attack, endurance and most importantly rally). If I were to go for a 5mt I would probably look at the new emco gear set being discussed in the motorsports forum on nasioc. That will be a phenomenal gear set. Far better than ppg.

-Matt

[StatGSR]

^ what about re-geared sti 6spd? only reason that has been pushed away from most 818 builds is because it wont fit inside the body work, but it sounds like your doing your own body anyway?

[Oppenheimer]

But the 5mt transmission is a compromised design that was never intended to deal with these sorts of torque figures or shock loads.

I can't help but think the same logic could be applied to turning the 818 into a Supercar killer. It wasn't designed for that, that is not its target use. But adventurous, enterprising persons such as yourself are going to do it anyway, for your own personal reasons, to the benefit of the rest of us, even though something like the GTM (or other kits) would be far more suited to that.

I do not know why you want to pour so much $$ on the 818, when its clear that same $$ could be used to better effect with a GTM or other. But I applaud your doing so. I would equally applaud any efforts for you to make a Subie box work for your needs, for my own selfish reasons, as that would probably have more trickle down benefit to other 818 builders. Yes, you will be paving the way for mega-power 818's no matter what path you take.

[Matty_STi]

^ what about re-geared sti 6spd? only reason that has been pushed away from most 818 builds is because it wont fit inside the body work, but it sounds like your doing your own body anyway?

The sti trans is too long and weighs much much more than the 5mt. Can't remember off the top of my head but well north of 100lbs I think approaching 200. But don't fully quote me on that.

The 5mt is a very compromised design for the model year that the 818 wrx donor is based on. As for doing something like beefing up the 5mt well it's been done. Hundreds of times. We know the limits of the 5mt. At the power levels I am looking at the 5mt all of a sudden becomes very very expensive to upgrade. I could spend $30k to make it beefy enough that I am comfortable putting a couple thousand track miles on it. And it still isn't the best transmission option. I believe that what I am choosing to do with the Porsche transaxle is far more pragmatic and can definitely help the 818 community. The 6mt would need to be beefed up and modified. The 5mt would need hugely expensive upgrades and in some circles it's seen as a consumable part. The g97 other than a conversion plate doesn't need to be modified at all and out of the box is more than capable of dealing with the shock loads I am goin to be generating.

As for the nature of the project. We know what the gtm can do, what an ultima can do, what the 5mt can handle and why the 6mt isn't a viable option. This project is about pushing the limits and seeing what the boundaries are for the 818. We don't know what the limits are, where the flaws and compromises are. Someone will have to push the limits to see where those compromises and limits are and then as a community we can look at overcoming those. That's the purpose of this. Push the limits and see where we can go from there. It's pretty rare that we are given a chance to take such a unique creation and go somewhere really extreme with it. That's the fun in this for me. There are so many unknowns despite all the known pieces we are working with. It's a great challenge!

Loving this discussion btw. I think it's really fleshing out the nature of this sort of build and what sort of thought process is involved! Lets keep it going!!

-Matt

[StatGSR]

well actually we don't know what the 5spd will do (how many wrx's are running around with FWD conversions? This has been a topic of debate for the last 2 years) same goes for the 6spd, i know its long, i said that, i know its heavy too, but again, how many FWD STi's are running around? heck a little weight at the back may help it planted for all we know. I think it would be more advantageous to see where either the 5spd or the 6spd in a FWD configuration with a built up gear set can take you. you are merely assuming there will be failures, you do not know there will be and with everything else you have planned, it kinda makes sense to keep part of your build strait forward and true to the 818s design.

[Matty_STi]

well actually we don't know what the 5spd will do (how many wrx's are running around with FWD conversions? This has been a topic of debate for the last 2 years) same goes for the 6spd, i know its long, i said that, i know its heavy too, but again, how many FWD STi's are running around? heck a little weight at the back may help it planted for all we know. I think it would be more advantageous to see where either the 5spd or the 6spd in a FWD configuration with a built up gear set can take you. you are merely assuming there will be failures, you do not know there will be and with everything else you have planned, it kinda makes sense to keep part of your build strait forward and true to the 818s design.

We do however know what shock loads these can take. A normal 818 sure a 5mt will be fine even with a bit more gumption. But I am putting r compound rubber with huge downforce. There will be big shock loads for sure. The drag guys essentially put most of the power to the rear and they chew up built 5mt's rally guys essentially have them as a consumable part. The wheels powered dont mean the shock loads are less. But we are re-engineering something that had a torque balance in mind and that torque would be vectored 60-70% in the opposite direction to where an 818 would send it. You already are dealing with a compromised design by nature and re-engineering it with more compromises. The scientist and engineer in me says this will break. The hard facts of these transmissions say they will break. The fact of the matter is they weren't designed to handle this sort of stress at all and to change that will be a huge undertaking at considerable cost.

To compare reworking a 5mt to my use versus a stock 818 being re-engineered for this are two very different things. The 5mt probably has 15x the design time in it compared to the entire 818 design. Not a knock against FFR. Just a nature of the complexity of modern gear boxes. My reworking of the 818 chassis is very much inline with what the chassis can handle based upon some simple materials analysis. The suspension is going to be reworked as well and honestly simple changes to the suspension can increase their abilities by orders of magnitude when done right. Gear box re-engineering not so much. That's why a simple gear upgrade can be on the high side of $20,000 and a full gear sequential setup can be a $70-100,000 affair.

Reworking the 6mt though possible is still a compromised approach. G97 boxes are designed for this sort of use.

A fwd subie won't tell you much anyways because under hard acceleration you have weight shift back unloading the front and lowering the shock loads. Rear mounting it with rear wheel drive will increase those loads. Conservation of momentum will happen.

Yes I could make a 5mt do what I want. But I don't want to spend 30-40 grand on a gear box setup that isn't optimal gives me one less gear and may still be problematic. I can spend half that and get a proven result that is much more optimal. The 5mt just doesn't cut it. And trying to force it to do this is just going to get more and more expensive with lower and lower returns. Besides if I can get a G97 to work we have found a better cheaper alternative with a proven track record and is perfectly suited to the goals of a big hp racecar/supercar killer. Gotta push the envelope but throwing money at a problem isn't very pragmatic or prudent.

Great points though!

-Matt

[Ravendas]

There's plenty of anecdotal and test evidence to show that spindle flex due to case flex and other issues cause gear separation.
Actually, there's not. That was floated a while back as the reason for the 5mt failures, and has since been roundly debunked. It's even covered in Unabomber's transmission FAQ (http://forums.nasioc.com/forums/showthread.php?t=665334).

[Matty_STi]

Actually, there's not. That was floated a while back as the reason for the 5mt failures, and has since been roundly debunked. It's even covered in Unabomber's transmission FAQ (http://forums.nasioc.com/forums/showthread.php?t=665334).

Sorry I should have reworded that I did a crap job of writing that actually and kind of mashed a few things together instead of clarifying, my bad. Case flex isn't the root cause of issues, the most important issue is the long unsupported shafts that when torqued like to pull apart. There is some case flex not huge but it is imparting additional stresses and increase the wear and accelerates the degradation of seals, bearings, the gears and shafts. There are also posts showing cracks on the 5mt cases.

The second thread is very relevant:

http://forums.nasioc.com/forums/showthread.php?t=1595188

http://forums.nasioc.com/forums/showthread.php?t=986710


As for what gearset I would choose for my build if I went 5mt - check out this thread:
http://forums.nasioc.com/forums/showthread.php?t=2474627

-Matt

[Desertrunner]

So Matt what sort of clutch do you plan to use?
Tony

[longislandwrx]

If I was running that power level through a G50 I would use a ATS double plate carbon clutch or similar.

[Matty_STi]

For the G97, probably a tilton carbon with carbon flywheel. twin puck. I've looked at the other carbon options and the tilton seems to have the best wear versus holding, versus cost of the carbon-carbon options.

-Matt

[07FIREBLADE]

With the G97 will the axles line up or will you have to make major modifications to the frame/suspension. What is the overall dimensions of the g97 vs 5mt

[BrandonDrums]

Here's what I think: I think SOMEONE should take the time to design a subaru based engine with longer bores. Just take a EJ25 engine, scan it, extend the tops of the case halves out by about an inch and pour it.

That small tweak would allow subaru engines to handle 600 hp on stock pistons. Reducing the bore to rod length ratio would save the engine a lot of unnecessary stress and would allow you to optimize the bore to stroke ratio for a more linear powerband.

[Matty_STi]

That's a lot of work to create a deck plate to extend the bore, new rod design, new crank design, new sleeve design, and so forth. and I bet the pistons still wouldn't take it because they tend to melt and crack under the loads already created. Besides you would probably spend 50 grand or so on an engine like that and to put stock pistons in would be completely insane, a small amount of det or a spike in cylinder pressure and you've got a goofed piston shredding the crap out of your uber exotic one of engine and probably end up crying like a baby. No thanks. Could this be done, sure, not for me though

I'm going destroked long rod big bore motor for lots of sky high revs and higher VE.

As for the G97 dunno exact dimensions, some modifications will have to happen likely.

-Matt

[longislandwrx]

G50... not sure what variant. 16455

appx

[Tom Veale]

Anyone thought of using the W8 engine and transaxle from a Passat? I think it is a short enough block to fit. Problem is that most transaxles are automatic. Width might be an issue and height might give a higher C/G.

TV