Engine power ratings

[bertie]

Just read in an automotive industry magazine how Ford got caught out by quoting the SVT Cobra at 320bhp.
Several people pointed out to them that on the dyno they made 30 - 40bhp less and so Ford recalled all 1999 production and retrofitted new exhausts and intake systems to get them back to quoted power.

Now remind me how much a "340 bhp" Griffith 500 engine or a "420 bhp" 4.5 AJP8 makes again?

[fish]

Hi Bertie

I think my Tuscan is pretty close to the quoted 360. I haven't had it dynoed but at Santa Pod I was pulling away from Dynoed 320 bhp Cossies even though I was still wheel spining upto 100mph.

So can't be far off then.

[kevinday]

Enough to be b****y fast!

[bertie]

Yes the Speed 6 appears to do what it says on the tin.
At the last test I saw the results from it made 358bhp calculated at the flywheel which is very good.

At the same tests the AJP and Rovers were somewhat different.

Just thought it was a good response form Ford.

[DIGGA]

Pretty sceptical about the declared figures, and also about rolling road figures that are 'corrected' from at-the-wheel to flywheel nummbers.

Having seem the collosal amount of wheelspin my own car had on the rollers, I think it better to use them for comparison of incremental gains, rather than absolute figures. There was an excellent link on this matter in a former PH thread (sorry I can;t remember which).

Only sure way to know is to get the lump out of the car!

[dannylt]

quote:
Yes the Speed 6 appears to do what it says on the tin.
At the last test I saw the results from it made 358bhp calculated at the flywheel which is very good.

At the same tests the AJP and Rovers were somewhat different.

Just thought it was a good response form Ford.

The speed 6 is an AJP! That Tuscan should have had 380 though - it was a red rose version. The 4.2 Cerbies were very close as well. It's only the 4.5's that are similar to the 4.2's...

[fish]

Unless I'm mistaken;

The speed 6 is totaly different to the AJP. The speed 6 is a straight six - the AJP is a V8.

The 4.0l S6 in standard tune is 360bhp, in the Tuscan S (previously Red Rose spec) it is 390bhp. The 3.6l S6 has a shorter stroke and revs slightly highr and is quoted at 350bhp. I understand the S6 in the Tuscan R can be tuned to taste upto about 450bhp and 4.2l

Don't knoe much about the AJP's but they are higher output.

P.S. there is a nice bit of writeup about the Tuscan development on the TVR web page under models, then Tuscan (in the top right of the page)



>> Edited by fish on Thursday 21st March 13:45

[dannylt]

AJP as in not Rover...

[nubbin]

I was down at Joospeed a couple of weeks ago, and he said that Rover V8's make 20-30% less than quoted figures, eg. the 4l is around 170-180bhp. However, the S6 and AJP V8 engines are genuinely much closer to quoted power outputs, maybe 5-10% less, but often on the button.

[fish]

AJP as in house V8 NOT rover based at all. They are extremely small raced base engines of 4.2 -4.5 litre only fitted to Cerberas and some race cars. It was going to be used as a replacement engine for the Griffith but didn't get developed in time.

[ap_smith]

Hmm well if Ford recalled their cars, I think I'll keep quiet about my '215 bhp' Impreza. Isn't it unusual (read: refreshing) for a manufacturer to be *under*stated?

[GuyR]

Tuscan should be quicker than a cossie since it weighs a lot less, so thats hardly a scientific power comparison........

As for wheelspin on rollers, you only get that if the dyno operator doesn't strap the cars down properly. I've seen 600bhp rear wheel cars (Toyota Supra)and several 650bhp 4wd cars (Skyline GTRs) dynoed without wheelspin, if setup properly on the rollers..........

[.mark]

[rant]
BHP at the wheels, at the fly wheel, 20% down 30% up. Who give a toss, is it bloody fast? Yes. GOOD!

So my 4.0l Chimaera doesn't actually have 240BHP? Still mullers most other cars on the road. Perhaps TVR should take a leaf out of Roll Royce's maual where to specific questions the answer is simply 'adequate'
[/rant]

[dannylt]

Adequate would be fine. But why quote wrong numbers? Nobody's arguing whether it's "enough" - it's all relative. Besides, it's never enough.

[bertie]

quote:
[rant]
BHP at the wheels, at the fly wheel, 20% down 30% up. Who give a toss, is it bloody fast? Yes. GOOD!

So my 4.0l Chimaera doesn't actually have 240BHP? Still mullers most other cars on the road. Perhaps TVR should take a leaf out of Roll Royce's maual where to specific questions the answer is simply 'adequate'
[/rant]

Strange that we're quite happy to accept this on a car because we all have an emotional connection to it, and I'm just as guilty as anyone else.

If it was a PC that was supposed to have a 700Mhz Pentium 4 in it and you opened it up and found a 400Mhz Pentium 3 I guess we'd all be straight back down PC World like a shot.
I can't imagine anyone saying "well it's fast enough for me so I won't bother" can you?

As has been said they're all plent fast enough so why not just quote the true figures?

[JonRB]

Because no-one down the pub would be impressed if your car "only" had 285bhp.

[DIGGA]

quote:
As for wheelspin on rollers, you only get that if the dyno operator doesn't strap the cars down properly

Quite true, but you don't get a DIRECT link to the engine, and you still have to factor (i.e. guess) the effect of transmission drag.

[bertie]

No, you can measure the losses with a "coast down" measurement and factor them back in.

It ends up fairly accurate, given the normal variation in rolling roads.

[GreenV8S]

quote:Because no-one down the pub would be impressed if your car "only" had 285bhp.

Oh dear

Peter Humphries (and a green V8S with "only" 285 BHP)

[Paceracing]

Peter,

I've seen you drive and i'm VERY impressed!:

Jas