Changing Rev limit on 4AGE blue top.

[Caveman]

Dont rely on maths and drivetrain calculations, etc

tp got my rpm all fuked up, apparently I redline below 7000rpm (around 6800) with a 4age. big load of crap.

only true way to tell is to hook up the dyno and the -ign output.

[big_boy]

is it cut by a relay/transistor if so you could just bridge it out

[Stealer Of Souls]

Dont rely on maths and drivetrain calculations, etc
tp got my rpm all fuked up, apparently I redline below 7000rpm (around 6800) with a 4age. big load of crap.
only true way to tell is to hook up the dyno and the -ign output.

Interesting... Surely the dyno's road speed can't be wrong since isn't it measured from the rollers... i didn't go from the TP RPM readout. I went off their road speed.
My maths is good. All the comparisons I've done between my calculations and actual on road values lines up pretty darn close.
You can't really argue with fixed ratio calculations. As an engineer you should know that.

[Caveman]

Yea sorry I didnt intend to put down your maths

the problem is you dont know for certain the accuracy of the dyno speed, tyre size, gear ratios, etc

eg a tyre diameter will change as speed increases. not by much but still introduces error

im just saying for a difinitive result, your -ign will provide a descrete and accurate result.

then work from there.

I think a speed sensor going into the ecu would help, as some cars lower the rpm limit while at idle

or run a megasquirt, and dont give me its too hard excuse, mr electrical engineer

[Stealer Of Souls]

Yea sorry I didnt intend to put down your maths
the problem is you dont know for certain the accuracy of the dyno speed, tyre size, gear ratios, etc
eg a tyre diameter will change as speed increases. not by much but still introduces error
im just saying for a difinitive result, your -ign will provide a descrete and accurate result.
then work from there.
I think a speed sensor going into the ecu would help, as some cars lower the rpm limit while at idle
or run a megasquirt, and dont give me its too hard excuse, mr electrical engineer

It's not too hard... I'm too lazy
At this stage I don't want to go through the process of any aftermarket ecus. Having done a bit of reading I've come to the conclusion that the factory ecu (for all it's limitations) is actually really good. I'm not outside it's boundaries yet, so for now I'll stick with it. And for the little changes I think I'd like to make I'll go for some of the interceptor type add ons.
I'll have to get back on the dyno again soon, and make sure the car is all warmed up and everything and see if it still seems to cut earlier than expected. I'll also chase up a speed sensor answer to eliminate that too.

[matt dunn]

did you allow for tyre slip if it was a rolling road dyno?


And the RPM limit is triggered buy the inputs from the dist into the brain of the ECU, and if you interupt them you will also interupt spark and therefore stop the car anyway.

There is no transistor or relay to bridge.

If there was an easy way of doint it there would be aftermarket RPM limit removal chips available buy some of the bigger companies that do chips.

[NZ_AE86]

Tyre size varies from one brand to another so working speeds out from that is a waste of time!

[matt dunn]

Tyre size varies from one brand to another so working speeds out from that is a waste of time!

yip, agree totally.

[dash]

On our nissan s13 forum, a 'crystal' was swapped in the ecu to raise the rev limit. Apparently they guy knew about ecus and how to calculate it. Experiment worked.
dunno if toyota ecu has one

[matt dunn]

On our nissan s13 forum, a 'crystal' was swapped in the ecu to raise the rev limit. Apparently they guy knew about ecus and how to calculate it. Experiment worked.
dunno if toyota ecu has one

Nissan, Subaru, Mitsi, all can be chipped one way or another and it is very common to do so.

Toyota's however, cannot be chipped.

[dash]

I'm referring to a 'crystal', not the eprom.
Here, check out this thread;
http://forums.freshalloy.com/showthread ... cu+crystal

On 'chipping' the ecu...
A handful of people (mostly europeans) have claimed to custom reprogram toyota 4age ecu - several posted on club4ag.
I can only recall one u.s. outfit that does so as well.
I dunno what the process involves tho, so it may be quite different from nissan, mitsu, etc.

[Mr Revhead]

google a guy called peter brock
see his results on cyrstals in cars