new ls6 same e.t.'s

[DemonSpeed]

Okay, with my old ls1 and the mods in my sig. I had a best time of 7.95 in the 1/8th with the avg. i guess around 8.1 or so. Since then (2 years later) I now have a brand new ls6 in with a custom tune to match it and guess what I just ran? an 8.15. WTF, I was expecting considerably better than this. Heres the thing though, I cant stall it up as high. the brakes just wont hold and I end up rolling through the lights. I used to stall to 3k and now can stall to about 2k. would that matter that much? I was guessing i would be in the 7's somewhere, how much would 1k diff in launch change it? One more thing i dont get. my 60' is 2 tenths quicker, my mph is 2 mph quicker. what gives? the only other change since then is a moser 12 bolt with the same gear ratio. any theories?

also want to mention that the car feels great on the road, better than before.

[rc74racer]

Did you have the car tuned before? You'd have to know what your RWHP was before and after to know what to expect.

[Bottesini]

There are alot of things that can make a difference, but a few of the things I see first are. The 12 bolt will eat up more power through parasitic loss than a 10 bolt. The weather can also make a huge difference in your times. Not to mention track prep etc.

[DemonSpeed]

yeah it was tuned before but with the ls1. Guess im going to replace my front brakes so I can stall it up more and see what happens. Is there any way to reduce the drag from the 12 bolt? diff fluid? Also anyone recommend some good brakes?

[rc74racer]

So what is the before and after RWHP?

[DemonSpeed]

dont know, never been dyno'ed. but ls6's usually dyno around at least 360 rwhp stock and ls1's my year are at 290 or so. So its around 60 to 70 rwhp gain or so. Very vague and all guesstimates I know. What do you guys think I SHOULD be running with my current mods?

[Bottesini]

yeah it was tuned before but with the ls1. Guess im going to replace my front brakes so I can stall it up more and see what happens. Is there any way to reduce the drag from the 12 bolt? diff fluid? Also anyone recommend some good brakes?

Not much you can do to help with the parasitic lose from the 12 bolt, except use lightweight parts. The entire reason it is a stronger rear is what makes it rob power.

With a tune, M6 and similar mods as you I was putting down 357 RWHP with an auto I would think in the 330s would be normal.

I am far from an auto expert, but I would bet a slightly bigger stall you would be able to gain a bit more time. I imagine you are running right about where you should be. When the starts align you might be able to run a 7.8 on a cold day.

[DemonSpeed]

i dont know, i think i should avg. quicker. I was at the same time (7.9 to 8.2) with an ls1 but keep in mind I have a new complete ls6 in now, i dont think a 12 bolt would negate 60 rwhp. question is how much diff. in e.t. would I see from stalling 1k higher (if I can get my brakes to hold)?

[adam3566]

i dont know, i think i should avg. quicker. I was at the same time (7.9 to 8.2) with an ls1 but keep in mind I have a new complete ls6 in now, i dont think a 12 bolt would negate 60 rwhp. question is how much diff. in e.t. would I see from stalling 1k higher (if I can get my brakes to hold)?

1k is hell of alot. still don't see how any of that is possible. You say you have a better 60 foot and 70 more ponies but yet run slower or the same? Doesn't make sense to me at all.

[silverz28camaro]

A 12 bolt eats about 10 hp, so the is a .1. what stall do you have. I have never had luck stalling my converter up. I let it idle and just mash the gas. With my ls1 with ls6 heads, intake and 224 cam, bolt ons, 2800 stall i run a 7.44 1/8. The trick to a 4l60e is is just this. When you brake tq it you are forcing more fluid into the converter creating heat and making to converter feel tighter. when you hit the gas from idle it allows the engine to quickly rev and "flash" the converter to a higher stall speend. Not to mention you are building extra heat under the hood.

How many mile are on your new ls6? if under 2,000 i wouldn't even be racing. Most people with newer vehicles or motors will notice power and fuel mileage increase as the motor loosens up. My buddy had an 06 gt with full bolt ons and ran a 13.3 @104. over the next year of putting over 10,000 mile on it and taking it to the strip over and over, his times just kept improving. He ended up with a 13.05 @ 106 no other changes, except for maybe driver, track prep, and weather.

Also double check the tune and maybe data log a few runs if you can. When i did the ls6 heads and 224 cam i was getting knock retard which was killing my mid range power.

Just a few things to try and look for.

What is your stall?

[DemonSpeed]

its a tci 3k stall. So it works better for you not stalling it up? Im going to have to try that. it does seem like my mid range is off, that would explain the better 60' same time. I have about 3k on it right now, so maybe it will still loosen up.

[silverz28camaro]

its a tci 3k stall. So it works better for you not stalling it up? Im going to have to try that. it does seem like my mid range is off, that would explain the better 60' same time. I have about 3k on it right now, so maybe it will still loosen up.

3,000 is on the low side for an ls6 or even an ls1.

i have/had a 2800 fuddle for the last year and would run

1.68 60' 7.58 1/8 @90 and 11.899 @ 114

then after i installed the ls6 heads and 224 cam i ran

1.70 60' 7.44 1/8 @ 92 AND 11.70 @117.

i FORGET WHAT MY 330 TIMES WERE BUT I DO REMEMBER THEY WERE THE SAME BEFORE AND AFTER the heads and cam.

my 2800 is in the mail right now and fuddle is re flashing it to 3400. They recommended that to me due to the heads and cam moving my power band up, and they also were the ones who told me to leave at idle for better times(traction permitting).

www.fuddleracing.com they have been good to me. try a bigger converter. the ls6 was meant to run at higher rpms anyway so let it. Some people will tell you that 3,000 is small even for a stock ls1 with headers.

[silverz28camaro]

what was the before and after 60' times?

[silverz28camaro]

Do you have the stock ls6 cam? if so i would change it out. Get at least a 228 cam and a 3400-3600 stall with some good tires.

[DemonSpeed]

well i found my old slips and i must have been smoking crack, my 60' times were about the same before. im still missing a few but theyre all about the same. but my mph is around 1-2 better. yeah i have the stock cam and I use e.t. streets. cant afford to do a cam right now, kinda broke

my best run the other day was 8.132 @79.95 with 1.88 60' and 5.55 330'
best run I could find of old was 8.116 @78.93 with 1.84 60' and 5.506 330'
so very similar except mph. although i did have a couple of 7.9's but cant find em.

[silverz28camaro]

looks like the same thing that happened to me is happening to you. worst 60' but better mph.

I'd say its the stall. with the ls6 heads and cam you took away low end to gain upper end. When you get the chance go bigger on the converter or, since you already have it, try leaving at idle.

[silverz28camaro]

Oh and if you don't already, get and underdrive pully from slp.

Not a huge gain but from the pulley being smaller it allows for quicker revs. so if you are leaving from idle with the new pulley you can get a little more stall out of your converter.

Other benefits are slightly better mpg and longer accessory life from everything spinning slower.

Oh and another is make sure you have an aluminum driveshaft. Mine was steel and i was able to find a local guy who had one from a 6 speed car for $100.

It was about 7 lbs lighter then the steel unit and with the 3.73 gears it really helped with top end.

[DemonSpeed]

thanks for all the help man, ill let you know how it turns out. I should be going again soon.

[silverz28camaro]

Also make notes on the shift points. I would look for about 6300 on the 1-2 ans 2-3 shifts

any less than that and you may be loosing time