Top Speed??

[tiger]

So whats the top speed of a 4.0 Chim with a serp engine and a T5 gearbox?

Somebody mention 170!! :eek:

Seemed a bit ott!

[SharkyTVR]

Possibly. Upon re-entry from orbit....

For a 4.0 in good health, I'm guessing more like 150-155

[TimW]

it will prob run out of puff at 145ish then an extra 2-3miles to get to 155-160. IMO a tuned one tho

[runt]

Autocar tested silver S798JRN , 12 .May ,99 - is she still alive ?

[oggs]

My was verified at 149 at Vmax in march.
Hoping to break that in July

Still a standard 400

[runt]

As to top speed , TVR tuned Rover V8 engines theoretically peak @ 5500 revs - 150 mph in 5th in Chimaera -so any car out there in good health should top 145 ? mine doesn ' t - I'm 50 , and might get a nose bleed..

[wizzpig]

All depends on the colour you see.































Green ones is fastest!

[jason1788]

How much difference does having the top down make? I haven't really had a serious chance to vmax mine, but it does seem to run out of puff at 130 (hood down), would need a long road to get 150!

[tacoma]

Cool Jason,

I didn't know they let us 'track' with the roof down!!!

I was given a finger wagging by a 'boy in blue' for doing 120 with a mate in the car top down. That was my lucky day,i slowed down they waved and drove on!!!

m

[Boosted LS1]

It won't make 170 with a rover engine. Aerodynamics will prevent that. You need something a lot more powerful to overcome the laws of physics

Boosted.

[jason1788]

Err.. umph.., it was in Germany on an Autobahn, of course

[rpulley]

Blue is the colour to have they are the fastest

[wizzpig]

rpulley said:

Blue is the colour to have they are the fastest

[deeen]

Boosted LS1 said:

It won't make 170 with a rover engine. Boosted.

Or with the rev limiter in place (167 IIRC)

[pullingpower]

I've heard of somebody from S.Yorks TVRCC getting 180mph+ from a 4.5L with just an upgraded camshaft. Could this be true?

[GreenV8S]

A standard Chimaera 5.0 puts out roughly 275 bhp and is good for about 150 mph give or take a bit. To go from there to 180 mph will require 75% more power, so that's roughly 500 bhp. From a cam change? I don't think so.

Assuming you manage to get the power, with the standard gearing the engine would be turning at close to 6700 rpm at that speed. A standard engine will do those revs exactly once, and you will be left with lots of spare bits afterwards.

On the other hand, speedos are notoriously inaccurate ...

[runt]

A 5OO should do more than that - see Autocar ,13 August 97, yellow 450 P798TFR. So did TVR exaggerate 500 power output by 50 horses ?

[19560]

GreenV8S said:

A standard Chimaera 5.0 puts out roughly 275 bhp and is good for about 150 mph give or take a bit. To go from there to 180 mph will require 75% more power.

How do you figure 75%? Above 100mph it's usually assumed to be virtually all aerodynamics as is proportional to the square of the speed so 50% more power should be enough and ties in with a Tuscan top speed amongst others. Same conclusion for a chimp though.

[GreenV8S]

lol, yes they're notorious for it.

If you want to talk in terms of TVR bhp instead of real world bhp, then to reach 180 mph you will need to find around 600 of them. Whichever way you look at it, that's an order of magnitude more than you could realistically expect to gain from a cam change.

[GreenV8S]

19560 said:

How do you figure 75%?

Drag (force) is proportional to speed squared, power is proportional to speed cubed. The increase from 150 to 180 is a factor of 1.2, 1.2 cubed is 1.73 ish.