very weird kph/mph issue

[Tom N]

I have been trying to figure out why my car seems to go slower at certain rpm points than it should. It is a 95 Lancer GSR with a evo 3 engine, ecu, turbo, front mount set up.
Tranny and rear end are stock for the car. I disconnected the drive shaft ( prop shaft to non Americans ) and manually checked the rear gear ratio and it is definitely 3.54.
Heres the weird part. According to sources the Lancer GSR has a final drive of 4.93 and the EVO 1-3 has a final drive of 5.44 as well as a 3.9 rear gear.

Well I had noticed when cruising at 4k rpms in 5th gear I am going about 76-78 mph and according to a gear calculator I should be going closer to 87mph.
I checked my mph in other gears to see if its just 5th thats off. Its not, 3rd and 4th show me going slower than the gear calculator shows at 3k and 4k rpms.
Now hears the crazy part.
If i take the 4.93 final drive ration out of the calculator and put 5.44 in as the final gear ratio that the evo 1-3`s with a 3.9 rear have instead of 4.93 like it should be for a car with a 3.54 rear gear my mph in 3rd 4th and 5th gear at 3k and 4k rpms are within 1mph af the calculator????????????
How in the hell is this? The car has a 3.54 rear not a 3.90.

 

[khubner1]

some one probably put in evo an evo gear set.

i know it's a completly different box to your but my fwd coupe gets the same readings as yours for those measurements. (had to convert mph to kph to figure it out though)
3.5krpm gets me 110kph which is around 68 mph

 

[Tom N]

some one probably put in evo an evo gear set.

i know it's a completly different box to your but my fwd coupe gets the same readings as yours for those measurements. (had to convert mph to kph to figure it out though)
3.5krpm gets me 110kph which is around 68 mph

The rear end is definitely a 3.54 not the 3.9 in the evo. I manually checked it. The tranny is a lancer GSR tranny according to the serial number onand I dont see how it could have evo 1-3 internals as 4th and 5th would give me more mph not less.

 

[Lister]

Tyre size????

 

[Tom N]

Tyre size????

205/55/15

 

[to4garret]

Some GSR's (RS?) also came with a close ratio gearset.

I have been in one GSR here locally that was doing around 60mph at 3.5krpm, much higher than the usual 3.0/3.2krpm. It did have a 3.545 rear end too because we checked.

GSRWRC would know for sure.

 

[Tom N]

The chasis code on this car and tranny are not of a RS but it must have some different internal gearing than that of a typically Lanser GSR. The car is a Japanese spec Lancer GSR. Were there different hearing used on them in Japan vs the UK or Australia?

 

[GSRWRC]

Gear ratios are across the board for Aussie spec and JDM GSRs, RS vs non RS.

The stock tyre size for a GSR is 185/60/14. Running 205/55/15s is an increase of 4.74% over stock according to a tyre calc. This will account for 5% of your lower reading.

The other thing is that if the gearbox has been opened up and rebuilt at some point durings it's life, it's possible the Speedo drive has been changed. W5M33s from different cars carried different speedo drives. If yours has one from an Evo, RVR or some random DSM instead of one for a GSR, it's possible your indicated speed might be further affected.

EVO-00X will be able to say which colour drive is for a standard GSR. (I can't remember off the top of my head)

 

[Tom N]

Speed is being taken from a gps not the speedometer.
So none of that matters.

 

[GSRWRC]

That information might have been helpful at the start of the thread....

 

[Tom N]

I could have swore I put that in my initial post. I even went back to quote it but apparently I didn't.

Is everyone positive the transfer case is 1.090?
It has a transfer case that looks just like the late 2g transfer case which I believe is not 1.090 but 1.074.
It doesn't have a transfer case that looks like a gvr4 or a 1g - early 2g DSM.