4.5 bhp - is this false advertising?

4.5 bhp - is this false advertising?

Author
Discussion

rakh1

Original Poster:

13 posts

228 months

Wednesday 26th February 2003
quotequote all
Hi all,

Been lurking and reading (thinking of buying a Cerbera when I sell my house soon).

My question is this:
It appears that few/none of the 4.5s actually make the 420bhp as stated by the factory. If this is the case is this not an example of false advertising by TVR. Surely, they should leave the factory with a min of 420bhp and not require a RR conversion to bring them back to spec. How do they get away with this?

Cheers - Rich

jeremyc

20,100 posts

257 months

Wednesday 26th February 2003
quotequote all
The performance is in line with what is quoted.

Be content with being able to talk about your "420bhp motor" at the pub without anyone being able to prove otherwise; they'll certainly not be able to catch you to check it.

It all comes down to how you want to measure the power - do you really want to take the engine out, strip it of ancilliaries and put it on a dyno? No, thought not.

If you really feel the need to prove something at the rolling road then perhaps you should be looking at a chipped'n'boosted Skyline with 1000bhp.....

rakh1

Original Poster:

13 posts

228 months

Wednesday 26th February 2003
quotequote all
Hi,

"If you really feel the need to prove something at the rolling road then perhaps you should be looking at a chipped'n'boosted Skyline with 1000bhp....."

It is not that I want to prove something, it is just that I read and hear of 4.2s being nearly as fast and indeed some people saying that 4.2s can be quicker. It just seems to make little sense to me that the 4.5 should be not that much different from the 4.2.

At the end of the day I think I would prefer a 4.5 as I understand that they are more reliable and come with larger brakes and hydratrack as std. I was just curious as to the discrepencies in the quoted and actual power of the cars.

Rich

pbrettle

3,280 posts

256 months

Wednesday 26th February 2003
quotequote all
That old chestnut again - does it really matter? So your car has 400 rather than 420BHP. You really going to sue TVR over that? Does it go like stink and sound great - yes. Does it do 60 in 4 and 100 in 10? Yes - so what is the problem?

As for 4.2 versus 4.5 - the 4.5 is smoother, less 'cammy' in comparison with early 4.2's and has all of the bits and bobs right. For example they dont do early 4.2 clutches anymore so it needs to be upgraded to a 4.5.... Very little in it in reality. And lets face it here - if you can drive the car so that the differences are noticable then you are better driver than pretty much all of us....

Cheers,

Paul

jeremyc

20,100 posts

257 months

Wednesday 26th February 2003
quotequote all

pbrettle said: Does it do 60 in 4 and 100 in 10? Yes - so what is the problem?
Thats 0-100 in 8.3 to you sonny. Oh, and 0-150 in 17.9

There, pub talk satisfied.

And Paul is correct; the 4.5 is generally considered the more rounded and sorted model, although in real world driving conditions you'd be hard pushed to tell it apart from a 4.2.

Get one and find out what its all about.

rakh1

Original Poster:

13 posts

228 months

Wednesday 26th February 2003
quotequote all
Hi,

"So your car has 400 rather than 420BHP. You really going to sue TVR over that?"

It was my understanding that it is not uncommon for the figure to be as low as 360 or 380. Quite a difference from the 420.

"And lets face it here - if you can drive the car so that the differences are noticable then you are better driver than pretty much all of us.... "

Fair point!

Cheers - R

tommomic

283 posts

243 months

Wednesday 26th February 2003
quotequote all

pbrettle said:

As for 4.2 versus 4.5 .... Very little in it in reality. And lets face it here - if you can drive the car so that the differences are noticable then you are better driver than pretty much all of us....

Cheers,

Paul


Totally agree with this - as I've said before I went for a 98 4.2 in the end. Tried them all, couldnt really see any difference between 4.2/4.5 and decided to save myself 5K and still get a car that is fully 'sorted' (ie. by the perception that post-97 the quality dramatically improved).

I'm sure 4.5 owners get pretty sick of hearing that their cars have no/not much more uumpfff than a 4.2, but I also get pretty sick of hearing that 4.5 are far superior quality than a 4.2. In the end, there seems so much disparity even between the same (supposed) engine sizes, its all down to the particular car.....

and dont rule out the S6 either!!

Cheers,
Tommo


sparks

1,217 posts

252 months

Wednesday 26th February 2003
quotequote all

rakh1 said: Hi,

"So your car has 400 rather than 420BHP. You really going to sue TVR over that?"

It was my understanding that it is not uncommon for the figure to be as low as 360 or 380. Quite a difference from the 420.

"And lets face it here - if you can drive the car so that the differences are noticable then you are better driver than pretty much all of us.... "

Fair point!

Cheers - R



There are many threads about this, but has anyone ever tested a 'shopping trolley'? It will be down on the manufacturers claims, just like a TVR, due to the power sapped by the ac, pas, exhaust etc, but no one knows figures as no one gets a eurobox on a rolling road. Maybe someone (Ted?) should arrange for a 2.0 vectra/mondeo to be rolling roaded, to see what the power is, to kill this perception dead.

Sparks



dannylt

1,906 posts

257 months

Wednesday 26th February 2003
quotequote all
Wrong. Many production cars in fact exceed their power numbers slightly. M3 owners, and Subaru owners see numbers very close to quoted.

TVRs in particular seem particularly bad, especially the 4.5. The Rover engines just as much so. They're still plenty fast though...

danny

smifffy

1,983 posts

239 months

Wednesday 26th February 2003
quotequote all
Indded, a quick visit to http://dyno.scoobynet.co.uk/ will show that many scoobies in standard form outstrip the claimed figures anyway.

I'm pretty damn confident that if my P1 went near a rolling road then it would chalk up the claimed figures too.

It's all down to marketing (which strangely TVR claim not to bother with). Personally I'd just concentrate on the 0-100 time and lap times around circuits rather BHP but I can understand the "pissed off" factor when an owner finds out that the car is no way near the stated figure.

Another annoying factor would be the inconsistency between TVR engines. Some produce massively better results than others which has to be a little gaulling if you've just spent 50k on one which hits the lower end of the scale.

bjwoods

5,014 posts

257 months

Wednesday 26th February 2003
quotequote all
There was a letter in this months Sprint (TVR club magazine)about this, by someone from Joospeed Performance Tuning and Development, on results seen on a rolling road

Seems that

4.2's produce around 330 to 360bhp (quoted 360)

but

4.5's produce 350bhp highest seen, norm 330 bhp, lowest seen was 312 bhp (quoted 420 bhp) What ??????

Tuscans (360 bhp models) are pretty bang on 360bhp
with one standard one producing 373 bhp.

So might be good idea to buy a late model 4.2s cerbera.

But as you all know it's torque that really matters!!!

B

>> Edited by bjwoods on Wednesday 26th February 13:27

whatever

2,174 posts

243 months

Wednesday 26th February 2003
quotequote all
I still thought the 4.5s showed an improvement in speed over the 4.2s above about 150mph?

If you think that's irrelevant, then why not consider the torque numbers/curves for your comparison rather than bhp? Surely it's the torque curve/value that gives you the acceleration and the bhp which contributes to top-speed?

BCA

8,605 posts

230 months

Wednesday 26th February 2003
quotequote all
Power claims and real power are easily judged.

German cars have to produce power within a certain tolerance, something to do with a TUV thingy.

Japanese cars are restricted to a "gentlemens agreement" of 276bhp - often japanese manufacturers simply claim this and then have more real power to get one up over thier competitors.

For the smaller more specialised manufacturers you might as well pick a number out of the air. I have heard of a number of manufacturer doing the same as TVR and overstating.

Shelby himself said that ferrari always over claim power for example.

At the end of the day, power doesnt matter, speed matters! The performance figures for the cars in magasines etc are a good indication of thier capabilities. Obviously, if you want 8.3 to 100 you will have to be a pretty capable driver with a complete disreguard to your car. The same goes for any reasonably powered car, conditions vary, abilities vary.

Most TVR's undoubtedly can be capable of ridiculously good figures in the right hands, whether they have the claimed power or not. If you think everything is about getting what some idiot in marketing thought would make a nice selling figure then you have lost the plot a little.

If you want a car that delivers the pace that it says on the tin however, dont hesitate to buy a 4.2/4.5.


Edited to say - the reason 4.5'seem/ might be faster (not going to risk saying "are" faster) is the torque spread throughout the rev range. Theres simply more of it on average, and its pretty flat on a 4.5 so it picks up better at low rpm. Its also the main reason for 4.5's feeling smoother.


>> Edited by BCA on Wednesday 26th February 13:52

sparks

1,217 posts

252 months

Wednesday 26th February 2003
quotequote all

dannylt said: Wrong. Many production cars in fact exceed their power numbers slightly. M3 owners, and Subaru owners see numbers very close to quoted.

TVRs in particular seem particularly bad, especially the 4.5. The Rover engines just as much so. They're still plenty fast though...

danny





Sorry, but having read alot about power and torque and rolling roads, alot of numbers bandied arround, are so called 'corrected figures' which may be accurate (I have no proof either way) but are often 125-150% of the wheel figure, which is just way too high. This especially relates to cars 'post performance mods'.

I am not saying you are wrong, but that rolling road correction figures are often way too high.

Sparks

PS see www.pumaracing.co.uk/setup01.htm

Thom

2,745 posts

246 months

Wednesday 26th February 2003
quotequote all

dannylt said: Wrong. Many production cars in fact exceed their power numbers slightly. M3 owners, and Subaru owners see numbers very close to quoted.

On the same note there was a time some Porsches offered better 0.60 times during road tests than the ones claimed by the factory.

e.g.: for the 968 CS the factory quoted the same figures as the 968 Lux, presumably to avoid compulsory homologation, whereas the CS was significantly quicker...

AllTorque

2,646 posts

242 months

Wednesday 26th February 2003
quotequote all
Sure is false advertising. I'd be mightily peed off with only 4.5BHP. My legs have probably got more than that (or at least my horse's legs!)....

joelk

175 posts

229 months

Wednesday 26th February 2003
quotequote all
I drive a 4.5 Cerbera. At one point, I also contemplated getting it remapped to get the full bhp out of it. Then I thought this car is really fast enough. It can beat anything. Getting it to go faster than it already does seems suicidal...

gazzab

19,438 posts

255 months

Wednesday 26th February 2003
quotequote all
Mine is 390 bhp per the dyno !!!








OK I am lying.

dannylt

1,906 posts

257 months

Wednesday 26th February 2003
quotequote all
Sparks - your comment about loss at the flywheel wasn't very informed. All the dynos which we've used correct back losses from a run down test. 20 to 25% losses through the transmission ARE typical.

danny

dannylt

1,906 posts

257 months

Wednesday 26th February 2003
quotequote all

bjwoods said: There was a letter in this months Sprint (TVR club magazine)about this, by someone from Joospeed Performance Tuning and Development, on results seen on a rolling road

Seems that

4.2's produce around 330 to 360bhp (quoted 360)

but

4.5's produce 350bhp highest seen, norm 330 bhp, lowest seen was 312 bhp (quoted 420 bhp) What ??????

Tuscans (360 bhp models) are pretty bang on 360bhp
with one standard one producing 373 bhp.

So might be good idea to buy a late model 4.2s cerbera.

But as you all know it's torque that really matters!!!

B
>> Edited by bjwoods on Wednesday 26th February 13:27


The highest 398 he quoted for a red rose 4.5 was indeed my car... which was 350 before the conversion. We've actually seen several 4.5's with 350 though. The 360bhp 4.2 belongs to Richard Prebble, but was also well down on torque. Joolz is often around on this forum also, but hopefully he's busy actually doing some work on cars right now

This has all been gone over in detail before - search back through the forum history!

danny