went out to the "test n tune" here on friday to see how my new mods have help my cars speed in 1/4.....

i first ran a 16.5 at 85.2 with a pooor launch

then rab a 16.4 at 85.5 with a slightly better launch and held third longer (till the end of the 1/4)

then ran a 16.3 at 85.57 with a ok launch and topping out third gear..

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last time i was out i ran a 16.9 with mod list being RB header to cat to poor muffler and a drop in K'N filter and some some slightly worn tires and shitty driving skilss

this time i went out with a a cone filter converstion ... new magnaflow CAT and free flow muffler and some new wider higher stickier tires and better ( not great ) driving

SHOUDLNT I BE FASTER!!! i remeber readin of guys with similar mods running high 15s... whats the deal?!?!?!?!!?

 

how are you launching

My old setup was as follows.

RB streetport header and center section, N1 muffler at the rear. Fuel pump. no emmissions, electric fan, edelbrock muffler, ect. B&G springs and tokico shocks.,
Kosie K1 racing wheels with 205/50/r15 tires.

Heres how I would launch
hold 3500 and simutaniously slam the gas and pop the clutch.

When I was drag racing. I would pull 8K and shift without releacing the gas.

Very fast. I pulled a 15.3 I think I cant remember.

Im looking for low 13s with my new turbo setup.

 

Well, when I dragrace with my '85 automatic ford escort, i put it on the floor and wait till its bouncin off the rev limiter real good, then just drop it into first, ride that out to the limiter, then second, then drive.

 

hey rollin still got the auto tranny? that might be your problem

 

i broke into the 14's with my setup then water seal went to **** a week later. so while it is in the shop i stuck a olds 350 rocket i was gonna use for dirt track in a spare 85 it should make it into the low 13's or 12's

jr

 

i agree, around 3500 rpms is best for the launch, after that it depends mostly on shifting....does anyone know how to double clutch, ive only ever heard of it, no ones given me a proper explanation...Other than that, it could be your location, your stuff could react better at a higher or lower altitude.

 

double clutching is used to downshift if i remember right. it's when you put the clutch in , shift to neutral, bring out the clutch, put the clutch back in, rev the engine to match rpms, then put it in the lower gear. its kinda halfway to heel-toe downshifting, and its supposedly easier on your tranny. i asked that same question after seeing fast and the furious a few years ago. but it has nothing to do with drag racing.

 

well what good is it then? lol

 

your right on double clutching. it does NOTHING for you in drag racing, it will slow you down. you have to press the clutch twice, how could it possibly be faster than pushing the clutch down once? when i drag race i do a small burnout to get the rocks off my tires, then i launch at 5k. im using the htr 200's and i never have traction problems at my track.

between shifts, dont let off the gas completely. just a little so you dont peg out your tac. i guess its called power shifting, its helped me a little, your rpm's wont drop and youll get a little more of a push.

 

double clutching is for downshifting, with control, you match the revs so the engine doesn't have to catch up tto the tranny, and there fore, you get a smoother, fast downshift, thats easier on the tranny, and easier to control, while turning

 

gatogunner thats was my old car.... i now have a 84 gsl-se.....

the auto gsl is collectin dust and needing a rebuild....

as for conditions affecting the speed i think that has o do with it some...

i was just talkin to my dad and some of his car buddies and they say that there cars are half a second faster in phoenix..and one that california guys come out here and are almost a full second slower ..

anyways... i guess i will have to go up to phoenix and test it.... haha

plus i was launchin at abou 2700.. i have 225/40/16s..... i could prolly get alil mire launch at 3000..but anything past that i think they will spin too much...... what do yall tink?

 

Well double clutching.. is not for down shifting.. Power shifting and double clutching it should be used together.. double clutching means.. while you are pressing the clutch in you are already pulling the gear out.. then when you start to release the clutch you are putting it into gear at the same time.. basically.. it's the quickest way to shift.. instead of "granny shifting" which is just slow.. and power shifting is just keeping the throttle open when you shift..

 

 

What is the elevation differance between the 2 tracks????

Ohhh by the way, if you have rubber out back as large as 225/40/16 you should easily be dropping the clutch, at around 3500-5500 Rpms. The only way to get a good launch in these cars, is to sacrafice a little tire spin for torque.

 

you got a new one?! man i guess that shows you how much i keep in contact with you guys. Damn motorcycle!

 

AHHHHHH. I cant stand it when people think they know what double clutching is and are wrong.

Double clutching is used when down shifting ONLY. It is not relevant to upshifting.

Double clutching is used for 2 reasons:
1. To save the tranny. When you down shift the car normaly, the engine revs up to match the new speed of the new gear.EG 3rd to 2nd, moves it about 1500 RPMs in my 82. By double clutching you are saving your synchro's from doing their job, by doing it for them. Result, when done correctly, longer tranny life.

2. The real reason for double clutching if you ask me is to prevent the car's weight from shifting.

Example: you are entering a turn, so you brake, and now your going 40 MPH at 3000 in 4th. When you leave that curve in 4th, you wont have the power to accelerate out of it because you've dropped out of the power band. Now, if you're taking this corner fast, really fast, by down shifting "straight" you'll be shifting a lot of weight to the front of the car as the engine trys to match the new speed that the new gear is moving. This weight shift may cause you to lose traction.

Instead you double clutch. Clutch in, **** to N, clutch out, gas to new RPM, clutch in, shift to new gear, clutch out. This prevents the cars weight from shifting forward, and alows you to safely downshift while in a high speed turn.

Now for a more clear example of the way it is done:
3rd gear 4000 rpms, ~ 35 MPH.
Slowing down, braking.

Clutch in, shift to N, clutch out, gas to 5500, clutch in shift to 2nd.

Presto, if matched correctly, no weight shift, and the speed continues to be controled by the brakes, not the engine fighting the transmission.

Now when up shifting, the RPMs drop going up gears, so just the moment of taking your foot off the gas drops the RPM's enough to make the transition somwhat smooth.

Double cluchting used to be the only way to downshift in old trannys without synchros.

adssoccer is correct. It saves your tranny, and can be combined with heal/toe, to brake and shift nicely in a curve.

Sorry for the rant.

 

to get the quickest reaction time, you have to count the lights, dont wait to see the green, it takes a bit of practice, but when the first light goes out, count the seconds in your head till it goes green, when you get this timing spot on, do it when your on the line and holding the revs, when the first light goes out, start counting and when you get to 0 or 5 or whatever it is you count, just drop the clutch and launch! you will be surprised just how low your reacton times will be!!!

 

thanks ... but reaction times done change your trap speed... the chances of beatin the guy next to me will get better but im lookin to be into the 15s... not the .5 reaction times... anywho...

i dont know the elevation changes but i know the elevation is significatnly higher here in tucson compared to phx and SoCal

 

Yea just like two thousand feet can affect a n/a 1/4 mile run by up to a full second.....
Try racing down at the Bonniville salt falts. about 50 feet below sea level. Your car will have more power than it ever has before.

 

167 degrees F eh? That will hurt times a little!
Anyways, you should look into your elevation and true track temps. The 85.5 mph seems a little low for an -SE with headers, exhaust, etc. It could be the elements though.
Thanks for posting the actual time slip. People are often quick to say get you 60' down wihtout looking at anything else. Yes, that ususally is the case for bad times. But, compairing the last 1/8 and traps will tell you how your car is running on the top end. For example, gained 15mph on the last 1/8 vs. 17 another time. What changed? Shift points, etc...
Anyhow, your short times are too high. Pratice a little. If you can knock .2 off the 60' (which is quite possible) then you will be in the 15's. Just don't forget to compare all the times and speeds between all your runs. Taking notes helps.

I'dhttps://www.rx7club.com/forum/showthread.php?s=&threadid=182383
It's for launching a FD, but the basics still apply.