Finallly made it to the track with the GT6152 today. Went to Englishtown's test and tune session. Temps were in the low 40's, sunny day, and not many people at the track.
My best run of the day:
60' 1.54
1/8 7.24@92.5
1/4 11.51@112.2
All my other runs were 11.5s and 11.6s at around 112. Not a single bad run the whole day!
I'm running a 23/21 timing TurboTweak chip. To be safe, I just left the timing at base values. I did have to add more fuel in through the chip because it did seem to be running on the lean side. I ran 27lbs of boost for most of the runs. On one run I ran 25lbs of boost and it ran 0.1 and 1 mph slower in both the 1/8 and 1/4. I ran 28" MT DR's (275/60/15s) to try and keep the rpms down. I'm running a 3200 9" Art Carr converter (not locking it) that seems like it has a lot of slip on the top end. I was turning 5400 rpm through the traps. With this converter it seems like I only pick up 20mph from the 1/8 to the 1/4. I tried a tighter converter previously and the car picked up almost 24mph with the converter locked, but overall it was slower because the 1/8 ET and mph were down.
I kept the tires at 20psi and launched at 10lbs of boost on the 1.54 60'. The first run I launched at 5lbs of boost and kept launching harder each run. My 60 foots, in order, were 1.64, 1.61, 1.58, 1.56, and 1.54. I am also using an RJC boost controller. I also leaned out the first gear fuel in my TurboTweak chip, which seemed to help. I had 6psi in the air bags to help prevent the tires rubbing on the launch. With more tweaking and launching even harder, I think 1.4s could be in the future.
Here's the rest of my combo:
50# MSD injectors
stock IC with dutt neck
stock cam
stock heads
stock throttle body/plenum
stock MAF
HR bar
no front sway bar
stock boxed lower controls arms, stock uppers, both with poly bushings
Lakewood drag shocks 50/50 rear, 70/30 front
big mouth cold air intake
power plate
THDP
ATR dual 3" exhaust
no cat
Dynotech Hi-Pro trans
Walbro 340
Alkycontrol progressive alky kit, using methanol with 93 octane
data logging with Directscan, EGT
using S10 wheel cylinders to hold boost, line loc during burnout
Very happy with my runs today.
It seems like the turbo did make a little more power running 27lbs boost compared to 25lbs boost. Hard to say how much more power though. With the stock cam I was already out of my power range at the rpms I was seeing. With another cam I might have picked up more. Plus I'm still using stock IC, throttle body, and heads. Might be flowing too much for my combo, hard to say.
Another thing I noticed is that I'm almost out of injector, even with the alky. After I added fuel through the chip, I was at 93% injector on the last run. Might have to bump up fuel pressure or add more alky if I run much faster.
The last thing is that I was still at a pretty safe timing of 23/21. I can probably run 26-27 timing in 1st/2nd gear, but not sure how much, if any, I should raise 3rd gear. I might try lowering the boost down to 25lbs and then add the timing, to give a little safety margin. My guess is that the timing will help more than the last couple lbs of boost with my stock IC/head combo.
Hopefully some others will have more feedback on this turbo. It worked good for me today!
