Second time Out : Whipple Cobra

[Jmurrz]

Hey guys, I am trying to figure out some technique to get a better 60' and also see if you guys think there are any issues with my trap speed.

The first time I went I was on my street tune ~580rwhp.

The next trip out, I changed my 3.25 to 3.00 upper and changed tunes to my race tune (Car 421). ~605rwhp

I am trying to figure out why my 1/8th mile mph has gone up so much but my quarter mile time has actually dropped. I am driving the same way I did last time, no power shifting but quick shifting.

I dumped the clutch off the 2-step around 3500 and spun, so I went to drop it down to 3k and broke a half shaft on the launch.

Any advice to the launch? I am on 26x10.5 MT Et Street Bias Plys. Also, does anyone know why my trap speed could be low? I jumped the Intercooler relay and it worked in the pits.

 

[Shadow Grey 03]

Icing it down, or just running the fluid through? Shift pts?

 

[Jmurrz]

Icing it down, or just running the fluid through? Shift pts?

No ice, but jumped the IC pump and gave it about 30 min cool down. I am shifting around 6,300.

 

[Shadow Grey 03]

It needs iced down for optimal back half pickup. With 600 wheel you should be picking up close to 30 on the back half, not 20.

 

[Jmurrz]

It needs iced down for optimal back half pickup. With 600 wheel you should be picking up close to 30 on the back half, not 20.

Thanks, I appreciate the input, I will try that next time. Any advice for launching?

 

[Shadow Grey 03]

Thanks, I appreciate the input, I will try that next time. Any advice for launching?

Try launching without the 2 step. Broken halfshafts aren't any fun.

 

[stangfreak03GT]

No ice, but jumped the IC pump and gave it about 30 min cool down. I am shifting around 6,300.

I would move your shift points to at least 6500. I shift my 2V at 6700!

 

[Jmurrz]

I would move your shift points to at least 6500. I shift my 2V at 6700!

I actually just looked at my Dyno sheet and my power does not drop off until about 7k. Maybe that will help with trap speed. How high can I rev it out without worrying about valve float?

 

[Jmurrz]

I actually just looked at my Dyno sheet and my power does not drop off until about 7k. Maybe that will help with trap speed. How high can I rev it out without worrying about valve float?

Anyone?

 

[black-plasma]

I never shifted above 6200 with my 2.3 Whipple. Are you doing 2nd gear burnout? What psi in tires?

 

[Jmurrz]

I never shifted above 6200 with my 2.3 Whipple. Are you doing 2nd gear burnout? What psi in tires?

Second gear burnouts with about 10-12 PSI

 

[Sladester2]

That 60 foot needs major work.. What tire are you on?

 

[Jmurrz]

That 60 foot needs major work.. What tire are you on?

I am really looking for 1.6x but I am on 26x10.5x16 MT ET street bias plys for now. I think my sweet spot is 3k dump off the 2 step. I snapped a halfshaft before I got to try it out. 3500 was spinning too hard.

 

[black-plasma]

Try a 28" slick and don't look back. You'll get 1.5's in your sleep. My best with IRS is 1.44.

 

[Jmurrz]

Try a 28" slick and don't look back. You'll get 1.5's in your sleep. My best with IRS is 1.44.

what RPM did you launch at?

 

[black-plasma]

what RPM did you launch at?

3-3.5k depending on track prep. I had still H&R race springs when it went 1.44, so not much weight transfer.

 

[Dixarect]

3-3.5k depending on track prep. I had still H&R race springs when it went 1.44, so not much weight transfer.

What psi? And what tires? that's a good 60'.

 

[BlckBox04]

i had 26x10 m/t et street slicks when I had irs and would launch at 6k and cut consistent 1.5x 60' with the two step so it all depends on your set up and how you drive it. Loosing mph with your car tuned for higher octane sounds like you're loosing power from heat soak and really high IAT temps. I agree you should be picking up almost 30 mph from the 1/8 at your power level. That first 60' is the most important part of you et so it starts with your launches. you should also data log for a piece of mind for that mph drop.

 

[black-plasma]

What psi? And what tires? that's a good 60'.

28" Hoosier slick, 11-12psi. I'm trying to get in the 1.3's with IRS.

 

[whitedevil95]

3-3.5k depending on track prep. I had still H&R race springs when it went 1.44, so not much weight transfer.

Was that off a 2 step?