12.71 Galant VR4

[Marcel]

Hi,
as you can see from the 1/4 mile timetable i drove a 12.71 sec time last weekend with 50hp Nos.
I still have some problems:

i got a bad wheelspin like ~15m "sideways".
Whats the cure for this , because there i am losing much time(60ft-1.897sec should be sth ~1,7-1,8)
I was using pretty tired Yokohama A520 slicks but they gave me huge wheelspin)

Also some of you who are using NOS, how do you start? With Nos on or off ??
we have mainly NOT glued strips here in estonia.

i noticed that i have driven the fastest mph on 1/4 mile! is it the difference of Galant vs Legnum or ........

Also one thing- I have not got the speed delimiter, but i was driving sth 185,42 km/h. ??????? hows that possible???

Markel

[bradc]

I noticed that earlier on in the day, nice work.

How wide are your tyres? Changing to slightly wider tyres might help you out a bit. What revs were you launching at? You might find launching a little slower might help you get off the line quicker. With my car I find that standing on the brakes with my left foot and revving the engine to about 2000rpm gets the car off the line really quick.

I think most of the nitrous guys are going to hit it once the car has got grip and is accelerating in the first gear that will let you use all the nitrous before you need to change gear again. This would probably be first or second.

The speed limiter may be at 190, I know that my car gets all the way to about 190 on the speedo before the limiter comes in. It also may be that if you have larger tyres than standard that the gearing would be off slighty, which in turn affects the speed your car reads.

[colVR4]

IIRC you need smaller diameter wheels with a larger sidewall for better traction for the 1/4 mile, so if you are running on 40 or 45 profiles that won't help. You would be better on 50 or greater.

[enigma]

What revs are you launching at to get wheelspin?

I launch at 3000rpm on full nitrous and get not a hint of wheelspin!

Not sure why you should hit a higher top speed. Normally higher top speed indicates more power, but I would expect this to be accompanied by a faster ET as well.

Did you drive in Auto or Tiptronic?

The speed limiter cuts in at a certain RPM, but its a bit vague and not exactly 180kmh, its also the ECUs perception of speed, if you have changed the size of your wheels it will obviously kick in at a slightly higher speed.

[AllBeItMine]

higher ET normally means more power or less weight... higher ETs can also mean bad starts. this may sound weird but if you get a good start, you actually have less track to accellerate on so you get a lower ET...

you're wheel spin does sound exessive however. you are either dumping the clutch at high RPM or you are using some ridiculously hard suspension that is not allowing any weight transfer. or your drag racing surface is just crap like ours at meremere.

[Marcel]

I am launching at 2500 rpm and nitrous on
Yokohama a520 225/50 R16

but the problem in estonia is that we have only 1-2 races with glued track (25-50m start).
I have to make some test runs and see if turning the nos on after start(some 0,5-1 sec ) would make any difference.
But still the speed is taken by professional equipment , my speedometer has only 180 kmh, but it seems to be sth 200kmh, when i was looking at it in the finish.
And i hold it in Drive i haven´t tried this tip mode at all on dragstrip.
How does it chańge with NOS on?
And the surface of the track is really crap.
The suspension is original VR4s


What tires are u using?

[enigma]

The tyres I used on my best run were 225/45/17 Toyo Proxes, but I have now got similar sized Avon Z3s (I think!).

No loss of traction on the glued drag strip or the concrete airfield. :inquisiti

Drive mode is better on the dragstrip, I have never managed to go faster in tip mode.

[valmes]

Great times Marcel!!!

Try using 235-45-R17 These are the best option... (Calculated)! :) Shouldn't be getting near a wheelspin... soft tyres do help... try 1,5 bar instead of 2,5.

[Marcel]

ok, but it is suggested to use smaller wheels, so the car can put down more power
????

next time i will try to do it with my regular tires 225/45 17

we also have a concrete airfield track, but the concrete is a little bumpy and not glued.

what shot of nitrous are you using dave, and others???

i couldnt get the 75hp shot working, there wasn´t enough fuel pressure(it looked like that)

what fuel pump is suggested?(Walbro???)

and what boost are u all running? 12.71 was run with 0,8 bar and 50 shot of NOS. And we tried to run 0,9 bar, but then i got boostcuts.

[colVR4]

Information taken from a drag racing web site

"Huge benefits can be gained from using the right tyre and wheel combinations. Low profile tyres and huge rims might look pretty, but rarely do they provide a performance enhancement on the drag strip. Try fat low pressure tyres and small wheels on the driven hubs, and skinny lightweight wheels on the coasting wheels. It may look weird, but this even works on FWD & 4WD cars."

The first are shown on the website as the right choice, with the second car the poor choice

[valmes]

Try CarTest2000. It will give you correct tire sizes for better 1/4 times!

[bradc]

I would suggest that you try lowering your tyre pressures as others have suggested before you go about buying new expensive tyres and see how much of a difference that makes for you.

[Kenneth]

I would suggest that you try lowering your tyre pressures as others have suggested before you go about buying new expensive tyres and see how much of a difference that makes for you.

read some where (cant remember where and am a bit too jet-lagged to bother searching again) that 1/4 mile times are most affected by tyre compound than by tyre size. ie: someone with biscuit tyres with a decent compound out running people with fats of a crap compound.

The site actually gave the mathmatical explanation of why too... made heaps of sense.

[bradc]

I guess it comes down to the amount of weight on the tyres still being the same. I would still expect that wider tyres would help a little bit though.