Thread: Size x Rpm

I have a nistune daughterboard (which effectively tunes the factory ecu).
Tuned fine up to 8500rpm, I believe the tuner adjusted the RPM scales to suit and didnt have an issue... Pretty sure you loose a little bit of resolution over the whole scale (with only x16 points to play with)
May look to push it to 9000rpm after header/exhaust upgrade if its still holding power up top.

Here is the funny thing.

From what I have seen with most SR20VEs that I have seen on a Standalone, is that from 8000-9000 RPMs the tuning up there is so close that not being able to make that adjustment is not even worth the effort. So if the timing and fuel is locked via your stock ECU you are well safe.

I am sure once cams get larger and peak HP is made from 8500-9500 RPMs the capabilty of the ECU to work properly will start to get critical.

I feel that peak HPs from 7000-8500 RPMs will suite the factory ECU just fine.


Anway for the guy who started this thread. If you want to stay on some sort of a budget build a 92mm x 86mm motor and have Benson sleeve the block. As far as head gaskets go contact MAZWORXs as their headgasket is the ****. This motor will be ok with N1 cams and with 12 to 1 compression should get you up to 230 WHP and 170 LB Ft Torque with no problem.

im in ireland so ill have to find someone over here, thank you andreas your a gent

That changes things a bit.

Finding someone to do this sleeving job properly is no easy task and many have paid out their butt because of it.

I feel that there are only about 3-4 people in the USA that can do this job right.


That being said a 87mm piston and 91mm crank might be the way to go as not to have any trouble.

a small gift for all your help guys, this is the n1 i hope to buy. mods are a de-cat, 5ziegen cat back and a 9k rev limit. note the evo lol
http://www.youtube.com/watch?v=ksQRFvncN30

N1 ECU
KA24E ECU's
and RB26 ECU's all have the ability to do do calculations and input/outputting.

the stock sr20de/ve ECU's are 8 bit and thus stop all calculating functions at 8012.5 RPM. This has nothing to do with anything else done to the motor, just the fact that the ECU can not calculate any higher than that. As the RPMs increase the The ECU can still trigger the injectors and coils in relation to the speed increase, but can not make adjustments.

Here is what happens above 8012.5 rpm.

The ECU is seeing a MAF voltage of say 5.00 volts and has an injector pulse width of say 20ms. The ECU see's this 5.00V MAF signal at 8000rpm, outputs the fuel injector pulse and just thinks it is at 8000rpm. If you rev the motor to 9000rpm, the ECU still thinks you are at 8000rpm even if you are physically at 9000rpm. The ECU just can not calculate above that. So, if your MAF voltage was 5.00V and had a fuel value of x and was doing a 20ms injector pulse, then from 8000-9000rpm, the fuel pulse will get smaller and smaller leaning the motor out because you are taking fuel for 8000rpm and spreading it out. This actually works out great if you peak HP at 8000rpm and then flatline and not building anymore power as you will have a near perfect A/F ratio.

Fuel may be all right especially if you're close to 100% duty cycle, but I wouldn't trust timing to be worth anything after 8,000 rpm. =D

First of all all SR ecus VE or DE are 16-bit. That is a fact.
RB26 has both 8-bit(GTR32) and 16-bit ecu versions. All can keep well above 8500rpm.
KA24 I do not know, we do not have them in Europe.

Also I am very curious to know how you found differencies in N1 ecu from other VE ecus except the extra injector drivers.





If you rescale the rpm to 9000rpm the ecu will continue to alter the values to limiter.

You are correct, most Nissan ecus are 16 bit.

I don't know about ecus outside of the US, but in the States our P10,B13,B14ecus can't make adjustments above 8,000 rpm, even when you rescale the rpm. We tried it on my engine and Ivan's and we revved the engine out to 9,000. The ecu basically takes the last fuel and ignition figures at 8k and apply to anything above 8k.

You can also see this limitation when setting the rev limiter and datalogging.

When you set the rev limiter above 8,100 rpm, you basically have no rev limiter. The ecu is not calculating above this rpm threshold.

Same thing apply to the datalogging. You can't datalog rpm, injector duty cylcle, fuel, ignition, water temp, ect.. above 8,000.

Tried traditional board or RT only?