School me up quickly on drag racing please

[Iain]

Russ,

You are a big boy and presumably understand all the risks associated with these events so I wont lecture you ! , what I would be doing is using this to optimise your start proceedures for normal racing. It is hard .... if not impossible... to find anywhere to practice starts here so this could be a good opportunity. We have our Motec screen set up to show % throttle position when the car is on the start line, we bring the revs up to be on the limiter, this can be acheived with as little as 20-30% throttle opening and walk out of the clutch. If the car bogs then bring the throttle % up to say 50% and try again and so on untill you acheive the correct launch %. Having said that we have just had a new set of ratios made for the car ( first gear used to be way to high) and we are still a long way from establishing what throttle opening works, maybe I should enter a drag meeting !


Good luck


Iain

 

[Andrew Robertson]

Hi Russ,

What I found when dragging my race and road cars previously was that a big burnout was not beneficial because usually the rubber I was running was not drag racing rubber, so I did enough to warm the tyres a bit and clean them up then staged the car.

I have found that high intake air temps resulting from heatsoak in the intake manifold and carb should be avoided too - another reason for not going too beserk on the burnout. Traction "feels" about 10-20% better than what you're used to, so if the car is prone to bogging you might need a few more RPM than your usual start line recipe.

My old XJ Jag was totally unsuited to drag racing with 60 foot times well over 2 seconds. It ran 11.7 @ 127 on Dunlop DZ02G semi slicks, and 11.2 with M/T ET street drag radials, so there is a big difference between what a circuit tyre and a drag tyre can do. I ran tyre pressures between 17 and 20psi.

have fun and post your timeslips!

Cheers, Andrew

 

[Russ Noble]

I'm surprised if you only need one shift - must have some very wide/long ratios. At Brighton quarter we needed 4th on occasions although if you can rev high enough you'll be ok.


If you can get below 12s - you're quick. (mph 120+)
If you can get below 11.5s - you're very quick. (mph 130+)

..

Paul got it pretty much bang on! I'm 'quick' but not 'very quick', 11.770 @132.27 mph, nevertheless got four wins out of four runs.

First three runs were in Lane 1 at about 12.1 and 130 mph but there was remains of an oil clean up from a blown trans at about 100m and I had to get out of it momentarily each time as it got very sideways.

The last run I managed to get Lane 2 and got the best time as the car stayed straight. It doesn't hook up very well compared to regular drag competitors but seems to go not too bad once it gets rolling. Have posted the actual time slip below. Here's what it says in case you can't read it

0.000 TREE--- .400
DIAL IN------- 0.00
REACTION---- 0.031
60 -----------2.402
660---------- 8.061
MPH1-------- 0.00
1320------- 11.770
MPH2----- 132.27
= = > >WINNER
FIRST ------4.945
STATUS
Autostart Disabled

Went out to have fun and didn't bother to alter the circuit race settings.

Only one gearchange, launched at about 4000 rpm in second had to control a bit of wheelspin, hit third at about 95mph and went through the traps almost on the redline. Fluked out on the ratios I guess...

So that's drag racing, been there done that, cross it off the list!

Thanks everybody for the advice.

 

[Russ Noble]

Some how the actual time slip fell off the previous post

 

[Randy V]

Congratulations Russ! :thumbsup:

Back when I used to run my dragster I used to characterize drag racing as;

Hour upon hour of boredom, punctuated with moments of sheer terror..

Glad to hear that it went well for you!

 

[Russ Noble]

Ah Randy, thanks.

I don't think double digit figures would be capable of introducing terror, so in my case..... hours and hours of boredom punctuated by moments of slightly less boredom.....

Some of the dragsters that were out there were pretty awesome pieces of kit, and whilst I could appreciate the engineering and dedication involved, I don't think thats a disipline that I would really be interested in pursuing.

I wanted to know the times the trusty Kiwi 40 was capable of in race trim, and now I do, but as far as drag racing goes, the whole experience had me feeling like a fish out of water!

 

[Andrew Robertson]

Russ thats pretty bloody rapid - good stuff.

Cheers, Andrew

 

[Kevin Box]

Good on you Russ!!

Everything is worth a try once.
Drag racing is bit like stock cars - not my cup of tea.

Hope all is well

KB

 

[Paul Thompson 'Hooligan']

Nice one Russ - :thumbsup:

I'd say that was a great result and certainly upheld the '40' flag....

Best Roy's 40 managed was an 11.8s at 132mph although that was on a road at Brighton Speed Trials and not on a prepared surface - although we did have slicks on.

It's a lot trickier than people realise but as you say, another one of life's tick boxes ticked....

I'm glad you had fun and even better that you 'drove it home'....:thumbsup:

 

[Pat Buckley]

Nice going - and fast!

11 second quarters are not common with street cars!

 

[Jason A]

My 2 cents worth

Dont bother with warming tyres up until you have had enough goes at launching that you think it will make a difference. Stage the car, hold you foot just off the ctutch engaging approx 10 - 15mm of travel. Try holding revs at 2500rpm. Let clutch out when seacond to last yellow lights up, by the time you have processed it and let it out the light will be green. Once you have grip feed power in accordingly. If having trouble with traction and you are above 5,000 rpm - short shift to settle car. Redline in each gear after that. See how that goes and modify accordingly. The first thing to improve on car is to lower rear tyre pressure to 20psi and put front up to 40. Have fun.

 

[Pete McCluskey.]

Congratulations Russ, your reaction time is really good. Plenty of life in the old dog yet.:thumbsup:

 

[James McNutt]

Well done Russ.