475whp ls6 displacing 5.7l

[John Milmont]

A buddy of mine just picked up a vette with quite a few mods. We took it to the tuner to make sure everything was sorted out. Word from the tuner is that its the strongest c5 z06 with a stock bottom end to ever cross his dyno.
The mustang dyno is saying 475 right now, a stock c6 z06 puts out 440 on the same dyno.

The car is still very streetable. Coming from working on Gen 1 SBC's, these numbers just shock me. I'm currently working on a 383 (6.2l) gen 1 SBC and I hope to get close to 500 fly HP. Thats with AFR heads and a little smaller cam than the vette. I cant get the RPM that the ls6 is getting though, its going up to 7000. I could probably run 6500 max but i dont plan on taking it much past 6000.

Specs of the ls6 off the top of my head:
cam: 239/24x
FAST intake/fuel rail 36# injectors
Ported and polished heads
ls7 lifters
aftermarket throttle body.
Long tube headers.

amazing how this adds up to around 550hp. Its almost 100hp per liter and still streetable.

 

[Dave Deerson]

I am a little skeptical of those numbers. A friend of mine has a built LS6 in an ex-Grand Am Vette with the following: Katech CNC milled/ported heads with larger valves, 12 to 1 compression,GM World Challenge cam,Fast intake with the 92mm throttle body,36# injectors, through long tube headers controlled by a GM ECM tuned on an engine dyno. His numbers were just over 500hp at the crank.
My LS6(stock heads) with 36# injectors and ASA cam puts out 451 at the crank. I'm not sure the LS6 intake ports support that kind of power. The LS3 heads flow much more air. Sometimes the numbers on the dyno are skewed a little................

Dave

 

[Rich E.]

I believe it. I had an LS6 in my Mazda RX7 that made 436 rwhp with a LG G5X3 cam, out of the box AFR 205's, long tubes, untouched LS6 intake and throttle body. Tony Mamo used to advertise a combo worth 500 rwhp from a LS6 a couple years back.

Of course mustang dyno's have been known to fib a bit in favor of a higher number soo........

 

[John Milmont]

well, the tuner said the 36# injectors are running about 75% duty cycle which is getting close to the max output. Dave, do you know the DC of your injectors? I assume that if its ingesting that much gas and the AFR is good, its burning it...

Rich, I have heard that about the mustang dyno as well. Its hard to compensate for that error since the amount of error is not liner with the amount of horsepower. Apparently, the more HP, the greater the percentage the error is.

We decided to cap the vettes engine at 6800 RPM. That is also the peak of power so its makes sense to cap it there anyway. I hear with the stock bottom end, its not good to go over 6800, though the car does have ARP bolts on the rods.

I just go the dyno print out and attached it. I wish it wasnt a PDF so i could darken in the plot. Looking over this, it does say the weather correction factor 'corrects' the power to 473.9; that could make the reading so high. It was pretty warm today though.

Max power: 441.1 @ 6424 RPM
with the correction factor: 473.9

Max Torque: 386.9 @ 5597
Corrected: 415.2

 

[Dave Deerson]

I believe it. I had an LS6 in my Mazda RX7 that made 436 rwhp with a LG G5X3 cam, out of the box AFR 205's, long tubes, untouched LS6 intake and throttle body. Tony Mamo used to advertise a combo worth 500 rwhp from a LS6 a couple years back.

Of course mustang dyno's have been known to fib a bit in favor of a higher number soo........

The stock heads,even when ported seem to not flow as well as the AFRs. My friend's LS6 that does make 500HP only made around 480 with the GM intake. It was only when the Fast intake and larger throttle body was installed did he see the 500. What I am Saying is that the LS6 needs to more airflow, either with a large cam and intake(like my friends WC cam and heavily worked heads) or better heads and milder streetable aftermarket cam).
I'm not calling anyone out, but through the years of seeing dyno results from multiple dynos( different brands,different locations,etc...) I only take the numbers as a relative tuning tool.since I always tune on the same dyno I am only concerned with the Delta or amount changed from a different tune or engine mod.Even engine dynos can read differently.The only time I am paying attention to the actual numbers is when racing in classes that are HP/weight based. You then see there is much disparity among the same brand dyno but multiple locations and operators.

 

[Rich E.]

The stock heads,even when ported seem to not flow as well as the AFRs. My friend's LS6 that does make 500HP only made around 480 with the GM intake. It was only when the Fast intake and larger throttle body was installed did he see the 500. What I am Saying is that the LS6 needs to more airflow, either with a large cam and intake(like my friends WC cam and heavily worked heads) or better heads and milder streetable aftermarket cam).
I'm not calling anyone out, but through the years of seeing dyno results from multiple dynos( different brands,different locations,etc...) I only take the numbers as a relative tuning tool.since I always tune on the same dyno I am only concerned with the Delta or amount changed from a different tune or engine mod.Even engine dynos can read differently.The only time I am paying attention to the actual numbers is when racing in classes that are HP/weight based. You then see there is much disparity among the same brand dyno but multiple locations and operators.

No worries Dave. I don't think anyone feels like the got called outl. I also agree with you on all points especially the disparity between dyno numbers. I've seen the same dyno post different #'s, same engine, same day, just different times of the day (temp).

And a 500rwhp LS6 isn't very streetable. Race car only IMO...:laugh: