Changing Rev limit on 4AGE blue top.

[sergei]

No way you will have valve bounce on 4AGE at 7000-8000rpm, it has to be somewhere arround 10k mark, my 20v revs till 9000rpm and no valve bounce (just a nasty fuel cut at the end, slamming brakes feeling)... BTW it has stock springs in it.
I had a redtop it revved till 8k.
You might have lower rev limiter due to SPD sensor not connected (wich is fed from dash).

[NA Drifter]

Sometimes it cut at 7200rpm, 7400rpm, sometimes 7800rpm still std ecu..

Do you mean the same ecu unit or different ecu units? I always thought mine went up to 7800 before cutting, but when I was on the dyno the sheet came back with a 7300ish cut. I thought it was weird, so worked out how fast it would've been going in that gear at that RPM and sure enough, 7300ish when it cut...

Does it have to do with temperatures and that? Perhaps cuts lower if engine cold????

Everything same every time... but just different rev limit.. donno why... also have a SAFCII for reading the max rpm output... could be the way the car been driven, temperature.. etc?

[sergei]

It is defenitly temperature dependant. (On colder it is lower).

[Caveman]

No way you will have valve bounce on 4AGE at 7000-8000rpm, it has to be somewhere arround 10k mark, my 20v revs till 9000rpm and no valve bounce (just a nasty fuel cut at the end, slamming brakes feeling)... BTW it has stock springs in it.
I had a redtop it revved till 8k.
You might have lower rev limiter due to SPD sensor not connected (wich is fed from dash).

This was my thought, lower rev limit while the car is sitting still

which dyno was it? a lot guess gear ratios to overlay rpm, usually its ralative to wheel speed. Unless they connected up to your coil...

[Stealer Of Souls]

It was at Torque Performance.
And yeah, I think it was done off roller speed with a ratio gathered from reading roller speed vs tacho at lower rpm...
Either way, I am reasonably confident that it's right and the cut was around 7300, as that matches my calculation using my gear ratios.

[pc]

My 3 bluetop ECUs always cut at 7600. I have one jap manual, jap auto, and one that i've been told is a NZ manual (but I don't think it is).

[big_boy]

they are speed cut tho according to other fourms 7225RPM un loaded for manual & 7330RPM of an auto also they are cold limted in stages of 5000,6000,7000RPM im unsure of the tempture at withc these are cut off but they deffently are

& 7850RPM in the max under load

[Stealer Of Souls]

It is defenitly temperature dependant. (On colder it is lower).

How did I miss this post?!?!?!?
But this would explain it. The car had managed to cool down before being put on the rollers...

[Mr Revhead]

ok

so we have established the difference between valve bounce and rev cut....


can anyone answer the original question?

[pc]

Ahhh yes the original question. Years ago I had heard that getting an NZ new ECU will raise my rev limit, as well as removing the speed cut. I bought an ECU and was told it was an NZ new. I didn't notice any difference in revs except the the fuel map in the middle near TVIS change over (dyno plot reference) is bad and I loose lots of power. I went back to my standard JDM ECU a couple of months ago and the car goes better.

So if you get the right NZ new ECU, maybe it will raise the rev limit.

[Stealer Of Souls]

ok
so we have established the difference between valve bounce and rev cut....
can anyone answer the original question?

Good point...
Although it may be a moot point. If the rev cut varies according to engine status (hot/cold, moving/stopped, etc) then what I need to do is get a dyno run with the engine at operating temperature (and find some way of making a speed signal for the ecu - damn that AE85 dash).

[Brick]

you cant really go by the rev counter on the dash, ysterday when i was driving along the link hand controller said 2,700rpm but the dash said 3,000rpm, and as it gets higher it gets less accurate. I use to think my old Fx rev limiter was at 8,200

[big_boy]

you can get this thing for link ECU`s for about $40 that splits the spedo drive in 2 one eletronic drive for the link ( or in your case the ECU) & one manual drive for the spedo if that would help

[TTEETT]

Just been for a drive to test where my GT hits its rev limiter, seems to be at 7,800rpm, and has no speed cut limiter. Its NZ assembled, I have a spare NZ-GT ECU in my shed for a rainy day, I have been told they are different before but never really believed it, the import blue-top motors normally have an censer on the exhaust manifold too don’t they?

[Stealer Of Souls]

you can get this thing for link ECU`s for about $40 that splits the spedo drive in 2 one eletronic drive for the link ( or in your case the ECU) & one manual drive for the spedo if that would help

That is useful. Even if I don't need the speedo output for the ecu, I do need to run some other stuff I've got. Any ideas where to check it out?

you cant really go by the rev counter on the dash, ysterday when i was driving along the link hand controller said 2,700rpm but the dash said 3,000rpm, and as it gets higher it gets less accurate. I use to think my old Fx rev limiter was at 8,200

May be true in some cases. In my case the tacho reads fine down low. Because it's an AE85 dash it starts to go bad after about 5.5k. Below 5.5k usually everything meshes up almost perfectly with calculated values.

Just been for a drive to test where my GT hits its rev limiter, seems to be at 7,800rpm, and has no speed cut limiter. Its NZ assembled, I have a spare NZ-GT ECU in my shed for a rainy day, I have been told they are different before but never really believed it, the import blue-top motors normally have an censer on the exhaust manifold too don’t they?

Mine has an exhaust O2 sensor. but it's dead... And it turns out the bluetop ecus don't care what the o2 sensor says anyway. They determine fuelling purely from maps.

[matt dunn]

Just been for a drive to test where my GT hits its rev limiter, seems to be at 7,800rpm, and has no speed cut limiter. Its NZ assembled, I have a spare NZ-GT ECU in my shed for a rainy day, I have been told they are different before but never really believed it, the import blue-top motors normally have an censer on the exhaust manifold too don’t they?

NZ new dont have speed limiters,
and have a fuel mixture adjuster under the bonnet instead of a O2 sensor.

[suberimakuri]

without reading every post:

Wire up an aftermarket ecu and you will find that the factory dash under reads at that sort of rpm. Hence why some cars revlimit at 7300 and others at 7800. Common.
Some dashes are better than others.
ECU's are all the same for each model/product number on the ecu.

On your motor, the ECU has fuel cut only at 7800. Fit aftermarket or adjustable limiter if you want more revs. gah.

なんでまたStealer_of_Soulsのポストを読んじゃかったかな。。

[Stealer Of Souls]

without reading every post:

Wire up an aftermarket ecu and you will find that the factory dash under reads at that sort of rpm. Hence why some cars revlimit at 7300 and others at 7800. Common.
Some dashes are better than others.
ECU's are all the same for each model/product number on the ecu.

On your motor, the ECU has fuel cut only at 7800. Fit aftermarket or adjustable limiter if you want more revs. gah.

なんでまたStealer_of_Soulsのポストを読んじゃかったかな。。

Cheers Karl.
My 7300 was from the dyno, not read from my dash (can't read from my dash cause it's a poos dash).
Can you suggest what to get to adjust the limiter? IE what to buy/build/steal.

What's the last line... don't make me get it translated...

[matt dunn]

My 7300 was from the dyno, not read from my dash (can't read from my dash cause it's a poos dash).
Can you suggest what to get to adjust the limiter? IE what to buy/build/steal.

How did the dyno know what revs you were doing,
they probably entered in a gear ratio and adjusted it to read the same as your revcounter, which if he entered in 1000rpm and it was doing 1100,
make the dyno read 10% out so out by about 700rpm at 7000.

You can buy aftermarket limiters to lower the rev limit but you cannot make the limit higher.
There is no way of upping the RPM limit that is set inside a particular Toyota ECU.
Some ecu's may or may not have different limits,
( supposedly FWD have a higher limit than RWD)
but have not done enough to confirm this.

Matt

[Stealer Of Souls]

How did the dyno know what revs you were doing,
they probably entered in a gear ratio and adjusted it to read the same as your revcounter, which if he entered in 1000rpm and it was doing 1100,
make the dyno read 10% out so out by about 700rpm at 7000.

Yeah. They probably entered the number by doing just that...
BUT... I check the numbers against calculated values... and it was bloody darn close.
According to the calculated values with 4.1:1 diff, 1.435:1 gear ratio (K50), 195/50-15 tyres.
7300rpm 3rd gear is 134.7kph.
The dyno road speed at the limiter was approx 133kph. And the dyno RPM was about 7250RPM.
That's too close to be coincidence.

So regardless of how they set the readout, unless there's a 10% variance in the dyno road speed it did limit at approximately 7300.


I assume the ECU does cut based upon the frequency it receives at it's RPM input?
Perhaps I can just build a circuit to play trickster...