rpm at highway speeds

[mindaugas]

What kind of rpm do people run at 65 - 70mph? Hills or flat, my VX seems to be stuck at 3k rpm @ 70mph. Seems high to me for a motor this size, but idk how transmission, gearing and all that impact it. My outback does 70 at 2200rpm which is prob a horrible comparison.

[VXorado]

Since our VXs only have 4 speed transmissions & come stock with 4.30 axle gearing, you can expect higher RPM when you hit highway speeds. My RPM is usually 2000-2500 at 65-70 MPH if i'm just cruising along but I have larger tires which will require less rpm to go the same speed as stock tires.

[Ldub]

Are you in "power mode" or "normal mode" with regard to the trans control button on the ctr console?

If in "power", try "normal", the TC will lock up at a lower rpm.

[deermagnet]

3000 at 70 mph is too much. To see if you're getting into overdrive just shift down to third gear when cruising at 60 mph. If the rpm's jump high you were in overdrive. Shift back to drive and the rpm's should drop back to where they were. If you shift to third gear and nothing at all happens then you were in third gear already and you're not getting up into overdrive and something is wrong.

Mark

[vt_maverick]

3K sounds about right to me and I get 15-17 MPG on the highway (not bad considering my heavier tires, rims, and Kilby skid plates). I find it hard to believe a 4-speed truck is going to go 70 MPH at 2000 RPM unless it's downhill.

[Y33TREKker]

I'd always considered the VX's rpm's at highway speeds high too. That's the trade-off for the VX's low-speed acceleration and high-torque capability though.

[mindaugas]

Hmm, maybe I'm not getting into OD. Do you think the fuel pressure regulator or EGR would cause a little higher rpm on the highway? FPR is shipping.

[blacksambo]

My highway speed is under 2500rpm, that's approx. 70mph. Same with my wife's '99 VX. So, I think you must have something going on. Maybe check the accuracy of your tach?

[deermagnet]

Yes, it should be under 2500 rpm, possibly as low as 22-2300 after TC lock-up in overdrive. Even without TC lock-up it should not be more than 2700 rpm in overdrive.

Everyone just report here what you're seeing and there will be no guessing.

Mark

[mindaugas]

thx, I'll let u guys know what it's at after I get the new FPR in.

[VXorado]

Are you in "power mode" or "normal mode" with regard to the trans control button on the ctr console?


I decided about a year ago to always run in "power mode" and haven't looked back. You get quicker shifting in power mode and my gas mileage has maintained the same 14-17 MPG. When you drive at highway speed the transmission will still shift to OD & lower the RPMs to normal until you start accelerating it will downshift to third gear pretty quickly.

When I was in "normal mode," The transmission always felt like it was trying to shift up constantly & too early where I would lose the power ban going up hills. It may just be my VX, Colorado altitude or larger wheels but my VX transmission feels much smoother on power mode.

[RickOKC]

I drove at 70MPH for a few seconds before a traffic jam slowed me down...

2350 - 2400 RPM (32" tires)

[BOARZHEAD]

Im at 2200 with my 37" tires at 70

[vt_maverick]

Drove 140 miles this morning, mostly on the interstate, but somehow forgot to look at the tach. :_brickwal: Driving another 150 something miles this afternoon though so I'll try to remember.

[rsteinmetz70112]

Im at 2200 with my 37" tires at 70

Bigger Tires = Lower RPM

[BigSwede]

FWIW (not much) my Trooper, with manual transmission, 35" tires, and 5.38 gears is turning around 3300 rpm at 75 mph. But here is the point - I still get 15-16 mpg at that speed on a lifted vehicle that was only rated for 17 highway by the EPA in stock form. And these DOHC engines aren't strained in the least by running that high of an rpm all day.

So I don't worry about it.

[mindaugas]

And these DOHC engines aren't strained in the least by running that high of an rpm all day

that's cuz yer trooper is a trooper

I stripped the bolt trying to get the cover off the FPR, might try to find some more alan wrenches or something, or have a shop do it. not looking forward to trying to get the rear one off.

[subject47]

I just finished a trip this past weekend 2600 rpm speedo read 66 mph but i was doing 70 verified via gps on 32" tires

[vt_maverick]

2600 RPM at 70-ish for me, although it varies based on whether you're going even slightly uphill or downhill and obviously when you're coasting vs. accelerating to keep 70. Regardless, with Kilby plates, oversize tires, heavier rims, cargo basket, and roof mounted spare I still got 17 MPG in mostly interstate driving through the mountains.

[mindaugas]

Gonna take it to a shop here in a bit to try and get that FPR out. I can't get past the first bolt I stripped.

[mindaugas]

Fuel pressure regulator and exhaust gas regulator both replaced, STILL high RPM at 70mph. AND, this is going down a f'n hill ... :( I tried with power off and on, and AC off and on, always the same RPM at 70mph. At least it's consistent.

http://www.vehicross.info/gallery/data/500/thumbs/IMAG0422.jpg (http://www.vehicross.info/gallery/showphoto.php?photo=21194)

In other news, the FPR and EGR fixed the start problem I was having.

[PK]

Some points to consider -
1. Did you try the overdrive test suggested by Mark in post #4?? Or count your gearshifts as you accelerate?? If you are not getting into 4th gear, that would account for about the difference you are experiencing. Your transmission selector might be out of adjustment, and you are driving around in 3rd all the time.
2. Is your transmission slipping?? That will account for higher revs, but only going uphill.
3. Do you know the vehicle history?? Previous owner might have changed the diff ratios if they were running bigger tyres at some point.
4. Do you have a Scangauge or similar, that you can test your RPM with?? Tacho in dash might be giving a false reading.

This is definitely not an engine problem.
It is a transmission, gearing, or tacho problem.

PK

[mindaugas]

Did you try the overdrive test suggested by Mark in post #4??
I did, sorry. I tested at 60 and 70, and both times 3rd jumped the RPM by about 1k. So it's definitely getting into OD.

2. No tranny slip at all.

3. I do not know the full history, but I doubt it ever had big tires. I really liked this one because it looked stock.

4. Nope, and although the motor isn't very loud, it feels like higher RPM simply through throttle control.

In other news, the FPR and EGR made it more responsive and generally drive better through the city. I also have 0 startup problems now.

[p_justin13]

I'm on stock size and commute interstate every day. 70-80 hovers right between 2500-3000 at all times for me and I'm still getting close to 19 MPG in the summer heat usually only 14-17 In winter

[mindaugas]

80 in a VX?

http://blog.dreamhost.com/wp-content/uploads/2011/03/Ludicrous-Speed.gif

[Ldub]

Recent long distance testing between Fgo & Hampton SC indicate 2250 rpm @ 70 mph...35" tires.