GTR Forum banner

1 - 20 of 20 Posts

·
Registered
Joined
·
4,145 Posts
Discussion Starter #1
Just wanted to know the top speed of a standard R33 GT-R V-spec.

Limited or not.

Am I right in thinking that its 155mph limited.

So what is it without the limiter.
 

·
Registered
Joined
·
1,885 Posts
The UK skylines maybe limited to 155.. dunno.

Japanese cars are limited to 112 mph.

A std R33 with std wheels and gearbox SHOULD (not will as I have not done it) do something like 192 MPH at its 8250 redline.

Dunno about the 34 but there are people on here who have gone around the 200 mark on the autobahn. with an altered gear ratio you can do silly speeds.

The record... I believe is currently held by Gary Passingham of GT art. his car has been clocked through the timing lights at bruntingthorpe doing 217 in one direction and 213 ? in the other, they used this figure on the website for their final top speed.

suffice to say they are plenty quick enough for the uk roads !!

by the way if you are after one I have one for sale..

regards
Steve
 

·
Registered
Joined
·
9,548 Posts
GTRs are geared pretty long but there is no way a stock car can hit the fuel cut out in top. Even less probable in an R34 with the 6 speed box. You'll need around 600bhp + to do that....
 

·
Registered
Joined
·
1,885 Posts
Exactly Dino,

Thats why Should is a theoretical value worked out by a PC, using the drag,weight,power ,revs and gearing.

I also don't know anyone who would try and do that to a std car.
I never take mine that high RPM wise I dear to think how much straight road youd need to pull off max RPM in top gear ...

Also if you have done the work for the 600bhp then the chances are the rev limit will be higher, so the top speed will also be higher, RPM's is what top speed is all about, BHP/torque just makes it happen quicker

have fun..

Steve
 

·
Registered
Joined
·
1,148 Posts
, RPM's is what top speed is all about, BHP/torque just makes it happen quicker
not entirely correct. Top speed is achieved where energy loss due to drag, friction etc is equal to the power output available to match it. On many cars this is the realistic top speed, but it is possible that some cars will hit an arbitrary limit (a rev limiter) before that happens.
 

·
Registered
Joined
·
1,885 Posts
I am not a physicist, but if a car red lines at 6000rpm and an identical (weight and drag etc..) one red lines at 10000 rpm the second one will eventually be faster even if the power output is the same as long as there is enough power to rev it that high.

The drag and weight factors are a side issue whan we are all talking about the same car (R33 V-spec).

/Steve
 

·
Registered
Joined
·
9,548 Posts
SteveC....in theory, yes I agree with you. You can just plot that top gear graph all the way out..so if you have a 800hp car with a 10000rpm limiter & stock transmission you could be traveling very very fast. Gearbox would probably shatter under the stress in practice but that is beside the point.

GTRs are not exactly aerodynamic, so you would need a few miles to see what she can do.
:p
 

·
Registered
Joined
·
1,885 Posts
I thought this whole discussion was hypothetical as the speed limit is 70mph:p and there aint a bit of track long enough to get a true top speed straight line speed, except maybe one of the huge ovals that the research places use.

The top secret supra just highlights the aerodynamic shortfall of the Skyline...

I think it was 246 mph, in a max power article, so it has to be true !!.

I got quite injured whilst I was reading the article but cheered up instantly when they said in the stats,, something like, heavily tuned RB26 engine and skyline GTR running gear.4wd etc..

Dunno what power but it was probably silly if top secret were involved:D

/Steve
 

·
Registered
Joined
·
97 Posts
ahhhhh
so its not juz me who notice the front of skylines are like a wall then?

hehehehe

LL
 

·
Registered
Joined
·
2,061 Posts
Steve,

Sorry mate, the change in max revs does not cause an increase in top speed, just gearing limited theoretical top speed (in a vacuum).

Top Speed is determined by the equilibrium situation, where available power (bhp) is matched by resistance to further acceleration (drag).

Assuming a CD of 0.36 and a frontal area of 22 square feet (R33 GTR), then the required power at the rearwheels to achieve the following speeds are as follows:

150mph 229bhp at wheels
160mph 279bhp at wheels
170mph 330bhp at wheels
180mph 382bhp at wheels
190mph 451bhp at wheels
200mph 520bhp at wheels

The above should be taken as approximates, due to many influencing factors such as tyre size, air-pressure etc. Please also note that the above are at speed, therefore the GTR will be in 2wd only and thus probably lose circa 15% transmission losses ie to get required engine power divide by 0.85

The above suggests a stock GTR (circa 300bhp), would make about 255bhp at wheels and thus do a true 155mph (ignore speedo).

A 400bhp GTR such as yours Steve, will have about 340bhp at rear wheels and would therefore do about 172mph. You will not reach the rev limiter.

Guy
 

·
Registered
Joined
·
1,885 Posts
That is quick enough for me !!
I only do 0-100 ish and that aint often.

thanks Guy, I think you posted the original speeds that I was thinking about, this was on the old original Forum.. hence my bad memory. nearly 2 years ago.

I remember someone saying about revs though, the higher the revs the faster the wheels turn.. how does raising the rev limit affect the perfomance of the cars with big cams, it is purely to allow the cam to work in it's optimum torque generating rev range ?

I know this might read like I am trying to belittle the responses but I would like to understand fully how the BHP,drag,gearing affect the top speed.

Cheers
Steve
 

·
Registered
Joined
·
1,885 Posts
Cross posting..

Yes Guy my bad stupid brain is getting all fuddled and mucked !!

you are right about the JUN one. The RB powered one was over 200 mph if I remember rightly (based on previous efforts/track record not likely.)

/Steve
 

·
Registered
Joined
·
2,061 Posts
Recs

Steve ,

You are correct, the rev limits are raised to enable the engine to operate where it makes more power. and this is down to cam specs.

If you raised the revs on a stock GTR it would be of no use, since power is falling by the existing redline anyway and you would go no faster by using extra revs.

However, if you fit much wilder cams, then you can make use of the extra revs. Thats why the dyno runs are only done until the point where power starts substantially falling off.

Guy
 

·
Registered
Joined
·
515 Posts
In case you're interested

My R32 GTSt (with cat-back exhaust and filter at the time) topped out at 256kph (Ultra meter) in 5th gear and ran out of puff at 6500rpm (7500 limiter).....turbo too small to produce any more speed. I'm hoping for 280kph with the Cossie T3 fitted!

Also the Lotus Exige that I was racing with couldn't keep up ;) I was late for a trackday at the time. I know....I'm a bad lad!

James
 
S

·
Guest
Joined
·
0 Posts
AH But

Surely the latent weight of Nagata's huge testicles counteract the tuned RB to an amount equal to that of putting two large Japanese bags of cement in the boot no?

Im getting my coat as we speak ;)
 

·
Registered
Joined
·
1,148 Posts
A further complexity to add to the equation is that when going for top speed, you have no choice about the engine revs.

For example, say your engine produced maxiumum power of 350 bhp at 6,500 rpm, and 6,500 rpm was geared so that it equalled 150 mph (these are made up figures, don't necessarily match a skyline).

Accelerate to 175 mph. The engine is now doing 7,500 rpm, and will be considerably off the power, since power peaked a while ago. And in practise, there may not be enough power at 7,500 rpm to maintain 175 mph, so you'd never have got that far even though your calculations from Guy's post said that you would be able to.

I really hope that make sense. I don't think it does.
 

·
Banned
Joined
·
3,561 Posts
Guy is entirely correct, weight has (virtually) no bearing in top speed it only effects how long it will take to achieve it!

Make your car slippery and it will need less power to achieve a top speed, the Soarer needs only 460hp to achieve a theoreticl 200mph!

When going for a top speed run, retract you mirrors and gain 3mph!
 
1 - 20 of 20 Posts
Top