transmission questiong for you techs

[synergy]

I have an rb25 with a s14 rear diff my gearing looks like this.

1st:25MPH2nd: 45MPH3rd: 70MPH4th: 95 MPH5th: 120MPH

On the highway in 5th gear im doing almost 5grand. Its totally rediculos. I have looked at some rear diff charts the stock 240 is a 4.10 the q45 is a 3.56 and it said with the 3.56 top speed should be around 165. That makes sense to me that i can only go 120 BUT i know other people with this setup that have normal RPMs thru the gears with stock s14 diffs

Whos car is messed up here? My transmission or they dont have stock diffs?

[Joe]

1) your tach isnt calibrated

2) the factory speed cut is 120mph.

3) stop being an idiot on the street.

[maryjane]

jesus 120 on the top of 5t? sounds like rb20 ratios with a 4-something rear end. thats sorta weak, but i think your tach isnt workj rite

[synergy]

1. Joe i think my tach is calibrated correctly I hit full boost at about 2500 RPMs if it was incorrect i figure that would be moe like 3-4k

2. I have figured the top speed by my crusing RPM of 4750 on the highway i have never gone over 80 in the car swear on my mothers grave.

I looked at the transmission and it looks like a normal rb25s1 transmission.

Maybe i will send out my tach to Carl to "make sure" it is calibrated correctly.

I thought someone messed with the ratios so it would trap 120s at the track or something like that.

[Thanielson]

well somthing does seem very off mine with a neo rb25 trans

1st 402nd 613rd 90 somthing4th idk5th on the dyno was 160 on a s14 diff.all on stock redline

your full boost sounds ok but what gear are you hiting full boost at for 2500 rpm?

what is your redline at?

[20DET]

well i know u guys are in MPH but my old cefiro with RB20DET from a R32 Skyline GTST and GTST 20det gearbox and 20det R32 LSD hits 170KPH in 3rd gear.if that helps any...

[20DET]

wouldnt a easy way to check if the tacho is calibrated by seeing what it says on idle???? and u cud also corispond with a digital tacho that u point at the front crank pully

[Carl H]

i'd say the tach is off man...even with an r33 auto final (4.36) highest i see cruising is a hair over 3k around 75.

[20DET]

and the factory speed cut isnt 120mph (200kph) its 180 kph

[synergy]

alright carl lol. When i first had the car idle was at like 1800 and oil PSI 35 at idle. WAY TOO HIGH. So it randomly droped to 14.7 and idle droped to 900-1100 and now it stalls. So when oil PSI is too high it idles high and also idles fine when the idle is closer to normal and the oil psi is normal it dies. Ill send my unit out carl and see if it actualy is the unit or not.