Turbo Cobra: 1st time to 1/4 track

[killspray]

Hey guys,

I went to Dallas Raceway and ran my car for the first time in the 1/4 mile. I had a blast... still learning though.

Setup:
Built 4.6 w/ 76mm Single Turbo
T-56
Built Solid Axle w/ 3:55 gears
Weld Bigs/Littles 26x10.5-15

All runs done with 2nd gear burnout

Run 1

Boost at 19psi
Tire Pressure @ 18psi
2-Step set at 4,500 (engaged too late and didn't build much boost)

Bogged off line

R/T .610
60’ 1.953
330 5.229
1/8 7.760
MPH 99.39
1000 9.876
1/4 11.670
MPH 122.66


Run 2

Boost at 19psi
Tire Pressure @ 16psi
2-Step set at 4,500 (engaged on time and built about 3.5lbs of boost)

Bogged a little off line

R/T .268
60’ 1.821
330 5.018
1/8 7.551
MPH 99.85
1000 9.647
1/4 11.429
MPH 125.09


Run 3

Boost at 19.5psi
Tire Pressure @ 15psi
2-Step set at 5,000 (engaged on time and built about 3.5lbs of boost)

Bogged a little off line again

Run was going great, lost power at end of track, blew a spark plug.

limped to nearest 24-hour Autozone and changed plugs. Not sure what it would have ran if I didn't lose power...

R/T .305
60’ 1.769
330 4.878
1/8 7.382
MPH 100.20
1000 9.491
1/4 11.300
MPH 121.49

 

[Double"O"]

nice!...there is certaily a lot left in that car

what kind of power are you making with that beast?

 

[killspray]

nice!...there is certaily a lot left in that car

what kind of power are you making with that beast?

Thanks man, right now I'm a little over 600rwhp.

I keep bogging man... I ran better 60' and 1/8th mile ET with my drag radials... I either need to build more boost on my 2-step or raise the tire pressure up to 20psi or something...

Once I hit 10sec ET in the 1/4 on this setup, I'm gonna put an E-85 tune on her and crank up the boost :beer: might need to upgrade from 60 to 80lb injectors...

 

[Double"O"]

that car will certainly go tens if you can get it out of the hole (hard to do with a stick car and turbo but certainly doable)

i did kinda expect a little more mph though...mph should go up though if you can get more boost built for the hit

 

[goat-ee]

I am in the 10-11psi range on a stock longblock B-head convertible(mods in sig) and am seeing pretty close to the same 1/4 traps as your setup but I am only in the 92-94mph range in the 1/8. Seems like your not pulling on the big end all that well. Something is amiss I would think. Hopefully you were just having the spark plug problem, although I would change them all if I had one bad.

I myself went to the strip the other day and pulled a 1.6 60' but wasn't pulling very well in the upper rpm range, and was thinking its about due for some new spark plugs.

 

[fangs99]

too bad your not in my area, i know a tunner to send you too. he has a alt mod that fixed spark blowout. he was running a 3.4 whipple crusher plus spray on stock coils and was able to open the gap on his plus.

 

[killspray]

I am in the 10-11psi range on a stock longblock B-head convertible(mods in sig) and am seeing pretty close to the same 1/4 traps as your setup but I am only in the 92-94mph range in the 1/8. Seems like your not pulling on the big end all that well. Something is amiss I would think. Hopefully you were just having the spark plug problem, although I would change them all if I had one bad.

I myself went to the strip the other day and pulled a 1.6 60' but wasn't pulling very well in the upper rpm range, and was thinking its about due for some new spark plugs.

What is your WOT box set at and how much boost are you building on take off??

 

[goat-ee]

What is your WOT box set at and how much boost are you building on take off??

To be honest I have only used the 2-step once (when it worked right), but I got a 1.6 60', so I haven't really dialed in the rpm yet. But that time was 4500rpm, to be honest not sure of what boost it builds, I haven't really looked. I have datalog of boost and rpm and will post it, but it appears that it builds boost immediately by looking at it.

I wondered if your using the No-Lift Shift feature on your box? I haven't been able to get it to really work the way I want it to yet, it seems like when I shift and it catches the rpm, that it takes awhile for the engine to really recover and it's just not pulling well after each shift. About the time it seems like it really pulls, it's time to shift again. And when I shift there is HUGE backfire!!! And I am not talking about he normal stutter it does at the line, I mean HUGE FREAKING BACKFIRE!! I am also wondering if another issue is that the rev limiter is set at 6900, and the shift light isn't set to come on until 6600. I am wondering if some of the problem is that I am hitting the rev limiter during the shift. Thinking about running again soon with the 2-step on, disabling the No-Lift shift and raising the rev limiter to something in the 7200rpm range!!

 

[LitleWhiteSnake]

you 1/8 mile traps are very nice man

 

[Droptop Snake]

Good passes. You've got to have a ton left in it. My best pass was on 275/40-17 Mickey Thompsons with my JT-Trim making 15psi. I have 3.73s, and was at 530/458 to the tire.

I got 7.30/98.8 at the 1/8th, and 11.27/123.95 out the back door. I know I have to be WAY down on torque compared to you. Get some seat time and let 'er shine!