18 replies to this topic

[1]

In terms of top speed being gearing limited what would they be for the F23 turbo or M32 gearbox? Using standard tyre sizes and taking into account the engine would be able to produce enough power to get there.

[vocky]

vxT revving to 6500 rpm top speed with a F23 would be approx 165mph M32 astra vxr box top speed would be approx 165 mph

[vocky]

so the same top end but you gain an extra gear in between

[Sticky]

vxT revving to 6500 rpm top speed with a F23 would be approx 165mph

M32 astra vxr box top speed would be approx 165 mph

You'd need a particularly long straight to get anywhere near that.

[slindborg]

You 'only' need 212Bhp at the wheels to hold that speed, using the VXT as the Cd as its the worst of the two. So call it 300bhp at the wheels to get there in any form of pace. that is you need 212bhp at the limiter at the wheels

Edited by slindborg, 24 November 2009 - 10:25 PM.

[1]

Has anyone fitted a different final drive in order to gain a higher topspeed in an F23? If so which one do you use? Thanks for the info.

[Duncan VXR]

Vocky my M32 sits lower rpm v's the 5 speed F23 top clog - 3.5k is 90mph. Or maybe I am loosing it???? I can confirm that above 160 the vx is not the most stable!!!! In fact above 150 gets a bit light I cannot see why you would want it geared for more than 160ish mph tbh other than for some extra mpg on motorway. Sure theere are diesel fd that could be swapped (did this on my vag conversion on the 5) DG

[slindborg]

I'm guessing someone is planing for TOTB.... The vx is a crap drag car unless you mod it to work properly but then it wont handle.

[starlight]

A plot of Roadload Power, as I had a bit of time, based on standard VX220T ...



And Gearing

Edited by pjohn151, 25 November 2009 - 10:47 AM.

[Sticky]

Has anyone fitted a different final drive in order to gain a higher topspeed in an F23?
If so which one do you use?
Thanks for the info.

Agree with Duncan, why would you want a higher top speed when you'd need so much power to get there especially with the rubbish aerodynamics.

The VX is about handling not out and out top speed. You'd be better considering a final drive to improve acceleration whilst reducing top speed. There is a 4.17 final drive available to replace the 3.95 in the F23 but the advantage isn't that great. I've done some calculations and am looking at a 5.1 FD to make a real difference. The next problem is finding someone to make one! Although I've solved that issue after a lot of phonecalls and people laughing at me

[starlight]

Hasn't the turbo got a 3.63 fdr I thought it was the NA that had a 3.95. Putting in the 3.95 to the Turbo would increase the 0-60mph time due to the extra shift of 2-3 to around 4.9sec from 4.7sec, but does reduce the 50-70mph in gear times by around 0.5sec. Vmax stays around the same. Going longer to 4.1fdr only really improves mid range acceleration at the expense of Vmax (~145mph@6500rpm ). Going 5.1fdr gives a Vmax of around 120mph. 1-2nd gear shift would be at ~40kph, 2-3rd ~70kph. A bit low to me, but each to their own...

Edited by pjohn151, 25 November 2009 - 11:38 AM.

[siztenboots]

probably quicker and cheaper to just change the size of the wheels , 15" or 18" for quicker acceleration or longer gearing ( not neccesarily higher top speed )

[1]

Good guess slindborg! Yes that is exactly why, first time using an F23 so just trying to get things right. Siztenboots, i have looked at wheels already have got some 235/65/15 mickey T's for the rear on strip. Thanks for the info guys.

[Sticky]

Hasn't the turbo got a 3.63 fdr

I thought it was the NA that had a 3.95. Putting in the 3.95 to the Turbo would increase the 0-60mph time due to the extra shift of 2-3 to around 4.9sec from 4.7sec, but does reduce the 50-70mph in gear times by around 0.5sec. Vmax stays around the same. Going longer to 4.1fdr only really improves mid range acceleration at the expense of Vmax (~145mph@6500rpm ). Going 5.1fdr gives a Vmax of around 120mph. 1-2nd gear shift would be at ~40kph, 2-3rd ~70kph. A bit low to me, but each to their own...

Apologies, I have an NA so have based my thoughts on that, should have read the first post a bit more carefully. Rubbish

The 5.1 is more appropriate for an NA as Vmax isn't down as low as 120 mph.

[Jameshs]

What is the VMax on na final drive?

[vocky]

What is the VMax on na final drive?

standard 6400 rpm limiter gives approx 155 mph

the vxT F23 would be better with a 2.2 na 3.95 final drive

and the 2.2 with a 4.17

of course if you raised the rpm limiter then silly speeds could be achieved;

vxT would hit 200 mph at approx 7750 rpm

2.2 na would need 8500rpm to do the same

and both would need some serious power

[Jameshs]

So what will i get with a limit of 6.5k rpm?

[Crazyfrog (Fab)]

So what will i get with a limit of 6.5k rpm?

168 mph with some luck

[starlight]

the vxT F23 would be better with a 2.2 na 3.95 final drive

IMHO it would ba a little too undergeared as the standing start times gets worse as you end up with 2 shifts to get to 60mph which is not ideal on a manual unless it is a fast acting ASM or DSG but would bring better higher gear acceleration...

As you say though, you would need some serious power to reach 200mph, check out my previously posted roadload curve...

Out of interest, what are the ratios for the M32 and fdr options?