1/4 mile launch help tuned 20vt

Hi guys

New 1/4 mile season starts soon

Previously I ran a 13.7 @ 109 @ crail with 2.4 to 60ft.

This time i aim to take this to about high 12 low 13 with some advice from the more experianced guys on board. what advice can you give to improve my time ie launch rpm change gear time and tyre pressure adv.

To be honest the time at crail was decent for the day(slippy) but looking back hyper ran 13.3 with lower power car than me not on the same day.

Lower your front tyres pressures to around 18psi and increase your rears to around 45-50psi. If you have adjustable suspension then firm up the rear and set the front quite soft. It's been years since I launched a Coupe so will leave what revs etc you need to some of the more experienced guys, also it's hard to say when to change gear without seeing your dyno graphs to know when your power tails off etc. A final tip that doesn't go down too well on cars with weak gearboxes/clutch set-ups is to full throttle up shift, it'll certainly save you time.

Aim for a 2.0 sec 60ft, difficult but possible.

Best of luck,

Jules.

Can you let me know what power you're running, and with what spec turbo, then I can try to give you a few suggestions

Its running gt28rsr all supporting mods and flea mapped dynod at 358bhp.

2.0 to 60 I doubt i could get that at crail

a 2 second 60 foot time is achievable, but it's about as good as it gets - I've done a 2.01 and I think Flea has got below 2 seconds with Hoosier drag tyres

2.318 60ft on way to a 13.61...
pzero's with 18s with about 19psi front 40 rear full fat LE 305bhp.
So 2.0 is definitely possible although 0.3 is still a lot.

Jonny,i have only managed to get a 13.2 in mine so far,so your time is good.
I ran a similar setup and got a 13.7.

Theres nothing that can be taught here,usually you'll have 10 launches and maybe only 2 good times.

So many variables.
Your car was deceptively quick after i built it for Rob and would give most high powered cars a good run for there money.

Practice, practice, practice.

I ran a 13.7 @ 109 with 270bhp at Santa Pod. It took 16 runs to get that

lol ive had a 13.7 aswell how odd

OK - for what it's worth, this is my launch technique

1) Hold revs at about 2,000rpm for a second or two
2) Floor the throttle, and as the revs rise, lift the clutch quickly
3) You will almost certainly get wheelspin - this is desirable - control this by moderating the throttle (probably between 75% - 100%)

Another method, which I've tried only once...

1) Hold revs at about 2,000rpm for a second or two
2) Floor the throttle, and as the revs rise, lift the clutch fairly quickly but not fully engaged
3) Balance the reduction of revs by slipping the clutch


Personally, I find it easier to control wheelspin than I do to modulate the clutch slip. The added bonus of the first method is that tyres are a lot cheaper than a Helix Organic clutch. The clutch smoke and horrible smell from method two was not something I care to repeat, but it did give me a 12.5

There are two main issues with method 1

1) The balance of throttle required to get a tiny bit of wheelspin and no clutch slip AND not bog down the engine is difficult to master and impossible to teach. I do it purely by 'feel' - that knowledge of your own car that only you can get from many thousands of miles behind the wheel

2) As I found out to my cost, if there is too much grip, the shock load through the transmission can be sufficient to break something. If you're lucky, the weakest point in the system will be your clutch, and you'll get some clutch slip. If you're less fortunate, something will break. If you're lucky, it will be a driveshaft (easily replaceable and in plentiful, cheap supply). If however, you're having a bad day, your differential will shatter, which in turn will punch holes through your gearbox casing. At October's Santa Pod meeting, two Coupes and several Pugs broke gearboxes, simply because grip levels were unusually high.

My recommendation is to go to a 'tuner' day at Santa Pod, where the number of entries is quite limited - you would probably manage a dozen or more runs. On a public day, you'll be lucky to get four runs in.

OK - for what it's worth, this is my launch technique

Give it the limiter,drop the lot and hope the diff holds .
If it does great.
Not the best for times but geat croud leaser

Nice n simple

the terminal speed seems high for 270bhp was it fully stripped?

No, just spare wheel removed. I've also had a 13.7 @ 118 @ Brize Norton but that was with about 320bhp.

Funnily enough from my mini drag racing days, we found we got less breakages setting off at higher revs keeping the motor away from peak torque, we used semi slicks though and did proper burnouts to get plenty of heat in the tyres, low rpm getaways we found broke diff pinions and stripped gears off the drop gear assembly.

Moral of drag racing " go hard or go home "

I went to crail yesterday. Im running a k&n filter and a gtec 1 chip nothing stripped shitty Tyres and ran a 14.3 but wasn't out to kill ma car so wasn't giving it full throttle launches .

I cant give you advise on a coupe but i cant imagine its much if any diffrence to any other turbo car at the strip

My old car was a r5gtt with 2.0 turbo conversion and i ran a 12.5 @ 108 mph and 60ft of 1.7 been hitting pod for a good few years now so heres what ive picked up along the way

1st tings 1st get yourself drag racing slicks, smallers the better but with as high side walls as possible, tire soften this up for a few weeks in advance if possible

Warm those slicks up good and proper with a burn out before you pull up to the line, you will want a fully working handbrake to do this properally

If you can get space savers on the rear, nice and pumped up nothing sift here this will cut bk on drag off the rear tyres

Suspenion should be as solid as a rock on the rear and medium to soft on the front

If its a time you after then forget trying to hit the throttle just because the light goes green, your time doesnt start till you move, remember this is for a time slip not a race against the person next to you

Moderator: text speak removed

You dont want to be sat on the limiter or sat at a constant rpm as this just creates vacum and you will bog down, hence why you keep the revs movin and fast between the 2 rpms to create boost

Then when youve found this use this as you launch position at pod so for instance you found yours was comin on boost about 4.5k at stand still, quick revs back and forth between 4-5k so you hitting on boost ready for when the light changes, when you feel ready as you rev up to 5k drop the clutch keeping the throttle planted this time and you should see a nice diffrence in your launch

You can slip the clutch in if you feel like its not the way for you just to drop the clutch

From then on in its perfect gear changes all the way up the strip

Best of luck

er most space savers have limited max MPH rating, please check the speed rating!

Yes sorry should have added this, skinny wheels with correct speed rating will also work very well

Also you will need to play with tyre pressures on the slick, if i remember rightly we went down to around 8-10psi (cold temp) for my m+h drag slicks

Also another saftey tip when you pass through the line at the end dont back straight off the throttle and hit the breaks, let the car coast for abit, theres plenty of run off plus the surface like superglue so will soon shave the speed off you before you have to start heavy braking