Guys, I just spoke to Nick at ARH and he is looking for someone to bring their car into their facility on Long Island to test fit/fabricate a set of headers. The thread by GXPayCheck shows that the connection pipes at the axle back are different from the G8 to the SS. It could be as simple as changing the connection style but they won't know until they physically get one at their shop. Nick said he would hook someone up so I suggest someone jump on it. If you do call, make sure you ask for Nick and you can tell him that Josh sent you. :cheers:
ARH is looking for a car to test fit headers
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I had looked into fitting a pair of their G8 headers on my SS for them to see if they fit. They wanted me to do all the work, and if I could get them to fit theyd bill me for them. I know it sounds cheap but I am not doing their R&D and then paying for the headers. Plus thats a ton of work to do and find out they dont fit. Just not in the business of working for free.
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But did you tell em Josh sent you
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This was before Josh...
I was told the same thing when I originally spoke to Steve @ ARH...That ARH would send me headers to see if they would fit...And I do agree, that is a lot of work, and if they fit they would bill me...
Yea that's why it's better if they can find someone local so they can do everything in house. They used my TBSS to develop headers for them. I wish I had a SS to lend them but I don't.
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So after using your TBSS did they give you the headers or bill you $1800 for them? I can kinda see why they would want to bill for them since they do fit the application however, I will just wait till they have a specific part for my car before I donate labor to another company. Want to help the SS community but tearing apart my brand new car and trying to fit parts made for another vehicle just doesnt really make sense to me. Also they never replied to my email about possible oil cooler clearance issues so I just let the idea die.
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Completely agree! If they want a car then they need to buy one just like Hennessey did.
If I put them on and they fit then they're mine....for free.
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I can understand billing me if I fail to provide pictures and feedback about fitment to help them but not just bill me because you want to extort free labor from me.
I did pay for them but not full retail. Nick did say he would hook up whoever brought a car to them. I agree that I wouldn't want to be test fitting parts hoping that they fit, but I know for a fact that it won't connect to the axle back anyways.
So they should buy a car to build one part for?? That makes no sense business wise...
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Not agreeing or dis-agreeing, but all the big dogs do it. Callaway, Hennessey, Pfadt, etc. I have a set of ARH LTs on my 1LE, and I do like their products, but you can't skimp on R&D. Plus people will pay more for the car on the pre-owned market because it was Brand X's test and development car.
However, I think ARH needs to find an automatic G8 GXP for test development for the SS sedan
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Anyone measure the exhaust pipe size looks 2" not 2/1/2" anyone know for sure. How do you kill 15 horse power this engine makes 430 in vett and 436 with NPP mufflers. The only thing I can come up with is the box that both pipes go into bends are not excessive so pipe size maybe it. Think 3" pipes might be the way to go.
z51vett
Doug
z51vett
Doug
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pipe sizing
I can report that the SS and Caprice PPV have the same pipe dimensions as far as axle-back - at the flange (PPV) or joint (SS) that connects the mufflers to the rest of the system.
It's 2.25" OD
Also, other than the large tip on SS muffler, the inlet & outlet pipe dimensions for PPV & SS are the same--again, 2.25".
SS muffler is noticeably lighter than PPV muffler, and are otherwise identical in case dimensions, pipe in/out positions, hangers, etc. The weight difference means there's less "guts" in the SS version--less packing, fewer tubes/chambers(?), etc.
About to mount a set of SS muffs on the PPV (thanks DangChung!), and my only concern is what happens in AFM (4 cylinder) mode, as far as exhaust resonance/drone.
I can report that the SS and Caprice PPV have the same pipe dimensions as far as axle-back - at the flange (PPV) or joint (SS) that connects the mufflers to the rest of the system.
It's 2.25" OD
Also, other than the large tip on SS muffler, the inlet & outlet pipe dimensions for PPV & SS are the same--again, 2.25".
SS muffler is noticeably lighter than PPV muffler, and are otherwise identical in case dimensions, pipe in/out positions, hangers, etc. The weight difference means there's less "guts" in the SS version--less packing, fewer tubes/chambers(?), etc.
About to mount a set of SS muffs on the PPV (thanks DangChung!), and my only concern is what happens in AFM (4 cylinder) mode, as far as exhaust resonance/drone.
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Bill:
Do you thing that a 1/4 more will give more power 2.50" verse 2.25. In the old days 2" was standard hipo was 2.5 and big blocks were 3". What do you think could the be the lost hp on the ls3 in the SS.
z51vett
Doug:dizzy:
Foot note my zo6 is 3" necks down to 2.5 at muffler the ss cats are 2.25 out and in I think.
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Cats actually have a reducer inside the inlet that restricts down to 1.75". That could account for some power lost.
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Corvette always gets the best power rating for a given engine package, when you look at air intake design, exhaust manifolds, cat volume, pipe sizing, etc.--the sports car gets a "tune" that is optimized to a different set of standards.
A 4-door sedan, even the SS, is not going to get the same tune from the standpoint of product positioning/price point, if nothing else. Other considerations include fuel economy (if the SS did have the same power level as LS3 in Corvette, the FE numbers would probably be lower than they are now), increased noise level with the higher flow exhaust, drivetrain durability with the higher power in a significantly heavier vehicle (SS compared to Corvette), etc. So, they did the next best thing, and tuned the mufflers of the SS to at least make it sound sportier.
Larger pipe size would be a given for an LS7 in the SS, for example--427CI engine pumps more air than 376CI, especially LS7 vs any other normally-aspirated production LS engine. Still, as the hot exhaust gets further away from the engine, it cools, the gas volume is reduced, and the piping size requirement also reduces--in addition to everything else, pipe sizing must also take into account weight, cost, and clearance in the chassis.
If you further consider that the Corvette is basically unrestricted as far as achieving very high speeds, and is capable of running at those speeds for extended periods, the exhaust sizing becomes important for the engine to sustain high output (thus, high air flow levels from engine air intake to exhaust exit), which allows the Corvette to run 175+ out of the box.
The SS, by contrast, is heavier, less aerodynamic, and really not equipped adequately to run at max or high sustained speed for any significant amount of time (smaller brakes, lack of cooler for diff or more effective coolers for other systems).
The SS likely benefits from the comparatively smaller-diameter stock exhaust system, as it is going to produce better torque at the more "normal" speed range (engine RPM) the sedan typically will see in daily use by the average owner.
In any case, exhaust pipe sizing is based on maintaining air flow through the system while meeting certain velocity parameters, which varies greatly by engine size, anticipated operating mode, and, I'm sure, a number of other factors--some already mentioned, and perhaps others I've not even thought about.
To answer you specific question, I think the use of 2.5" pipe WOULD result in more power capability, but only at the higher end of the engine RPM range (combined with appropriate tuning tweaks). I doubt there would be much--if any--real benefit outside of that.
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Pontiac G8 Performance Exhaust System | G8 Ultra High Flow Converters 2008-2009 Pontiac G8 | Performance Exhaust System
This link shows a little bit of how restrictive the cats on these cars can really be. I realize that they are G8 cats but I would be shocked to find out that they are any different on the SS.
This link shows a little bit of how restrictive the cats on these cars can really be. I realize that they are G8 cats but I would be shocked to find out that they are any different on the SS.
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Just for general info, a Quick and Dirty Exhaust System calculation I came across says that a 400 hp vehicle with a dual exhaust system only needs 2 1/4 – 2 1/2 inch pipes. Anything larger is overkill.
So based on that, 2 1/2" diameter sounds to be about the right size for the typical volume of air required at 415 HP.
Site: How To Calculate Muffler Size and Exhaust Pipe Diameter | Exhaust Videos
So based on that, 2 1/2" diameter sounds to be about the right size for the typical volume of air required at 415 HP.
Site: How To Calculate Muffler Size and Exhaust Pipe Diameter | Exhaust Videos
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Car has a cat off each manifold, a resonator just before the IRS and a muffler at each echaust tip.
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