Removing the rev limiter?

[Richie]

I've been told removing the rev limiter on my car could increase performance

First, I'm not even sure if I have a rev limiter, how do I find out?

Second, wouldn't taking revs past the engines 'safe' limit be dangerous? Or is it like supermarket food? they put a 'use by' date about a week before you can still eat it? i.e. it's possible to squeeze more revs out safetly

thanks again

[Martin F]

Yes you do have a rev limiter, can't remember what the exact figure is without looking it up.

Removing it or reving past it is not a decision to take lightly as it can have detremental effects on an engine. However it's generally agreed that Toyota over engineered a lot of the MKIV Supra and experience seems to indicate that the stock engine can be revved up to about 8k with no real alterations required.

However on stock turbo's this is fruitless.

If you look at a stock (or BPU) power graph you will see power start to drop off as you get close to redline so reving further is not going to gain you anything. Its only if you have a big turbo(s) that your rev limiter can present an issue.

So in summary whoever told you that removing your rev limiter would increase your performance is full of brown stuff.

[alex h]

Increasing Rev's is good for NA engines mainly. Turbo engines don't need to worry so much, I suggest you worry about the turbo's long before you worry about revs.

[Richie]

thanks for the info

[Richie]

I also heard a way to increase top speed is to "remove the fuse from the traction control" but with my model this would not work, seems this is a mod only for UK model TT's

[Martin F]

Yep, removing the traction fuse on UK spec cars will remove the top speed limiter at 155mph. On a Jap spec you need to use a speed limit delimiter.

[The Hornet]

Yup, that magical little black box fitted to my J-spec to change from KPH to MPH de-limits mine fine and goes well past 155 mph (so i'm told)


Grant

[Richie]

Originally Posted by [b

Quote[/b] (Martin F @ Dec. 02 2004,23:32)]On a Jap spec you need to use a speed limit delimiter.

Sounds interesting, Do all Jap imports have a speed limiter? What change could fitting a 'speed limit delimiter' make? Would it decrease my rev's at high speed and thus allow me to go faster?

[Martin F]

Yes all Jap specs have speed limiter at 112mph (approx). Depending on the KMH to MPH conversion your car has received this may have been moved to a higher speed.

'Decreasing your revs to make you go faster' is a bit of a contradictory statement.

The SLD cap's (for the want of a better term) the speed signal seen by the ECU so that speed cut never occurs. This is the speed signal not the RPM signal.

[Richie]

Originally Posted by [b

Quote[/b] (Martin F @ Dec. 03 2004,17:23)]Yes all Jap specs have speed limiter at 112mph (approx). Depending on the KMH to MPH conversion your car has received this may have been moved to a higher speed.

'Decreasing your revs to make you go faster' is a bit of a contradictory statement.

The SLD cap's (for the want of a better term) the speed signal seen by the ECU so that speed cut never occurs. This is the speed signal not the RPM signal.

That's strange, my speed dial goes up to 180Kph as I continue accelerating past this point the needle simply comes to a stop, but acceleration continues. This happens until I'm doing approx 6000rpm in 5th gear (don't want to go into the red zone). Thus the only reason I can go no faster is because my engine cannot go pass its maximum rev limit for my top gear.

That's what I mean't by decreasing the revs at high speed, if I could reach the same speed say 130mph with only 4000rpm then I would have another 2000rpm on my rev counter to go to reach a higher top speed


Hope that makes sense. I'm approximating but I'd say I've reached about 140mph on a nice stretch of m/way, so I guess there is no speed limiter there