top speed rb25det

[nomenai]

any idea whats the top speed in the rb25det standar transmission.I research found nothing
Modified by nomenai at 6:19 PM 8/19/2007

[Carl H]

final drive is what determines the top speed, not the trans.find out the 5th gear ratio and then the final drive you wish to use and that will give you your theroretical top speed.i know using a j30 diff (3.86) on the rb20's trans revving to a redline of 8k it can theroreticaly approach 215mph from what i remember.

[DrifterProdigy85]

RPM, Tire Diameter, 5th Gear, and Final Drive make the top speed. Stock tires are 195/60-15, 5th Gear is .759, and stock R&P is 4.083. After figuring out the math, its 151mph @ 6500rpm.
Modified by DrifterProdigy85 at 10:25 PM 8/19/2007

[Carl H]

and at 151 you better have some hellacious downforce because 130 in my s14 resulted in a super light tail end.

[DJButton]

At that point a GT spec wing would actually have a purpose... dang we must have a bunch of 150 mph+ honda's here!! lol

Actually, I've never bothered to research that before but kinda wanted to know how to determine it, thanks guys!

[Shocker]

I've made a few pulls to 6k in 5th before, once to 6200, which with my rear end and taller tires is about 150mph. The car could have still gone faster. I simply let out. It was just BPU.

Lowered s-13 HB with control arms, camber arms, toe arms. It felt rock solid not for a minute I was scared of the car, just of police. Its done about 125 on a local circuit track as well.

Tested 4th gear with GPS. Redline is 128mph in 4th. with 4.11's and 245/55/16's.

runs were done on an open highway in the middle of the night, not a headlight in sight.

[IowaRB240SX]

2 notes:

1st, I had my B16 CRX to 145 and it was scary as hell. No wing for downforce and it wanted to skitter all over the road. I was only at 5500 rpm and my redline was 9000.

2nd, using your formula, can you figure out my top speed. 285/30 19's, 4.30 final, standard rb25 5th gear, 8000 redline.
Modified by IowaRB240SX at 11:37 AM 8/20/2007

[garage-c]

http://www.catherineandken.co.uk/sti/tyres.html

top speed calculator...

Gear ratios for RB25DET MT:1. 3.2142. 1.9253. 1.3024. 1.0005. 0.752

Stock 240sx FD R&P ratio:4.083:1

My RB25 with the 4.636 FD im running and 255/40/17's gets me to 153mph at 7200rpm (chipped rom). Not really any need to go faster than that on public roads so I'm happy. The final drive gives a nice kick in the *** on acceleration

In case anyone was wondering, cruising on the highway at 80mph puts me at almost 4000 rpm. And the gas mileage SUCKS.
Modified by garage-c at 11:26 AM 8/20/2007

[IowaRB240SX]

Sweet, thanks. I plugged in my info and got a top speed of 182. Not that I will ever get to go that fast. if I drop my final drive to 4.11, I can get 191! Right now I am running a Skyline 4.30 rear end.

[rbfastback]

whats the top speed af an rb20?

[IowaRB240SX]

motor size doesn't matter. Depends on your transmission gearing, final gearing, and tire diameter. Click the link and plug in your info.

[Darius]

motor size doesn't matter. Depends on your transmission gearing, final gearing, and tire diameter. Click the link and plug in your info.

Unless the top speed is drag limited. (i.e. the motor doesn't have enough hp at the top end to push the profile of the car through the air at the theoretical maximum speed.)

[Carl H]

dont forget that with increased speeds it changes the aerodynamic requirements of the car, and with the addition of any aero you have that pesky thing called drag induced by it.if the motor doesnt have enough power to overcome the aero drag induced from the car or plain old wind resistance/friction then its never gonna reach its theroetical top speed.on my car i have a fairly large adjustable wing, with its adjustability im able to set the car up for almost any driving style and i have to say even a minor change ends up with drastic results.

[IowaRB240SX]

Yes, such is the case with the Bugatti Veyron 16.4. It has a drag limited to p speed of 253. But would go faster if it could cut the air better.

[Shocker]

on my car i have a fairly large adjustable wing.

since when?! pics?

[OpeLok]

simple solution to know for sure

GPS + Long strech of empty road = fun times and know for sure

[DrifterProdigy85]

Ive taken my 400whp SR to the 7500pm limiter in 5th on the highway twice. For some reason the car tracked perfectly straight at 170+mph using stock suspension. I wouldnt dare try to turn at that speed though.