3" Cat Back Exhaust Question

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TEXAS HEAT

Greenie N00B Member
I figured I would ask this question here since I have a "safety blanket" I know it's probably been covered elsewhere time and time again, but I felt it was worth soliciting feedback from other members to help me decide if it is worth spending the money on. So here goes:

I have a 2008 MS3 which has the following mods;
HPFP Internals
JBR Tru 3" Intake
Corksport TMIC
Corksport Racepipe
Corksport BPV
AP with Stratified Stage 3 E85 Flash Tune
ITV 22's Gapped at .026
E30

I've been on the fence for some time now about upgrading the turbo to a BNR S3, but I'm not sure I want to go down that path at the moment. My questions is... given my level of modification what is the consensus on adding a 3" exhaust to my existing set-up? Will there be a noticeable improvement in power, response or both, or will it just lower my WGDC and not equate to any gains? Looking for feedback, good, bad or indifferent. Thanks!
 
On Gen1, not really. That said. I am about 350hp, and I have a 3" corksport that I got for a steal. It sounds amazing, but I understood that up to 500 hp, stock is ok for Gen1.
 
I wonder if it would reduce power drop-off north of 5500rpm? I realize the K04 is pretty much out of breath regardless, but any efficiency gains might have merit, especially in the upper regions. I know I'm on borrowed time with the original stock turbo especially as hard as I'm pushing it at this point and the fact it already smokes on occasion, but the engine itself is holding up well thus far. I would pull the trigger on the S3 or Corksport turbo, I just don't want to pony up for a engine rebuild shortly thereafter. It seems that once you start pushing north of 350-360 hp on stock internals, your engine is on borrowed time. Sorry for the ramble...
[doublepost=1458771771][/doublepost]I've heard the Corksport exhaust is super sweet!
 
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Negative. Won't help. I have been a beta tester for the Corksport turbo and the powerband goes up well close to, if not over 7k. I'll need to check an old log.

Stock block is good for up to 500, you will be fine.
 
Not sure about Genwon, but on Genpu a full, catless 3" is worth 10-15whp in certain areas of the powerband, but your max power numbers will be similar (K04 is the limiting factor). When I was being tuned on my Genpu for my BNR S3, I got stuck at 360whp. Went full 3" and then hit 395whp on the same map.
 
Raider said:
It's. Gen1 thing.
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You mean the exhaust? This stock block is good up to 500 is news to me. I've always heard 380 or so for safety, and that's with the superior Pu pistons, VC, and better ECU logic (C/L fuel trims, etc.) I guess it's all in the tune.
 
Redline said:
You mean the exhaust? This stock block is good up to 500 is news to me. I've always heard 380 or so for safety, and that's with the superior Pu pistons, VC, and better ECU logic (C/L fuel trims, etc.) I guess it's all in the tune.
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I'm pretty sure Nishan has been running around with ~500whp on his stock block for quite some time now. With PI though obviously. all in the tune I guess
 
LOLWRX said:
I'm pretty sure Nishan has been running around with ~500whp on his stock block for quite some time now. With PI though obviously. all in the tune I guess
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500whp = a lot of heat, and that's what kills ringlands. Didn't Justin have popped ringlands on 3 of 4 pistons when he finally built, and he was only on a 420whp tune? Then again, it's the torque that snaps rods. So maybe he found some kind of balance.
 
LOLWRX said:
I'm pretty sure Nishan has been running around with ~500whp on his stock block for quite some time now. With PI though obviously. all in the tune I guess
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In this case it's not really all in the tune IMO. Regardless of whether it's a great tune or a "good enough" tune, his engine has to generate a certain amount of heat to make that power, and heat kills pistons. I don't know how he gets away with that kind of power, if that's what he's running day in day out, but I have a few guesses:

1) I know he's using a good port injection system, likely running a high E mix (=no knock) and probably has excellent, even distribution of fuel. Can run a lower AFR because PI (=less heat).
2) A very efficient, free-flowing intake and exhaust system, including the turbo. He may have also had head work done to increase VE. This helps heat evacuation from the cylinders.
3) Usage - I doubt the car has seen track usage at that power level. I would be interested to drive the car hard for 30 minutes on that tune and see how it holds up - or more likely, doesn't. If you only drive your car on the street, autocross, drag strip, etc...short controlled bursts of power, it doesn't generate much heat and you can get away with running a lot of power.

Personally my plan is to keep my car below 375 whp, probably more towards the 340-350 vicinity for track usage when all is said and done. I will of course try to push it to see how much I can get out of it before I dial it in down. I have read a lot of threads on MSF on this subject, and after a while you start to see a pattern with ringlands...my observation, 9 times out of 10 it's people running high power on midsize to large turbos (3071 and larger), particularly when tuned on gas. And you'd say "gas is prone to knock and knock kills ringlands". This is true but my feeling (based on nothing) is that heat is the real silent killer here.
 
VTMongoose said:
In this case it's not really all in the tune IMO. Regardless of whether it's a great tune or a "good enough" tune, his engine has to generate a certain amount of heat to make that power, and heat kills pistons.

Personally my plan is to keep my car below 375 whp, probably more towards the 340-350 vicinity for track usage when all is said and done. I will of course try to push it to see how much I can get out of it before I dial it in down. I have read a lot of threads on MSF on this subject, and after a while you start to see a pattern with ringlands...my observation, 9 times out of 10 it's people running high power on midsize to large turbos (3071 and larger), particularly when tuned on gas. And you'd say "gas is prone to knock and knock kills ringlands". This is true but my feeling (based on nothing) is that heat is the real silent killer here.
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Totally agree. Justin was spraying a crapton of methanol, which should've kept the combustion chambers cool. But 3 compromised pistons out of 4 speaks volumes. And we're talking about 420. 500 is another 80whp worth of heat on top of that.
 
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