i have a dowel pinned motor and want to know if it safe to up the rev limit, currently it is set @ 8000rpm
Is there any real horsepower gains to be had by doing so or would the consequences out way any benefit? (engine life)

How high to u guys set your rev limiter for?

 

9100....

 

7... but i hadnot opened up the motor yet and just had no real idea what the barrings looked like

ill probably go to 8500-9 aslong as barrings are in good shape and i dont have any issues with oil pressure after the rebuild

 

Mines set at 8500 right now with the PFC, might go a little higher later.

 

9600 but soon it will be 10000 on the new engine... balancing rox

 

what mods are essential in being able to increase the rev limit?

 

hell some people rev out untouched motors to 9500! in general tho, Clearancing of the rotors, lighten the rotors, fully balanced rotating assembly.

 

Main and rotor bearing clearance, rotor clearancing (rotor tips and side clearance relative to rotor housing width), oil pressures, boost (or lack of) pressures, rotor and counter weight weight, and apex seal type are just a couple things that can determine redline or max engine RPM.

~Mike..........

 

zach!! can my shiet do this?? lol

 

I left the line quite a few times at 10K but usually 8500 would get it done.

 

With my stock port FD, I had the rev limiter set at 8,500rpms. On my application, it was pointless to rev it much past there. It made peak power at 7kprms, so I generally would shift it at 8k when racing. I gave it a 500 rpm increase, so I could take it a bit higher with the shift from 2nd to 3rd.

On my new motor, I asked that Rob at Pineapple to try to keep max power below 9k. Without going into details, its a nice sized street port. CJ

 

people have done it, but it's not always a good idea

 

Look at your dyno sheets (assuming you had a tune on a dyno) and when your power drops off, thats when you should shift granted your taking into account your RPM drop between gears (you want to stay in the fat part of your power band). If your loosing power (due to manifold type/length, diameter etc. and type of turbo and boost pressures) you won't have any need to exceed super high rev limits.

~Mike..............

 

on point

 

I started at 8,500 with my S4 rotors and was getting a little outer bearing wear so reduced it to 8,000 on the next build (though that one saw ~60mph in 1st due to mis shift without problems).

Last season I had S5 rotors, clearanced the bearings a bit more (still have babbit), puck clutch and went ahead and ran it to 9,000rpm. Mainly so I could keep it in 2nd for the auto-x/hillclimb on the short straights.

Sometimes I want to hold off shifting and go beyond peak power to avoid two more shifts (one up- one down), sometimes to keep the chassis settled and sometimes to avoid traction problems.

 

9k

 

you should set the rev limit really high or ditch it altogether, hit the limiter too long and the engine comes apart

 

Go really high, and you'll be putting stationary gears, and bearings in your motor. Not to mention, steel apex seals do have rev limits...., to many RPMs, and you're looking at disaster. With that said, newer apex seals are 100x better than older ones. But still not a good idea to give them alot of RPMs over and over. My .02, CJ

 

On my engine it sees 10500 frequently.

I dont use mazda apex seals though and my bearings have been modified etc and alot of other mods have been done.

 

s4 rotors here, rev limit is 8300 but i never take it over 8000 for the sake of the motor and because the stock FC tach maxes at 8000 anyway. turbo is a 60-1 T04S.

 

10k...

 

Mine's set to 8,300rpm.

Joe

 

this is the motor using the stock limiter, it took a while to diagnose that one, it took someone who had been building roadrace motors for a long time and had seen the same thing...
http://www.fc3spro.com/TECH/HOF/K2RD/k2rdhof01.html

the next engine we just ran it to 9400, and the bearings are tired, but the engine stayed together.

not saying hitting the limiter for a couple seconds is bad, its ok, but hitting it for long periods can be.

 

mine is set at 8200 in E6K....

question.....should i use fuel cut or ign cut for rev limit in haltech?

stock FC ignition + crane Hi6 on leading coil...

 

I tried both and now use fuel cut rev limit on the E6K.

I used to have ignition cut but I now feel it was too harsh to be bumping regularly.