RPM question..

I was just wondering what RPM you are running at say, 70mph, or at least what the range should be? I usually run 65-70 at 3k or a little more..it seems as if the car should have another gear though it doesn't. I was just wondering if this was normal? I know the car can go a lot faster, but when I do it sounds like the engine is working extremely hard and I don't want to damage anything..

that sounds pretty much right... my car 5th gear 3grand 70mph

Yea that rpm is fine. I can't say for sure for automatics but sounds right. Also are engines are loud so don't worry too much. Do your automatics come with Overdrive if so you can lower rpm across the whole band with that on at the expense of performance

You are right, it does seem that the car should have another gear given regular highway cruising speeds, but I think most Mitsus are like that, except for the 6 speeds. 4-bangers are buzzy little motors anyway, and the final drive gear in your case sacrifices a comfortable cruise RPM for higher performance. Same thing on my 3000GT, I swear at 3000rpm I'm doing only 65 mph, as well as on my 4-banger Galant. Just just the gearing they came with. I'll be putting in a 16% taller 5th gear on my GT once the tranny goes out (hopefully not to soon).

Just for reference, at 70 mph in 4th gear my car stays at about 2,500 rpm.

Ha ha, shut up Chrysler boy :p. Just playing man. The 420a is mated to a Chrysler tranny isnt it?

I am considering getting the taller 5th gear for my Talon. Only thing is I dont want to need that gear in the 1/4 and have it too long to be in good power band. How fast would you be going in 4th around 7k? Granted I will be shifting past then but just for reference :).

Just for reference, at 70 mph in 4th gear my car stays at about 2,500 rpm.


Really? I'm at the 3.5-4k range at that speed and gear.

Really? I'm at the 3.5-4k range at that speed and gear.

yea sound about correct but yea i'd ask about eclipses 2500 ...

In 5th, my needles are aligned perfectly. When on the highway, rpms and mph are pointed straight up. I could go for a 6th gear. Someone make one for me, ok? Thanks.

yea sound about correct but yea i'd ask about eclipses 2500 ...

You guys want a picture? I will take one with my phone on the interstate. With the cruise set at 70 mph, rpm is at 2500 and I'm assuming it's in 4th since that's my final drive gear with the O/D on.

The 420a is mated to a Chrysler tranny isnt it?

I'm pretty sure it is.

Yes, the 420a is mated to a Chrylser tranny.

I know that I drive a Ford :( but they didn't really use much common sense when they built these trannys. They made a shift point at regular cruising speed at about 32 mph, why would they do that? Just tryin to maintain normal speed in town makes the tranny constently shift up and down.

Doing 70 in over drive (4th gear), my car is at 3000 RPM. The needle on the RPM gauge looks like it says 2800-2900 but my s-afc reads 3000 rpm's. Sounds like the tranny is fine thunderchicken!

I know that I drive a Ford :( but they didn't really use much common sense when they built these trannys. They made a shift point at regular cruising speed at about 32 mph, why would they do that? Just tryin to maintain normal speed in town makes the tranny constently shift up and down.
Are you describing mitsu auto or ford when you say "these trannys"?

Thanks all, I was just curious :P I guess my mind still hasn't completely transferred from the 95 thunderbird to the DSM world. With that v8, I would run about 1700rpm at 70-75 :D.

Really? I'm at the 3.5-4k range at that speed and gear.
I took a pic this weekend. Enjoy those who doubt.

http://img71.imageshack.us/img71/9867/pic05wk1.jpg (http://imageshack.us)

Thats weird as hell, its an automatic right? I'll try to get a pic of mine tonight.

Thats weird as hell, its an automatic right? I'll try to get a pic of mine tonight.

Yep, auto. Not by choice though :)

Different motor and trannys then 4g63 cars set up. I bey you get amazing gas mileage. I get like 16mpg in city(low 20's on highway). Sucks!

What does that thing run at without the OD on, probably somewhere close to the 3.5-4k range if I remember correctly. And just based on the fact that its an auto will completely differentiate it from a manual, totally different gearings.

Ofcourse. Are the autos 4 or 5 speed? And 70k miles, I'm jealous, I'm about 600 miles from doubling that.

Autos have 4 main gears and a "5th" gear which is Overdrive, that's what keeps the RPMs so low on the highway/interstate. It's an economy gear (but I'm sure you already knew that)

Yup yup, must be nice. Buzzing along at 3-3.5k gets a bit nerve wracking sometimes.

I bey you get amazing gas mileage.
Around town, not so much. I average somewhere in the mid 20's, with about half of my driving interstate. If I just based it on interstate driving, I get close to 30 if I set the cruise at 70. That's wintertime though, in the summer I had a best of 33-34 mpg interstate.

What does that thing run at without the OD on, probably somewhere close to the 3.5-4k range if I remember correctly.
Yeah, if I turn the OD off it jumps to around there. I think it actually downshifts though when I do that, because when I turn it back on it shifts down to about 3k and then makes it's way back down to 2.5k.

And 70k miles, I'm jealous, I'm about 600 miles from doubling that.
After my trip today I am a few miles shy of 77k. I got it with about 55k 2 1/2 years ago.

Well, the overdrive is sort of a whole another gear, but it's not a "physical" gear, all that happens is the computer goes into "economy" mode and does not give a shit about what kind of power it's putting out, it's only there to increase mileage and decrease emissions. It feels like it downshifts because it goes back into the "powerband", and then when you turn it back on, it takes a few seconds before it can calculate the best RPM for the speed that you're at.