andre sinclair

iTrader: (36)

Well,
I just got of the dyno and the care made 343 Rwhp @ 15PSI BOOST. Air Fuel Ratio`s were 12.2 to 12.5 across the board. However, when I went on a road test the car drove great and shifted at 6500rpms in drive (D) range. When I shifted the car manually with the hold button on, the car tends to bogs down when it comes to 6000-6500 rpm range. If you shift the car it will shift tight, but I thought that I could rev the motor to 8000 rpm. (manually)

Please let me know if anyone has experience this problem.

My mods are:

PFs Computer (purple)
PFs Intercooler, air duct and cold air intake.
98, Supra pump up-grade
B9ev cold plugs and 10mm magnecor wires
Petitt down pipe and Cat back exhaust

fastcarfreak

dont your think reving your motor to 8000 rpms is a little to high? Our cars start losing power at 6800 rpms, so what would be the point. Not to mention, you are already putting down way to much power for the stock auto tranny and you want it to shift at 8000 rpms. You should to the auto to manual swap, you will probably make more power to the ground through less drivetrain loss.

Ball joint

iTrader: (6)

I wouldnt say hes making to much power for the tranny because no one has really been able to say what exactly the tranny can hold. On my current setup iam running 12psi and I am not having any problems at all with the tranny. I definetely want to know if you run into any issues though. That and they made the rev limit on the autos 7k cause the tranny cant handle that high of rpm.

areXseven

iTrader: (1)

Actually,.. my FD will rev to 9K pretty effortless. But as mentioned in prior posts,..top HP in a stock Auto FD is established at 6200 rpm. It's got a Reman with less than 25K and rebuilt Twins with less than 3K on them.

andre sinclair

iTrader: (36)

Well,
To answer your first question...a transmission swap is out of the question, reason being that I `m paralyzed from an earlier auto accident. In reference to the durability of the FD `s transmission...I have a 79 Turbo Wide body 5 speed. 2 yrs ago I did an auto transmission swap and installed a Jatco 3 speed. The car has no problem revving to 9000 rpms and made over 400 RWHP@20psi. That transmission design and car is over 22 years old. Furthermore, the third Gen. auto. transmission are more durable than people think for a friend of mind has a auto 3rd Gen. and he rev `s it to 8000 rpm all day long.

andre sinclair

iTrader: (36)

Does anyone know about the torque reduction sensor on the auto transmission?

DrunkenBowler

I know nothing of that. My recommendation for you would be to get an aftermarket torque converter. Instead of the 2200 rpm stall that's in the stock T.C., you can get ones with like 4000 rpm stalls. If you're really feelin' "frisky," get one with a 5000 rpm stall. It would be a lot harder to drive in the rain but who cares. You would launch harder than a manual tranny. That's why drag racing is moving towards auto trannys. They get more consistant times and better launches.

speeddemon7

i definatly like what im hearing here. Sorry to ask a dumb question but whats the difference between a stall speed of 2200 rpms versus 4000 rpms? How would this help launching? would you have to brake torque to 4000 rpms and then let go of the brake ? thanx

F0RSAKEN

4k rpm stall converter would let you rev the engine higher before it actually sent power to the wheels, thus allowing you to build more boost for the launch.

andre sinclair

iTrader: (36)

I have a 3200 stall converter on my single turbo first gen. Despite of the higher lockup i feel that the lower stall/stock will be more benificial for the stock twins. Also, there`s a torque reduction sensor...read the manual in the auto tranny section. I don`t really know what`s its function though.

fastcarfreak

Im sorry, i didnt know your condition. Well since that is out of the question, im sure there is a company that makes a nice auto upgrade for our cars. Maybe they just modify the stock one? But i still do feel that your making too much power for your tranny. I feel its only a matter of time before it lets go. Hey, maybe that a good thing, because if it does decide to blow, it gives you a reason to upgrade, right? Good luck regardless.

adam

Rx-7Addict

iTrader: (2)

and your engine is not blown? That is wayyyyy too lean, im surprised you still have a working motor

fastcarfreak

he is right, 12.5 is definately pushing it. That is good power though, i hope your motor holds up.

danmc77

The problem with a high stall speed is that it sucks for every-day driving. If you have a 4,000 or 5,000 stall speed, your trans doesn't lock up until you hit that RPM. that means that every time you are under 4K or 5k, the trans is slipping and your engine is revving. It can get annoying very fast. Not to mention that when that power hits the ground at the high RPM, you're really going to take off even if you don't want to. That sucks when your in traffic or in the rain.

andre sinclair

iTrader: (36)

I have been running it like this for about a year now. I notice that the stock ECU before my upgrades were done was running into the 9.0-9.5. Personally, I feel that this medium of 12.2 is decent in reference to the present upgrades...Tell me what you think(should I go down to 11.0-11.5). I checked my plugs after installing a fresh set and a month of hard driving and they look perfect in comparison a fresh stock and a month of driving. I didn't want to have excess fuel which would eventually lead to carbon break down...(sticking side seals).

Insight is always appreciated, Attached is a pic of the car.

andre sinclair

iTrader: (36)

bump

Speed of light

iTrader: (8)

Originally posted by danmc77

Absolutely right. It's wonderful at the drag strip, but ONLY at the drag strip. Its purpose is to let the engine come up into its powerband before it transmits the power to the tranny. Unless your car weighs less than about 2000 lbs., I would not go more than 500 rpm above the stock stall speed for any type of daily driver. High stall converters are also very inefficient, even when being pushed hard under load above the stall speed. (Keep in mind that the converter is already responsible for the most hp loss in the powertrain, unless it's truely locked up.)

The best analogy that I can think of for street driving a car with a HS converter is that its just like driving a boat... seriously!!! Rev it up and wait for it to move.

This is a testimonial as to why these HS converters suck on the street. This actually happened to me:

I was pulled over by a cop one night who thought I was drunk. He said that I sounded like I was driving drunk. When he discovered that I wasn't drinking, he insisted that I wasn't working the clutch properly, that I was upshifting too late and that I needed to learn how to drive. I explained to him that it was an automatic with a "loose" converter. He was thoroughly unimpressed. In order to redeem his traffic stop, Beauford T. Justice proceeded to write me up for excessive noise from the exhaust. (BTW: That was 20 years ago. Today that same exhaust would be considered quite. As Dylan sang, "... Times, they are a changin'..." )


FWIW: The move towards automatics in drag racing is not recent. It took place about 35-40 years ago for most cars not governed by class rules. Turns out most serious racers figured out that you can win more races when you're not betting against yourself [shifting], among other advantages.

bajaman

There is no way I'd put a higher speed converter on a car that is driven daily, and especially not on a FD. These auto tranny cars can be a handful anyway, the way the power comes on combined with that intial sluggishness what a lot of people do is push the 'go-pedal' down more than they intend or need and suddenly you have a LOT more power than you expect. If the conditions are even marginally slick it makes for lots of wheelspin when you don't want it. Putting a higher stall speed converter in would just exacerbate the problem.


As for the torque reduction sensor - I *THINK* that this may be keyed to the power steering pump pressure output. Our cars have "speed sensitive" power steering systems as we all know. There has to be a way for the ECU to know what the vehicle speed is in order to reduce the amount of hydraulic assist at road speeds. This is just what I think, but to me it is one of only a few things that make sense, as the only other time a 'torque reduction' output signal would be useful would be on a car that incorporated this coupled to the ABS brake system to eliminate wheelspin.
This is interersting....I am going to have to read up on it.......

speeddemon7

yeah.someone find out about this torque reduction system.I bet dissableing this would give auto fd's a bit more torque.Hell i want a little wheelspin.Just so i know my car has *****.LOL
Seriously though.I doubt wheelspin will be a problem with any of our cars.
Who here has had wheelspin from a dead stop without brake torqueing?
Not me thats for damn sure.

weaklink

the torque reduction system is in place to smooth shifts and reduce shift shock. The stock stall is around 3K. Over 4K is not streetable, so I don't think the torque converter is a cost effective way to go faster. get a 4.33 rear end. that's my next mod.

andre sinclair

iTrader: (36)

Finally figured it out...It seems that the Auto. FDs` have what is call Torque Reduction Signal. This signal is received at the Engine Control Unit (ECU) from the Speed sensor and Pulse generator located on the auto tranny. The input signal going to the ECU must be disconnected in order not to kill the power from the engine (To me it `s like a traction control on my Lexus). I disconnected the signal going into the ECU (2H) For those who have a workshop manual you can look on page K-38 and see exactly which wire it is.

Car rev to 8000 rpm with ease.

cirQuis

how much does swapping auto to manual run? what parts are involved? yet...is it worth it?

bajaman

Cool! Have you experienced any driveability issues?

1QWIK7

iTrader: (33)

is it me or did he just say he made over 380hp to the wheels with the little list of mods he wrote???

or did he add something and i didnt see it? not to mention he's auto..

andre sinclair

iTrader: (36)

The Car made 343 RWHP @ 15psi. However I have fatten it up to 11.0-10.9 using my innovative wide band so i`m convince that the RWHP # is lower than 343 since it running richer than before. In reference to the drivability issues, the check engine light flashed once and then went off. I cleared the code by taking the postive battery terminal off and then touch the negitive battery post. All seems to be O.K. so far.

I