hey guys can u tell me what rpm a vlt manual should be doing when crusing along at 110 i am getting 2750, but i think this may be a little high

should be about 2400rpm, you changed your diff ratio or anything like that?

no however this was a conversion, orgionally auto any reason to y this is occuring?

what size wheels/tyres you using?, is it an MX7 or R33 box?, could a previous owner have changed the diff ratio?, is your tacho working ok?, is your speedo reading correctly??, these are all things you need ton look at.

thanx for that 87 calais i am running 225's 16" clubbies, i was told by previous owner RB30ET manual gearbox therefore i assume mx7. tacho works fine, speedo doesnt kick in till about 20km/h not sure bout diff ratio, have to ask

87 cal is right,im at 2600 at 110kph.im using 225/50/16 aso.

mine is 2,500 rpm at 110 k's with 16" wheels, hope that helps

yeah thanx fellas, there is a little variation when crusing at 110, in my case 2750 revs, this is max boost for a stock motor at this rpm isnt it? does it cause any significant wear on the turbo crusing for an hour or 2 at fullboost?

im on about 2400 with 18" wheels

ill work it out for 16s with 225/50/16 tyres. your turbo wont be making much, if any boost when cruising, boost will rise as the engine loads up. Turbos dont make boost from engine rpm, the make boost from exhaust gas density, the more load on an engine, the more boost it makes.

ok, if its an MX7 tranny in 5th, with stock 3.45 ratio, rpm at 110kph should be: 225/50/16 = 2436rpm 235/45/17 = 2391rpm 245/40/18 = 2355rpm now, with you 16's, if your diff ratio was 3.89 your rpm would be 2747rpm, if you had 3.91 gears your rpm would be 2761rpm. so sounds to me like your diffs had a ratio change along the lines.

mines an auto N/A and runs at about 2000rpm at 100kph, sound normal?

yep, should be about 1962rpm

thanx heaps 87 calais, so with the rpm im getting, i must have close to 3.91 gears? these r skyline gears rnt they? are there any advantages or disadvantages of this sort of gearing over standard gearing?

Quote: Originally Posted by 87calais yep, should be about 1962rpm Is that with or without lock up ? If with lockup, wat should it be without ?

my car runs about ~2400~2500rpm with 3.7 diff and 17"s....

Quote: Originally Posted by Midz Is that with or without lock up ? If with lockup, wat should it be without ? That would be assuming a direct input into the tranny, so with lockup on. Without lockup, hard to say, would depend just how much slip was in the convertor and i would guess that it would vary from car to car. i would guess somewhere around 2100 - 2200. Unplug your lockup solenoid and take your car for a spin , let us know the results.

Quote: Originally Posted by 87calais ok, if its an MX7 tranny in 5th, with stock 3.45 ratio, rpm at 110kph should be: 225/50/16 = 2436rpm 235/45/17 = 2391rpm 245/40/18 = 2355rpm now, with you 16's, if your diff ratio was 3.89 your rpm would be 2747rpm, if you had 3.91 gears your rpm would be 2761rpm. so sounds to me like your diffs had a ratio change along the lines. How does this work, with the speedo connected at the gear box? The speedo reading itself should be the same no matter what wheels are fitted. Just wondering how you equated these figures?

depends on the rolling circumferance of the tyre, so it will change. also depends on the diff gearing as to what speed the speedo reads as the speedo is calibrated for standard tyres and 3.45 diff gears. hey, cause normal vl's had 14"s and calais had 15"s does that mean the speedo's will be calibrated slightly differently?

You could have monster truck tyres on your car and 5.11 diff gears, and it would still read factory rpm @ 110kph if your speedo hasn't been calibrated. Your speedo will say 110kph and your tacho would read factory, but you would be doing a different speed.