turbogarrett

iTrader: (1)

i was wondering what would be a safe maximum rpm to run. i have a pettit streetported motor, pfc, non seq and all the bolt ons. the reason i ask is that the one time i have drag raced the car this year, i was hitting the 8100 rpm redline right before the end of the 1/4 mile at about 110 mph, which forced me to coast through or shift to 4th which didn't help. i was running only 9 lbs of boost at the time, so maybe it won't be an issue when it's tuned at 14 lbs.

rotaryrex7

Not sure what's safe but last week at the track I accidentally shifted from 3rd to second at 8,000 rpm with no damage. I haven't figured out what that would have pushed the rpm to but I'd rather not know. If you have a stock ECU you'll hit fuel cut which is not a good thing.

Jim

fastcarfreak

Dave from KDR told me that they run rotary engines 9-10k rpms all the time, he says they love to be reved, and not to baby the car because of carbon build up.

Wargasm

If you really let the clutch all the way out, it would have sent the engine RPM up to around 11,500 RPM.

My guess is that you "felt" something might be wrong and didn't fully release it, so your actual RPM may have been more like 9500 or something if you pushed the clutch back in right away before it grabbed.

Brian

Rx-7$4$me

seriously it depends on your mods the most IMO. for example a mostly stock car the power starts to seriously drop after 7k rpms, so there almost isnt a point unless your trying to stay within a certain RPM range.

once you get more mods, the motor can breathe much better at those RPMS, and the power doesnt trail off.

kyle@insight

He listed his mods, which were pretty substantial.

You'll be having to go to 4th anyway when you go to 14psi so just shift at 8k

Rx-7$4$me

oh I know, I was refering to everyone who had questions about when to shift, so they could decide based on their mods or dyno plots.

Steve

turbogarrett

iTrader: (1)

9 or 10 k rpm's! i think i'll take it to 8500 at the most. i doubt my 100k mile twins would like that. there didn't seem to be any loss in power at 8100 unlike when i was sequential and many mods ago.

JOES95RX7

Racing Beat claims 8500rpm is the magic number. anything more and then you need rotor side clearanceing. rotor and eccentric shaft balancing and race bearings. One thing with high reving the rotary is the gear on the rotors can back out and lock up on the side housing. You can get it perminately installed with a machining process that uses a lock ring. but I wont get into that. Get the Racing Beat catolog and read through the tech tips.

turbogarrett

iTrader: (1)

thanx joe, that's what i was looking for.

Rx-7$4$me

Even if you go to 8500 rpms you need the mods to support it, otherwise your power will trail off horribly.

ZeroBanger

I have about 80 runs at the dragstrip and I always shift at 8000 RPM.

Fatman0203

I always shift at 8000 too, but LoL just cause I read this thread I went to see how far I can go, w00t w00t hit fuel cut at 8700 or something "oh well "