3400 Revs At 100Kph Whats Going On??!!

[mutley-60]

hi guys , i have a MANUAL 5SPEED 1990 sx seca 1.6 AE 93 4A-GE with axle-642 trans C52 tires are 185/60R14,

My issue is that the motor is revving at 3400 while at 100kph, sounds like it is way too high.

i have a mate with a 4door hatch corolla with the same engine and axle /trans codes but with 195/50R15 tires and his car rus 3000RPM at 100kph

i have made a comparison of the two tire sizes on a tire calculator and there is a minute difference in tire diameter so the revs should be the same.

 

when i bought the car the guy said it was not the original motor, but it is a 4A-GE engine

however he did not mention the gearbox

 

does anybody have an idea what might be going on??

is there another gearbox out of another model that has different ratios that may have been fitted???

 

any help will be appreciated, thanks

 

cheers mark 0403987379

[Twincam16seca]

i have an ae82 twincam seca & that sits about the same rpm, so the ratios maybe a bit different and the box may have been swaped over at sdome point as they bolt up.

[Subaru_kid]

Same story, still does 6.3L/100km on the freeway... problem?

[altezzaclub]

Jack up one front wheel and turn the motor with a spanner until you've turn the wheel exactly half a turn. Then do the same to his and see if he gets the same engine turns. That will give you the two overall ratios, there may be differences in either the diff or the gearbox.

 

Youy could try 4th on both cars if they all use 1:1 4th, that will give you the diff ratios. With one wheel on the ground the one in the air will turn twice as fast...

 

I get 3300rpm in 5th in the KE70 on 14" tyres, and they made a big difference over the 13". Might pay to measure the distance each tyre travels over one rev, rather than usng the tyre calculator.

[mutley-60]

hi guys, thank you,lots of good ideas

the car is getting about 10 lltrs per 100k,( same as my 98 camry wagon), it just feels and sounds not happy on the freeway!!!

what i will do is put my mates wheels off his car on mine and takei it for a drive then go from there.

its just baffiling that the other corolla is doing a flat 3000RPM. go fogure.LOL

thank you all very much

cheers mark

[philbey]

Probably just running different diff ratios.

[droola]

i have exact same spec car as you and thats complely normal, top speed should just be on 190 on a flat road too FYI haha

[bAKER]

you seem to be getting bad economy, id be checking the timing. My 4a gets about 7.5L, when she's getting thrashed.

Although I have an auto diff in mine so she sits a bit higher, rev wise.

Edited July 28, 2012 by bAKER

[mike100]

my corolla ae101 runs 4age 20v with c56 5 speed revs same as yours on freeway at 100k 14 inch wheels , sounds fine to me.

[Subaru_kid]

Check timing with a timing light (don't forget to bridge it when doing this) and get a new O2 sensor.