heymoej

iTrader: (67)

i went to the track last friday & i am dissapointed my car ran a best of 12.5 @ 113 last time i went to the track.(lid,filter,cai,160 stat,smooth bellows,headers & ory,gmmg,410 gears & nittos)i just put a ls6 intake & true duals on a month ago & i was hopeing for a low 12.2 @ 116 or so,my best now with all of this was a 12.7 @ 111.what did i do wrong??? some people have told me it might be the duals & i am not geting enough back pressure???? please help!!!!!!!

LS1-450

iTrader: (33)

Did you have the car tuned after increasing the air flow? Those are some awesome mod's., they may just need to be tuned. There have been enough changes made to your car to warrant a dyno tune. Get it to a dyno & find out what's up. You've got to get the air/fuel mix correct in order to build power. Timing advances can also be adjusted to help build power.

BTW, 12.5 to 12.7 & 113 to 111 could be weather conditions, driver related, track related, tire pressure related, a number of things. Can tell you for sure that it's not your duals. Spend the money & bring it to a dyno.

300bhp/ton

well lets see there are 1000's of variables that affect times what ONE is the cause of this?

Seriously, track prep and weather conditions have to be some major factors. Not to mention how the driver was performing on the night. These will nealy always be the main causes for performance variations.

Now to the car.

If you went from the LS1 to the LS6 manifold, yes there should be a gain, but possible only 20rwhp. Enough to make a difference, but not a massive difference.

This mod alone really should be dyno tuned, even if it's only to check that every thing is as it should be, but with a tune more power should be availble making use of this mod.

Although unlikely, but adding this without a tune and other mods which you already have assuming they haven't been tuned either. There is a possibility that you are making less power than with the Ls1 intake. This is remote but perfectly feasable if the a/f is too far out of wack.

As for the exhaust.

Well true duals can provide goo gains, but by the sound of it you had a good setup so any gain was probably only going to be minimal.

Back pressure is not the issue, a good exhaust is about flow efficency and scavening.

A good Y setup should have very similar scavenging abilities of a X setup, and provided the flow rate of the silencers is sufficent it will make for a very efficent exhaust. hence race cars usually use a Y instead of duals, as in a Corvette GT race car.

A dual setup may well have effected how the exhaust flows, so it would not be suprising if you are only making the same or less power from the swap.

Lots of people probably won't like this but it really doesn't alter the fact.

Remeber a GOOD dual setup will be better than an AVERAGE Y setup.

But if you had a GOOD Y setup and went to an AVERAGE dual setup there will be no power gains, and more likely losses.


I recommend you get a tune and then try the car again on at least 2 differen occasions, noting carefully the weather conditoins, wind direction and such.