I just had my car tuned and dynoed after installing its latest round of goodies. When I bought the car it had a crate ls6 in it and the owner said the heads had been taken off and been cleaned up by hand at a local shop. He could not really elaborate on the amount of work that had been done to them. This past year I installed 1 3/4 LT's, catless y-pipe, SLP lid, and P&P TB and GMMG catback. The car made 375whp and 375wtq. After adding a BTR stage 4 cam, Fast 92 intake and Nick Williams 92 TB and a UDP the car made 439whp and 398wtq on the same dyno. I also added a 9inch with 4.11's and a steel drive shaft since the last dyno as well. I could not be happier with the car. The tune is spot on and for such a large cam the drivability is extremely impressive. I can not wait to get this thing down the track and she what she does .

 

Not bad......but i would have expected a tad more out of it . Even when it was bolt-ons.

 

Yea I did too honestly. I have seen this dyno hurt feelings before though and after all, it is just a dyno. It trapped 115.75 with the bolt ons so I feel like it was running pretty good.

 

115 with bolt-ons was terrible for a ls6 in a fcar. I trapped almost 120 with very simple bolt-ons with my ls6 at almost full weight......with the same bolt ons(diffrrent cat back) on my ls1 i trapped almost 113( ls1 intake to). Did you run it in bad da or have added weight?

 

No it should have been a decent DA and the car is a stock weight hardtop. I was on a stock clutch that had a little slip to it. How ever, from other threads, it seems like my numbers aren't to terribly bad. Seems ls6 cars trapping from 114-118 is pretty normal? Does anyone else have an opinion?

 

All i can tell you is what mine has done. First time on the dyno it made 403whp, some break in and a injector change it made 407whp.......now it would make about 430whp on the same dyno. It ran 12.2 @117 118 on the stock tune and stock gear. Tuned and with 4.10s it went 11.8 @119.8 that was at very near full weight........now well that's in the sig. It's had a best trap of 131.

To be honest i think it has more in it.

What rpm you turn it?

 

You trapped 131 with 417 rwhp? Even at 430 I cant see it trapping anywhere near 130. JTM's numbers look right to me.

 

Now that I think about it, my shifting could have contributed to a slower trap speed. I had the limiter set at 6600 but was shifting closer to 6000 because my tack is so lazy and I cant tell what rpm it is really at.

 

Hio's car does run 10's with a bolt on ls6 at 131 thats true but its been a long time getting there, its not the typical bolt on car however theres nothing truly "special" on it either. my ls6 with bolt ons made 390 and i still had some more stuff that could have went on it. a bolt on ls6 is usually between 385-400whp on a c5z or 390-400 on an fbody because of the lighter drivetrain. however 375 could have just been a low reading dyno.

now with your car I agree 118-120 should have been seen with bolt ons. Depending on da and weather. If the clutch was slipping that coud have been an issue as well. i would expect the new setup to trap over 120. You are absolutley killing it by shifting that low. with a stock ls6 my limiter was set to 6800 and i shifted around 65, i just learned what 6500 actually looked like on the tach. get a shift light if you're not as confident. i'm willing to bet that there is another 3 mph in just doing that. an ls6 with no cam peaks right around 6k so by shifting there you're losing out on 4-500 rpm of peak power as the cam will carry for another 500 rpm.

too many people see poor running cars now and its sad because they think its the norm. people see a bolt on ls1 fbody running high 12s at 109 and think it fantastic, when in reality thats pretty horrible if its an m6 car. I've seen bolt on ls1 cars go 113 all day long with the right setup so I'd expect a lot more from an ls6.

sorry man i'm not bashing you or the car lol just saying it has more in it. lol

 

Thanks redbird. I didn't take it as any bashing lol. The issue with the tach is it seems to change in every gear. I will be ordering a shift light before my next track outing for sure. I didn't think I was leaving that much on the table by shifting it a 500rpms early but it makes since.

 

Good post red.

Well that's what it does. Btw....the bolt-on ls6 record is 135. I've been foolin with this engine/car for a long time. I have went from very basic bolt-ons with it to what it is now.
Shifting that low rpm is killing your et and mph. The stock ls6 cam should peak around 6400 and carry the power very well. I shift about 6800 according to my logs. Hell when i get to tinkering with it again I'm gonna move the limiter up to 7200. It nails the limiter @ 7 k now like no body's business.

Think about it like this jtm....a ls6 makes 60 more hp than a ls1 and has a extended rpm range . To me 115 is not steller even for a bolt-on ls1 these days.

 

JTM2085 - Your dyno numbers are right where they should be. You figure a strong cam only LS1 car would be around 400rwhp. Adding LS6 243s heads would be another 20, then add the FAST 92mm setup, add 20. Plus your running a 9" rear which will cost you some power. Id be happy with your numbers. Also trapping 115+mph with bolt ons is very good.

Years ago, I had a H/C setup that was making 416rwhp. (originally made 430/400, but the A/F went super rich after I added 3" dual exhaust) Anyways, in my 100% full weight WS6 3650lbs, 17s all around running BFG DR's I went 11.9@120 with a 1.7 60' (stock 10 bolt w/4:10s). Do some research and you will see a typically H/C/LS6 intake car, full weight will run 11s at 120-122ish.

Ignore HioSSilver and his full weight, 417rwhp and 131mph trap BS.

 

Car is not full weight now dude. Seems you may have some comprehension issues. No bs about it. That's why I listed the times I ran for comparison at/near full weight.

here's the dyno sheet for a full bolt on ls6. That dyno is the change from 1.7 to1.8 rockers. That's when it had the 10 bolt in it. It has a fab 9 now. This dyno reads 3.5% low to the local dj around here. I made 413 on the dj here and since I have picked up 18hp.




Here's the run. Car has ran a between this and 11.22 for many years now. It has even did a controversial 10.7 pass. Personally I think it can do a 10.6~. Still workin on the chassis after the fab 9 install.


I have no reason to bullshit you.