Your Exhaust System

[LCD Gauges]

What headers are you using? Short/Mid/ Long Tube length?

Have you installed mufflers, and/catalytics?

Is anyone using open pipe?

I'd also like to see photos of the header collector if you have them; particularly the inside of the collector showing the primary tubes merging (can't seem to locate any).

Any issues with your system with respect to roll-cage clearance?

I don't think I'm going to use the h-pipe/x-pipe as the plan is to fabricate an airbox to collect air from under the spoiler area. This will have to sit between the tail pipes,
just over the transaxle. I'll need room to make sufficient heat shielding, and mounting to secure the box.

Thanks in advance...this search feature is tough to sort through!

[VD2021]

Tino,

In my goal to keep the overall cost down (and the decibels too) I decided to go with a set of BBK short headers. They're ceramic coated, a direct C5 fit and have good reviews. I am running these with the kit's cats and a set of turbo mufflers. Right now the "H" is removed and the exhaust is separated. I am very satisfied with the lowered decibels it yields (I have some video/sound clips on my site of the exhaust as well as some of the carting videos. http://gtmbuild.weebly.com/engine.html).

I do, however like the exhaust note that the "H" and the "X" gives the system. I currently have two extra "H" pipes that I plan to use to try at least one addition system. I want to put the "H" back and still keep the turbo mufflers. Space is the issue and I don't want the stock tips protruding too far as I have seen on a few GTMs.

[mikespms]

Hi Tino,

Heartthrod exhaust did some testing on cat back systems using x pipes and h pipes and according to them the h pipe made more power. Bigger is not always better when it comes to exhaust systems,I am using a ls6 with short tube heathers, cats , h pipe and resonator tips it sounds good not too loud. If you are staying around 500 Hp that combo should be good. I held back from engine work and concentrated on getting all the corvette systems working on my car. I will see how it runs after is tuned.

[LCD Gauges]

Gene, ...

Hey, if you're going to call me Gene, at least give me the guy's body work skills too! ;)

Thanks for the quick replies; I'll check out your setups later this evening.

Interesting that Hearthrod was able to find power using any sort of cross-over. How much difference are we talking, 2-5 HP? Were the pipe lengths, diameters, and cat. units the same?

Exhaust (and intake) tuning really responds to length of pipe sections, as well as diameter, so I'm wondering if the changes in their test setup were contributing to the values. Any chance
you have a link to their test page? I'd like to check it out!

Thanks people.

[crash]

I used the stock crate engine cast iron exhaust manifolds on my LS3 engine and with just a few external engine mods built 530 HP. Stock intake, stock throttle body, stock exhaust manifolds. There is nothing wrong with the stock parts and they build plenty of power. I am taking my new setup to the dyno today on the Mendeola Transaxles Baja Designs FFR PDG GTM to see how the old girl runs. It is an LS2 with LS3 top end, and again, stock intake and exhaust. You can see the video of the muffler I made here...

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

Here's a pic of the new exhaust on the old LS1...

11469

I am attempting to actually lower the HP a bit with the smaller displacement LS2. The corresponding improvement in fuel economy should be the desired trade off. :)

As you can see, the shortened muffler that I made allows the air box to be in the normal position, and also acheives the X pipe setup.

[VD2021]

Hey, if you're going to call me Gene, at least give me the guy's body work skills too! ;)

Thanks for the quick replies; I'll check out your setups later this evening.




Tino,
Sorry.....Brain fart:o?

[mikespms]

Check out this video on YouTube:

http://www.youtube.com/watch?v=sSdKV6Fsq1g&feature=youtube_gdata_player


Sent from my iPhone

[LCD Gauges]

I'm a little skeptical of those numbers after watching the video on my phone.
I'll have to have a closer look when I'm at home.

The reason I'm doubtful is because of the extensive testing performed by the
likes of David Vizard, Reher-Morrison Racing, and books like, "Scientific Design
of Intake and Exhaust System" authored by Philip H Smith, & John C Morrison

I've read through several texts, and tried a bunch of tuning on my previous cars
with the biggest gains coming via less restrictive, tuned length systems. I have
a program called "PipeMax" which calculates the diameter, and length of exhaust
pipes.

Big gains comes from tuning the length of the pipe to the RPM (frequency of pulses)
range that the engine performs within (or peak average). I have not found a source
that provides significant gains from applying an H, or X cross-over pipe.

Moving a reflective surface like a catalytic converter, or muffler changes the power
curve dramatically. Even an open ended pipe being cut by a few inches will alter the
peak power RPm. The analogy used in the book is imagine cutting one of the pipes
on a pipe ogran, then playing the associated note...it wont resonate at the original
frequency, and therefore changes the sound.

In an engine environment the timing of the reflected pulse back to the exhaust port
by a longer/shorter pipe could mean increasing pressure, or reducing pressure as
the valve is cycling open. The sound (pipe organ) is also affected.

I'm guessing the systems compared in the video are two extremely different concepts/
designs, and could not be A/B tested.

[Fred Brewer]

I did these a long time ago,,, before the Kooks were available. No cats,, just the x-pipe and spiral flows. It may end up being loud.

http://lsspecialists.com/header1-1.jpg

http://lsspecialists.com/Header2-2.jpg

[mikespms]

Hey Tino,

All the things you mention are true and proven facts specialy on race and modified engines. There are lost of variables cams,heads,compresion ratios,valve timing,duration,intake/exhaust runner volume, valve size,fuel/air systems just to mention a few before we get to the exhaust system. But I think they are comparing the difference of a stock engine with stock exhaust to a free flowing cat back system there is no mention of tuning or air intake.

[Gopher]

I had Stainless Steel MFG make these merge collectors for my 427. There 4 into 1 back to 4

[LCD Gauges]

But I think they are comparing the difference of a stock engine with stock exhaust to a free flowing cat back system there is no mention of tuning or air intake.

Yes, that must be it. Initially I assumed that he was stating that a cross-over pipe would add that power because of how Stacey phrased
the question.

THank you everyone for the photos. I"ll have to take some measurements, and see what options are avaiable. When I researched
before buying the GTM, I was told that long tubes would not work...now I see the light!

[crash]

What you guys have danced around is what I have studied and found to be the case when it comes to improving performance with the exhaust system. I'm not gonna spell it out, because I consider it somewhat of a trade secret, but I do believe you are on the right track Tino.

The reason I use a X crossover type muffler is because it can significantly reduce noise levels without significantly harming power output. I'm not looking for gains, just not a lot of drop in power outputs. We have an 85 dB limit. That's pretty low. The stock GTM exhaust doesn't even come close to meeting that requirement. I will undoubtedly have to add a few things to try and quiet the beast further to meet that limit. :(

[LCD Gauges]

Del.

[LCD Gauges]

I did these a long time ago,,, before the Kooks were available. No cats,, just the x-pipe and spiral flows. It may end up being loud.


I had a similar setup on a street car (80 Z28, 355 SBC). Let me re-write your quote:

"I did these a long time ago,,, before the Kooks were available. No cats,, just the x-pipe and spiral flows. It's GONNA BE INSANELY FREAKIN' LOUD!"

;)

[noother]

Crash, I think I'm headed down a similar path.

I just ordered the Kooks headers from Shane but want/need to be quieter than the complete kooks sysytem w/o cats. Ted at Quick Racing Products had a comtomer's car with the Kooks system at his place when I picked up my sway bar from him. It sounded and looked incredible but probably a tad too loud for Laguna Seca and Thunderhill at night.

I'm trying to get my engine down as low as possible with the low profile dry sump pan from ARE (1.9" vs 4.75" for the LS376/480 pan). This brings frame clearance problems into play. Shane reported there was about 1-1/4" verticle header clearance to the frame members ahead of the lower control arm mounts. The crossmember is also about an inch below the front of the pan so I could just take the easy inch and make some solid mounts for the c5 engine mount brackets. I tend to not take the easy path so.....the crossmember is coming out, the frame rails will be moved outboard, and I'll mill up some kind of front motor plate engine mounts. This will make more room for the Raceline five stage dry sump pump and oil lines and I should be able to drop the engine down a few inches.

I google'd "x vs h pipe exhaust" and found alot of discussion on merrits of each. It's generally reported that an H-pipe can make a couple more horsepower but size and placement can be critical to achieving any gains. X-pipes can be as much as 8db quieter than an H and a found quite a few references on LS1tech forum that people loved the sound of their X-piped vehicles. X-pipe location doesn't seem as important as H. Interstingly I found several references to Y-pipes having the best power over H and X, and quiet as well. I'm more of a function over form type of guy and wouldn't mind merging into a single outlet but silencing 4" is a challenge (I have 4" magnaflows on my '67 camaro folllowing 2-1/4" to 4" Borla collector mufflers and it is still loud). We only have a little bit of space for exhaust without getting all speghetti on piping so I'ts got to be short and effective.

I really like what you did to that Magnaflow Crash. How is the noise level? Dyno results? exciting!

I called Magnaflow and asked about that muffler (I assume it's the 12469), the tech stated that that muffler has an internal Y-pipe to a single 3" and back to a Y outlet, all perforated. Obviously this is pretty much what you detailed in your video. Nice work by the way.

Magnaflow also makes one 4" longer (12699) the tech stated it has a proper internal X-pipe and should not cause any significant losses but would probably be down just few horsepower from separate 3" mufflers on a 500 hp engine. I know you didn't have room because of the airbox on the car but I'm routing the intake over to the port side scoop so this may be a possibility for me if I have room. I'm out of town through the weekend so I'll measure come next week.

Great discussion here.

Mark

[noother]

00SS_M6LS1, here's a few collector photos as requested:

One is the Kooks, the other is a pair of S&P (Street and Performance) shorties that I decided not to use and donated to the PDG team. I'm guessing that they are ahead of Crash's system 'upside down'. They have a unique bolt-on collector that appears to be quite efficient.

I bought the ceramic coated BBK late model C5 shorties as well and have them bolted to the FFR exhaust right now. They fit perfect, are a direct bolt-on and are a great upgrade to the C5 manifolds. My only problem is I can only lower my engine about 1/4" before they stick the exhaust out the bottom of the car. I'll be posting them for sale soon (pm if anyone is interested in more details)

I think the Kooks will work for me, third time is a charm.

mark

[crash]

I actually made up an alternate exhaust system with thos BBKs for the LS1. I must say that I was not impress with the collector area of those headers. I actually think the stock cast iron headers may prove to be quite good. They are esentially an oval tubed tri-Y design that is very short and compact. The engine builder was surprised that we easily made over 500 HP with that LS3 with stock exhaust. He "thinks" he can make 50 more HP with "proper" headers, but I really have my doubts. Target is 500, so as long as we get there on RWHP, I'll put the couple thousand $$ for custom headers elsewhere in the car.

I make the front engine plate for LS engines, but they won't fit into a stock GTM. I also run a 4 stage pump plus a deaerator, so that requires using something other than the stock engine mounts. One thing effects another, so I also make a balancer hub for the LS when the engine plate is used and there is no longer a front oil pump on the crank. It also easily fits a double row timing chain, which, as you may know, the single row is a point of failure on the LS3 engines. It also requires either a Stewart water pump, or spacers on the stock pump, and Jones Racing Products cog pulleys and belts. ($$$)I haven't finalized production or pricing yet, but the setup has been on the dyno and it works great. I'm thinking in the neighborhood of $2k for the plate, mounting hardware, and balancer hub. Hub allows the use of an ATI balancer right up against the block. Lots of things in the works. :)

[crash]

With some hesitation about releasing info about a product that isn't 100% ready to go to market yet...


here is a picture for referrence:

[noother]

[QUOTE=crash;70816]I actually made up an alternate exhaust system with thos BBKs......QUOTE]

The BBK's aren't very pretty inside, but neither are the LS1 manifolds and that donut gasket they both flow through. The BBK's are 1-3/4" and were 12lb lighter than cast if I remember right and look a million times better (if you care about looks). I'm kind of a weight freak and heat management is a big focus on my build. The shorties seem easier to wrap and the ceramic coating inside and out should keep them from turning into tubular rust.

I have heard that the shorties don't help power any but I've only heard of losing power with the small 1-5/8" shorties. Plus 50hp with proper headers? Wow!

I'll post a pic of the BBK collector and donut gasket when I get back to the shop next week.

I've got a set of ls2 and ls3 manifolds I'll let go cheap if anyone wants them, Crash makes a stainless ls3 mating flange. Cleaning up the shop.

[LCD Gauges]

00SS_M6LS1, here's a few collector photos as requested:

One is the Kooks

Thanks for posting these. As I build up the 'nuts' to give Crash a call, here are some tips that you might find valuable for your engine build.

11513

The photo shows a collector that is a bit more advanced than the average retail part. The flashing you see at the end of the primaries
(inside the tubes) should be ground down. If anyone has purchased a set of headers with this sort of production weld, take some time to clean
up the bead. It's not a show stopper, but gaining an extra pony here, and there never hurts!

We're at a disadvantage to keep things quiet, and make tons of power with such a tight mid-engine layout. There isn't much room for tuning
when you need to angle the exhaust up over the rear axles, and terminate the system within a few feet afterwards. Within that area, we're
looking for a "muffler" that can drop a bazillion dB...using a straight-through type canister. Now, that's a shot in the butt!

Bigger primaries tend to help in cases when the setup you need to replace is shrouding exhaust port. The last thing you want to bolt-on is an
exhaust manifold, or header tube that is smaller than the port - it creates a lip/impeding step that degrades exhaust flow out of the cylinder,
and cause all sorts of issues with pressure during the overlap portion of the cam cycle.

If you haven't already bolted up your exhaust, make a template, and/or measure the size of the ports vs. the size of the primary tube. Make
sure the primary tube is about 1/16" bigger than the closest edge when the two mate (square port/oval port/ round port). I find that using
a template, or a cheap set of gaskets will help you determine how the manifolds line up after torquing the bolts. Just undo everything, and
check the impressions on either side.

These aren't secrets; they are very well known tips that have been published in texts, and discussed on tuning forums. Hopefully they'll help
us break the dyno numbers we seek!

As for me, I'm looking for the longest tube header that doesn't require chopping up the roll cage, or growing a third arm to install. Maybe
something that sweeps the tubes backward, and up which angles the collector toward the axle as opposed to the ground. It will make fabricating
the remainder of the system easier.

The collector also needs to be designed properly. Not something like this:
1151011511
But more like this:
11512

If nothing else, I'll have someone with stellar welding skills modify the collector.

[noother]

Great stuff Tino. We haven't covered materials here. Stainless doesn't conduct heat as much as mild steel and this is a big deal in a hot engine bay.

I recently fabricated a coolant Y manifold for my return cooling since I'm using a remote electric water pump. I used 1-1/4" .082" wall 304 stainless tubing and I was quite shocked when I fully welded it on one end of it and just 5-6" away I could hold on to the piece with no glove on.......and it stayed that way. I have known for years it conducted heat more slowly but experiencing this had me in awe. This, plus corrosion resistance, and it's hard for me to justify not going with anything other than stainless.

When i was researching exhaust materials yesterday some threads mentioned titanium and inconel. Super expensive and very specialized welding processes prohibit most from taking the idea anywhere past a discussion level. I'll just abandon that thought right there.


So to me it looks like it's hard to beat Shane's Kooks system if you value the horsepower and want an easy 'pay and bolt it on' system. The cats tone it down a little I have read.

If you want all the horsepower and need it quiet, long tube headers (Shane again, please order, I'm on the waiting list :cool:) and custom pipes with an X and the most muffler you can fit seems to be the order.

Cheapest- Cast ls1 manifolds to FFR exhaust.

Improvements to FFR exhaust- Add some Borla's like Cheney's H-Pipe, maybe coated or SS Shorty headers.

LS3 manifolds flow well, need some custom attachment or custom system.

Mark

[LCD Gauges]

At the moment I'm checking out these from Patriot. I'm going to call tomorrow for more specs on material, flange thickness, and hopefully a photo view inside the collector.
From the outside, it appears to be fine. The only thing that might be an issue is the 02 sensor location, but that's an easy fix.
11520
Or these if they'll fit:
11519

Are the Kooks6500RHS the model you will be ordering Mark?
11521

[noother]

Tino, I dont think any of those will fit the frame. I just assumed people knew about the custom Kooks system that Shane offers. Is he not on this forum? My bad.

Check it out here:

http://www.ffcars.com/forums/42-factory-five-gtm-forum/295351-8-16-12-kooks-custom-gtm-exhaust-system-ready-take-orders.html

[kabacj]

With some hesitation about releasing info about a product that isn't 100% ready to go to market yet...


here is a picture for reference:

That's a cool setup crash. Two alternators or am I seeing things? I also did some research into packaging the dry sump. Looks like you have it figured out.



Noother said:

I'm trying to get my engine down as low as possible with the low profile dry sump pan from ARE (1.9" vs 4.75" for the LS376/480 pan). This brings frame clearance problems into play. Shane reported there was about 1-1/4" verticle header clearance to the frame members ahead of the lower control arm mounts. The crossmember is also about an inch below the front of the pan so I could just take the easy inch and make some solid mounts for the c5 engine mount brackets. I tend to not take the easy path so.....the crossmember is coming out, the frame rails will be moved outboard, and I'll mill up some kind of front motor plate engine mounts. This will make more room for the Raceline five stage dry sump pump and oil lines and I should be able to drop the engine down a few inches.

How much do you think you can lower the motor with a 2 inch thick dry sump pan. I noticed that the bell housing also drops down quite a bit so seems like you can pick up 3 inches or vs a stock pan, but after that the oil pan is not the lowest part of the drive line.

I have left this part of the build till the winter because I want to get my car out on the track the first week of October. Of course it will not be show paint, just primer, but I have tons of work ahead of me.

John

[LCD Gauges]

Mark, thanks for the link. Shane posts here quite often, but Ihave not seen the Kooks custom headers until now.
I'm hoping to find an alternative through my supplier to avoid additional shipping/brokerage fees from US orders.
The Patriot header tubes appear to bend in close to the block. Ill post the results after getting the info.
The Kooks set does look mighty tastey, and hassle free though!

[VD2021]

The Kooks set does look mighty tastey, and hassle free though!

And don't forget Loud.....But it does have a very nice exhaust note.

[LCD Gauges]

Has anyone tried mounting mufflers in the space behind the rear tires?

[noother]

Noother said:

I'm trying to get my engine down as low as possible.......

How much do you think you can lower the motor with a 2 inch thick dry sump pan. I noticed that the bell housing also drops down quite a bit so seems like you can pick up 3 inches or vs a stock pan, but after that the oil pan is not the lowest part of the drive line.

I have left this part of the build till the winter because I want to get my car out on the track the first week of October. Of course it will not be show paint, just primer, but I have tons of work ahead of me.

John


John and Crash, lets get a dry sump thread going, lots to cover. I called ARE a few weeks ago and we can get a group buy with three pans with about a 12.5% discount of the web prices. They make a double row timing chain as well (as Crash touched on) I plan on getting, we can also group buy on this with three. I'll get a tread started soon.

As per the part that pertains to exhaust, Shane reported that the Kooks headers lowest part is about 2-3/8" below the pan to block mating surface. Without all the parts in hand, this looks to be my lowest part. Now, I dont mind hanging this out the bottom since I will have some kind of skid strip immediately next to it. I purchased Russ Thompsons skid kit early in my build but then changed the framing with my tunnel mods and will be further changing the framing. I will be coming up with a whole new system that will help the aero under the car, I hope, but thats a whole 'nother subject, whew!

So, what was the question? Oh, yes, how low? Low enough, but not too low ;-)

I'll have to get more parts in-hand to figure that out but the bellhousing may be the limiter. I'm thinking of trying to get the apex turn to the diffuser right up to the bellhousing area by modding the frame behind the front lower A-arm mount to slope up and end up above the aft mount instead of inside it. Yah, Im getting carried away, I must have fallen off the mod wagon.....

Mark

[VD2021]

Has anyone tried mounting mufflers in the space behind the rear tires?

Tino,
Check out Steve's build. There's a great view of the exhaust from ~2:14 mark.
http://youtu.be/MyZV4g7E2-Y

http://www.ffcars.com/forums/42-factory-five-gtm-forum/256516-pretty-cool-build-4.html#post2491322

[LCD Gauges]

^ That's one hell of a dash install he's got going on! The more I see the finished exhaust, and available space...the more I just want to say, "screw the neighbours" and
run straight pipe. :cool:

[VD2021]

^ That's one hell of a dash install he's got going on! The more I see the finished exhaust, and available space...the more I just want to say, "screw the neighbours" and
run straight pipe. :cool:

The neighbors will only get it for a moment and from a distance, you on the other hand will have impairment 3000–6000 Hz range hearing.

[noother]

The neighbors will only get it for a moment and from a distance, you on the other hand will have impairment 3000–6000 Hz range hearing.

Isn't that the range of the female voice?

[LCD Gauges]

I had to laugh at that one Mark. Even the wife looked over...I better close this window quick!

[VD2021]

isn't that the range of the female voice?

rotflmbo

[STLMARSHALL]

I just installed an LS1 into my Daytona and thought I would give you my ideas for an exhaust. I went with the block hugger headers for clearance issues into a 2.5" SS pipes into 2 magnaflows. No x or h pipe. They are the 14363 and are only 11" long. I was amazed how quiet they are. At idle the car is as quiet as some stock systems. On the gas they do get louder but not bad at all. I would guess them in the high 80 db range on the track. The engine is a stock 2003 LS1 and made 350 RWHP. I would think 2 magnaflows on about any engine will be acceptable for just about anyone.

http://i464.photobucket.com/albums/rr2/mmarshall01/LS1%20conversion/DSC_2887.jpg

http://i464.photobucket.com/albums/rr2/mmarshall01/LS1%20conversion/20120511_170751.jpg

[noother]

With some hesitation about releasing info about a product that isn't 100% ready to go to market yet...


here is a picture for referrence:

That's one impressive system there Crash! I can immagine theimmense amount of hours that went into that.

I found pictures of my LS3 manifolds I took a while back, unfortunately no outlet flange shot. Easy to see the tri-Y here. Did you do any porting/smoothing to get those hp numbers? How did the the 6 liter dyno session go?

http://i617.photobucket.com/albums/tt260/noother268/Misc/iphone912.jpg

http://i617.photobucket.com/albums/tt260/noother268/Misc/iphone911.jpg

[LCD Gauges]

STLMarshall,
That is a wicked looking front end. How did you route the exhaust pipe to the muffler?
Im guessing that the exhaust manifolds are reversed for each bank?

[LCD Gauges]

GM really did their homework with the Gen III/IV series engines, and exhaust. So much that it has cast a shadow on the Gen I SBC era.
The exhaust manifolds on the LS7 really focused on performance tuning with formed square tubing, and mufflers with valves that opened under heavy throttle to reduce restriction to flow.



It would be nice to stuff a set of those mufflers in the GTM to get the best of both worlds.
Either that, or use an electric dump to switch between muffler, and open pipe.

[STLMARSHALL]

STLMarshall,
That is a wicked looking front end. How did you route the exhaust pipe to the muffler?
Im guessing that the exhaust manifolds are reversed for each bank?

Tight tuck headers were mounted normally, then a 90 forward and a 180 back to the mufflers. I was suprised how quiet the mufflers made it.

http://i464.photobucket.com/albums/rr2/mmarshall01/LS1%20conversion/20120416_230418.jpg

http://i464.photobucket.com/albums/rr2/mmarshall01/LS1%20conversion/DSC_2911.jpg

[crash]

That's one impressive system there Crash! I can immagine theimmense amount of hours that went into that.

I found pictures of my LS3 manifolds I took a while back, unfortunately no outlet flange shot. Easy to see the tri-Y here. Did you do any porting/smoothing to get those hp numbers? How did the the 6 liter dyno session go?



The only thing I did was open up the throat from 2.5 inches to 3 inches to match my exhaust system.

[LCD Gauges]

The only thing I did was open up the throat from 2.5 inches to 3 inches to match my exhaust system.

That (and the collector area) are the most sensitive areas to making big gains. Having a step on the clyinder head inbound (back toward the exhaust valve)
reduces the chance of reversion, and high pressure during the top end of the exhaust stroke, and overlap period when a reflection occurs.

Just looking at some of the stock casted manifolds compared to a good performance header tells the story when looking into the exhaust runners.
Even most headers that I've seen require grinding at the flange.
1166611665