loss of power #2 rpm Question

[shorty10]

I cruz at around 2,100 and shift at around 3,200 i seem to be babying my car guess i'm worried of putting massive wear on the engine

What rpm do you cruz at, And what (normal)rpm do you shift at, Again this is a stock 1.7

[jkeyzer]

I almost always cruise above 3000. Mostly because the engine makes no power below that. I shift around 4-4.5k because things start to get loud. So I shift a lot. I am not particularly thrilled with the power band of the mighty 1.7.

[WOODPIE]

According to the Transmission Diagram in the owners manual, you should be seeing about 2800 rpm at 65 mph, but this is with the stock sized tires, 165 R 15. Lower profile tires will increase the RPM at any given speed.

I routinely shift the same way you do, sorta babying the car I guess, but I'll wind it out once in a while. Going over a mountain, it seems that once the RPM's fall to 2400, and there is still more mountain in front of me, the engine will continue to slow. I don't like to see the RPM's below 2000 in that situation, so I'll downshift. Sometimes, regretably, I will even have to drop back into 3rd gear to get to the top of Burnt Mountain, here in Ga. This is with a 2.0, but there isn't that huge of a difference in performance amoung the three configurations of 4 cylinder engines. One thing I've seen is my cylinder head temps are lower when I cruise at 65-70 than if I just putt along at 55-60 mph. The cooling system seems to do a better job at higher RPM's (to a point) and also the oil pressure should be higher, which is a good thing because the oil is also acting as part of the cooling system. Sometimes babying these engines isn't really babying them at all!

Ed

[shorty10]

anyone else? i see that 28 people have read the post . please post id like to know what all you guys shift ans cruz at

thanks to all that help

[robinaube]

Tire diameter and gearing are the main factors on rpm vs speed. When my car is cruising down the highway at 70-ish, its turning 3400rpm.

I'm running 72 914 2.0 with side shifter (stock gearing), 205/50x15 Khumo Victoracers.

[shorty10]

i'm not really asking about gear ratios here
what i am asking is what are your (normal) avarage speed that you cruz at and what rpm do you normally shift at

[M. Hendrix]

Like I said before, you are LUGGING in a gear higher than where you should be, up that 1000 rpm, roll @ 3100, and shift at 4500, unless you don't need to go faster, choose the gear that keeps you in the 3 thousands range.


M

[elwood-914]

My car just runs better above 3000 RPM. I shift at over 4000 Rpm. It just seems to like it better in those ranges.

[Dave at Pelican Parts]

In my car, cruising is (was) around 3500 RPM.

--DD

[shorty10]

sweet thanks guys by the way any reason im getting 23mpg i filled my tank all the way to the brim and the car was right at empty after 350 miles shouldnt i be getting around 34? car is stock perfectly fine in every way besides that when i start the car up cold it will stall unless i gas it a little also it chugs and has no power at all untill it gets warm the prevous owner said that the aux air regulators fine and that a mechanic said that the FI needed to be tweaked. ? (to fix the chugging)

[M. Hendrix]

Chugging?

Crank the car, sit there, hold it at 1800-2000 rpm. (if your AAR doesn't)

After 2-3 minutes, you are safe to drive.

Until the car idles warm (should be 900-1100) stay below 3000rpm. After it idles warm, stay below 4000 for a couple extra minutes.

TOTAL WARM IDLE TIME=Around 12 minutes

If this isn't answering your question, you aren't babying your motor, you are destroying it.

I know it's hard to understand after driving water cooled motors, but the powerband is where the airflow is, you know that big fan? Make it spin.

Your heads are going to grenade if you keep lugging.

Your fuel consumption will go UP (I meant down. Ed ) if you drive it harder too... it's probably just about fouled out by now, from lugging... clean your plugs.

M

[SGB]

My car has a split personality-
It will motor around on pretty level surfaces, adequately accelerating through the gears and shifting at about 3200. Its even almost quiet when I drive this way. But the car really doesn't like it much. I'm not in the torque range at all, so the engine has to strain to accelerate. The timing isn't as advanced as at higher rpms, and the flow characteristics for the combustion processes work best from prolly 3300 to 4300 rpm. I really baby my 914, but it works best when I drive it HARD. Revving to 5000 or even 5200. Even though it will cruise along at 2800 in 5th, I try to keep it in the 3300 to 3500 rpm range for continuous operation (unless I am on a long trip where op temps are higher than I see in my usual 30 minute intervals using the 914). I've read many times that "lugging" the engine is BAD. Maybe low oil pressure? Strain on the cam gear? I dunno. I say drive it! REV that motor. You will discover the real personality of you car. I sorta worry that something might break, but if you gotta baby it around that much, its not a sports car, just a poser. If it breaks because I reved over 4000 rpm, it was not "going to break soon", it was "already broken!"

[shorty10]

no i was just asking about the rpm for normal driving i only drive it when its nice and warm

i was just wondering why the car is chugging thats all im guessing somthing with the FI

dont worry i dont race the engine when cold...

[M. Hendrix]

Sounds like you never do..

Give it the grits man!


M

[Joe Sharp]

I just had a talk with /L about this the car dose not make any power until after 4000 if you don't rev to 5300 you will never know how much power you have on hand.It accelrates best between 4000 and 5000.
Joe

[shorty10]

i was talking about how the car has no power when cold

[Bruce Allert]

Most things don't have power when cold. You could consider it a safety factor so you don't go driving hard before it's warm cause it just won't...
Mine idles between 1200 & 1500 when first started and is idling aroound 900 in about 12 min. after casual driving However I still take it up to at least 3500 between shifts. Once warm It sees 4K+ & cruises above 3K at the very least.

........b

[woodman]

My Hemi cruises at 75 @ 1600 rpm. Go figger.

[Andyrew]

I shift at 3.2k if im crusing for a while..
but if im going through the gears, about 3.5k.
I have no power after 4.5k (go figure, cant figure it out...).
I guess im not the best one to look at.. But Im hearing that shifting high is good... I guess that the faster the fan goes the cooler the engine is getting.. wierd.

Andrew

[norustscott]

I regularly shift @ 4.5K...Wait, I always shift @ 4.5 K...you can't take it with you and you can always rebuild. Ever hear somebody drvie a type four bus...first to second, 5K without thought...


reasons to bump your shifting habits up 1K

1. Lugging, bad...cam wear. cooling... gas mileage
2. Oil pressure is directly propotional to RPM
3. It is not a bus..have fun...