RED MX5

As others have said, there have been documented failures of the F22C when reved to 9k, but it has not been conclusively proven that the failures were actually caused by the higher redline. The damage is such that the increased redline is highly suspect, but the jury is still out. That is why everyone says that it depends on who you ask. Ask me, and I'll tell you that I don't really know for sure yet, and at least I know that's right.

Given what I have seen up to this point I have to see reving the F22C to 9k as a risk, not because it *will* cause the engine to fail, but because it *might* cause the engine to fail. I'm perfectly content to let others take the risks, because I'd rather learn from their mistakes than from my own.

If you are a risk taker, go for it, and keep us posted.

LegendaryHarry

if you increase the redline... how do you know when you hit it? or cluster stops at 8k

and if u get an ap1 cluster. its sucks cause you cant even hit "redline"

autometer 10k gauge. out of the question. haha

Neutered Sputniks

Custom gauge?

RED MX5

I think there may be some issues in using the AP2/F22C cluster with the an F20C ECU, because all the guages in the cluster are different. As an alternate, you could probably use a later model EUDM cluster (newer gauge layout but 9k redline).

LOL, but I'd be more concerned about engine life at 9k than about the instrument cluster.

Dark

Many AP2 owners that have run/are running an AP1 ecu explain that they experience lower mid-range torque/power (thanks to the tune on the AP1 ecu, thus the need for a tune).
The AP2 head is more capable of 9k rpm compared to the AP1 head, also the AP2 cams weren't designed to make much power past 8k and the piston speed will surpass that of the AP1.

The only real danger is piston speed but a bad tune/no tune will also pose a problem.

RED MX5

But there is no way to tune the AP1/F20C ECU.

LostMotion

The problem is dramatically increased sleeve wear above 8500 RPMs.

And when I use the word dramatic, I mean within a couple thousand track miles if you are in the 8400+ RPM range for long periods of time such as staying at 8600 RPMs around a long turn, for instance (as opposed to only on your way to the next gear). It's the increased side forces which are at work.

You're not going to send a piston through your hood or anything.

Dark

I'd imagine someone could use an AFC/Emanage/etc.

RED MX5

^^ And our blocks are not sleeved, so the wear goes directly to the block (cylinder walls) and piston rings. The cylinder wall damage in the failures we've seen is downright nasty.

The open deck on Honda engines is also probably a factor as side loads increase.

RED MX5

But if you're going with a piggy back, wouldn't it make more sense to get a piggyback that would let you set the rev limit, and just stick with the F22C ECU?

If I gotta tune, I'd really rather go with a standalong EMS than piggyback an older ECU.