Will_s

iTrader: (7)

When I bought my 90 rx7 last september the seller said he had removed the revlimiter. I ussually shift around 7k when accelerating fast but this last time it got away from me and went past 8k without hitting a rev limiter like my tII did. A large street port and upgraded turbo gives me a peaky power band. The ecu looks to be a stock s5 turbo computer but when I plugged in a spare that was given to me with the car, it started fine but ran really rough. Maybe a bad spare or the current one is chipped. The spare also had r1 written on it. I guess what my question is, is what can be done to remove a revlimiter? I don't have a problem with it but I would like to know what is on my car.

SpeedOfLife

iTrader: (16)

It'd be best to tell us what you can see, like the number on the ECU and numbers printed/stamped on anything else you have a question about, otherwise we may not be able to offer much help.

Black91n/a

I thought the rev limiters on S5's were at 9000rpm anyway, so there's no point unless you've got some serious intermal mods to keep the engine together at those revs, otherwise it's a recipe for disaster as the rotor tips smack the irons and the apex seals skip across the housings among other things. I've had mine to about 8500rpm before with no hint of the rev limiter.

DavidHolmesIII

http://www.youtube.com/watch?v=iKXaCOj_p28
Look what these idiots did.

Will_s

iTrader: (7)

My tach ends at 8k, do automatics have a different tachometer.

Will_s

iTrader: (7)

honestly it doesn't matter as I am buying a lt10 by months end. Just curious, it probably has a rev limiter but I just didn't see it because my tach ends at 8k unlike the 9k in the video.

MmSadda

iTrader: (2)

Um, the only car to have a 9k tach was the s5 n/a.

Black91n/a

No, S5 NA MT, the autoboxes were still 7k redline due to the transmission not being rated for 8k.

V8slayer

rev limiters give hints?

wtdpn115

only had a rotor left anyways
so much hate

Will_s

iTrader: (7)

my car used to be an auto but was converted. on another note is it bad to have solid transmission mounts and rubber motor mounts.

Black91n/a

What I meant by that is that there was no sign of it activating even once.

DavidHolmesIII

yeah, that means he still had half an engine. now he has none.

Sideways7

iTrader: (7)

He also destroyed perfectly good donor parts.

As for the rev limiter, it was my understanding it is at 8.5k on all FC's since that is generally where you have to have a scatter shield to go any higher. I know my s4 has it at 8500.

SirCygnus

iTrader: (1)

such as one rotor and some misc internals and irons? give me a break. people have way too many of these.

scathcart

If the car was converted, its quite possible the ECU was also changed to the MT version, resulting in the higher 8800 rev limit.

Yes, it is bad to have solid mounts on the transmission and not on the transmission. When the engine rocks on accel or decel, the rubber engine mounts allow it free movement. The only thing attempting to prevent this movement will be on the transmission mounts. Provided the transmission mount is not of severely poor quality and is massively flexing, the end result of this scenario is typically a cracked transmission case.
But do not fret. You can prevent this, quite easily. One way is to install stock rubber transmissions mounts. Another is to install solid engine mounts, although the transmission case can still crack when the chassis twists under hard launch, cornering, or braking.
My preferred option is to remove the bolts that attach the solid tranmission mounts to the transmission. Take a piece of aluminum cold rod, and run a die down it to put threads on it, and cut them to a little longer than your bolts. at the center of the stud, use a rotary tool or a hacksaw to slightly form a small groove. Now replace the bolts with this aluminum stud, using something like alox, or penetrox, or anti-seize on the threads to prevent the aluminum from seizing to the iron nuts. Don't overtorque your new aluminum fasteners, you will need to torque to much less than factory specs.

Now, with your new aluminum studs, instead of your transmission case ever cracking, should your chassis twist enough or your engine rock enough, your studs will snap at the groove instead.

Cars are all a matter of compromise. You can run straight rubber mounts with unbreakable iron bolts, but you give up throttle response. You can run solid mounts with iron bolts and get much improved throttle response, but you risk cracking your tranny case. You can run solid mounts with iron bolts on the engine and aluminum studs on the transmission, and transfer the possible failure point to an easily replacable item.
On race cars, I do the latter. On the street, run rubber mounts.

scathcart

The rev limiter is at 7800 on as4's, 8800 on S5's. If you think yours is at 8500 with the stock S4 ECU, check your tach for accuracy.

powrdby13B

I've never heard of an rx7 with a rev limiter but the motor is balanced to 8500, I've revved at LEAST that high in a bone stock car (by accident) without hitting a rev limiter, I rebuilt a motor for high RPMS and never had to take said rev limiter out to hit said high rpms, and a friend revved too high and blew his motor about 6 mos ago (more than 8500). So I would argue that rx7's dont have rev limiters.

scathcart

You'd be wrong.

Black91n/a

Well maybe the rev limiter's no longer working. It's entirely possible on these old ECU's, especially given the car's other electrical issues, cold solder joints and all.

NZConvertible

As per the FSM, the S5's rev limit is 8500rpm. The S4's is not documented.