I decided to take my car to the track for the first time a few days ago. This was also my first time racing at the track. I drive the car everyday. I was having issues getting off the line properly. I don't think i was launching high enough, 4500 rpm. I bogged out the hole every time I tried to launch. But I think I did pretty good for my first time!

My question to you guys is what is a safe rpm to launch at without having to worry about breaking anything, and whats a good way to launch?

1990 Mazda Rx7 TurboII
Stock turbo 8lbs of boost
Walboro 255
Racing Beat exhaust
Front mount Intercooler
ACT 6 puck sprung Clutch
ACT Extreme Pressure Plate

Any tips would be greatly appreciated. Thanks!!



This is the car...

 

that's not bad dude hopefully i get some good numbers down the line on my stock turbo II...

 

Not bad at all for a stock TII.

When I still had a stock flywheel I used to launch at 4500 and it worked well. I continued pressing the gas while slipping the clutch to control wheelspin.

 

thats excellent.

I can never get into the 13s with the stock turbo lol.
Wheel hop seems to be limiting me badly. Launching is alright for me, just slip the clutch getting 2.1 on 60' with hankook RS2, but shifting from 1st to 2nd for me give me some serious wheel hop so I have to let go of the throttle some, which in turn hurts my time bad. Did a 14.003. Really need to fix this wheel hop by installing these MMR diff mounts, but Ive been too lazy.

You got an excellent time!!!
I got a stock flywheel. I launch mines at 5k and I tend to try and make the rpm stay there by slipping the clutch and slowly pressing on the gas, by the time I fully let go of the clutch its a perfect launch for me with little to no wheelspin. 2.1 sec, sometimes 2.0 for the 60'

 

I had a little wheel hop with stock mounts when I had the stock flywheel certainly not enough to make me get off the throttle (then again I only managed a 9 sec 1/8th...). I later discovered that one of my motor mounts was completely sheared which probably had a lot to do with it.

I switched to the MMR engine and trans mounts when I installed the clutch and lightened flywheel, I also installed a pinion snubber. Unfortunately I'm still running the stock rear diff mounts because the MMR mounts are in another diff that I'm going to rebuild/shim. The wheel hop is awful, far worse than with the stock setup, I really need to get this diff finished.

 

Thanks for the reply guys. I find it really difficult to slip the clutch. I've only been driving the car for about a year and i just putt he clutch in. It likes to "kick back"... I'm going back to the track next week to try to get into the low 13's.

I was also chirping 2nd, 3rd, and 4th gear when I shifted. So if i can get it to "hook" that should lower my time.

 

So I went back to the track on Wednesday. This time, when I launched I spun all of first, and part of second gear. I slipped the clutch at around 5500 RPM. I got the 60' down to 2.0, but only was able to run a 13.6 @ 101mph.

Reason being, I think my tranny is F***ed. I was having a very difficult time getting the car into gear. That night I made 11 runs, and NEVER got the car to shift into 4th on my first try. Sometimes I would miss 2nd and 3rd gear too.

The tranny still works, just not when I want to shift at high RPM's. Any ideas what could be wrong?

Ill Post the slip a little later on.

Thanks.

 

Now, 101 mph is more in line to what I'd expect on the 550 cc injectors. Isn't the HP required to go 107 require more injector. My guess the A/F ratio @ 107 mph w/ the 550's is in the extreme danger zone.

 

That makes sense... I have an autometer narrow band A/F ratio gauge. The only color I saw was green. The light was only about 1-2 bars from the end. I know thats not the most accurate gauge but it should be kinda correct. Right?

 

I wouldnt put any trust into a narrowband A/F ratio gauge. They are proven to be inaccurate.

As for your times, awesome job. With the 107mph, you are inline for a high 12 second pass, even with the stock turbo.

 

nice time!

 

Work on your launch, a 1.9 '60 is certainly doable with street tires. The only thing you should expect a narrowband to show you is whether you are RICH or LEAN, never HOW rich or lean.

 

nice thats a pretty good run for almost stock

 

there junk trash it if your going to get into track events, all it does is say theres fuel running threw the system it wont every tell you if your rich or lean unless your on and off the throttle..

i have a pinnion snubber i could sell to anybody, that will kill the wheel hop problems and a set of 4x680cc low-imp. injectors that could help in your stock setup but you would at least need a s-afc to get them inline for daily use..

but good runs and nice car. love a yellow fc