Q for the 5 speed efi peeps.

When i had my old engine, when i hit 3k in 3rd gear, i would be going 90kph. Now, 3rd gear @ 3k rpm it JUST gets to around 78kph.

Its been around a year and a half i think since ive had this motor so i cant be sure if it was 90kph but i think it was.

70-78 in 3rd 3k

what? in third im 60 - 70 at 3k, at 4k im around 80-90.

Q for the 5 speed efi peeps. When i had my old engine, when i hit 3k in 3rd gear, i would be going 90kph. Now, 3rd gear @ 3k rpm it JUST gets to around 78kph. Its been around a year and a half i think since ive had this motor so i cant be sure if it was 90kph but i think it was.

Hey Gemini !
The engine dose not in any way alter the speed you are doing in a certain gear at a set amount of rev's !
The gearbox & diff ratios along with the tyre profiles are the only 3 things that alter the road speed to the revolutions of the motor !

Hope that has cleared it up for you !

Nic
WA

went and tested out today after readin this. 80km/h in 3rd @ 3k up a slight hill. Just cos mines auto doesnt mean i dont get to reply to thread ! haha

Hey Gemini !
The engine dose not in any way alter the speed you are doing in a certain gear at a set amount of rev's !
The gearbox & diff ratios along with the tyre profiles are the only 3 things that alter the road speed to the revolutions of the motor !

Hope that has cleared it up for you !

Nic
WA

What could have cuased my car not to do 90k at 3k rpm in third then ?

You may have changed the speedo sender unit for an auto where the ratios will be different.

Are you sure your speedo is acurate?

The gearbox & diff ratios along with the tyre profiles are the only 3 things that alter the road speed to the revolutions of the motor !

True, but the car dosn't know that, the speedo is set for the standard g-box and diff ratio's on standard tyres

What could have cuased my car not to do 90k at 3k rpm in third then ?

Tyre wear also alters the final speedo reading (but noo to the extent you are experienceing)

when you change from 4th gear to fifth gear have a look at how much the revs drop.
if the revs dont drop then there is somthing wrong with the vacum operation for 5th gear, this can cause the input shaft to stay in the wrong position which has the effect of lowering all your gear ratio's.

when you change from 4th gear to fifth gear have a look at how much the revs drop.
if the revs dont drop then there is somthing wrong with the vacum operation for 5th gear, this can cause the input shaft to stay in the wrong position which has the effect of lowering all your gear ratio's.

Hmmm ok ill check that out. WHat do you mean it the revs wont drop ? it would just stay there ? or it will drop pretty slowly ?

I noticed that when i could hit 90 in 3rd when i put the clutch down, the revs used to drop prettty fast but now it doesnt drop as fast.

when my OD button for some bizarre reason got stuck one day and i was going onto the freeway needing to do 110kph, i ended up sitting on 3000rpm the whole way doing a nice cruisey 100kph.

no low down balls but heaps a up high room with that zorst system :D

when you change from 4th gear to fifth gear have a look at how much the revs drop.
if the revs dont drop then there is somthing wrong with the vacum operation for 5th gear, this can cause the input shaft to stay in the wrong position which has the effect of lowering all your gear ratio's.
only the tm have the vac operated 5th and im fairly sure hes got a tn

only the tm have the vac operated 5th and im fairly sure hes got a tn

Yeah i have a TN.

ah yeah disregard what i said then, oh and mine does 3000rpm at 70 in 3rd.

I will recheck, but on the very short run I could do it, I was at 65-66 km/h in 3rd at 3000 RPM, with a TN 5 speed EFI on standard 185/75 14 tyres.

I would have swarn that it was faster.

60-65kmh for my 5spd TP....

in 3rd at 2500rpm my tp is at 80klms

Just goes to show how inaccurate everybody's tachos and speedos are! Mine included! On a hot day they read differently than on a cold day! LOL Any crossfire between plug leads on a wet day seems to REALLY throw the tacho off.