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-   -   Doing some drag (https://www.miataturbo.net/dynos-timesheets-21/doing-some-drag-86994/)

aidandj 12-17-2015 06:57 PM


Originally Posted by 18psi (Post 1293041)
I was about to say, "so did aidan" :giggle:

:fawk:

miata2fast 12-19-2015 04:16 PM


Originally Posted by sixshooter (Post 1292790)
Troy will say wrinkle wall slicks, I bet.

I would suggest Spec Miata Hoosier takeoffs as a compromise because they are free or nearly free. They will be slower than wrinkles but will be streetable. The rain compound is even softer and not hard to find, but does usually have a tread pattern.

I'm cheap.

Using road race slicks for drag racing is like wearing hockey skates to play football. You got to wear the right shoes for the sport you are playing.

You are right about my recommendation though. In a car that is already making enough power and clutch to utilize them, no other modification will knock more time off your ET per dollar spent than a properly sized set of slicks.

pdexta 12-19-2015 10:07 PM

I ended up ordering some MT ET Streets in 215/60/14. Going to put them on my stock na8 wheels and see how they do.

Are axles usually the first thing to go or is the rearend? I though about buying an extra axle so I could just swap it at the track if I break one.

aidandj 12-19-2015 10:22 PM


Originally Posted by pdexta (Post 1293488)
I ended up ordering some MT ET Streets in 215/60/14. Going to put them on my stock na8 wheels and see how they do.

Are axles usually the first thing to go or is the rearend? I though about buying an extra axle so I could just swap it at the track if I break one.

Wheelhop will break torsens at 220hp.

sixshooter 12-19-2015 10:24 PM

Troy was breaking them when the wheel hub center was not aligned with the diff due to ride height. The axle shaft should be in a straight line and the cv joints not bent for best results.

fivehundredton 12-21-2015 08:44 AM


Originally Posted by sixshooter (Post 1293494)
Troy was breaking them when the wheel hub center was not aligned with the diff due to ride height. The axle shaft should be in a straight line and the cv joints not bent for best results.

I can't help but think that "The axle shaft should be in a straight line and the cv joints not bent for best results" should include the words: "at squat on launch"

pdexta 01-16-2016 02:18 PM

1 Attachment(s)
Just got home from the 1/4 mile this time. Car ran fantastic 100 mile drive there, made 5 11 second passes, 100 mile drive back home.

I couldn't get the car to launch for crap. It was either bogging really bad or blowing the tires off. I think with a halfway decent driver it would have been sub 11.5 all day.

Best ET was 11.68, Best trap was 124.18.

https://www.miataturbo.net/attachmen...ine=1452971919

18psi 01-16-2016 02:20 PM

DUDE!!

That's FAST!

Congrats. :likecat:

patsmx5 01-16-2016 02:58 PM

Very nice! That's damn fast. What tire/LSD were you running at the time?

pdexta 01-16-2016 04:01 PM


Originally Posted by patsmx5 (Post 1299922)
Very nice! That's damn fast. What tire/LSD were you running at the time?

215/60/14 ET Street Radial on a stock NA8 wheel. 3.90 torsen and a 6 speed.

I may try again in a month or so. The alignment is maxed out in the rear at -1.8 degrees and I can see a lot of wear on the inside of the tires. If I go back I'm going to raise it an inch in the back so it'll bring the camber downs some and hopefully help get off the line a little.

18psi 01-16-2016 04:35 PM

yeah, many drag guys actually run positive so that when it squats the wheels are at 0* and the axles are perfectly horizontal. there's lots of little tricks to it, but you're already smoking fast. c6 z06 fast.

patsmx5 01-16-2016 06:00 PM


Originally Posted by pdexta (Post 1299931)
215/60/14 ET Street Radial on a stock NA8 wheel. 3.90 torsen and a 6 speed.

I may try again in a month or so. The alignment is maxed out in the rear at -1.8 degrees and I can see a lot of wear on the inside of the tires. If I go back I'm going to raise it an inch in the back so it'll bring the camber downs some and hopefully help get off the line a little.

I think you can do a lot better on those tires. What tire pressure are you running?

I'm running that same tire on a 225-50-15 on stock wheels and I've run a 1.76 60' when I had 35 PSI pressure in them. I aired them down last night to 16 PSI and found out these things hook like crazy when aired down, enough that I smoked my ACT XT trying to launch it without bogging at 20+ PSI on launch control. I'm at -1.3 camber in the rear.

pdexta 01-16-2016 06:34 PM

They're at 15psi.

I think setting up launch control and leaving in 2nd would be my best chance for a good '60, but also my best chance to scatter chunks of drivetrain all over the track. I definitely need to figure something out because there's certainly more left in it. I'm just totally lost when it comes to setting up a car for drag racing.

patsmx5 01-16-2016 06:36 PM

If you have any datalogs of the launches I could look at them and see if I can find anything to improve your launch. I launch in 1st on my car. If you car spins in 1st you can setup launch control to pull timing to soften the power in 1st for traction/drivetrain happiness.

Also I'm guessing you were not using launch control? If so, that will help 60' a ton, turbo car without launch control is HARD to get a good 60' because no boost...

18psi 01-16-2016 06:38 PM

if 2nd helps you leave softly without bogging or wheel hopping, it likely wouldn't be any harder on the drivetrain.
hard bog/hop is what kills it the fastest

you'd have to really up your LC rpm tho

pdexta 01-16-2016 06:53 PM

Correct, I wasn't using launch control. I've played with it a few times on other cars but never could get it working right. I'm pretty much retarded with megasquirt with anything beyond adjusting a fuel/ignition table. I didn't datalog any of the runs, in retrospect that probably would have been a good idea.

Downmented 01-20-2016 01:52 PM

First off, amazing results so far, and congrats on accomplishing your initial goal, not only did you run a good 11second pass, but you dove deep into the 11s compared to where you were before. I'm certainly no drag racing expert, however from my personal experience here are a few ideas/ tips to possibly help you out.

First thing id suggest is making small changes to the setup at any given time, like 1 change at a time, then go out and make a pass. The more changes you make, the less effective your progress is going to be. If you choose to change tire pressure, only change tire pressure so you can diagnose your time slips on comparison to your previous slips.
Learn how to read, and analyze your time slips, it helps you to learn what you did or did not do correctly on particular passes.
As others have said, a proper launch control is going to help you a lot in the long run, it's one less factor you need to take into consideration while launching and will also help you remain consistent, consistency is key here.

Another thing to keep in mind is that if you focus on lowering that 60', your end et/ trap will significantly be impacted by that, for every fraction of time you can take off of the 60' it will reflect 10fold by the end of the 1320. A 1.7 or 1.6 60' with a clean run would have likely put you into the 11.3/11.4 range assuming you hit all of your shift points.

Buy yourself a digital tire pressure gauge and check pressure before and after each run, also the taller the tire you can fit, the better that will help your gearing out.

What gear did you cross the line in and at what RPM?
Post some pics of the car with the track tire setup, I'm interested in seeing it :)


Best of luck to you the next time you head out, and remember that the only person you are in competition with is yourself.

thumpetto007 01-24-2016 01:58 PM

I cant read.

patsmx5 01-25-2016 02:45 AM

1 Attachment(s)

Originally Posted by pdexta (Post 1299970)
Correct, I wasn't using launch control. I've played with it a few times on other cars but never could get it working right. I'm pretty much retarded with megasquirt with anything beyond adjusting a fuel/ignition table. I didn't datalog any of the runs, in retrospect that probably would have been a good idea.

This is what your car will launch like with your tires once you get launch control setup and dialed in. It makes ALL the difference. This was a 1.74 60'.


This was a 1.75 60'


Pic from one of those videos:

https://www.miataturbo.net/attachmen...ine=1453709147

18psi 01-25-2016 11:55 AM

hahaha picking up the nose like a boss :likecat:


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