Toolrocks

iTrader: (1)

I can't afford to search so sorry if this has been posted. If all the rev limiter does is cut power to the fuel pump then I'm going to extend my rev limiter by applying power to the fuel pump by a window switch (RPM switch). I don't know if the ECU does more at rev limit. I'm afraid to extend my fuel pump operation if the ECU no longer properly calculates A/F ratios and timing and other parameters. Anyone know? Thanks.

Chickan

iTrader: (12)

the rev limiter is there to protect your engine, you might want to think twice before removing it. Also of note, unless your car is sc/turbo'd/nos/mevi+ecu, revving higher really isn't going to produce much power, and might even slow you down, as NA cars without some serious help (mentioned above or possibly cams) are useless above 6.5-7k or so

Zamorskii

iTrader: (2)

There is more than just a fuel cut off. As said above it is for a reason. If you try to spin your engine higher than set rev.limit w/o mods to camshafts, valve springs, so on valves won't be able to keep pace with pistons => they meet at some point and .... ouch

Broaner

iTrader: (10)

Its funny how all you newbies get in on this stuff. I think he has a very valid point. What if he has a MEVI but not the $500 for ECU right now. With a switch to the pump he has a perfect bypass on the rev limiter. This is all assuming he doesn't do something stupid like rev to 9K.

Toolrocks

iTrader: (1)

Thanks all for the input, I do have a VI and I am going to be spraying NOS. An ECU is not in my future, however, if I can extend my redline (within reason), it will greatly improve my times. Thanks

ch13f

I don't think anyone on this board has tried doing what you explained, but if all the ECU is doing is cutting power to the fuel pump, then it sounds do-able. Good luck.

If you are sucessful, I think a lot of guys with MEVI are going to be quite happy.

ABK

don't worry guys (newbies) vqs are DOHC and you won't end up with valve float unless you go to skyhigh rpms like 7,500 or 8k. I think you can extend your redline with SAFC II maybe just plain AFC, I remember reading about it somewhere, not totaly sure but you might wonna check it out.

Toolrocks

iTrader: (1)

do the bumpy bump. Just looking for some more input before I attempt to blow up my second engine. Wish me luck.

MaxKlinger

Just remember,

Kinetic Energy = (1/2)(Mass)(Velocity squared)

In other words, as you increase your RPM, the stresses on the pistons, rods, rings, crank, and bearings increases EXPONENTIALLY. Stress = bad.

This is even worse when you eat holes in the pistons by using NOS.

If you're trying to blow up your engine, you're definetly headed in the right direction.

If you do it, be sure to post dyno charts! I'd like to see just how far the MEVI extends the HP/torque curves. (Yeah I know really I sound like a typical engineering geek ).

DAVE Sz

iTrader: (2)

If an ECU is not in your future then the MEVI shouldn't have been either. Unless you drive on the highway A LOT you just lost some mid range power with the mevi. If you do a lot of high way driving then it does give a power increase for passing. If no one has been able to do what you want yet, I doubt you'd be able to do it as well.

Toolrocks

iTrader: (1)

Thanks for the physics class (haha). I plan to spray NOS only between 3500 and 6000 and then extend the redline only to the absolute lowest point where my shifting will take me back into the sweet spot of my power curve. Thanks again everyone for the input and I will definitely post dynos.

Toolrocks

iTrader: (1)

I got the MEVI long before anyone knew its effects. I am very happy with it and being a manual kinda compensates a little for the midrange loss. I am going to go talk with a Nissan tech at my local dealer to find out more about the rev limiter. Hopefully he'll be cool and not want to lecture me.

j_bryan

iTrader: (1)

Steve good luck on the rev-limiter workaround. I should be getting my JWT ECU soon (though I'm not holding my breath). If you want to do any comparision dyno testing (workaround vs ECU) let me know.

JeffesonM

iTrader: (5)

Do you have a MEVI?

nismology

iTrader: (8)

People have already revved to 7200 RPM with stock internals so you might wanna read up.

First of all the reason the VQ can rev so high without valve float isn't because it DOHC. The reason VQ's can rev so high is because they have direct-acting camshafts with no rocker arms or traditional lifters so the rotating mass of the valvetrain is kept to a minimum. And with the VQ's super short stroke and low rod-stroke ratio, a VQ could easily see 8K RPM with upgraded valve springs.

Secondly, you can't raise the rev-limit with a S-AFC or any equivalent air-fuel controller.