Marco

I have a question.
the Mugen ECU does nice gains to the F20C(yes I know an EMS can probabaly gain more, but even UL said the Mugen ECU was damn inpressive)
So, With its remappeping, timing advance, and etc, how would the Mugen ECU wok in a F22C???
I am really curious
Thanks

Elistan

The Mugen ECU works well in the F20C because the stock ECU (especially the 00-01 version) are tuned to use a lot of fuel - more than is optimal for power. The Mugen ECU leans things up a bit - think of the gains 00-01 owners get with a VAFC.

The 00-01 ECU seems to be a good match for the F22C because of that richness - the extra displacement requires that extra fuel.

I'd be worried that a 2.0 liter tuned Mugen ECU would be dangerously lean if used with an F22C engine. But that's just speculation.

Wisconsin S2k

the F22 had a change in the crank giving it a longer stroke. however, to prevent the pistons from being shoved up into the head as well as a drastic increase in compression from longer stroke, they shortened the rods.

as elistan already put, you do not determine shift points by shifting just after you hit peak power. you use the torque being made at the wheels and multiply it by the gearing. so even if you're only making 105lb/ft at 9500rpm in 1st gear, it's still more power than you'd be making at say 6500rpm at 130lb/ft in 2nd gear. if you are shifting at peak power, you're short shifting and you're going to be much slower.

"you think nothing will break"?? ok? and you know more than every other person who has voiced concern about this? like UL? the man who is famous for his dyno shop, and does the Research & Development for hondata in his dyno shop? the man who has built race S2000's and has several teams? I believe one of his teams doesn't go any higher than 8400rpm on the F22 because they threw a rod taking it to 9k.

as for boost, boost has nothing to do with piston speed, which is the main issue here.

why would I make the point? the point is that the car still makes useable power. that said, the guy has to rebuild his engine about every month because of the stress and damage it does revving to 11,500rpm. and no he's not using stock rods, bolts, etc, because he'd destroy his engine even quicker if he did, since yes the piston speed would be too high.

also, the rod bolts are the main area of concern regarding the piston speed.

slipstream444

Almost 11,000 RPM ... nonsense.
The folks that have mechanically over-revved their engines to approx 10,800 RPM needed new motors. This magical number is where Honda gurantees the engine will come apart. This number came straight from the model engineer.

I accidentally mechanically over-revved my S2000 to approzimately 10,200 RPM without any damage - and I was lucky. I spent the next 20,000 miles checking things like the retainers every 5,000 miles to ensure the engine wasn't slowly coming apart. Luckily the engine is was still running like a champ before I put the car in long-term storage.

Nothing in the F20C is designed to tolerate 11,000 RPM.

Wisconsin S2k

uh, did I ever say they were stock parts?

the member I was referring to revs his car to 11,500rpm. however, even with aftermarket parts such as valves, retainers, springs, rods, etc, he still has to "rebuild" parts of the engine every other month.

my point was that he did this without changing the flow characteristics. in other words, the aftermarket parts did not increase the flow coming into the engine. the aftermarket parts allowed him to rev to 11,500rpm, which he does.

Sideways

Doesn't that engine have reground cams? That would change the flow characteristics.

AusS2000

My gawd there is a lot of in this thread. Some of us need to take Engine Design 101 before typing in here again.

The head should not be the problem. The F20C head handles 9000rpm so I assume the F22C head should be fine. There are a few different parts but I suspect they are stronger rather than weaker.
Rod length does not affect stroke. It does affect rod angle and sidewall loading.
The F22C has a longer stroke and shorter rod and hence has a geometrically higher piston acceleration and speed at any given RPM.

My input: People around here are always asking for definitives even though we know that this is an imperfect world which can only be measured in terms of probability.

So here's what we know:
Some users have run the F22C to 9K successfully.
Some users have killed F20Cs in normal recommended operating conditions.

All I can conclude from this is that if you run an F22C to 9000rpm the rate of failure (X out of 100) will increase and the MTBF (mean time before failure) will decrease. However as I doubt the sample set will be big enough it will be hard to ever verify this prediction. Buyer beware.