1/4 mile drag racing

[nialloftara]

Right now 21' 650mm 145 /395. Its tough you've gotta balance ride height, gearing, width, profile, downforce, and poweband.

[strop]

The more power you have, the tighter the tolerances are. They must be balanced by the aero too. I managed to crack 7.69 myself but want to change my approach... At any rate I was running 255/70R13 fronts and 395/45R13 rears.

What I don't understand is luilakkie's aero setup... And how the initial sector times are so good!

[nialloftara]

Less power, wider torque band, and lighter car, would be my guess, Though he might be rrunning awd still, he never answered you before.

[Luilakkie]

AWD + max tyre width + minimum size wheel + 10 inch rim

aero setup: little changes time at a time, saw what worked out.

[nialloftara]

Hmm 3 distinctly different approaches to the limit, this sounds very promising. I can't wait to get back and start improving my idea.

[Luilakkie]

Is changing the year also allowed on class A?

Because when that's the case.......

[nialloftara]

Nope class 2014 for all classes except the 70's one.

[nialloftara]

Destroked and overbored the engine to allow a 9000rpm redline, lightened the car a bit, adjusted the turbo output to make up for the liter of displacement I lost, I'm using a 7.55 liter running just 8hp and 200 ft-lb's less torque then the 8.6 was, but it's 50 kilo's lighter and now routed through a 4 speed box thanks to a wider torque band. Various smaller tweaks were made but those were the main ones.

[strop]

Well done!

I know where my car can improve now. It needs to balance power and weight to get off the line faster... Once I do that I can actually reduce down force.

EDIT: Also realised that in the same way as the ride height affects performance around the track, so too does it appear to affect performance on the strip, though it's not so much to do with bottoming out, seeing as hardening the suspension reduces bottom out penalty but does not affect the times at all... wonder how that works.

Having adjusted this, running 2585hp, but with a 4 speed transmission courtesy of Maloney's tipoff, I've got plenty of 7.66s to play with now, but have yet to find my way past this! It just seems my build slightly prefers the high downforce settings, and I simply marvel at how the other builds run a much lower downforce (and drag) setup and now have virtually identical sector times. Also I should add, my block is still Mg as opposed to Fe, Al, or AlSi, and if I make it any heavier than it is now, I blow my tyres!

SleipnirDrag.png (868.83 KiB) Viewed 7043 times

This is actually properly exciting stuff, a very enjoyable rivalry/cooperation that embodies three different approaches yet governed and improved by the same principles. While drag is not my main interest, I'm glad I got into this.

[strop]

Bump due to me editing my previous post!

[Lothoren]

Holy moly in a bucket, Do you even think its possible to reach under 7.6?

[strop]

It'll be hard for me, using my high power build, to do that... I've already reached what appears to be the optimum ride height for my car and I can't play around with the components as I could as my tyre tolerances are pretty low now!

[nialloftara]

If you are using the downforce cladding remember that the ride height will affect the bonus given by it.

[strop]

As you can see I still haven't reached a full understanding of how those factors interact. Wonder what happens if I change cladding...

[strop]

Just as a nod to the real life roots of this contest, here's a 2500hp Fastback (with a 6.4L Chevy small block with dual 82 turbos) putting in sub 8 second quarters at Tulsa!