RR Result (Joo, take a look please)

[JensenA]

17 of us from TVRCC-3C went to a Rolling Road day at BTEC Racing yesterday. Here are the results for the Cerberas - and the others for comparison, and a copy of my graph.
Joo (TCS) seeing as I am coming up on Thursday to get mt induction and re-map done. Does this give you any hints as to what needs to be done, and what could be wrong?


Cerbera - 4.5L V8 AJP - 325.8 bhp, 331.2 ft lb < My car

Cerbera - 4.2L V8 AJP - 339.7 bhp, 312.1 ft lb
Cerbera - 4.2L V8 AJP - 322.0 bhp, 295.0 ft lb
Cerbera - Speed 6 - 308.1 bhp, 297.3 ft lb.
Cerbera - 4.2LV8 AJP - 299.1 bhp, 275.8 ft lb

Chimaera - 4.5L Rover V8 - 242.2 bhp, 273.3 ft lb
Chimaera - 4.5L Rover V8 - 224.3 bhp, 240.2 ft lb
Chimaera - 4L Rover V8 - 206.3 bhp, 221 ft lb.

Griffith - 5L Rover V8 - 231.8 bhp, 254.7 ft lb
Griffith - 5L Rover V8 - 278.1 bhp, 332.1 ft lb
Griffith - 5L Rover V8 - 244.3 bhp, 288.2 ft lb
Griffith - 5L Rover V8 - 251.8 bhp, 292.4 ft lb

Typhoon - Speed 6 - 337.8 bhp, 299.3 ft lb

Noble - 2.5L twin turbo Duratec - 276.8 bhp, 253.4 ft lb

V8S - 4L Rover V8 - 219.4 bhp, 221.6 ft lb
Tuscan - Speed 6 - 346.1 bhp, 294.9 ft lb
3000M - 3.1L V6 - 162.2 bhp, 179.8 ft lb

[The AJP Griff]

Thats a very wavy toque curve,is that normal?

[Guillotine]

Wheelspin, broke away at peak power.

Edited by Guillotine on Sunday 3rd June 18:57

[JensenA]

Guillotine said:

Wheelspin, broke away at peak power.

Edited by Guillotine on Sunday 3rd June 18:57

I knew So that's what it was! there was a reasonable explanation !

[HarryW]

Peak(ish) Torque maybe not power.
However it did it on both runs, more likely to be the characteristic and state of tune of the engine.

[twizellb]

So the one and only Tuscan made more HP than all the cerb's surely shome mistake there jools!.that can't be right, surely not, no, no way, never.
Please put us all out of our misery,how can this be!
Looking forward to your reply.

[HarryW]

Pretty standard and normal for a health S6 to make 350/290 ish. The S6's if healthy are quite consistant, even the 3.6's and 4ltrs seem to be very similar, which does make you wonder if there really is any capacity difference in them

[BCA]

JensenA said:

Joo (TCS) Does this give you any hints as to what needs to be done, and what could be wrong?

Cerbera - 4.5L V8 AJP - 325.8 bhp, 331.2 ft lb < My car

I think he'll think it needs a remap and induction... Not too bad, power is a little low - I should think with the above mods it'll approach or be part of the 400bhp club.

Edit: I expected a little more of the Typhon. Still absolutely love them though.

Edited by BCA on Sunday 3rd June 21:45

[Byker28i]

I'm on a course this week so cant scan mine, but my 4.2 had a nice smooth torque and bhp graph. A Rapid rise in torque to 2500 revs and then a nice smooth gentle rise.

Whats a normal air/fuel mix. The operator thought mine was lean at around 14%

Edited by Byker28i on Sunday 3rd June 21:47

[Mars]

Byker28i said:

I'm on a course this week so cant scan mine, but my 4.2 had a nice smooth torque and bhp graph. A Rapid rise in torque to 2500 revs and then a nice smooth gentle rise.

Whats a normal air/fuel mix. The operator thought mine was lean at around 14%

Edited by Byker28i on Sunday 3rd June 21:47

Air to Fuel ratio, often quoted as AFR, is at stoich at 14.7:1. A lower number means richer mixture.

14%, assuming that translates to the amount of fuel in the air, is about 7AFR which is probaby too rich to actually fire.

I think he meant literally 14AFR (not a percentage) in which case it is close to stoich but *where* it was at 14AFR is more important. On a light throttle, a lean mixture makes better economy. If this is on full throttle, and it maintained 14AFR throughout the rev range, then I agree that it is lean. You probably make max power at an AFR of about 13, although Joolz will know specific figures better than me. I don't yet have a full set of figures and stats for this engine.

[BCA]

A.G. said:

BCA said:

I expected a little more of the Typhon. Still absolutely love them though.

Edited by BCA on Sunday 3rd June 21:45

Why would you expect more?

Oh sorry thats because in any of the scant TVR blurb you may come across, a Typhon was a supercharged S6, hence your possibly subliminal heightened expectation.

No, I assumed it would have the normal 4.0 six, however, having drooled over the various bits of detailing and admired the effort that went into so much of the cars design (from a functional point of view as well as aesthetic.) - I thought the least it would do was produce a figure closer to the more optimal set up sixes as an example; 373bhp is the most I've heard of a standard car. The fact it was beaten by a standard Tuscan on the day is a little disappointing.

As a long term TVR fanatic I tend to ignore everything that the PR blurb says and prefer to talk with owners/witness the performance/spec of various models first hand.

Edited by BCA on Sunday 3rd June 23:25

[dempsey]

Alan,
Jools got my 4.5 up to over 410bhp with the whirlwind kit and remap. More significantly the power curve just straightlines up to 7000rpm with no hiccoughs.
Makes for a wall of acceleration with no flat spots or hesitation.
Thoroughly recommended.

[ridds]

My money's on fuelling. Typical over-fuel torque curve.

[trackcar]

They look like normal 4.5 unmapped/long induction graphs to me. They have the characteristic double camel hump profile which is entirely consistent with a std 4.5 engine.

I was under the impression that dastek's gave slightly higher reading than we're used to but i have to say that all those cars look to be in the right ball park bhp wise so that points to your 4.5 being a good average car and assuming it makes similar hp when it goes on my dyno i see no reason to start looking for anything wrong at all. If it makes 330hp up here we're on for 400hp when finished.

fingers crossed see you thursday bright and early (well 9 ish if you can lol) .. did you get my mail about me having to be away from here at noon on friday?

Cerbs give best hp in my experience at lambda 0.95 (about 14:1 afr) so a mixture somewhere near 14:1 through the hp range is good for hp .. if it was a track car under constant heavy load you'd maybe want to go richer for safety, but hp always goes down as you richen them up past lambda 0.9. For some reason cerbs seem particularly sensitive to mixture, far more than the rover v8 anyway.

[JensenA]

Thanks Joo, thats reassured me a lot. yes I did get your email, see you Thursday - Can't wait to drive it back

[Duke Thrust]

trackcar said:

They look like normal 4.5 unmapped/long induction graphs to me. They have the characteristic double camel hump profile which is entirely consistent with a std 4.5 engine.

I was under the impression that dastek's gave slightly higher reading than we're used to but i have to say that all those cars look to be in the right ball park bhp wise so that points to your 4.5 being a good average car and assuming it makes similar hp when it goes on my dyno i see no reason to start looking for anything wrong at all. If it makes 330hp up here we're on for 400hp when finished.

fingers crossed see you thursday bright and early (well 9 ish if you can lol) .. did you get my mail about me having to be away from here at noon on friday?

Cerbs give best hp in my experience at lambda 0.95 (about 14:1 afr) so a mixture somewhere near 14:1 through the hp range is good for hp .. if it was a track car under constant heavy load you'd maybe want to go richer for safety, but hp always goes down as you richen them up past lambda 0.9. For some reason cerbs seem particularly sensitive to mixture, far more than the rover v8 anyway.

Hi Joo,

Tried calling you number on Saturday, will try again today. Mine is the 299BHP cerb. I knew it felt down on power but it seems to be way down, it has a terrible stutter under 2500RPM as well.

I'll post some screen shots of the ECU data that I took yesterday, would welcome opinions on what the problems is.

[Mars]

trackcar said:

Cerbs give best hp in my experience at lambda 0.95 (about 14:1 afr) so a mixture somewhere near 14:1 through the hp range is good for hp .. if it was a track car under constant heavy load you'd maybe want to go richer for safety, but hp always goes down as you richen them up past lambda 0.9. For some reason cerbs seem particularly sensitive to mixture, far more than the rover v8 anyway.

That's extremely interesting. I'd like to believe that it was intentional on behalf of the designer(s) but whatever the reason, max power near to stoich is good for economy too.

[ridds]

Don't forget about you valve and cat temps though.

Eunning that lean at peak power can put those components very close to their temperature limits.

[Byker28i]

Mine was the 322bhp Cerbera - hence why Alan was worried. I think he'd have hated me even more if his old car made more power than his new one

[JensenA]

Huge sigh of relief ! (but only by a measley 3hp)