I took the Bullitt back to the dragstrip. With the Whipple on this time

[GreenS550]

Well, I took my Bullitt back to the DS a couple of days ago.

Ran terrible times. With bias ply MT 275 Street R (cheater slicks). These things stick like mad. Anyhow ran low 12s until I started to use launch control. Finally ran an 11.79 at 120 launching at 5,500. Just sidestepped the clutch and felt almost as though the front wheels came up. I should have launched at 6-6500 RPM. The car makes 627 rwhp at 7200 RPM so with a good driver (not me) should do 10s I would think. I crossed the 1/4 mile in 3rd gear.

I quit after 8 runs as the clutch was slipping slightly on the 2-3 shift. Did not smell good.

When I had the '11 GT with the same rear gearing with a Roush, my times were slightly better with Nitto drag radials launching at 3K or so with the MT82. That long first gear in our Bullitts is a bear to get it moving quick. My best 60' was 1.79.

The bright spot is how wondrful the Whipple is tuned out of the box. smooth increasing acceleration to redline. And. the clutch is fine after cooling down.

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[Shifting_Gears]

Your MPH is way, way low for the power you’re making.

Do you think the belt is possibly slipping causing you to lose boost? Or possibly the clutch is slipping more than you think. You should probably be trapping into the 130mph range.

I wouldn’t worry about the times - the car is making the power to get you well into the 10’s with the right traction. Sounds like you’re figuring the launches out.

 

[SoCalTim]

Launching at 5500+ RPM sounds like too much, IMO. Clutch is not going to like that, thats for sure.

 

[GreenS550]

It was my first time using bias ply mts. The grip was incredible. But when the car grabbed out of the hole, it has to make up that long gearing. Lower rpm launches and the car would bog. I actually think that higher rpms with those tires or slipperier tires like nitto 555 extremes which I used on the 11.

I also saw the times of the fellow on this forum that did 11.9s NA launching at 6500. That's amazing.

My 2-3 shift had some slippage so I know I lost mph there. I also might have been shifting at to low if an rpm.

I appreciate everyone's comments.

 

[Shifting_Gears]

What where your shift points? Could be it as well.

Either way, the car is making the power to shoot you into the 10’s!

 

[Rockgt302]

I have a 15 with stage 2 whipple making 650 on a mustang dyno at 7k rpms. Mt82 with 331s. On nitto nt05s not the DR, I ran 12.2 at 128. Spun the tires through 1st and 2nd.

 

[bluebeastsrt]

Post the slip. I bet you were spinning like crazy. On multiple shifts.

 

[Rockgt302]

Post the slip. I bet you were spinning like crazy. On multiple shifts.

I can't find my slip. I could tell you the 60ft time was a dismal 2.5xx. Just picked up a set of MT street SS tires and might go back next weekend. Hoping for better results but worried about using them on the mt82

 

[bluebeastsrt]

I can't find my slip. I could tell you the 60ft time was a dismal 2.5xx. Just picked up a set of MT street SS tires and might go back next weekend. Hoping for better results but worried about using them on the mt82

I would recomend getting a full set of slicks. Probably wouldn’t hurt to have a set of replacement axles on hot standby also.

 

[SidewaysMike]

Well, I took my Bullitt back to the DS a couple of days ago.

The bright spot is how wondrful the Whipple is tuned out of the box. smooth increasing acceleration to redline. And. the clutch is fine after cooling down.

Where did you get the Whipple from?

 

[Det_Riot]

The Whipple tune is very very conservative. While it made the power on the dyno, I'd be very interested to see what it looked like during the runs. If you were running it with traction on, once the car senses wheel spin, the throttle body will close to 25% and then linearly open back up until the next shift (at least that's what it does on the A10's). With the long first gear your best bet will be to bring the RPM up higher and slip it out of the hole, especially if you're on stock driveline. The best thing to do if you're trying to nail down the side step launch is to start high and work down until you find that fine line between too much and too little RPM

 

[w3rkn]

Any aftermarket GT500 DCT laying around anywhere..?

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