1st 1/4 Mile runs: Bullet

[Twin Turbo]

Did a few runs today, with the guys from the local Club

My times have improved from last year been 14.4 down to 14.09Secs - but having issues with wheel spinning - so removing RFT is the next project.

View: https://youtu.be/22Pj3ejdASo

View: https://www.youtube.com/watch?v=RliHTcGvcVc


I was competing against an 335D (remaped)

This runn
335D: 13.64 Secs
E89: 14.18 Secs

Best Time's
335d: 13.52
Z4:14.09

Best trap speed
335D: 106.32Mph
Z4: 103.89Mph

 

[Brian H]

Well done, something I would like to do, not a clue what my car is capable of on a 1/4 mile?

 

[Twin Turbo]

Well done, something I would like to do, not a clue what my car is capable of on a 1/4 mile?

I think 13.7secs

 

[littlefeller]

looks like avon park (shakespeare raceway)

 

[oldcarman]

Great runs but if I may comment you're losing time and RPM's between shifts. Don't lift off the accelerator and slip your foot off the clutch pedal as it gets to the floor and literally throw your shifter into the next gear! HTH's JIM

 

[Twin Turbo]

I tried different techniques - even power shifting - Foot on gass all the time and left foot on cluch to change gear - did not make much difference really. My biggest issue was wheel spinning through the gears.

I also noticed - launching from 3k, the car got bogged down at launch

 

[Tfp]

I used to visit Santa Pod quite a bit.

Any road car doing sub 14 second runs is very respectable.

 

[zedwheels]

Nice run twin turbo, I'm going to have to watch out for you on the Pod!!

 

[oldcarman]

How much air are you running in your tires? Try dropping it down and see if that helps out with the wheel spin. As for big get your revs up to a point where it's gone. JIM

 

[Twin Turbo]

I reduced my tyre pressure but made no difference - as RFT walls are so strong still well spinning down the track.

@zedwheels I wanted to get sub 14 - so you still are the champion - I don't think I can beat your time; Either you or another 3 Ltr will take the crown.

What I did not know was:

1) Press clutch in full
2) Select 1st gear
3) Press gas on full

Maximum revs is 3,000

 

[zedwheels]

This year there will be a few Z3 ///Ms and 4s going down so no crowns this year me thinks! But we will still enjoy trying.

 

[oldcarman]

Didn't realize that you had RFT's. Any way you can get a hold of a set of winter tires as they have a softer compound and should bite better. The RFT's Are why you are getting wheel spin for sure! What you want is a tire with a soft tread and side wall so you can drop your pressure right down to increase the size of your footprint on the track. Why are you restricted to 3000RPM at launch? JIM

 

[Tfp]

What I did not know was:

1) Press clutch in full
2) Select 1st gear
3) Press gas on full

Maximum revs is 3,000

So I guess the ECU knows the car isn't moving and is controlling the revs?

Clever stuff.

You'd probably just get wheelspin at higher revs anyhow.

I've seen people get a spare set of drive wheels and fit some seriously sticky tyres, even slicks, but then you risk breaking your car as the tarmac on the pod is very sticky.

My old motor used to snap driveshafts.

 

[Twin Turbo]

Well I have new rubber next month - unfortunately my winters are 225 - so not an great amount of rubber.

I did drop my rft down to 20 psi and still had wheel spin @ 60mph + only afterwords I read that did not matter what psi I had I would still have the same issues.

Thinking of going for 265 on the rear

 

[oldcarman]

The bigger the tire on the rear the bigger your footprint will be on the tarmac and yes you can drop the tire pressure down to zero with the RFT tires and get the same result as the sidewalls are so stiff. I wouldn't recommend going with slicks because as @Tfp states you can do a lot of damage! Something you can look at is setting up your turbos so they come on in stages which would give you a chance to come off the line with less boost and have the boost build as you progress down the track. At 14.09 you should be able to crack into the 13's quite easily you are so close now. What are your reaction times looking like? Are they consistent? A lot of races are won or lost at the lights contrary to at the end of the track. Wish I was over there to see how your cars suspension is working. Another thing to try is boost up your front tire pressure and run a narrower tire to combat rolling resistance. I could go on and on but consistency is paramount because once you get it you can then start experimenting. Try to get each run as close to identical as the previous runs first of all. HTH. JIM

 

[Lee]

When I was on at pod I dropped my rears down to 15psi. It made a massive difference getting off the line for me.

Lee

 

[oldcarman]

I'm searching through my hundreds of old car magazines for an article that shows how dropping said pressure increases your tire's footprint on the ground. The bigger the patch the more tread grabbing and more traction!! JIM