How High can the Si rev?

[dannyboy's06Si]

How high do you all think the Si could rev with out damaging any engine internals or blowing any gaskets?

[shawn-o]

Originally Posted by dannyboy's06Si

How high do you all think the Si could rev with out damaging any engine internals or blowing any gaskets?

i believe theres a rev limiter/fuel cut at 8500 rpm for a reason.

[Spargo]

shawn-o is half right, its there for a reason but people have raised it, I've heard of 9 even 10, but then you're just being foolish. A glance at a dyno will show you power starts to drop off up there anyway, no use it going that far, if you want more power, go fi.

-Spargo

[dannyboy's06Si]

The rev limit is actually 8,300. I was just wondering how far the engine can rev with out damage? 9,500? 10,500?

[GlennS]

Well, if Honda puts the redline at 8,000 RPM, than that's it.
(Someone here said that the valves will hit the pistons at around 10k RPM.)
Guess I'd not rev it above 8K...I mean what would be the point? :-)

[BLU BY U]

(bone stock) i bet it could safely rev to 9000, but it stops making power at 8200....so no point really.

ask kyle (ohsiguy) he drives like a nut case and frequently tests the rev limiter :)

[dannyboy's06Si]

Originally Posted by BLU BY U

(bone stock) i bet it could safely rev to 9000, but it stops making power at 8200....so no point really.

ask kyle (ohsiguy) he drives like a nut case and frequently tests the rev limiter :)

How does ohsiguy test the rev limiter, does he not have a rev limiter any more. When I shift for max power, I shift right before the rev limiter kicks in, and if im not quick enough with the shift it will hit the rev limiter on occasion. Is it not good to hit the rev limiter?

I know that if the rev limiter fails than it may result in engine damage. But our rev limiters are set to a lower rpm than the car can actually handle. Our rev limiters are 8,300. As blu said the car can most likely handle 9,000 rpm's salfely. And the hondata reflash raises the rev limit.

[Tom1222]

Originally Posted by dannyboy's06Si

The rev limit is actually 8,300. I was just wondering how far the engine can rev with out damage? 9,500? 10,500?

Nope. Plus why would you want to? Any abuse like that WILL damage the engine. Running it hard will put more engine wear onto the engine.
The peak power curve is around 7800rpm so taking it much higher than that would be futile. Besides the fuel cut off hits around 8300 rpm...

[Tom1222]

Hondadata raises the rev limit to 8600rpm. I don't think 9000rpm would be safe. At least not for long.

[dannyboy's06Si]

Originally Posted by Tom1222

The peak power curve is around 7800rpm so taking it much higher than that would be futile. Besides the fuel cut off hits around 8300 rpm...

Why would Hondata raise the rev limit to 8,600rpm?

[crazyj]

Anything past 9k your gonna probably start to float the valves and cause engine damage. Just my 2cents

[dannyboy's06Si]

..........?

[dannyboy's06Si]

When shifting for max power in the Si is it better to shift at 7,800 or 8,200?

[crazyj]

Valve float is:
http://en.wikipedia.org/wiki/Valve_float

[HAQER]

Even though 8300 to 8600 is not that big of a jump, Hondata probably raised it so we can shift where our rev limiter is right now without it occasionally cutting the fuel off if we don't shift in time.

I know I have hit the limiter a couple of times racing, Now if the limiter was 300rpm higher, I coulf still shift at 8300 without worrying about the fuel cutoff.

That's not necessarily why they raised it, but that's how I would use it.

[Shark Tek]

That is easy be the first one to try it (a pioneer in K20 rpm limit) and look for a way to remove the rev limiter and tell us which is the breaking point for the K20Z3.


I agree with crazyj passing the 9K RPM point will be very risky.

[sonitex]

There is an rpm span when the warning light comes on and blinks, and if you continue to increase the rpm, the limiter will kick in. I believe the warning light comes on at about 7800 rpms, then the limiter kicks in about 8300 rpm. I ask for your best advise here....when I feel like pushing my Si on an empty stretch of road just to feel it's capacity for power, I start in first gear and reach the warning light before I shift to second, and do the same going to third, fourth etc. Is this the best way to get the max power from the Si engine??

[Rownan]

Getting the best power delivery out of an engine isn't about getting it as close to peak rpm as possible, it's also about where your revs drop to in the next gear. If you are dropping too far down in the powerband at each shift then you are not maximizing your power output.

If you don't wait until redline to shift in a stock SI then you are in danger of falling out of vtec, which is BAD BAD BAD for power output.. The k20 is a dog out of vtec. Of course with a reflash you can lower the engagement point but still if you shift before ~8200 you are slowing yourself down between shifts.

Stock redline in the k20z3 is the perfect spot to shift to make maximum power, the problem is you are in danger of bouncing off the limiter which is even worse than shifting early because of the fuel cut. Hondata moves the redline up but that doesn't mean you should run it higher, ~8300 is a good shift point to put you right back into the sweetspot in the powerband.

Of course modifications can change the powerband dramatically.. A little bit of headwork, titanium retainers/stoppers will allow your engine to rev much higher to make use of an even larger powerband. In stock form I imagine 9k would be destructive for the k20 but with some headwork it could be made to rev higher then 10,000rpm. Whether you have the other mods to make use of that wider powerband is a different story...

[Wu36Ca]

From what I have heard the v-tec kicks in at 7,800 rpm. Isn't the purpose of teh vtec defeated if you have to switch gears almost immediately after it is engaged?

[Rownan]

Originally Posted by Wu36Ca

From what I have heard the v-tec kicks in at 7,800 rpm. Isn't the purpose of teh vtec defeated if you have to switch gears almost immediately after it is engaged?

No, vtec engages at ~6100 rpm on the k20.