RPM's Vs. MPH

e11evon · Post by **e11evon** » February 2nd, 2007, 6:18 pm

Hey guys...I was driving my roommates four banger 90 automatic honda accord and took it up to 80 MPH, and the RPM meter was showing 3,000 rpms. So I get in my manual 93 GS and take it up to 80 MPH, and my RPM meter was bewteen 6,000 to 6,500 ready to redline...is this accurate for a K8? If not why would the Rpm's show that type of reading?

93-Spec-Edn · Post by **93-Spec-Edn** » February 2nd, 2007, 8:44 pm

80 mph is about 130kmh. SHould be around 4000-4500 rpm. The mx-3 v6 revs about a 1000rpm higher than other cars. Thats how its designed. This is in 5th gear.. what gear were u in 3 or 4??

hgallegos915 · Post by **hgallegos915** » February 2nd, 2007, 11:21 pm

We got short gears. I love them.

XxantwawnxX · Post by **XxantwawnxX** » February 2nd, 2007, 11:44 pm

at 80 u should be at around 4000 rpm in 5th gear..which leads me to beleave u were in 4th....

Mnemonic · Post by **Mnemonic** » February 3rd, 2007, 1:29 am

XxantwawnxX wrote:at 80 u should be at around 4000 rpm in 5th gear..which leads me to beleave u were in 4th....

agreed

e11evon · Post by **e11evon** » February 3rd, 2007, 10:58 am

ok last night I tested again.

1st gear ( 20mph @ 6500 rpms)

2nd gear ( 35mph @ 6500 rpms )

3rd gear ( 50mph @ 6500 rpms)

4th gear ( 65mph @ 6500 rpms)

5th gear ( 80mph @ 6500 rpms)

Here is something I need mention...I did swap out the speedometer,rpm, gas & water temp assembly about a year ago. Someone did an engine swap prior to me buying the car back in 2002... from a 93 k8 to a 94 k8 (there are some small differences: water pump for sure)...I had the clutch replaced about 7 months ago...the guy that switch my clutch also cleaned out my transmission...when he went to replace some seals on the tranny...he said the tranny did not belong to an mx-3.

I am definitely not in fourth gear going 80 at 6500rpms....could it be a vacuum leak, sometimes the rpms go up but no power then al of a sudden it launches off like crazy (around 5000 to 6500rpms in any gear).

XxantwawnxX · Post by **XxantwawnxX** » February 3rd, 2007, 12:09 pm

Sounds like a slipping clutch.

Tunes67 · Post by **Tunes67** » February 3rd, 2007, 12:19 pm

Sounds to me like the Tach is giving a false reading.. if its launching hard around 6500.. sounds like the Vris is kicking in.. and since that happens at a lower RPM.. sounds like the Tach is messed up.

Tunes67

Nd4SpdSe · Post by **Nd4SpdSe** » February 3rd, 2007, 1:25 pm

e11evon wrote:I am definitely not in fourth gear going 80 at 6500rpms....could it be a vacuum leak, sometimes the rpms go up but no power then al of a sudden it launches off like crazy (around 5000 to 6500rpms in any gear).

RPM's vs Speed is a fixed value. The motor is basically tied physically to the wheels. So you should always be doing say 4000rpms at 80mph in 5th unless you change something between the tranny and the wheels (say, a taller gearing tranny, or larger/smaller diameter wheels, or obviously, if your spinning your tires), but typically, you'll always be at the same RPM's at a given speed.

As mentioned, there's 2 possibilities. But what would probably be a good idea is for an experienced Mx-3'er to drive in your car, drive it or as passenger, doesn't really matter, probably best as a driver. But someone who's driven their car long enough where they can shift just by feeling and hearing the motor rev and not need to look at the tachometer.

I dont know what a slipping clutch feels like, but for what i read and heard, it should feel exactly like it's slipping, hard acceleration should be inconsistant, like trying to drag on wet or snowy roads. Same should be when on the highway, revs should be jumping around a bit, and just slip more if you punch it. And it should get worse over time, even on the same drive it'll heat up and slip more, and over time it'll wear out really fast

But i'd first get a first-hand second opinion from an experienced Mx-3'er, and go from there.

e11evon · Post by **e11evon** » February 7th, 2007, 1:13 pm

OK, now that it was mentioned....I took my car up to 70 mph in fourth gear somewhere at 7500 to 8000 rpms (I know dangerous), it didnt sound like the engine was stressing and the VRIS thingy was kicking in everytime around 6000 to 6500(I am assuming 6500 should be reading somewhere around 4500)...for some reason my tach is reading up 2000 rpms...I am guessing no one else has encountered this problem.

XxantwawnxX · Post by **XxantwawnxX** » February 7th, 2007, 5:06 pm

what does it say ur car idles at??

e11evon · Post by **e11evon** » February 8th, 2007, 1:50 am

My car starts its idle around 2000 rpms, on a cold morning...after driving half a mile and coming to a stop sign, it idles around 1100 rpms.

hharb · Post by **hharb** » February 8th, 2007, 2:57 am

idle rmps sound fine to me, mine normally starts up at 1900-2000, goes down accordingly until its hot enough and normally stops at 1100 rpm or a bit lower. since the idle rpms make sense i'd say that the tach is fine, so that one got illiminated, so u should be looking at the other possible reasons behind the high reving, if u know someone who has an mx3 it could become easier since you can compare the behaviour of the two cars.

e11evon · Post by **e11evon** » February 8th, 2007, 1:13 pm

Well I wouldn't think the Idle Rpms would show an inaccurate read out...When I am at 6500 rpms in any gear, the engine does not sound hi reving or decelerates fast like it would if I red lined 3 gear then let off the gas. Does the K8 have a rev limiter? I don't want to find out the hard way. Also I thought our cars are suppose to ilde at like 700 rpms?

XxantwawnxX · Post by **XxantwawnxX** » February 8th, 2007, 3:07 pm

put the car in like 3rd or 4th gear (standing still ) REV it up reallly high and dump the clutch...if the car stalls out right away ur clutch might not be bad..if the rpm's just keep going then ur clutch is slipping. Oh make sure ur ebrake is on also to add extra load.