Just took the car out for some baseline G Tech runs (94 automatic w/ upgraded downpipe, otherwise bone stock). First run was 16.0 @ 99mph. second run was a 15.76 @ 97. What is wrong with this car? Aren't they supposed to be low 14's to high 13's stock? I know the automatic cars are slower off the line... but THAT much slower? What can we do to get this thing to run the way it's supposed to run? Or are the automatic cars just that much slower due to the very slow launching ability's?


Thanks
Chuck

 

Is it possible that one turbo may be bad? Is there a small and a big turbo on these cars? The car has very little power until 4500-5000 rpm when the boost kicks in. I'm thinking that if there's a small turbo made to make the bottom end power, shouldn't it be a little more zippy? The car takes off slower than a VW Bug, but when it hits about 4500 rpm she's flyin. Does this sound normal, or is something possibly wrong?

Thanks
Chuck

 

Automatic FD's are supposed to go 14.5 in the 1/4 stock. Either you need to work on launching it, somethings wrong with the car(like boost pattern isn't 10-8-10?) or your G-Tech is off. I've known G-Techs to be wrong in the past, I am not sure if people were using them wrong or if it's just that hard to get a little box to calculate correctly.

 

And yes it could be possible that you have boost issue. Although I've never driven an auto FD so I don't know the "feel" of them. The 4500 kick in should be when your 2nd turbo comes online. Both turbos are the same size. It's possible that you could have low boost(not 10lbs) on your 1st turbo, but supposedly you have to make at least 7psi on your first turbo before the 2nd one will come online. Do you have a boost gauge?

 

Not yet, we just ordered one. And if this means anything... this car couldn't spin the tires off the line if we wanted to, and burnouts are definetely out of the question. It is a serious pooch off the line until 4500 rpm. Almost anything could beat this thing off the line! I've experienced driving beside normal cars that drive normal from a stop light and I can't even keep up with them. I really think it should have more bottom end power than this. If not, NEVER BUY AN AUTO CAR! It's pathetic!

Chuck

 

go buy a boost gauge right now and hook it up

 

So do you think it's a boost problem then? I hope so! What exactly is this 10-8-10 so I know when I hook up the gauge?

Thanks
Chuck

 

These are the numbers for a 5spd car(hence it saying in 3rd gear). I would imagine that a automatic car should have the same boost patterns but maybe someone with an auto can help you out more. This is just how much boost a stock 5spd FD should see at these RPMS.

At WOT, 3d gear, everything stock, boost cycle is (rpm's approximate):

rpm psi
3,000 10
4,500 8 (as 2d turbo comes on)
4,500+ 10 (recovers almost immediately)
6,000+ 8 (and holds to redline)


Taken from http://www.scuderiaciriani.com/rx7/index.html a very good site for answering questions about FD's.

 

Interesting... well by the feel of things I can be almost for certain we DO NOT have 10 lbs of boost at 3k rpm! Is there any way to test the turbo without a boost gauge? I don't think the guage will be here for a few days since I just ordered it today.

Thanks
Chuck

 

ok, i ran a 15.2 in the 1/4 with my auto...but that was with out most of the stuff i have now...only a downpipe, and exhaust...and the wheels...but i was running a 10-8-10, at the time..right now i'm running a 10-8-12 i think...yah but it should a little better, not much though

 

Is it a real pooch off the line?


Later
Chuck

 

ohh hell yah...get use to it, or get a high performance torque converter from Level 10...but yah other than that its dog slow off the line

 

If you're getting good boost at high rpms, then your primary is definately coming on line and pulling at least 7-8 psi. I've heard people with auto FD's mention before that the only way to get a good launch is to do tricks kinda like break stands, but I have a manual so I don't know for sure. You just need to figure out how to launch at a decent rpm, at least 3-4k.

 

i test drove a few auto FD's and they were prety nasty off the line, but kicked up pretty fast after the second turbo kicked in. About the GTECh, its hard to get a good launch using the gtech even with my manual, i never had enough time to try out a full 1/4th but the 0-60s were bad. like 6.1, 5.8, stuff like that.

 

Hmm, ok, well maybe it is acting normal. Kind of dissapointing for a car that you would hope to be faster, but oh well. I'll look into that torque convertor. Know what stall speed it is?

Thanks
Chuck

 

i think 3500k
heard it realy helps thou

 

3500 sounds about right for this car. I'm sure it would make a big difference. Anything to help this car launch will. That is the main thing killing it, because really the trap speeds aren't too bad. Should do 14's w/ a good launch I would think. I'll give it a shot.

Thanks
Chuck

 

Yes it is a pooch from dead stop. Use hold function in "L" with left foot on brake to floor. Push accelerator down till stall at "3000 rpm" and let go of brake.

The car should jump but not necessarly spin immediately, maybe a little after turbos spool up again.

When car gets 5500 to 6000 at WOT depress hold button to shift to second before red line. Keeping in WOT push selector up to S. ECU will shift 2nd to third probably better than you can.

This is the best you can do with the automatic.

The car is a disappointment off the line, but rolling 10 to 15 mile an hour and up you can hang with the manuals.

 

The number one way to get more low end on the auto is to get 4.33 rear in gears in place of the 3.90 stock gears. This provides 10% more torque to the rear tires and at the same time get rpm's up faster, thus turbo lag is reduced.

The only other mod I believe will help from 0 to 3000 rpm is underdrive pulleys to reduce unnecessary horsepower.

 

Ok, so maybe I'll look into gears and a stall convertor to wake this baby up... Thanks for the help!

Chuck

 

430 bucks for a ring a pinion gear!? Phew, I'm used to workin on my Camaro! Ok, so is there any cheaper alternative for a gear set? And I've tried to do a search for that torque convertor but am coming up with nothing. Can someone please give me a link?
BTW. New question... The car is going to have a CAI, catback, and larger downpipe... what should be done next? Intercooler and radiator, or gears and stall convertor? Or.... tuning?

Thanks
Chuck

 

First off, welcome to the club and congrats on your new FD.

I too own an auto so I feel your pain. Just a little background for ya, this is the same automatic tranny thats used in the MPV minivan and Mazda 929 so dont expect much outa it.

All the comments up to now are spot on... and your Gtech times sound normal, given you havent perfected the auto FD yet.

4.33 gears and upgraded Torque Conv. are a real help, but its a dead end cause....

Countless auto FD owners have dump thousands in mods and are barely able to muster stock 5spd times.

Dont go down that road, I know Im not. Do the basic reliability mods. (Downpipe, Silicon Vacuum hose job, CatBack, radiator, AST, fuel filter, plug wires, and a boost gauge) And focus on getting the car in top running order.

DO NOT run boost above stock levels (get a cheapo manual boost controller if need be)

Detonation is the number 1 FD killer...I woulndt advise on running a CAI, downpipe, hiflo cat/midpipe, and catback is asking for trouble (without tuning)

Dont waste your money on any HP mods yet, save for a rebuild or turbos (how many miles on your car anyway?)

Then when your ready, do a 5spd swap ($2.5k) at a good shop that specializes in this, (do a search for 5spd conversion)
and fall in love with your 7 all over again

 

The car is actually my brothers. It's got 80k miles on it and is in excellent condition inside and out. https://www.rx7club.com/photo/index....=14445&thumb=1 Since I'm kind of the performance one of the two I'm helping him get it running to where it should be. Unfortunately I'm seeing now the auto is a big limiting factor on these cars. With late model Camaros like I work on, the auto cars will keep up with the manual car w/ as little as a stall convertor... They have a lot more low end torque though... So I've been focusing on trying to do some basic modifications for a little more power and reliability. Looks like we should probably get a Pettit computer when we put on the cai and exhaust... Then I'd LIKE to upgrade the intercooler and radiator. After that I'd probably call it good. Unless it's still not enough and he wants to put in lower gears and a stall convertor... But it sounds like his money would be better spent in a manual conversion. That doesn't sound like a bad idea to me. Eventually he'll probably get tired of the auto I'm sure. So I'll help him with that when the time comes. For now I think it sounds like he should just enjoy the car and do some basic bolt ons.

Thanks for the help
Chuck
my ride: www.barncandles.com/camaro/Chucks.htm
383 in the works hopefully producing around 500 hp

 

with a DP, catback, and hi flow cat, I managed a best of 13.6 with my gtech by brake torquing. 0-60 was 5.2. After that I got a intake, SMIC, and a PFC. Trust me, you CAN spin the tires from a stop in an auto. I've done it several times on accident, including getting sideways on the way home from RP. It only took about 2 hours of fun to destroy the transmission. I had it rebuilt with level 10 rebuild kit and TC. Stock stall is 3000. I got a TC with 3300-3500. They didn't recommend over 3500 for the street. I don't think you can buy a TC there outright anymore, but can send yours in to be modified. I'm not sure if it makes a difference. I haven't made any more passes with the gtech since then, mainly because my brake torquing days are over, I don't advise it. I have bigger tires now, 265s in the back and so it is harder to spin from a stop, but I still do on accident sometimes. It also chirps the tires when it shifts into second. I once shared the naysayers' utilitarian views, but damn its hard not to mod these cars. Right now the car is at marvelspeed for a rebuild with 3mm hurley seals, street port, apex rx6 single turbo, FMIC, etc. etc. Its possible I may sell some old parts to help with the cost like my Greddy SMIC, apex intake, Bonez cat, or my old TC for him to send in. Originally I planned to keep all of that so that I could return the car to stock if I needed to, but if it will help a fellow auto driver enjoy his car more I might be persuaded to part with some. Plus those parts probably have less than 5K on them, except for the TC which had around 48K. Good luck.

 

just to let you know, the pettit ecu is not available for the auto. the only ones im aware of are:
-peter ferrel pms- which im running on my auto, happy so far
-apex power fc- which you lose the hold function, not an option for me
-AEM- which i got tired of waiting for

and yeah i seriously beleive a geo metro can beat me off the line. but, when i try to bring the rpms up by power braking my car stalls around 17-1800. perhaps my torque converter is shot.