Twin-turbo setup

[Frank818]

Do you think a twin-turbo setup would physically fit the 818 engine bay?


Why a TT? Just looking at options, here.
Basically to get more torque in the low-mid, like full boost around 2500 or so while reaching a peak torque of 350-400whp (I don't care about whp and top end hp). Smaller turbos boost faster. I need maximum torque from 2000 to 5000 or 2500 to 5500 (not the same amount necessarily, but a very generous amount from as low as 2000-2500 and up to 5000-5500). I don't know Subaru engines well enough (and even less their dyno charts) to guess what configuration would be the closest to my goal (probably none can reach it), but I know that a well designed and controlled TT setup is excellent for low and mid ranges.

Unless there is another option with a single turbo setup... I have read the thread about Subaru engines are like legos http://forums.nasioc.com/forums/showthread.php?t=2141800&page=1, but of course not all configurations are listed there and very rare those with approx power band numbers. :)

[Mechie3]

The Subaru TT motor wasn't all that great.

[Frank818]

Cuz of the turbos? Or the overall design of it?
Cuz if it's just the turbos that were crap, that's easy to change for higher quality or better suited, but if it's the overall design of the TT configuration, that's something else.

[PhyrraM]

The Twin turbo will fit an 818. The exhaust will be on you, as the FFR provided pieces won't work. One of the FFR 818 prototype chassis had one installed. There are picture here on these forums to be found.

The two turbos are different sizes, with a fairly complex system of vacuum controlled valves in the exhaust to direct the gasses properly and at the right time. From the factory they suffered from poor small-turbo-to-large-turbo changeover, creating a large torque dip in the midrange. Subaru folks have dubbed this "The Valley of Death".

Other than that, they are basically the same as all the other 2-liter Subaru turbo motors.

[Frank818]

Oh that's the one?
I have read about the different sizes Subaru TT engine, yes, might have been in your TidBits actually. lolll

I was thinking of a TT setup using equal size turbos. Then that doesn't exist as OEM and would be on me to build and tune.

I wonder if would be worth it, then. Maybe I can ask 818donors.com (AJW Performance) if I decide to do business with them.

[Xusia]

Others can correct me if I'm wrong, but it's my understanding you could get the stock turbo to spool more quickly (stock is like ~3000 RPM?) by doing various easy things like porting, polishing, wrapping, better crosspipe, etc. With a 2.5L engine, I think you could achieve your goals (given the low weight of the 818).

BTW, in a previous post you mentioned not having a comparable from a weight perspective. The Lotus Elise is very close, and in stock trim has LESS HP than a even a stock 2.0L WRX. I suggest watching some videos and looking at the Elise performance numbers. That will give you some kind of idea how much of difference the low weight will make!

[Nuul]

I'm sure you could do it if you were determined. It's not going to be easy though with all the plumbing required.

http://i.imgur.com/0VKZ50s.jpg

[BipDBo]

Why do you need more torque in the low end? I assume you will have a stick and clutch, so you can pre-rev. More importantly, you'll have all of the power going to two wheels rather than four, and the car will be close to half the weight of the WRX. With a single turbo, in first gear you'll have more torque than you need to break traction up through your higher rpms.

[Xusia]

Another thing to read: Wayne Presley was one of the test drivers who helped set up the suspension. He has been very forthcoming about the performance apsects of the car. I highly suggest reading his posts.

The reason I'm pointing this out is because I think you are WAY underestimating the stock performance of this car. With even modest upgrades, it's a serious killer. I think it will be easy to get the result you are looking for with less power and mods than you think! :)

[THE ITALIAN]

I thought of this option, but from the performance data we got from FFR, I think the car would be very over powered.
Just the fact that the traction control would sound like a good idea with ONE turbo, two would look cool, but not needed when you could achieve a hell of a power band if you beefed it up to 400 HP.
Managing the single turbo would be my goal .
My first Turbo was a Porsche and when that spooled up (around 2350 rpm), it was dangerous as it just felt like it doubled HP in a matter of seconds. that's scary around corners. Someone will do it though...................

[Mechie3]

That setup Nuul posted doesn't make low end power. :lol:

Using equal turbos may or may not help, depending on exhaust routing. Subaru's partly have poor low end because of the long exhaust path to the turbo. The newer legacy GT's had a low front mount turbo that was amazing for low end. it won't fit the 818 without a good amount of work/relocation of fuel tank.

If you have two small turbos though, you're essentially feeding them 1/2 the total exhaust gases, but you could possibly shorten the exhaust path. All in all, I don't think the time and effort is worth the gains (if any) compared to a stock 2.5 AVCS. If you really want, find a 2008+STI motor with dual AVCS.

[Frank818]

Street riding keeps me in the low end most of the time and I don't want to downshift to reach an appropriate amount of torque to get the car moving forward. Besides, if max torque is at 6000 on a small engine with big turbo, I'll very rarely use it, so I'm better off with something big in the low and use it every time I drive.

I am not concerned about 1st gear. What concerns me are 3-4-5th in the lower band.

Now that being said, I am freakin out a bit cuz it's hard to know what an OEM EJ20 will do on an 818 say from 2000 to 5000. I think I'll wait for some of you guys to finish up your build (or someone to test FFR's 818) and see how quick the car is in that range. Maybe it's more than enough, but I can't compare with cars I have experience with.

Maybe learning by those Lotus videos will help too.

[Mechie3]

My 06 WRX (now my donor):

Stock heads, stock block, stock turbo, modified exhaust and intake bits. 21psi. This is showing WHP and WTQ.

http://i139.photobucket.com/albums/q291/mechie3/CraigsDyno-1.jpg

Unlike my 02 w/VF39 (sti turbo) I didn't downshift to pass people and I rarely waited for boost unless I was lugging along in 5th gear.

[Frank818]

The reason I'm pointing this out is because I think you are WAY underestimating the stock performance of this car. With even modest upgrades, it's a serious killer. I think it will be easy to get the result you are looking for with less power and mods than you think! :)

Better underestimating than over, this way I'll be sooooooooo happy when I first drive it. lolllll
Just making fun, but you are absolutely right, like I just replied at the same time above, I am simply freakin out a bit, thinking a 2.0 with good boost will not push enough in the low end. I may be very wrong and if yes, god I'll be so happy. :)

I'll re-read his posts (Wayne's).

[Frank818]

I thought of this option, but from the performance data we got from FFR, I think the car would be very over powered.
Just the fact that the traction control would sound like a good idea with ONE turbo, two would look cool, but not needed when you could achieve a hell of a power band if you beefed it up to 400 HP.
Managing the single turbo would be my goal .
My first Turbo was a Porsche and when that spooled up (around 2350 rpm), it was dangerous as it just felt like it doubled HP in a matter of seconds. that's scary around corners. Someone will do it though...................

Agreed. Difference is, Porsches have the engine behind the rear wheels, weight transfer is quite different, but still the basics are similar, yes.

I'll stick to the idea even the EJ20 has more than enough torque around 2500 to make that car move more than most of other cars on the road. :)

[Frank818]

That setup Nuul posted doesn't make low end power. :lol:

Using equal turbos may or may not help, depending on exhaust routing. Subaru's partly have poor low end because of the long exhaust path to the turbo. The newer legacy GT's had a low front mount turbo that was amazing for low end. it won't fit the 818 without a good amount of work/relocation of fuel tank.

If you have two small turbos though, you're essentially feeding them 1/2 the total exhaust gases, but you could possibly shorten the exhaust path. All in all, I don't think the time and effort is worth the gains (if any) compared to a stock 2.5 AVCS. If you really want, find a 2008+STI motor with dual AVCS.

See that's what I was talking about in a post somewhere: I don't understand (yet) enough the subaru engines to think about variables like this one (exhaust length). Really appreciated you took the time to feed me on that. :)

A long exhaust is bad for lag and since this time I don't want to go through the extensive R&D (and $) I did with my old VW, I don't think I'm one who'll try TT. :)

Now about that 08+ STI motor. lolll A 08 engine could fit? But then again, buy a 02-07 donor, sell the engine, by a 08+ engine... worth the costs? Maybe, maybe not. Do I want to go through all that? I'll think about it. :) I think I should stay simple.
Not sure I read about newer engines yet, I've seen some about the FA/FB20, but not much.

[Frank818]

My 06 WRX (now my donor):

Stock heads, stock block, stock turbo, modified exhaust and intake bits. 21psi. This is showing WHP and WTQ.

http://i139.photobucket.com/albums/q291/mechie3/CraigsDyno-1.jpg

Unlike my 02 w/VF39 (sti turbo) I didn't downshift to pass people and I rarely waited for boost unless I was lugging along in 5th gear.

There's a picture in there? I'll wait when I come back home, in this computer sometimes embedded pictures don't show.

But you know what, you convinced me quite good on that 06 WRX. If you say stock (except a FEW bits) you never downshift to pass people on a what 3100lbs car, then you've just convinced me. :)
So you're saying that EJ25 is quite good.

[longislandwrx]

It's a picture of his dyno making full boost before 3k and 350ftlb.

Turbos are so good today, and sequentials are just such a pain. I don't think they've appeared on a production motor for 8 years now.

Stick with an efficient single.

I didn't see what you power goal is.

[Nuul]

Now about that 08+ STI motor. lolll A 08 engine could fit? But then again, buy a 02-07 donor, sell the engine, by a 08+ engine... worth the costs? Maybe, maybe not. Do I want to go through all that? I'll think about it. :) I think I should stay simple. Not sure I read about newer engines yet, I've seen some about the FA/FB20, but not much.

It will fit. You'll also have to get an ECU that can use it. I'm actually plugging the AVCS holes in my intake cams since I don't feel like redoing the ECU for a 500 RPM quicker spool.

[Mechie3]

There's a picture in there? I'll wait when I come back home, in this computer sometimes embedded pictures don't show.

But you know what, you convinced me quite good on that 06 WRX. If you say stock (except a FEW bits) you never downshift to pass people on a what 3100lbs car, then you've just convinced me. :)
So you're saying that EJ25 is quite good.

Few is relative...lol.

Intake
silicone turbo inlet
PNP throttle body (DIY)
PNP intake manifold (got it free from Grimmspeed ;) )
TGV Delete (you can DIY, it's not hard)
PNP exhaust manifold
Grimmspeed Xpipe
Grimmspeed uppipe

I recently sold the manifold, uppipe, and xpipe for a tubular header. Got the header for $300 used. Sold the grimmspeed stuff for $430. :D

[Frank818]

Those parts should not cost that much. It's less than when you open the block, change it, change head, valves, pistons, etc... so it looks promising. :)

FFR will provide the headers, right? They are tubular?

[Frank818]

It's a picture of his dyno making full boost before 3k and 350whp.

Turbos are so good today, and sequentials are just such a pain. I don't think they've appeared on a production motor for 8 years now.

Stick with an efficient single.

I didn't see what you power goal is.

Ha, well that's good to know! I am surprised, I didn't think the engine could make it like that. :)

My power goal?
I was thinking of 350-375wtq. No need for more if I look at power/weight ratios.
Who knows now after all I learned here today, I think 350wtq (reliable, not some cheap built, of course) will be more than enough.

[Frank818]

It will fit. You'll also have to get an ECU that can use it. I'm actually plugging the AVCS holes in my intake cams since I don't feel like redoing the ECU for a 500 RPM quicker spool.

I'll keep that in mind. If I ever get lucky to find a good deal, I'll keep it on my list of choices.

[Canadian818]

There's previous posts about this. I really want to try parrell twins on an EJ, much like the water cooled Porsche turbos. Short manifolds, turbos mounted beside the transmission down low, two intercoolers, maybe even two throttle bodies with just a cross-over pipe to equal pressure between banks. However, I'm going to drive it for a year first, cause it might be all I can handle with a stock engine, for awhile anyway.

[Frank818]

My 06 WRX (now my donor):

Stock heads, stock block, stock turbo, modified exhaust and intake bits. 21psi. This is showing WHP and WTQ.

http://i139.photobucket.com/albums/q291/mechie3/CraigsDyno-1.jpg

Unlike my 02 w/VF39 (sti turbo) I didn't downshift to pass people and I rarely waited for boost unless I was lugging along in 5th gear.

Ok I see it now, I'm impressed by the fact you're making 100+awtq over awhp. But at 2000 you already have 200awtq. :)

[Mechie3]

It's a picture of his dyno making full boost before 3k and 350whp.



351 Wtq...only 243whp (it's only a td04 turbo).



FFR is not providing headers (use the stock manifold, or buy aftermarket). The only downside of the stock setup I had was at high rpms (highway) you could feel it tapering off. For autocross it was awesome (though frustrating when you torched the inside tires on corner exit :devil: ).

[Frank818]

But if you change the turbo, you might get more in the higher rpms but you may also lose in the bottom. Usually it ends up to that, the trick being to find the best match for your personal taste.

[papajon1000]

If I were to ever do a twin turbo setup it would most definitely be a compound arrangement, like the diesel guys do. You could use the tdo4 as the high pressure turbo and use a larger turbo as the low pressure or atmospheric turbo.

[THE ITALIAN]

[QUOTE=Frank818;104942]Agreed. Difference is, Porsches have the engine behind the rear wheels, weight transfer is quite different, but still the basics are similar, yes.
Yes they are in the back, on this car they did it on purpose. Porsche did so the engine could have a "headstart" ...it was always trying to get in the front.

[Movieman]

Just reading through this and my first thought was " I think if you stick a bone stock NA 2.5 engine in the 818 the first time you roll on the power your going to do a OMG! and wonder why you ever thought you'd need "more"...
Now that's just my thinking and what the heck do I know but my gut tells me that will be true..

[Frank818]

Just reading through this and my first thought was " I think if you stick a bone stock NA 2.5 engine in the 818 the first time you roll on the power your going to do a OMG! and wonder why you ever thought you'd need "more"...
Now that's just my thinking and what the heck do I know but my gut tells me that will be true..

The more I read about it and the more I see you guys discussing my topics the more I think a mere 165hp will kick ***. lolll
I can't wait for the first one to finish his project and read his driving impressions. :)

[Movieman]

The more I read about it and the more I see you guys discussing my topics the more I think a mere 165hp will kick ***. lolll
I can't wait for the first one to finish his project and read his driving impressions. :)
My thinking is all power to weight with a little bit of frontal area tossed in and if you take 1828LBS and divide by say 250HP your at 7.3LBS/HP and that is pretty darned fast.
At 300HP your at 6.09LBS/HP
At 350HP your at 5.22LBS/HP
I don't even want to imagine anything above that..:D

[Goldwing]

I did some digging around trying to find the engine/turbo, etc. combination to meet my goals, which generally sound similar to yours. What I found, and guys, feel free to correct me, I got the impression that building for more than 300 whp seems to be the point at which you start sacrificing low end grunt for high end craziness. Up to that point the low end should be solid, and opting for the 2.5 already gives you a little extra low end torque. Those thoughts led me to decide to build a 2.5 with a VF48 turbo. Throw in a 3" DP for good measure followed by a good tune. Then just hoping it isn't waaaay too much. A little polishing if I have extra time before I take delivery couldn't hurt either, I guess.

[Frank818]

My thinking is all power to weight with a little bit of frontal area tossed in and if you take 1828LBS and divide by say 250HP your at 7.3LBS/HP and that is pretty darned fast.
At 300HP your at 6.09LBS/HP
At 350HP your at 5.22LBS/HP
I don't even want to imagine anything above that..:D

Yes, absolutely.
As a reference, the GTM LS7 505hp is at 4.65LBS/HP :)
2350lbs divided by 505hp. And a crap load of torque from that V8. :)

A Bugatti Veyron GV 3.48LBS/HP
A Zonda Revolucion 2.99LBS/HP
And a Venom Hennessey 2.24LBS/HP

loooollllllllllllll :P

[Frank818]

I did some digging around trying to find the engine/turbo, etc. combination to meet my goals, which generally sound similar to yours. What I found, and guys, feel free to correct me, I got the impression that building for more than 300 whp seems to be the point at which you start sacrificing low end grunt for high end craziness. Up to that point the low end should be solid, and opting for the 2.5 already gives you a little extra low end torque. Those thoughts led me to decide to build a 2.5 with a VF48 turbo. Throw in a 3" DP for good measure followed by a good tune. Then just hoping it isn't waaaay too much. A little polishing if I have extra time before I take delivery couldn't hurt either, I guess.

You're talking whp not wtq here, right?

There's always a shifting point yes, unless technology changes enough to jeopardize all the calculations. lolll

[Movieman]

Yes, absolutely.
As a reference, the GTM LS7 505hp is at 4.65LBS/HP :)
2350lbs divided by 505hp. And a crap load of torque from that V8. :)

A Bugatti Veyron 0.72LBS/HP
A Zonda Revolucion 0.62LBS/HP
And a Venom Hennessey 0.463LBS/HP

loooollllllllllllll :P

I'm just thinking back to 1970 when my buddy bought a SS396 Chevelle with the 350HP motor,4 speed M22 and 3:55 rear and the OMG feeling when that thing was on the torque curve and that had to be a solid 3700+lbs or maybe 11-12LBS/HP.. Oh, forgot, it was $3700.00...:D

[Frank818]

lloooooolllllllllll :D

1.00LB/$!!!!!

[philly15]

This is my old car I sold to my friend just tuned on e85 couple days ago. Lots of bolt on mods all on the stock td04 on a 2002 wrx with 182,000 miles. Everything is original on the car and he made some solid numbers. It definitely pulls hard and that's in a 3200 lb car with 2 of us. Now add an 1800 lb car and a 2.5 L...would be insane.

http://i981.photobucket.com/albums/ae293/philly1515/image.jpg (http://s981.photobucket.com/user/philly1515/media/image.jpg.html)

[Nuul]

My thinking is all power to weight with a little bit of frontal area tossed in and if you take 1828LBS and divide by say 250HP your at 7.3LBS/HP and that is pretty darned fast.
At 300HP your at 6.09LBS/HP
At 350HP your at 5.22LBS/HP
I don't even want to imagine anything above that..:D

And yet I've seen some people toss out 400+ WHP as a goal on here. I'm of the school of thought that anything over 300 in this car is probably going to get you killed unless you are one helluva driver. I'm thinking more and more that I need to get an Access Port instead of going open source tuned so I can have a DD map and a 300 WHP E85 tune for when I'm feeling the need for speed.

[Evan78]

A Bugatti Veyron 0.72LBS/HP
A Zonda Revolucion 0.62LBS/HP
And a Venom Hennessey 0.463LBS/HP

loooollllllllllllll :PI smell a math error here. The 4000+ pound Veyron would practically need top fuel dragster power to reach 0.72 pounds per horsepower.

[Twinspool]

Less talking, more building.

One of the coolest aspects of this car is that when completed, you'll know every nut, bolt and rivet holding it together. Just get them on the road and then start deciding what the performance envelope needs to feel like. The number that feels right vs the number that people keep talking about on here is going to wildly different I'll bet.

[Frank818]

I smell a math error here. The 4000+ pound Veyron would practically need top fuel dragster power to reach 0.72 pounds per horsepower.

Sorry, I should have said Veyron Grand Vitesse. It has 1200hp instead of only 1001. :)

[Frank818]

This is my old car I sold to my friend just tuned on e85 couple days ago. Lots of bolt on mods all on the stock td04 on a 2002 wrx with 182,000 miles. Everything is original on the car and he made some solid numbers. It definitely pulls hard and that's in a 3200 lb car with 2 of us. Now add an 1800 lb car and a 2.5 L...would be insane.

http://i981.photobucket.com/albums/ae293/philly1515/image.jpg (http://s981.photobucket.com/user/philly1515/media/image.jpg.html)

Those numbers look nice and for a 2.0. Then definitely a 2.5 with small bolt ons or a great tune would most probably be sufficient enough.

Question, is it the TD04 that can't keep up 20psi up to 7000 or it's tuned to let go a couple of pounds while rpms increase?

[metalmaker12]

2.0 wrx or jdm sti, wrx or Sti 2.5, or a 2.2, anything will make the 818 fly. I personally think a higher reving 2.0 with avcs (ej207) is the best stock option for the 818.

The td04 just can't keep up above 7k so it drops off

[Mechie3]

The TD04 runs out of capacity at higher rpms. It simply can't feed enough fast enough so it drops off.

[Frank818]

That's what it looked like to me, tnx for confirming.

[AMW1011]

A Bugatti Veyron 0.72LBS/HP
A Zonda Revolucion 0.62LBS/HP
And a Venom Hennessey 0.463LBS/HP


Sorry, I should have said Veyron Grand Vitesse. It has 1200hp instead of only 1001. :)

No really the math is way off. It's:
A Bugatti Veyron Vitesse = 3.66LBS/HP
A Zonda Revolucion 2.95LBS/HP
And a Venom Hennessey 2.20LBS/HP

[THE ITALIAN]

You get the idea.
The Roadster.
I have low HP in mine compared to many(300HP). The SPEC cars have 225 HP. It is very very fast, faster than the driver on any given day.
2150 lbs a 302 and the engine might as well be considered "MID ENGINE". If I made it faster, I would be making it slower since I couldn't get it to "lock up".
Right now it locks up and scoots and better than my friends $200k Shelby 640 HP roadster.

Look at the road & track stats; this thing really goes and if 3.8 secs isn't fast enough for you, your nuts. I would concentrate on handling, already knowing you have a very fast car either Turbo or not.
If your building a drag racer, I think you are in the wrong place.

[Frank818]

No really the math is way off. It's:
A Bugatti Veyron Vitesse = 3.66LBS/HP
A Zonda Revolucion 2.95LBS/HP
And a Venom Hennessey 2.20LBS/HP

I am so an a**hole!! I am in Canada (that's not the reason why I am an a**hole!!! loooooolllllllllllll) so we use KGS. Usually I always convert from LBS to KGS, so I need to DIVIDE by 2. Which is what I did here, but my numbers where already in KGS!! So I was 4 times off! I should have multiplied by 2. Can't make a 10yo math and I plan on building an 818... my brakes will end up being 6.4" and not 12.8"! lolll On 9" wheels.... :)

I'll edit my post. tnx :)

[Evan78]

Those numbers look nice and for a 2.0. Then definitely a 2.5 with small bolt ons or a great tune would most probably be sufficient enough.

Question, is it the TD04 that can't keep up 20psi up to 7000 or it's tuned to let go a couple of pounds while rpms increase?Keep in mind that the fuel was E85 for that chart. That makes a huge difference. A 2.0L with TD04 will typically yield 220-230 hp and ft/lbs on 91-93 octane. Philly may have done a lot more work than typical (I have no idea), but there's not much to be had over 230 when using pump gas.

[philly15]

there are definitely a few more than the standard bolt ons for a "stage 2" setup on that car. the car was dynoed on 93 a week ago and it put down right as you say in the 230 whp area and iirc it was around 260 ft lbs of torque. The reason i wanted to post the chart was merely to demonstrate the capability of just a 2.0 motor. and one that has 182,000 miles at that. the car gets auto x'd and drag raced a lot and she is still going! i mean 250 ft lbs of torque to the wheels at 3000 rpm in a 3200 lb car is pretty darn solid, and peak torque at 3800. she pulls hard for sure. would be a great deal of fun for the 818. ive had 3 2.0 L wrxs and honestly im contemplating selling my ej255 just to go get another 2.0 L. imo the 2.0 seems smoother over all especially the ej207's. the 2.0 would definitely be plenty of motor in the 818 thats for sure.

also here is some of the mods on that car:
-jdm sti TMIC
-grimmspeed ceramic coated EWG up pipe
-tial 38mm waste gate
-grimmspeed hybrid setup with MBC and EBCS
-injector dynamics 1000 cc injectors
-cobb SF intake
-invidia catless downpipe
-ebay cobb replica catback
-ebay silicone turbo inlet and post maf tube

[metalmaker12]

I agree the 2.0 wrx and even more the jdm ej207 are smoother than the 2.5's in stock trim and the power band has more top end range. When it comes to brute power the ej257 does put up the numbers, but I would take a ej207 any day over it.

[philly15]

^i totally agree, ill be switching to an ej207 down the road i feel its a much better setup for a light weight car like this, but for now the ej255 will get me through until im done with school, unless some one wants to buy an ej255.....

[Frank818]

I am googling around to find dynos of the jdm ej207. I have access to these engines very close from where I live, no shipping charges. I'm interested to see the numbers below 3500. I know it can rev to 8500+ with a lot of hp over there, but I don't know about low end yet. Just trying to compare with 255s and 257s.

[metalmaker12]

The ej207 is the best Sti engine period

[metalmaker12]

^i totally agree, ill be switching to an ej207 down the road i feel its a much better setup for a light weight car like this, but for now the ej255 will get me through until im done with school, unless some one wants to buy an ej255.....

How much you want, as you might know I am selling donor packages and someone wants one. Pm me with details and your contact info and Kalstar or I will call you over the next week.


The ej207 has plenty of low end grunt and lives strong up high, plus its powerband is remarkable, it is hands down the best stock engine for the 818. I got one!!! The ej257 has awesome low end punch and good hp, but it just feels rougher when reving up, like it is not balanced as well and as we all know does not have the head flow of a ej207 v8 up

[Frank818]

The ej207 has plenty of low end grunt and lives strong up high, plus its powerband is remarkable, it is hands down the best stock engine for the 818. I got one!!! The ej257 has awesome low end punch and good hp, but it just feels rougher when reving up, like it is not balanced as well and as we all know does not have the head flow of a ej207 v8 up

Well I read and found many things, I'll try to get a ej207, v7 to 9.

V7 has got forged pistons, unlike 8 and 9. And a faster spool cuz apparently the twinscroll is just a bit slower to spool. If that's true.

[philly15]

I don't know how true this is but I thought I read somewhere some of the v8's had forged internals? Or maybe that's the spec-c motors? Not sure on the validity of that though

[metalmaker12]

Spec c

[Frank818]

There are so many possibilities and versions out of these engines, it's just crazy.

[Frank818]

The Lotus Elise is very close, and in stock trim has LESS HP than a even a stock 2.0L WRX. I suggest watching some videos and looking at the Elise performance numbers. That will give you some kind of idea how much of difference the low weight will make!

The Elise S has a power to weight ratio of 235bhp per ton, does 0-60 in 4.2. According to Lotus website.
818 with say 300whp (345bhp or so) would have a p to w ratio of 406bhp, assuming it weighs 850kgs. Not much far of TWICE the Elise S!!
The GTM LS7, 456bhp per ton.

I don't need more to be convinved 300-325whp is more than enough, and with that I know I'll have over 325-350wtq.

I need to sell my car... and quick! But I think it's going to take a looong time before I find a buyer for a reasonable price... oh well.

[philly15]

Spec c

ah thats what i was thinking. thanks for the confirmation!

[philly15]

How much you want, as you might know I am selling donor packages and someone wants one. Pm me with details and your contact info and Kalstar or I will call you over the next week.

i dont know what i want to do yet exactly. i already did some stuff to it, put on a 12mm oil pump, new water pump/gates racing timing belt, im rebuilding the heads and upgrading valves and springs, so not sure i wanna sell yet after the work i did to it. Im gonna see what i can find for 2.0 L motors or even ej22's first and weigh some costs and what not before i decide on selling.

[Cj_]

If you really want to impress, compound turbo setup

19018

http://www.atsdiesel.com/ats2/templates/template_06.asp?p=2029422272&c=36

[bnr32jason]

I would say if you want full boost (1-1.5 bar) by 2500-3000rpm, do what I'm doing. Find yourself a VF36 twin-scroll setup and put it on a 2006-07 WRX 2.5L AVCS motor. I've seen people making 380 torque at the wheels on the 2.0 with that turbo so it should meet your goals. It might run out of breath up top, but some minor modifications and tuning should get it breathing quite well close to redline.

Of course it's not as unique or "cool" as a twin turbo setup, but it's 100x less complex and meets your requirements.

[Frank818]

If you really want to impress, compound turbo setup

19018

http://www.atsdiesel.com/ats2/templates/template_06.asp?p=2029422272&c=36

LOL!! That's interesting, I've never heard of that before!
Probably needs some good R&D to make that fit on the EJ and 818, but yes, impressive. :)

[Frank818]

I would say if you want full boost (1-1.5 bar) by 2500-3000rpm, do what I'm doing. Find yourself a VF36 twin-scroll setup and put it on a 2006-07 WRX 2.5L AVCS motor. I've seen people making 380 torque at the wheels on the 2.0 with that turbo so it should meet your goals. It might run out of breath up top, but some minor modifications and tuning should get it breathing quite well close to redline.

Of course it's not as unique or "cool" as a twin turbo setup, but it's 100x less complex and meets your requirements.

Honestly the TT setup was just a potential solution or suggestion to meet my goal. Anything that would meet my goal should be fine and of course the simpler the better! I'll keep your suggestion on my list of engine choices, now I wonder which turbo could do the same on a EJ207, if any turbo can...

[bnr32jason]

Honestly the TT setup was just a potential solution or suggestion to meet my goal. Anything that would meet my goal should be fine and of course the simpler the better! I'll keep your suggestion on my list of engine choices, now I wonder which turbo could do the same on a EJ207, if any turbo can...

I'm still somewhat new to Subaru engines, although I have done quite a bit of reading and research. I haven't found a OEM turbo that spools faster than the VF36 that can still make 300-350whp. This is due to a titanium wheel, ball-bearing setup, etc. It's a difficult turbo to find though, and normally commands a premium price. You also have to get the twin scroll downpipe as well. Now there probably is a somewhat equivalent aftermarket turbo that could provide similar spool characteristics and power/torque capability, but I'm not sure what to recommend for aftermarket turbos.

But if you want very quick spoolup time like me, especially on a EJ207, you are going to want twin-scroll.

[Frank818]

I think the expertise and contacts that AJW Performance have in that world may be of good help for me. You can tell them what you require and they will find the best setup. Of course might need to pay premiums for the parts here and there, but they will build it for you and tune it for you. Maybe in my case it's better if I get a donor from them and upgrade the engine, rather than finding a donor here and being on my own after. BUT, if I am really lucky and get a stupidly awesome deal on a donor here, I won't spit on it. lolll

[bnr32jason]

I'm probably going with a donor pallet from AJW or one of the other suppliers as well. I've only got a 2-car garage and several cars, so I don't have the space or the time to do a full tear-down myself.

[Cj_]

Definately an interesting setup, but I do agree that the plumbing would be a challenge.

There is a great build covering a compound setup on an Eclipse, http://www.dsmtuners.com/forums/custom-fabrication/336541-my-compound-turbo-set-up.html

[Mechie3]

Let's stir the pot! :lol:

http://forums.nasioc.com/forums/showthread.php?t=2545428

Just posting that for everyones info. The original TT WRX has made a comeback. Posted dyno sheets and other stuff. Even the owner agrees it's more for originality and show than for performance. Take from it what you will.

[Frank818]

Stupid work proxy is blocking the embedded pictures, I guess from photobucket and those places. I'll check on the dyno curves tonight. Curves, not numbers. 600awhp I don't care. I care about how it's delivered along the band. The only reason why I would want TT (of equal size) is cuz I think the curves would be better than single turbo, meaning high torque in the low and keeping it up to redline. Of course it might take a lot of money to R&D all that on the 818.

Which plumbing is a challenge on the 818? The exhaust or intake? Or both? lol

[icky]

Check out this thread on nasioc, saw this a while ago and I'm am going with this turbo aswell(gtx28), maybe a bit much for his stock shorblock but mine will not be stock. Also looking at the torque curve, it could have been flater with a flater boost curve.

http://forums.nasioc.com/forums/showthread.php?t=2509735&highlight=gtx28+sti

[Frank818]

Is the dyno chart in the first post? If yes, that one too I'll check tonight. Stupid proxy.

[Mechie3]

The TT spools rather late.

[icky]

Watch his vid linked from his thread, thing launches like a beast, probably the reason he got a low et.

The first pick is a dyno, also if you opened the heads up a little (usdm sti), mild cams, less boost, you could get a pretty flat torque curve from 3.5 k to redline. That's my plan anyway, block being built next week and then in to my forester till I get the kit.

[Frank818]

The TT spools rather late.

Well if I understood what I read he's using 2 GT28s. One single GT28 could be used for the entire 2.5L, so obviously the turbos are a bit big for every 1.25L, no?

A GTX2867 is best suited from 1.8L to 3.0L. Now he's using on 1.25L.
Am I missing something?

[Frank818]

also if you opened the heads up a little (usdm sti), mild cams, less boost, you could get a pretty flat torque curve from 3.5 k to redline.

And maybe a 9.5CR? To keep more torque in the lows, if using not too much boost.

[icky]

Edit: stupid phone double post.

[icky]

My shortblock will be new case halfs, new oem heat treated sti crank, Manley turbo tuff I beam rods, cp pistons at 9.0:1. Heads are still good, Mild port on usdm sti heads, back cut valves, bc 272's. Not sure what it will produce since my build is so different than his stock longblock, well see in a month or two.

That car has a single turbo, I was posting it to show that you will probably get what you want out of a single. Imo, the only reason two turbos would bennifit a car, is if it was diesel and compounded (100+ psi) or if you just could not fit a single turbo that flows as much as you needed.

[Frank818]

Well I really don't like the dyno graphs. :( I can't see what he's getting good out of this setup.

[Xusia]

I can't see what he's getting good out of this setup.

Well, according to the guy who posted it (emphasis added):


...Even the owner agrees it's more for originality and show than for performance.

[icky]

I think that turbo will be perfect for me at a much lower psi than he's running. If you follow the boost and torque curve, ther is much to gain. I really havent found many performance turbos in that small of size but i am always interested in anothers take on things, thats why i posted, to ger others opinins. With my set up I think I can get a pretty flat curve right around 300 ft/lbs from 3-7.5 k. Just ordered my block, should be ready next week sometime, then well see what it produces a mile high. Since I have a year wait, I plan on getting the motor set up and tested thoroughly.

And like I said, only posted that as an example that a single turbo can do what twins can do, then some. Very few circumstances in which twins would be beneficial, especially on this car. One turbo spools faster than two of equal flow, weather its for low or high hp.

[Wayne Presley]

Very few circumstances in which twins would be beneficial, especially on this car. One turbo spools faster than two of equal flow, weather its for low or high hp.
I disagree, properly sized twins will always spool faster than a properly sized single. The TT car in the above reference make its power like it does because the turbos are sized to make that much HP (610 at the wheels, about 760-770 FWHP) and the cams in it. I could take the same motor with slightly smaller cams, with GT2560's, .64 AR housings and make full boost at 3500-4000 RPM and still make 420 whp. You have to size your turbos based on your end game HP.

[icky]

That sounds very similar to that gtx28 graph. I could see twins having a better boost threshold because the smaller inertia, but from an efficiency standpoint, everything else being equal, the single takes it. I would love to see some smaller turbos right under each head, as close as possible to get rid of the 2+ ft of turbo manifold. I would never do it still, for many reasons besides performance, cost being a big one.