I do a lot of highway driving for my internship this summer and was wondering what kind of rpm everyone else is turning at speeds around 70 mph.

Since I converted to a T5 my car has been running at like 2500 at 70 mph. Could this lead to premature engine failure?

 

The T5 has a (numerically) higher Overdrive than the 700r4 so you will have higher RPMs. 2500 is no big deal. My BMW spins about 2700 RPM at 70 mph with a 3.73 rear. You could put a (numerically) lower rear end in your car to lower cruise RPMs but it would also hinder acceleration.

 

Do you know what RPM other thirdgens run at at highway speeds?

2500 rpm might not be that big of a deal for a BMW or other cars because different engines behave differently. Some 4 cylinders idle close to 2k but red line at like 9k.

 

for a 700R4 we'd be expecting low,mid 2000's for 70mph. maybe 2300 or so. I'll run nearly 2600 right now, but that's because my TCC selenoid is shot and doesn't lock the convertor (and i was wondering why my miliage went to hell). 2500 RPMs isn't going to kill the engine, atleast no time soon. What do normal T-5s run at at highway speed? have u tried the Tech Conversion page, you could simply enter your tire size, tranny ratio, rear gear combo then find out how ur looking, and if u simply want to get lower rpm's find a v8 axel with 2.73s or something, and u'll be fine.

 

2500 rpm @ cruise isn't gonna hurt anything.. period.

 

3.1 + T5 @ 80MPH = 3000RPM for me. And thats my average spped on the highway.

 

what 4 cyl idles at close to 2k rpms?

as far as cars go though I used to have a 71 camaro with 4.11 in the rear running a TH350
just imagine what driving down the freeway at 70mph with no overdrive

 

i run about 2700-2800 at 70 mph with a 700r4 and 3.73 rear gears. when i had 4.10 rear gears, i was a little over 3000 rpms @ 70.

 

wont hurt anything at all and you probably have 3.42 gears in your car

 

my 86 stang had the german 4spd = no od which put 70 a little higher than you, was real good for acceleration, but hwy sucked a big one

 

At 80 mph, my Formula is turning just over 2000 rpm with 3.42's and a .63:1 OD in the T5. I could really use 3.73's, because it starts making it's power around 2800.

 

my old V6 camaro usually at 75 around 2700.

My new car that I am working on will see into the 3K range. Which is fine for me, that is the beginning of the power band in it.

 

Thanks for all your help. What kind of gas mileage do you guys get at those speeds?

 

My camaro typically got 320-340 miles to the tank. I did it by tank, not MPG. But a calculator tells me about 26-28 MPG.

 

I do 75 on interstate and churning out 2100 rpm in overdrive and 3,000 rpm in D. after 90+ mph my rpms are in the 4,000 range.

 

still hoping you could explain that

 

Sorry, maybe my numbers are a little bit off. That wasnt the point of this thread. My friends acura RSX-S idles at 1500, thats what I was thinking of when I wrote that. I guess I should have said 1500 instead of 2k if you want to nit pick.

 

Mine turns about 1600 at 70, thank *** for torque.

 

Yea, I figured V8's would turn lower RPMs.

 

If it idels at that there is something worng.

I have never seen a 4 banger, or rotary even that idles above 1K. Mostly around 9-950

Hell even **** rockets idle at 950... Nothing to be nit picky about it, it's just flat out wrong.

 

more or less just trying to figure it out
most cars are set for an idle of 750 or so
some around 650 and some around 800

that is generally about average
now granted I have seen a fw 8's idling around 1200 rpms but they are also running about 250-260* of duration and have a huge lumpdadelumpdade idle to them


but if your friends rsx-s is idling that high something isn't right

 

mine idles at 1400- 1500 thanks to a big fing vacuum leak

 

bringing this one back a bit. Was meaning to check and compare.

80mph @ 2900-3000rpm

3.4lt
700r4
3.73 axle
235/60/15 tires.

Looks like its about right

 

@70mph, I don't even go into OD. rpms are too low.

I generally will cruise in overdrive at 80 or above, otherwise I don't use it.
70 in drive (1:1 w/ 3.23's)- 2950rpms (good powerband)
70 in OD (.70)----------------2050rpms (Lags and downshifts if I press throttle slightly more)

80 in drive-3350rpms (getting high for just cruising, but still fine)
80 in OD- 2350rpms (just getting into powerband, cruises decent)

---------------------------------------------
locking in D (3rd) and racing gives me;

60mph-2500 (sitting barely into the powerband range. It will stay here if roll into it fairly good coming out of a corner. Stab it- and it will downshift for a few then re-up to 3rd unless I lock it down and hold it)

100mph-4200rpms (can cruise at this rpm all day if needed)

123.3mph (what my GPS clocked me on Califspeedway in 3rd[D])- 5200rpms. I don't have to nor do I go into OD on the course.

Edit:I can run the whole course in two gears, 2nd and D. And I manually shift them. 5 of the 21 turns I lock down to 2nd, slowest corner is aprox 40mph @ 2750, then up to 80@5500, then bump to D.

This is why I went from 3.42's down to 3.23's. They are better suited for road gears with the auto and powerband.