power loss at around 7000 RPM
 

Hi all,

When I push hard my 3rd Gen RX7 oftenly I get a 1 second power loss at around 7000 RPM (not always the same; sometimes less RPM sometimes more). Then I insist on the throttle and it gains the normal power till the rev limiter. The power loss (or better like a sudden engine brake) lasts only 1 second.

Any Ideas?

Sport Compact Magazine had a similiar problem in their project FD. It ended up being a faulty ignition coil harness.

What is your boost like at that RPM?

I mean it could be several things causing the loss in power, not to mention that it IS rather high up in RPMs. Unless you have a LOT of mods, you really won't notice a power increase past 7000rpm.

Yeah, that happens to me, but at ~6250 RPM and only in gears 3 and up. I immediately blamed my computer, but that could be wrong. The A/F meter just drops to lean for those few rpms, boost stays high, engine gets really loud, then it picks up and goes again. Weird. Oh, and it doesn't do it <10 lbs of boost, i don't think.
~Tom

Hyperite - It really sounds as if you're running into fuel cut from overboosting. Your A/F meter going lean suggests that as well. If you have excessive modifications done to the air-flow path, without an ECU upgrade, that might lead to overboosting (and running lean).

To the original poster - post here about your car's situation - any modifications, repairs, etc.

Well, I just bought my RX7 and I know that my first turbo is boosted. I spoke to the previous owner and he said that he boosted from .9 bar to 1.0. The boost meter pattern 10-8-10 now. Before the problem it used to reach even more than 12.
Other mods : K&N Filters and mid to rear stainless steel exhaust pipe.

It could also be that, too.

Do you feel a big buckle when you get it up there, or does it just progressevly get slower? If you ARE running into fuel cut, the car will feel as if someone just hit you from behind. Does it feel like one BIG power drop, does it feel gradual, or does it feel as if it is sputtering?

Change your plugs and see if that helps. Once in awhile I get fuel cut at around 6500 rpms and it's because I'm running high boost. But if I change plugs it'll be fine for a while anyways.

I know, fuel cut was what i thought too. It's a remapped ECU good for 1 bar, and it continues to run rich after the hump and get's 12psi all the way to redline no problem. I think it might be that a few points in the fuel map are just missing...i'll find out in the spring when i get a PFC i guess. And no, it's not a progressive power loss, it's just WHAM (i get tossed forward a little), then WHAM (i get slammed back into my seat w/ the force of 300+ HP).
~Tom

Maltese RX7, where do you live in Malta, i live in Malta too.
It could be a fuel cut off or speed cut. Japanese RX7's have a speed cut at 180 km/h. Most probably it's a fuel cut off.
Post a pic of your car.

Most probably it is a fuel cut due to turbo overboost. You are right. Now I will try it out with less boost.

If it is a fuel cut because of an overboost (as we are thinking) am I risking damaging something???

Another thing that I noticed is that when it was doing it most I was running without the turbo K&N filter (accidentaly) because it fell. After I put on the K&N again it has not done it again yet.

To colin the other maltese guy : Yes I live in Malta. Don't have photos yet 'cause I just bought it. What do you think about setting up a Malta RX7 Club?