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So, after two years and a crap load of time, I finally dynoed my vette.
its a 2005, Z51, M6. 17K miles.
Mods are:- TSP ported LS3 heads
- Gwatney ported OEM LS3 intake
- Gwatney ported OEM LS2 throttle body
- Cam Motion Titan 2 cam 222/230 113 +3
- Comp Cams 1.8 steel roller rockers (.630/.621)
- Johnson 2110 lifters
- LS3/Z06 aFe Magnum FORCE Stage-2 Intake
- LS3 MAF sensor - blade style
- "Vette-Air" cold Air intake scoop
- Std. speed ATI harmonic balancer
- ARH 1 7/8 headers with cats
- C6 Grand Sport MPP Mufflers with NPP in a Box
- C5r timing chain
- C6 Z06 brakes
MRR 755 Wheels - C7 ZR1 Style
- Front - 18x9.5, offset +56, 275/35-18
- Rear - 19x11, offset +79, 305/30-19
The car was throughly heat soak before being dynoed. I had spent 2 hours driving 67 miles in 95 degree weather to get to dyno, the last hour was stop and go driving. Tuner said it would have made 10 more HP if it wasn't heat soaked.
The car made 471 RWHP and 445 torque. 400 ft/lbs from 2800 to redline and I guess 300 ft/lbs from 2K.
Last edited by Dave_in_VA; Jul 9, 2022 at 03:12 PM.
That's for the advise while I was planning my build.
This was a budget build, $5K in total parts including the headers and some specialty labor.
The TSP ported/polished LS3 heads with Gwatney ported/rod-modded LS3 intake and ported OEM throttle body combined with the 1 7/8 headers got a 97% dynamic efficiency on the dyno. Tuner said that was huge.
The tuner said my LS2 throttle body was likely the limiting factor on more power. He suggested a 102 TB, colder day, and more aggressive tune would get me 500 HP. That seems optimistic.
The small cam is key to the torque. It can be driven in almost any gear from 1200 RPM or so to redline without ill effects.
That's for the advise while I was planning my build.
This was a budget build, $5K in total parts including the headers and some specialty labor.
The TSP ported/polished LS3 heads with Gwatney ported/rod-modded LS3 intake and ported OEM throttle body combined with the 1 7/8 headers got a 97% dynamic efficiency on the dyno. Tuner said that was huge.
The tuner said my LS2 throttle body was likely the limiting factor on more power. He suggested a 102 TB, colder day, and more aggressive tune would get me 500 HP. That seems optimistic.
The small cam is key to the torque. It can be driven in almost any gear from 1200 RPM or so to redline without ill effects.
I think the LS2 and LS3 throttle bodies are both 90mm. There's a vac port behind the throttle body. Check for vacuum there at wide open throttle. If there's no vacuum there, a bigger throttle body won't do anything except empty your wallet. I think the 90mm starts becoming a restriction at around 550 rwhp. The LS7 boys can benefit from bigger throttle bodies because they're just getting cranked up at 550 wheel. It takes a tremendously bad assed LS2 or 3 to get in that neck of the woods.
Just went out and looked. The port I was thinking about must have been on my Heartbeat blower. My unblown LS3 has a hard plastic line there that I assume is part of the PCV system. I guess that's why it's so difficult to find vacuum for the bi mode mufflers. You could use the port on the back of the intake manifold or T into that line if you're using it for bi modes. I think vacuum anywhere in the intake manifold at max RPM and WOT would indicate a restriction in the throttle body or CAI.
I found 4" of vacuum right behind the throttle body on that Heartbeat blown LS3, but that was at 660+ rwhp. Also drilled and tapped a hole between the throttle body and air filter. No vac there so the CAI wasn't the culprit.
And yeah, I taped a tennis shoe to the dash and set the vac gauge in the shoe. Ran a line out the widow and under the hood. Pretty much full blown redneck.....but I is one. It worked. My son saw it and just shook his head.
My tuner said a cooler engine with maybe a little more aggressive AFR could get another 15 HP or so. He also said a larger throttle body would help, but the OEM LS3 intake doesn't port-match with a 102 TB so this might be a minimal gain.
This fall I will go back to the dyno on a cold day and see what a cool engine does in terms of power.
So Forum, what would another .0150 milling of the heads give? The downside to this is would require fly-cutting of the pistons.
However, fly-cutting and another milling of heads is easier/quicker than a cam change.
Also, I'm not wild about another cam as I really love my torque curve. From 1500 onward, it pulls hard. I really don't want a peaky cam that's hard to drive.
Thoughts anybody? Or should I just shut-up and like what I got :-)
Milling the heads along with a bigger cam could get you over 500. Not going to happen with just a compression bump. A cam big enough to get you over 500 at the wheels is going to cost you some power down low also. Is your intake manifold rod modded?
Not sure about chasing the dyno numbers if happy w/ SOP dyno. And if get to 500 WHP STD will likely want to get there SAE after that leading to more $$ spent to get every HP. (Think the difference is somewhere around 4% between STD / SAE)
Agree with motorhead on TB. Factory does not seem to be a bottle neck if 500 WHP is the goal. If really contemplating cam change, Spin's cam netted 62 WHP / 23 WTQ with excellent manners in my case. No low RPM issues at all. Drives like stock (until get into the throttle) with current tune and 4 degrees overlap. Very smooth.
Really like your setup. Looks like a proper NA build IMO.
Your already making good power I would address the 05 differential first. with 06+ differential and 4.10s .and enjoy the car
Fortunately or unfortunately, next Saturday a stage IV Z06 T56 trans and differential are being installed, 2.97 gear set. 3.42 rear. Agree about weak 05 diffs! This was not my plan until the trans started having problems.
Originally Posted by old motorhead
Is your intake manifold rod modded?
Yes, TB is ported also.
Originally Posted by VolSince69
Not sure about chasing the dyno numbers if happy w/ SOP dyno.
SOP is very good.
Originally Posted by VolSince69
Factory does not seem to be a bottle neck if 500 WHP is the goal.
This is my take also.
Originally Posted by VolSince69
If really contemplating cam change...
A bigger cam would be complicated. It would involve fly-cutting the pistons, removing the rack, etc. which is a big project. I currently zero margin for a bigger cam due to PTV issues
Originally Posted by VolSince69
Really like your setup. Looks like a proper NA build IMO.
I know I'm being wishful. First 220 RWHP cost about $5K in parts.
Next 34 RWHP would likely cost another $5K. Very bad math!
Last edited by Dave_in_VA; Jun 29, 2022 at 09:33 PM.
I hadn't thought about it that way, but put CAI and headers plus a tune on a LS7 and it would be very close.
Here are all the mods:
Those are some great numbers. Especially with the smaller cam!! Congrats! But I disagree on the statement 'put a CAI and headers plus a tune on a LS7 and it would be very close.' Headers, tune, and a CAI on an LS7, and you should see much better than 471whp. Not taking anything away from your build, because, like I said, you've got some killer numbers there. Guess it would depend on what you'd call close. I think with a bit more cam you would be close to, or better than, the LS7 you mentioned. But I'd leave it as it is. Again, congrats!!!
Dyno Results
