A few questions for all of you that are 1/4 mile warriors ( with a Porsche)

1- At at rpm do you launch the car
2- How much boost out of the line
3- Rev limiter setting

thanks !

 

pm DMAFFO he has the 1/4 mile launches and shift rpm down.

 

First of all, I am no 1/4 expert, as my first visit to a 1/4 mile track was 2 years ago...that said, I did manage an 11.01, 11.08 and several 11.1's, 11.2's with trap speeds in the low 130's. This is what I learned:

Launch: Anything much over 3,500 RPM's results in massive wheel spin and a slow 60' time for me, but that's on street tires. The high RPM clutch dumps, which sound fast are not.

Shifting: My best times were shifting at or near 7,100 RPM's. I think Dmaffo shifted lower, but that is due to the nature of a speed shift. DMaffo told me he speed shifted all gears, which I don't think many here would be willing to try. I have considered it, but just can not get myself to shift through the gears while steadily holding the pedal to the floor the entire time. One mis-shift and you will be rebuilding the transmission. Not a huge expense, but none the less a decent expense with down time, hassle, etc.

Boost: With a 6speed, I don't think you have a choice of building boost off the line - the tip may be different.

Hope this helps a little. Here's a video: http://videos.streetfire.net/video/1...rag_130301.htm

 

Tito,

Presumably you are asking about a 996 turbo with all-wheel drive?
The best (2) 6 speed all-wheel drive guys are JoeTwinT and Divexxtreme, I believe.

Good luck, you are a great drag racer!

MK

 

JOhn D,
So a speed shift is where you keep your foot in it, but still use the clutch?

 

yesssssssssss

 

did some speed shifting with old corvettes my current p car is to scary to speed shift 4 me the old hurst shifters where hard to beat in my day . how safe is dumping the clutch in an moded 01 have kevins clutch .

 

There are just too many variables to this question, It depends on the mods and the weather of course, my car has been converted to two wheel drive and when I'm at the track I run the stock hollows turbo twists with drag radials. I am having a local guy cut down my fronts rims to 5" in width and use them as skinnies. I leave on no boost and depending if the track has been glued or not. honestly I walk the car out because my car has pretty bad wheel hop and its just simply safer.best way is to get out there and get some seat time and do what works best for your car.I shift my car at approx 6800, 6900.Looking at your sig you have been pretty fast, I'm curious to know what car was this 10.76 ran in?

 

I use to drag race in the past with american musclecars. But they were all auto-tranny cars with high stall converters which act like clutch dumps.

Although these cars can take a lot of Hp and torque above stock, you have to realize that these are NOT drag cars so I'd be interested in knowing how many clutch dumps and speedshifts have been done before problems were noted.

 

anyone here who has logged quarter mile runs with his vbox/driftbox/pbox on an official drag strip with time print out?

I enhanced my data log scanner tools with some distance features and rollout and I would like to prove that the resulting times are within 0.1 sec with the ET of the official track time.

 

I don't recommend speed-shifting (AKA power-shifting) these cars. Especially considering the known syncro issues.

Just lift and shift, very quickly.

 

The other day (actually about 2 weeks ago) I overheard the tuner, who was tuning the GT2 at the drag strip say that he could clutchless shift the tranny in that car because of how stout it was built. I have not ever tried clutchless shifting in a manual tranny, but have heard of it and seen it done in older cars. Who here has done that succesfully?

RS38, your 1/4 mile trap speed is impressive for only 540 crank HP. Your car must be very light, cool...

 

Bone stock car launching at 5,500 rpm and slipping the clutch netted a 1.61 60'.

I launch my car at 4,400rpm-4,600 and slip the clutch and went 1.68 60'. Both cars no PSM. Shifted at 7K RPM limiter, hitting the limiter cost 1-3 tenths depending on the gear it was done on the passes I've done so.


I log all my quartermile passes with the V-Box RS38 but haven't compared them, I usually just do it to see the 0-60 time and the 60-130 time. Next time I will try and check the Vbox against the timeslip on a run or two.

 

what should a 600 rwhp full weight turbo run with a good driver in the 1/4 et mph

 

If it's making a true 600 to the ground, then you could expect in the 10.7-10.9 range @ 133-135. Of course this will require a solid 60' time.

Most full weight cars making this much power are in the 11.0-11.2 range at similar trap speeds...mostly because it's not always easy to get a good launch.