Rev Limit..8000rpm?

[EndLeSS]

hey hey,

Just thought of this question yesterday...Is the rev limit of the NSX really 8000rpm, or is it electronically limited like a lot of cars? *coughcoughMercedesToyotacough*
Since the S2000 can rip it to 9000rpm, I think the NSX is electronically limited, but there is a huge chance that I could be wrong.

If there is a rev limiter, would there be any difference in performance/etc that would happen if it was removed? Or it would put too much stress on the engine, and screw it up?
Any ideas?

l8z

 

[Edo]

I know its electronically limited..thats for sure. As many other owners have undoubtedly found out the rev limiter kicks in at 8200rpm's or so. I have done this MANY times coming through corners while not paying attention to the RPM's. The car seems like it could easily rev to 9000 or more with some simple fuel mapping or some such.

 

[Andrie Hartanto]

I heard it is not recommended to go over 8500rpm in an NSX unless u have modified oil pump (due to different design with pump and oil management) and valve spring. i might be wrong. Lud?

 

[Lud]

You cannot simply "remove the rev limiter." It is part of the ECU software. You need to reprogram the ECU chip to change the maximum allowed RPM under throttle. When the engine is cold the rev limiter is lower. It is the same for any modern car I can think of - they just have different limits set.

What will happen if you raise it to say 9000 RPM? Unless you have rebuilt some of your engine and oil pump internals, there is a good chance you will blow your engine after a short period of time near the 9000 RPM mark. The S2000 designed to rev that high; the NSX is not.

Andrie is also correct that the stock oil pump gears tend to grenade if you spend time in the 8500+ RPM range. Shattered oil pump gears mean the engine is no longer getting oil and so aare typically closely followed by a blown engine.

The purpose of the rev limiter is to help prevent people from destroying the engine. It is a Good Thing and if you have to ask why it's there you definitely should not be trying to defeat it.

Rememer that the rev limiter can only stop you from applying more throttle. It can't do anything about you downshifting to too low a gear. If you are going say 120 MPH and drop it into second gear and you'll be turning well over 10,000 RPM for a short period of time. After that you will probably have your car in the shop for a long period of time.

[This message has been edited by Lud (edited 27 June 2000).]

 

[Edo]

So what you are saying is that with a more powerful Oil Pump, like the Comptech High volume oil pump, you could go over 9,000rpm's safely then? (Provided you get a newly re-programmed ECU of course). Are the engine components able to withstand that sort of RPM's?
And lastly..is the engine capable of actually generating more power at higher RPM's. Higher RPM's are good, but not if your Torque curve plummets downward.

 

[Lud]

Originally posted by Edo:
So what you are saying is that with a more powerful Oil Pump, like the Comptech High volume oil pump, you could go over 9,000rpm's safely then?

No, I'm saying the stock oil pump gears are often the first thing to go even below 9000 RPM.

Are the engine components able to withstand that sort of RPM's?

You need to do other internal work if you want it to reliably turn 9000+ RPM. If anyone is serious about it, call Comptech and I'm sure they can discuss your needs and give you some pricing.

And lastly..is the engine capable of actually generating more power at higher RPM's. Higher RPM's are good, but not if your Torque curve plummets downward.

Here you have hit on the key question! Until you have heavily modified your car (I'm not talking about intake/headers/exhaust here..) there is no point in setting it up to run higher RPMs. If you look at a dyno run on a stock or mostly stock car the curve drops off sharply as it nears 8000 RPM. Peak power is in the low 7000s.

 

[EndLeSS]

hey hey,

Hope you guys don't think that this is a stupid question, so here goes.

Since peak power in at low 7000rpms (like what Lud said), obviously VTEC has cut in (As far as I remember, VTEC kicks in at 5600rpm...but once again I could be wrong)
Can't you get a VTEC timer to adjust when VTEC kicks in, and get more low end power? I'm sure that this is hella complicated to say the least, but would it work? Just wondering....

l8z

 

[maomaonsx]

pretty much all cars' RPM are "electronicly limited" Otherwise, your rev will just keep climbing untill your engine is destroyed.

Endless: It is possible to adjust VTEC *along* with air/fuel ratio to shift the power band, but you would not be able to achieve any power gains.

------------------
Please visit my NSX tuning page! Mods, Japanese NSX related stuff, pics!
http://www.geocities.com/Tokyo/Dojo/6073/index.html

 

[Lud]

Originally posted by EndLeSS:
Can't you get a VTEC timer to adjust when VTEC kicks in, and get more low end power? I'm sure that this is hella complicated to say the least, but would it work? Just wondering....

Simply switching a stock or mostly stock NSX engine to the high-RPM cam profile at a lower RPM does not gain you power. In fact it will rob you of some low-end torque. Read the FAQ re: the operation of VTEC and the part about VTEC controllers.

 

[David]

Raising the redline can be useful on a heavily modified engine. My supercharged motor (also had cams, valve springs, oil pump gears, heads, fuel system mods, etc.) made increasing hp all the way to its new 8500 rpm redline and probably would have kept increasing beyond that. However, most motors will not see any performance improvement as they are past the peak hp well before 8000 rpm.