ColinB

A few months ago I decided that my much-cossetted car looks great but it was having too easy a life and had better earn it's keep so to speak. Fortunately this coincided with an initiative of my local Porsche Club (Cape) to introduce more competitive events in place of the established once-a-month lunch runs which were seeing a decline in attendance. The first one I (We? car+me) attended was a track day in April where we had a whale of a time but didn't push for best performance, rather a 'feel the water' exercise.

Last weekend was a high speed and 1/4-mile event on a long military runway though unfortunately only 2.4km (1.5m) was available on the day.
Well to cut a long story short the top end runs were disastrous. I misidentified the end-of-run marker first time out and tapped off too early. The other runs I had a misfire so the first run was actually my best at 204kph (127mph). Dismal!

On the 1/4-mile head-to-head sprints the misfire had mysteriously disappeared and I scored some good times, finishing 2nd in class with a best run of 13.4secs (No ET recorded) but I know my launch technique was pretty amateur and I could do better next time, which will be in late spring (November). Soo...

Do any of you drag stars over there have any tips for me? We have a proper set of Xmas tree start lights and I think I've got that worked out, but problem was, 1 sec off the line the tyres were spinning and we'd hit the rev limiter so losing time in the 1-2 shift. It also happened in the 2-3 shift occasionally. I wondered if I should attempt a 2nd gear start but didn't get a chance to try it out.

It was an excellent weekend, about 50 cars turned out and "we" earned a little 'street cred'. Practice will no doubt make better if not perfect and in November I (we) want to come away with the class winner's trophy so all advice will be gratefully accepted and put into practice.

Colin
89GT

SharkSkin

OK, leaving aside for a moment what may happen to your car as a result... I'm assuming you have a 5 speed. If you can get a 2nd gear start with SOME wheelspin over the first 20 yards or so, you may get a better time. I had a car of about the same power/weight as Andy's Ride or a Devek stroker, and it had really tall gears, 2.72:1. Think ~475HP NA, 3300 lbs. The car was a 67 Dodge R/T with the 10.5:1 440 magnum. Anyway, if I tried to maximize traction I would get low 13's: 13.3, 13.4 @ around 123-125mph. If I let it have some wheelspin in the first 20-30 yards I could break into the 12's and get over 130mph.

The key is to have just a little wheelspin; not enough to get lots of tire smoke, just enough to get the revs up a little closer to the powerband. If you have enough torque to pull this off, the little bit of speed/time lost to wheelspin will be far less than what's lost on the 1-2 shift. Hopefully you have LSD/PSD.

Also, baking the tires a bit right before launch makes them stickier. Burning them in a small puddle of bleach will get them even hotter and stickier. If you really wanted to make it a drag car you'd put a line-lock on to help bake the tires. Try searching this forum for "line-lock".

Lagavulin

Excellent time!

ColinB

Sharkskin
Thanks for the good advice. I'll try that. Yes it's manual and has the 40% LSD. It's all original, 'bone stock' or whatever you say there. Euro 330 HP no cats, airbags etc and weighs in at about 1520kg. I don't want to make it an all-out drag car really, and anyway the chances of finding line-lock here are close to zero. (We only got television in 1975!). I was thinking more along the lines of revs, tyre pressures, compounds, suspension, etc.

Colin

Randy V

Increase the tire pressure on the fronts, and decrease the pressure on the rears.

SharkSkin

I just had a strange idea. Back in the day, one of the "tricks" used was to jack up the front of the car to help weight transfer onto the rear wheels:



Maybe you could jack up your shark just prior to the run and try it with the suspension not yet settled and see if you get better launches.

heinrich

Liewe land Colin, that is a killer number. We are at sea level here too, and we're running catless also, and no-one locally I can remember has had a 13.4 except a very highly-modded GTS. Nothing dismal about 13.4sec 1/4-mi in a 928.

Heinrich

GoRideSno

13.4 is extremely quick for a 928. Good Job Colin.

SharkSkin,
I am going to try the jack it up trick next time I go to the track. thx

Andy K

ColinB

Thanks all. Your comments are very encouraging. I can't wait to try this again but unfortunately for the next few weeks I'm off to sea. Will post again on this subject when I have new figures.

Colin
89 GT

SharkSkin

Hey, you never know, right? It may not make a quantifiable difference, but it will only cost you 1/4 mile worth of gas, oil & rubber to find out.