Romulus22

Im curious to see what RPM's people are willing to cruise on the highways to maintain the "street" of their "street cars". I'm talking highways speeds of steady flowing traffic. 65-75, no one goes 55 anymore.

Im pretty much maxed on rear gear and I'm not used to driving a car with no OD so it seems like my car revs to the moon on the highway. I don't have a tach yet but the gear calculator says I should be in the 2500-3000 RPM range on a 26" tire with 3:00 gear.

Rok_Star_Bars

LS1 with cam, T-56, and 4.10 with 6th gear cruising 80 mph @ 2200 rpm with 26” tire. Avg 17ish mpg city/highway combined

HCI2000SS

iTrader: (2)

Same for me on RPM and gas mileage

Utinator

I have a stock LS1/4L60/.323 gear, and get about 2050 rpms at 70 mph. I am getting a 4L80 this week, so we'll see if that changes anything. My goal is 2000 rpms or less at 70 mph.

Michael Yount

iTrader: (1)

98CayenneT/A

If anything you will see a slight bump in rpms due to the 4l80e having a very very slight higher Od ratio.

4l60e Od ratio .70 : 1
4l80e Od ratio .75 : 1

98CayenneT/A

4l60e with 3.73's and 26 in. tire I'm at 2700 rpm's at 80 mph which I do all the time on my way to my track a hour away.

2500 rpm's @ 70 mph

Michael Yount

iTrader: (1)

FirstYrLS1Z

iTrader: (4)

I ran 4.56s'/A4 for 4 years,2007-2011,the 4.56 rear end is going back in as soon as weather warms up.
My freeway RPM(off the ScanGaugeII) was 2500 at 60mph and 3000 at 72mph.
Five trips from Cleveland Ohio to Florida with 4.56s'. One time coming back in South Carolina on I26,hooked up with a fast moving group of cars and was in cruise control at 4000 rpm for about an hour.

RPM WS6

iTrader: (3)

Some of the replies above don't necessarily seem to be answering your question. It seems that you're more interested in how high (rpms) folks would be willing to live with, not necessarily what their cars currently do.

If so, I would say this depends somewhat on things like exhaust system and interior insulation, but much of it will still be a matter of personal tolerance. 2500-3000rpm is going to be a lot more manageable in a full interior car with a relatively quiet exhaust, vs. the opposite. My '71 has no OD which puts me in the 2500+ range for speeds over 65mph. My exhaust is loud but not TOO loud, and it's got full carpet and interior. I don't find this to be a problem, but I don't cruise on the expressway with this car very often. I don't think I'd be comfortable cruising for long periods at 3000rpm+ in this particular application, though I might feel differently with a quieter exhaust or more interior insulation.

Romulus22

I really didn't specify that great but yeah I was leaning towards the higher geared cars or the cars without OD. Seeing how high people cruise at. Regardless that info might help someone else too.

And you're correct. If I was in a car with better insulation it might be that bad, but I'm on a bare bones no excess weight setup. So the noise is that much louder. I don't mind taking back roads but there's going to be times when I need to go 1+ hrs to a track and I won't have a trailer 99% of the time.

AnotherWs6

iTrader: (17)

I'm at a little under 3,000rpm in my old Suburban at 75mph and I'm fine with it. No insulation, just a rubber mat. 3 grand is realistic limit. That has a 3.08 and a fairly short tire with no OD so close to you.

Utinator

That's not good. I was thinking about swapping the 10-bolt rear end for a 9" (different gear ratio), but I'm not ready to do that anytime soon. Hopefully the rpms won't go up too much. We shall see.

jhshnh

SteenH

For my car about 3k is tolerable, any more than that and it just feels out of its comfort zone, slightly annoying, etc.

01ssreda4

iTrader: (96)

I did 4.30s in my yukon and cruised at 3k pretty regularly and didnt care for it. Car is about the same with 4.10s. Ive back both down in gearing to the 2500 rpm range. No clue why that 500 rpm makes that much difference in my mind.

kingtal0n

iTrader: (1)

Using 4l80e, 26"~ tire
I went from 4.11 to 3.69 around 3200lbs and mileage improved from about 19 to 22~mpg highway.

Injector duty didn't budget. I was cruising 15~mph faster at the same someRPM using the same amount of fuel. If I could change the rear even lower to 3.5 or 3.4 I would.

I need my V8 engines to cruise well below 3k. Its too fast for such heavy parts to spin constantly. I drive slower if necessary until I get the right gear/tire. I do ALOT of long distance driving so this is essential for longevity, oil quality, temperature, and of course fuel use. my 2.0L 400whp nissan engine can sit on 3k all day np though.

Utinator

I just got the car back with a 4L80e. Now, I cruise 70mph at about 2250 rpms. I prefer to keep my highway rpms at or below 2000, but that's just my preference. It's not loud at that rpm, even though it has headers now. It's my daily driver, so I like to get respectable fuel mileage.

I was thinking about finding a taller tire. I'm thinking that will get me close to 70 mph and 2000 rpms again. The other option would be to change gears. I'm not sure I want to do that right now.