Hi everyone, i just had to tell.

a year ago i bought a silver 1997 TT from SW, took it to Norway and due to duty system in Norway, i converted all TT stuff to my 1998 Coupe.
Sold the silver car to a good friend.

Before i took it over i had it dynoed (MTI), it had 488 rwhp uncorrcted and 453 rwtq.
When i swapped it over to my car, i bought LPE stage II heads and their GT2 cam, LS6 intake.
And i used LS1Edit to tune it, with a little help from nospam.

A week ago, we installed a new Dynojet 248 in my friends "farm house" and last night i dynoed my TT.
First dyno pull showed 450rwhp and 476rwtq (corrected, DIN) ??? wtf.....

Then we attached A/F sensor and now i see my problem, my A/F ratio is
11:1 from 3400 rpm (where i start, i have auto) and drop below 10:1 all the way to redline 6700 rpm. (it will not show any lower than 10:1)

We increased boost from 5 psi to 8 psi, and now i got
515 rwhp and 547rwtq, A/F ratio a little better, but still below 11:1 all the way to redline.

This run i had a passenger to keep an eye on my boost gauge during dyno pull.
He said boost dropped as i was getting close to redline, it dropped from 8 psi to 6 psi, so it seems that LPE stage 1+ turbo is not capable of flowing any more, does this make sense ?

Anyone know how much HP/TQ will increase if i get a correct A/F 12.8:1 ?

 

You're tune (AF) is costing you 20-40rwhp. I'd call Ed Potter at LPE...he really knows these setups. If it where my car I would set the boost at 8psi and get an ls1 edit dyno tune and set the af at 12.3 : 1 on a dynojet as it will run leaner on the street. Which injectors and fuel pump are you using? What was the correction factor on the sae as an uncorrected run in Houston may show 20-40 more rwhp in the cooler months so you are not comparting apple to apples. Those turbos should easily flow enough to hold 8psi...may be a wastegate problem.Good luck on a great package! :cheers:

 

What exhaust are you running?
The boost drop off might be because the exhaust is becoming a restriction. :yesnod:

 

I am putting in new rods, new piston setup from MTI, so i hope the crank is up to it.
Boost, i will be aiming for 8 psi street and 10 psi drag racing.

SlowC5, i still have my cats in place, they will also be removed before spring :-)

Then tune it on a dyno, aiming for the suggested 12.3:1 and see where that leaves me.

SlowC5, you still have your car ?
Any good hint regarding tuning fule curve under boost ?


TIA