[Mk2] [NA] 150mph in 4th gear from an NA!!!

[j17sparky]

All of this conjecture is meaningless. You can work out top speed mathematically from rpm, gear ratios and tyre diameter.

For a stock normally aspirated car that means a mechanical limit of 138mph - assuming a long enough straight to wind it up that high - and 158mph for a turbocharged car.

Thats what i was looking for, cheers


PS - do you think its petty that i take great enjoyment from ripping the pish out of him?

[Greddy-Matt]

Pintovit - Ah right sorry no I am talking about actual speed as indicated by GPS, (tom tom in my case) not indicated speed on the speedo

My speedo over reads to about 7-8% so when you do the math 137-140mph indicated speed is similar to 130mph GPS verified so it looks like we're actually both talking about the same sort of speeds here ergo we're both right

Still be good to have an N/A thrash tho...
And yes more than happy to come to you, anything for some sun!

[black2]

do you think his speedo is still in kph not mph

[Pete J]

All of this conjecture is meaningless. You can work out top speed mathematically from rpm, gear ratios and tyre diameter.

For a stock normally aspirated car that means a mechanical limit of 138mph - assuming a long enough straight to wind it up that high - and 158mph for a turbocharged car.

That reads a stock turbo revs higher than a stock NA

Obviously theres also engine power in those calculations.... love to see the calculator you used

[Leon.]

That reads a stock turbo revs higher than a stock NA

Why?

[Pete J]

NA's top out because there is not enough power to reach 7250rpm in 5th. Not because the gear ratios wont allow over 138mph.

Edit: Got me wondering now... are Turbos geared differently?

[JAP BOY]

Get your selves over to Brunthers airfield!
This !seem to be a regular discussion

[Bender Unit]

Top speed in a straight line is pointless anyway, what does it prove? If he didnt do that speed sideways with his arm out the window, with smoke pouring off his tires then he's gay!

Having topped my turbo out at TOTB at 152 (after a 2 mile run) I seriously doubt a NA would do it on the public roads unless your mate is shot in the head.

[marcnoonan]

I've got a Rev1 N/A on which the gear ratios are different to Tubbies and "ACCORDING TO THE CLOCK" it hits 137mph in forth. Variation is applicable of course.

Marc

[Driftlimits Performance]

I thought 'mechanically' (gbox) the tubby can get 172mph

[Stefen]

I think it's important to establish the facts.

These are from a Rev 3 N/A:









Before anyone drops off the seat in disbelief, there is no load on the car, therefore it is reving freely.

The last picture was taken briefly at the limiter.

The most I have ever seen (on a runway) was just under 140.

[Hellboy]

NA's top out because there is not enough power to reach 7250rpm in 5th. Not because the gear ratios wont allow over 138mph.

Edit: Got me wondering now... are Turbos geared differently?

yes

[BenF]

Top speed is limited by the maximum work the car can do against (mostly) air resistance.

Give the shape of the Mk2, 160bhp-ish will get you to 125-130mph, and 220-240bhp to 155ish - resistance increases exponentially with speed which is why all the turbo'd extra power only gains another 20-30mph top speed

[nuttasie]

I reckon my rev 1 could do 135mph in fifth.And to be honest it was faster than a previous rev3 and my current rev4 .

[Greddy-Matt]

Actually thinking of the variables in this makes my head hurt, vehicle weight/drag/tyre size and drag/air temperature/humidity/density/HP output and of course the important one colour...

Can anyone clear up if N/A's and in particular the rev 1 have closer gear ratios...?

*edited by request*

[nuttasie]

edited

[iblis]

Can anyone clear up if N/A's and in particular the rev 1 have closer gear ratios...?

I did not calculate these myself, so I can't swear they are 100% accurate.

Rev1/2 N/A:
5th: 0.82
4th: 1.03
3rd: 1.32
2nd: 1.96
1st: 3.29
Final Drive: 3.94

Rev1/2 Turbo:
5th: 0.73
4th: 0.92
3rd: 1.32
2nd: 1.91
1st: 3.23
Final Drive: 4.29

... my rev1 NA...on a side note it was faster than a previous rev3 and my current rev4 .

The rev 1/2 has a better power to weight than rev3/4

[marcnoonan]

One from April..................from me

I have a rev1 UK and the limiter speed for the gearing is:
1st 40
2nd 70
3rd 110
4th 137
5th 160+,

and from the Dukes Rev2 Tubby

1st 30/31
2nd 61/2
3rd 92/3
4th 120/2
5th 160+

Defo different

[shibby!]

I thought the Rev1's had longer gearing than Rev 2 and Rev3.

But no one could confirm this.

Nick

[ctc_celtic]

when i bought my g-limited rev3 first i could have got 150mph in 4th no problem.
reason being there was a cheap speed converter and the standard clock is 14% over anyway, so i would say my speedo was about 30% out, easy.
when i took it for a test drive we went up a dual carriage way and i said 'i see they clocks are still in Kph' the seller no 'there converted and Mph' at which point i laughed out loud.