Buy the magazing :)

If you dont know what the $200X Challenge, independent races get a budget of dollars per year. ei: 2006A.D. = $2,006 to work with. Thats to buy the car, modify it, and rape it in autocross and drag, and being disected by a group of techies to get engineering points. The $2006 winner was a 88(I think) NA converted to a 350 and autobox.


IF you NEED proof, these should suffice

Drag Launches http://www.youtube.com/watch?v=HE1lu6eveWo
Autocross http://www.youtube.com/watch?v=75gYftQpy2Y

cool vids but i still dont see the 11s 1/4 mile with an open rear...

Heres Grassroots Motorsports page with the event results.

http://grassrootsmotorsports.com/new...006-challenge/

If you look at the first contestant (first place 88 RX7) It says 10.926 seconds in the drag time column.

My mistake on the videos, that is video of a car from THIS years GRM challenge. The car that I am speaking of is a two-tone blue white S4. That car was featured in the Sept 2007 issue (iIIRC) and is even on the cover

Here is a picture of that car.

http://clemsonscc.com/Gallery/media....61031175058612

If you want me to scan a copy of the article where the owner mentions retaining the original NA rear, I can this weekend.

[sarcasm]Don't you know thats blasphemy?? Once the N/A rear hear's people talking about over 160whp, it gets antsy and starts looking for ways to off itself. You'll never run real power through an N/A rear!! :rofl: :lol:[/sarcasm]

n/a doesnt mean open rear. some n/a came stock with a lsd, not an open rear.

I know that "AI" is the current fad on these forums, but I think it will be a cold day in hell before I attach any "bottles" (which includes nitrous) to my car. :) In my opinion, once you add something that is depleted during hard driving (aux injection, nitrous, CO2 sprays, etc.) then the car is no longer a street car. Obviously few others share that view.

I'm not entirely worried about raising the boost. Every turbo engine that I've been involved with for the last 5 years (except one) has been high compression and there have been no issues with high boost. The key more then anything is keeping the A/F ratios below 11 once you get past 15 PSI or so (depending on turbo) and being conservative with the timing (around 12 degrees max at high boost).

There's really no intention of running 20-25 PSI. That's just crazy. :) I expect around 17-18 PSI will be all I'll ever need.

I'll check my timeslips at lunch today, because now I'm curious.

Best 60 foot time of the night was 2.13.

Except for the fact that the t2 rear end is 1" larger in diameter.

I too have abused plenty of drivelines and have witnessed components in the N/A rear end break. One specific example was the stub shafts breaking during a drag launch on street tires. The engine powering this breakage was a 185rwhp supercharged 13b. Ultimately, the result was due to a fatigue failure, and the "straw that broke the camels back" was the drag launch. However, a t2 rear end, with larger diameter ring, case, and stub shafts will withstand more fatigue and higher torque levels.

Good job, get that thing in the 12's already.

Your trap speeds (around 110 mph) reflect roughly 300 rwhp. Also, the video seems to show very little wheel spin, except when you shifted into 4th gear, where some wheel spin happened. It didn't appear that you had spin all the way through 4th gear.

im making 300rwhp, and there is no way i would even chirp the tires in 4th. i barely spin in 2nd

Yes, there's that as well.

I actually saw (well, I didn't see with my own eyes but I got the phone call a few hours later...) the same thing happen on a TII diff. The car was running a smallish TD07 on a half bridge with a set of slicks out back. Sheared stub shaft right off which destroyed the half shaft and I believe the diff casing.

I won't be running non-street tires at the 1/4 mile so the traction limiter will always be the relativly small tires.

The car made at 387 RWHP on a Dynocom dyno as mentioned earlier in the thread. It's hard to get any sort of good times with virtually no traction, as I'm sure you know. The launches were soft, there was no burnout and at least one wheel was spinning down most of the track. :)

Honestly with the open diff I'd say that it's a bit dangerous to drive the car. Any more then 30% throttle and the rear swings out. As soon as the engine is above 5K one or both tires are spinning.

I'll likely be picking up an LSD soon.

dude, get a hair cut, : D. nice job at the dyno!

I would definately suggest going with the TII rear end. Not only is the ring bigger, but the stub shafts and axles are sturdier.
Heres what wheelhop did to my NA OPEN rear end.
My front diff mount was broken, so this isnt a common occurance, but I wasnt even launching that hard.
Just happened to be on sticky pavement. Wheel hop is a bitch.

I believe you have a pinion snubber, correct Aaron?
That should help greatly in reducing the chance of something like that happening.
But if you do a lot of drag racing, its something that could happen.


http://i33.photobucket.com/albums/d8.../RX7/diff1.jpg
http://i33.photobucket.com/albums/d8.../RX7/diff2.jpg

Aaron, its probably already been answered but, is your whole drivetrain n/a? tranny, rear, clutch and all?










Nevermind, I see that it is.

same thing that happened to my buddies. Not that it can't happen to a t2 rear end, but the t2 rear end is much more stout. It was designed for the extra torque provided by the turbo engine, but hey, what do mazda engineers know??

That stub shaft got owned

you guys are missing a key point your gearing could be slowing you down alot
the TII has a 4.10 final drive ratio which isn't crazy aggressive but what is the n/a ....i thought it had a 3.9 FD????????? i don't know what the actual numbers are? plus look at the differenace in the gearing in the transmission's,

my mx-3 for example only has 200hp at the crank stock....maybe pushin 225hp with my mods but it has a 4.38 final drive weighs just under 2700lbs without me
runs consistant low 14's @ 98mph (14.18-14.44) at spartaand thats with bald tires and some "issues" the exact same cars with a 4.10 trannny has troubles breaking out of the 15's
your mph doesn't show very much tire spinning.....when you spin the hell outta your tires down the track your end mph is usually alot higher but slower times and your ET and mph's are pretty close to one another...which to me says its not so much of a traction issue as it is a gearing one.
i would hate to see tina violated by my mx-3 and a 75 shot of nos hahaha

oh aaron p.s i have a 86 base with 117 000 kms i could sell you the tranny and open diff for $200 for it all or $100 for either one


toss some OS Giken close ratio gears and an aftermarket lsd and you should be good to go

aaron your not the only one with traction issues...just keep her pinned to the floor and hold the f*ck on!
http://videos.streetfire.net/search/...da013d3e80.htm

If I blow up the NA diff (which I am certain I will do at one point), I really don't care. I think the point has been completely missed here. I would rather spend time/money modifying what Mazda put on the car then simply replace with TII stuff. Maybe I will end up with a TII diff, maybe not. Maybe I will put aftermarket parts in the NA diff and have custom shafts made, maybe not. It all really depends.

I would appreciate it if people could get off the NA vs. TII parts direction that this thread has taken and keep it on topic. I went through all this stuff a lot of years ago with the first turbo-NA setup and am not keen on repeating the same old arguments.

The current diff plan is to simply pick up an LSD and bolt it in. It's likely I'll swap in an aftermarket center section since I plan to replace all the bearings anyway. At that time, the components (stub shafts, etc.) can be shotpeened and cryo treated.

andy'sautowreckers has a low kms gxl lsd diff they were gonna sell me for 100 bucks
i think it was around 135kms in the silver rx7

Exactly I have no idea why aarons NA driveline parts don't break. I have talked to him about it before and am not trying to argue the point with him as he seems to be happy. But i've gone through two rears and one was an open diff, and two trannys, everything had plenty of good clean oil and was in good shape when i started with it. The parts simpley could not handle my launches, my best recorded 60ft was a 2.1 but i know i've done better. I've broken stub shafts in the rear and grenaded 1st and 2nd gears in trannys. But just to show i'm not knocking him i am going to be using NA parts on my car with a turbo, I don't think i'll be lauching on slick with those parts tho

i bet that car is a BLAST after 3500 lol! you're right that torque curve is pretty freakin' awesome!

i'm sure i'd probably have to bring plenty of extra pairs of pants to drive it

(because i'd keep soiling them)

(with joy)

:icon_tup: Your custom UIM is awesome.

you know what I think you should run the na driveline until it blows, then run the tII driveline until that blows and tell us which one you had more fun blowing up and which took longer, then you should crank the boost up to 30 and see if that will make the na motor pop because it obviously can't handle a turbo. and when that happens you should put in a V8, because their better anyway


just kidding nice car, sweet build, I'm jealous.. my car doesn't even run :(

wow man, awesome numbers for the setup, congrats!

Ah yes, wheel spin through 4th, reminds me of my stock turbo, and IC'd car running 15.0 @ 101mph with 195's in the rear, it was a sleeper when it would hook!

Looks good Aaron