3.2 Safe Rev Limit

[North Coast Cab]

I believe the factory rev limit on a 3.2 is 6350RPM's. What do you think is a safe limit once the head studs and rod bolts have been replaced with race quality products? Stock rods, P's & C's.

John

[herman maire]

Unless you up grade the rods I would not go above 6900 but even that I think is pushing it.

I have decided to buy after market rods for my 3.6 just so I never have to deal with a busted rod. $1600 seems cheap in the long run to NOT have to deal with rod problems.

[randywebb]

I'm told on good authority that the stock rods are good for some high revs.

You will need Aase or similar springs and keepers - mine are Ti.

With all that, 7,000 is said to be safe maybe 7.5k -- but it obviously depends on the load the motor is under. Neutral is easy; pulling at top speed is not.

[masraum]

Factory redline is set to 6250, but factory rev limit is set to 6520 except on the club sports which was set to 6840 IRRC. I believe the rods are basically turbo rods except for the factory rod bolts which need to be upgraded.

[88-diamondblue]

I upgraded the rod bolts to ARP and put Camgrinders performance springs on the valves. Both SteveW and Henry from Suertec agreed the 7000 was fine as long as I upgraded the hardware. I had SteveW set the redline at 7000 but have only been close to that a couple of times. With the cam I have the power drops off at 6500-6600 rpm. The time that it helps is at the track and you don't have enough track to shift before the next corner. Going to put the car on the dyno this next Wednesday. Time to tune that chip.

[dentist90]

Lightweight pistons and strong con rods are part of the equation... but what about the valve train? Free and easy revs are going to be a problem if your valves don't get out of the way in time. Or are these Porsche valves light enough that they're not a limiting factor at these RPM's? I don't know

[YTNUKLR]

I would say that 7000 is safe for big-valve cars, 3.0+ w/ stock valve train, springs, etc. Under-3.0, with smaller valves, I think ~7500 is safe with stock valve train, early 911S's pull easily 7300 and don't miss a beat anything under 7.5k, consistently.

Titanium retainers (and any lightening of the valve train) certainly reduce load on the engine, upgraded springs merely allow it to rev higher before breaking. Unless you need revs in excess of 7-7.5k rpm, stronger valve springs will only make the engine work harder.

Stock 3.2 rods can take 7k+ rpm, balanced correctly and with ARP or similar hardware. In 3.2 engines, I've never seen rod failure, only the failure of stock rod bolts, when over-revved (significant damage to crankshaft is the result).

[North Coast Cab]

Stock rods
ARP rod bolts
Supertech head studs
Stock Valves/Springs

[Por_sha911]

Opinion for newbies reading this (from someone who stayed at the Holiday Inn): keep in mind that there is a difference between hitting the rev limit once in a while versus every shift. If you like to hit the top end you better make sure your change the oil on a regular basis (consider syth) and keep an eye on the temps.