Todd

Simple question on shifting/clutching revisiting an older thread. How low of an RPM will you run before shifting? I often (in fairness to the clutch) am off the clutch pedal by 1600 rpm from a standstill. And, some times will run the the car at 2000 rpm in third. It seems to have the power, and motor just chugs along fine. I generally use higher reves on the car when shifing, but from stop to first I am on and off the clutch very fast. Is it ok to run the car at 2000 rpm? I remeber reading in the manual that shift points were min. 2800, but that is where the clutch starts getting its wear. How many of you let the engine "work" in low RPM rather than shifting ect to a lower gear. This is really in stop-go driving and multiple traffic lights. On the E-Way I shift at about 4000-5500..

slevy951

From a standstill, I'm off the clutch around 2000-2500 RPM. Shifting thru the gears from 4-5K. I vaguely remember reading somewhere not to go below 2K while driving. Not sure where I read that now.

Greg Hammond

I'm usually off the clutch at 1300-1500 RPM in first gear when starting off gently. You only need to use the clutch enough to prevent the vehicle from stalling.

As for engine longevity, it's better to cruise at a minimum of 2000 RPM regardless of what gear you're in. This ensures adequate oil pressure -and- flow. Also, "lugging" the engine at low RPM can create excessive EGTs and increase the chance of pre-ignition.

Greg

Tabor

Me too.

adrial

Like Greg and Tabor, I try to be off the clutch by a max of 1500rpm..usually 1200-1300 sometimes 1000.
I'll drive with it below 2k if in 3rd or below and I'm not going up a hill or trying to really accelerate, just slowly but surely get up to speed.
It's necesary to have the car below 2k rpm IMHO at somepoints, other than starting out. Like slowly down to 5-10mph....shifting into first takes too much effort for me to be comfortable...so I just stick with 2nd.

--Adrial

Dan in Pasadena

Adrial, Are you saying you never shift down to first gear? If you get down to low speed (5-10mph per your post) you always stay in second gear? If so you are lugging your engine. The compunter is probably compensating but your engine is subject to pinging and that is hard on it. Specifically the wrist pins. Other opinions? Not shifting into first just because it's "too hard"? I don't get it. Or did I completly misunderstand what you were trying to say?

Lizard944

It's in the owners' manual. Something like "don't allow the engine to lope below 2K while in 5th gear"... IIRC

sd01

Yep, my '84 manual warns against "lugging the engine". Gives minimum shift points. Seems like they were really concerned about this stuff, understandably.

But I say if it ain't broke, er um I mean if it hasn't broken, then do what you like.

I'm a mid-3K's shifter, 2K from a start. After driving GM automatics all my life, can't get used to that high revving sound...subconciously think I'm gonna break something. But getting used to the 4K+ range the more I drive the car.

MAS

"I'm usually off the clutch at 1300-1500 RPM in first gear when starting off gently. You only need to use the clutch enough to prevent the vehicle from stalling"

Same here... I can shift my 87 924S really low too, and the engine seems, feels and sounds perfectly happy.

-MAS

adrial

Uhhh...
Well, by too hard I mean essentially not possible. I think it's 5-10 mph that I'll stay in 2nd, the speedo isn't too easily read going that slowly. Whatever speed, the rpm is typically between 1000 and 1500. There have been many times when I knew I should have gone to 1st, but no matter how hard I pushed (within reason), it wouldn't slide into first. Worn synchro's maybe? I don't think so...Cause the one time I tried double clutching, it didn't slide into first any easier. Is there a lockout maybe? Another 951'er noticed similar behavior in his '86 with 130k or so miles.

Then again...how often are we going 5-10mph in the suburbs?

The only sound I notice at low rpm in 2nd or 3rd is a whole lot of bass. I can't hear any pinging, but then again the car has a knock sensor so I shouldn't be hearing any pinging if the knock sensor is working right.

Maybe if I'm going 5-10mph I'll slow down to 2, shift to 1st and drive away normally...I'll give that a shot tomorow when it's not raining. I just washed/waxed it so I don't wanna throw my 3 hours of work out the window.


I'd like to hear more about this subject regarding how bad it is for the engine to be lugged.

Edit:
After reading Page 49 of my manual...it doesn't say anything about not lugging the engine, but does give minimum shift points. In the text it seems to concentrate more on the max downshift points than min upshift points.
Anyway it seems like all min upshift points put the engine at right about 2000rpm after the shift...