[6spdhyperblue]

That’s good info.

Before anyone extrapolates those results to NA bolton power levels, how important is scavenging on a boosted motor vs NA?

Id also wonder about egt difference on a boosted motor

[NA18CamaroSS]

My original premise is based on N/A motors. Boosted motors are a different animal-the stock exhaust manifolds are definitely a restriction at twice the stock power level. The information is good though. Nice to see someone doing a useful comparison. That chart should definitely be available to the ZL1 and boosted SS guys.

[travislambert]

Originally Posted by NA18CamaroSS

My original premise is based on N/A motors. Boosted motors are a different animal-the stock exhaust manifolds are definitely a restriction at twice the stock power level. The information is good though. Nice to see someone doing a useful comparison. That chart should definitely be available to the ZL1 and boosted SS guys.

I edited my original post with a disclaimer showing this data is from a boosted LT4.

My thought was this data was still on-topic, but you're absolutely right about it being a different animal. I didn't intend for anyone to be misled.

[DaveC113]

Originally Posted by NA18CamaroSS

My original premise is based on N/A motors. Boosted motors are a different animal-the stock exhaust manifolds are definitely a restriction at twice the stock power level. The information is good though. Nice to see someone doing a useful comparison. That chart should definitely be available to the ZL1 and boosted SS guys.

I wouldn't call a ~20 hp difference near 1k hp levels a restriction, personally. The headers do make for a nice improvement though.

travislambert, thanks for posting that graph, it's interesting to see. I actually can't believe how good the stock manifolds are, especially when you consider how bad they used to be!

[DaveC113]

Originally Posted by 6spdhyperblue

That’s good info.

Before anyone extrapolates those results to NA bolton power levels, how important is scavenging on a boosted motor vs NA?

Id also wonder about egt difference on a boosted motor

With superchargers it's pretty much the same as NA as far as exhaust header design, with the caveat the supercharged motor likely makes power at lower rpms vs a high performance NA motor, hp peak does does change the optimal design, but so will a cam with a NA motor.

With turbos, it seems like the priority is to get the turbo as close to the heads as possible even if you sacrifice scavenging.

I'm not up to date on the very latest in forced induction design though, but looking at the "hot V" turbocharged V8 motors everyone is making these days, and I think BMW is basically bolting the turbo to the head of their I6s as well, makes me think there is no scavenging going on, or very little.

[s346k]

Originally Posted by DaveC113

With turbos, it seems like the priority is to get the turbo as close to the heads as possible even if you sacrifice scavenging.

idk how much turbo size plays a role but i did see a 1/8 no prep square body s10 tonight with the turbo behind (and above) the cab. it had no issues getting down.

[17camaroSS]

Originally Posted by s346k

idk how much turbo size plays a role but i did see a 1/8 no prep square body s10 tonight with the turbo behind (and above) the cab. it had no issues getting down.

Lol, you went to Muncie’s big end banger didn’t you? 😆

[s346k]

Originally Posted by 17camaroSS

Lol, you went to Muncie’s big end banger didn’t you? 😆

hell yeah. i left when one of the other square body s10s decided to surf the guardrail. and i was slightly concerned about the rain and some bald gy sc3s.

[wnta1ss]

Is your hypothesis based on your 'loss' of 7 hp using long tubes instead of stock exhaust manifolds? I think that the explanation is, something is probably wrong with your car, not really with the headers. Plenty of people already have tested headers on the SS and found gains. Furthermore, like 6spdhyperblue mentioned, bolt-on cars using long tubes are faster on the dragstrip. Check out the fast list, bolt-on SS: the quickest cars all have long tubes, then behind a bunch of them is a cat-delete car, then right behind him is an all-stock-exhaust car (mine). Looks like for a bolt-on SS, cat deletes gain a little hp over the stock exhaust, and then long tubes gain even a little more.