R34 Gtt Top Speed

[AJ001]

Hi everyone,

Recently on a long track, the Apexi AVC-R (EBC) fitted in my R34 GTT, clocked 302km/h as the top speed during the length of the Journey, i have an after market Nismo Meter which shows speeds upto 300Km/h but unfortunately i was lookin on the track and not the speedometer. Although I do remember shifting to the fifth gear cause the revs were upto 6.7 on the 4th gear (never had to floor car above 4th gear) and after shifting into 5th i was still pushing on the pedal.

As for other mods, the car has a Front Mount Intercooler, the Apexi EBC as listed above, full 3.5inch cat back exhaust and was running it on 0.76 Kg/cm2 Boost.

Do you guys think the AVC-R has recorded some false value? or is 302km/h a comfortable speed for the RB25DETT engine? the car is 1998 so the engine is not brand new?

Any expert opinion or comments guys? im confused?

[Marlin]

Not a chance in hell is that right champ.

[burkill]

i've seen a gtr go 331km/h or something.

[Scottydoo]

i've seen a gtr go 331km/h or something.

His car is not a GTR though...

I doubt a GT-T would be geared to get anywhere near 302km/h let alone have the power to get there with only those mods

[Granthem]

No chance.

[RICCA]

No chance maybe 250/270 unless you got a freak r34

[clip14]

whats your diff ratio, and tire size? work out your theoretical geared top speed

then you will need to find out your drag coefficient which isnt usually very accessible data unless you either

1. have a wind tunnel

2. find your actual top speed and have accurate power figures as well

ps. 302kmh is approx 187mph thats pretty fast for a standard skyline

two main components for calculating theoretical top speed

rolling resistance

drag due to air resistance

rolling resistance is fairly linear so easy to calculate

drag due to air resistance has a cube relationship to speed.

so the increase of 250kmh to 300kmh is a factor of 1.2

the power increase you need is the cube of this factor (1.2) = 1.728

using very average numbers for coefficient of friction, average combustion efficiency and average drivetrain losses, you need 408hp (flywheel hp) to reach 187mph. very rough numbers though but just to give you the scale of things.

Edited October 15, 2008 by clip14

[.:: GimpS-R34 ::.]

speed limter? no mention of an aftermarket ecu?? and nothing about removing speed limiter.. so i assume max speed at 180... if not i don't think you'd get that speed on 0.76 Boost...

[GTR-N1]

...not with a 3.6 diff

BTW Thelma & Louise didn't even reach that speed in the last few seconds in the T-Bird!

[.:: GimpS-R34 ::.]

...not with a 3.6 diff

BTW Thelma & Louise didn't even reach that speed in the last few seconds in the T-Bird!

NOt even in the drop?

[satanic]

Hmm interesting thread... *subscribing*

I hit 265km/hr on a pretty worked RB25 before... that was the reading off my F-CON Navigator (I only have a 180km/hr dash), and am not sure if its entirely accurate.

[R31Nismoid]

The AVC-R is probably wrong by a good 60=80km/h

Sounds more like 202km/h to ne

[GTR-N1]

...not with a 3.6 diff

BTW Thelma & Louise didn't even reach that speed in the last few seconds in the T-Bird!

In reply to the post above,

the T-Bird after leaving the cliff will accelerate to the point of terminal velocity where the wind resistance balances out the gravitational pull.

The T-Bird's terminal velocity would be a maximum of 60m/sec = 135mph = 216Km/Hr

[AJ001]

speed limter? no mention of an aftermarket ecu?? and nothing about removing speed limiter.. so i assume max speed at 180... if not i don't think you'd get that speed on 0.76 Boost...

The speed limiter isn't in place and its an after market Nismo Speedometer so reads upto 320km/h and yes its calibrated!