How fast is my cerb?
Discussion
Ok please help me cos I'm confused, I bought my cerb cos i saw the clarkson vid with it smoking all the fastest cars of the time, then i saw the posts about cerbs not making the power they claim, but thought it still beat them all on the vid so prehaps the other cars claims are incorrect. Untill i looked at some posts on here that say the car was a 5L and very none standard. Can the cars match the the 0-60 times and top end claimed by TVR?
Don't get me wrong the car is very very fast, bike fast and i have had some fast bikes. Also are the clocks correct cos I've seen 170 in 4th many times but my gps says 150ish.Thanks in advance.
Don't get me wrong the car is very very fast, bike fast and i have had some fast bikes. Also are the clocks correct cos I've seen 170 in 4th many times but my gps says 150ish.Thanks in advance.
Ahem. Not in this country of course! Thought I'd just add that for you in case the anti-fun brigade get on your back.
Can't comment on the spedo inaccuracy as I haven't compared mine against a gps reading.
From my own reading of these forums I seem to remember that the Clarkson car was a 4.2 with the 4.5 style intake trumpets. I would imagine that it was put together more carefully than the average engine so probably did make the 360bhp claimed.
If you do more reading around and compare rolling road figures from SRR's rollers you will find that without mods, the 4.5 is sometimes less powerful than some standard 4.2's (not always). I've probably stirred a hornets nest there so anyone feel free to correct me if I'm talking drivel.
You are right though, it is indecently fast.
Scott
By the way Liam? (toady) My speedo is steady at all speeds. Don't know what could be causing your problem. Hope someone else has a suggestion as I would imagine that it is a bit annoying.
>> Edited by purpleheadedcerb on Sunday 27th November 21:24
Can't comment on the spedo inaccuracy as I haven't compared mine against a gps reading.
From my own reading of these forums I seem to remember that the Clarkson car was a 4.2 with the 4.5 style intake trumpets. I would imagine that it was put together more carefully than the average engine so probably did make the 360bhp claimed.
If you do more reading around and compare rolling road figures from SRR's rollers you will find that without mods, the 4.5 is sometimes less powerful than some standard 4.2's (not always). I've probably stirred a hornets nest there so anyone feel free to correct me if I'm talking drivel.
You are right though, it is indecently fast.
Scott
By the way Liam? (toady) My speedo is steady at all speeds. Don't know what could be causing your problem. Hope someone else has a suggestion as I would imagine that it is a bit annoying.
>> Edited by purpleheadedcerb on Sunday 27th November 21:24
That particular 4.2 was pretty standard, it had the carbon intakes before TVR decided against them, IIRC a source close to the factory said the only mod was something like a decat... which gains no power unless using linked decat pipes.
As mentioned on this thread, its been dyno'd at 360 or thereabouts by Autocar or whoever it was that was sceptical at the time.
As mentioned on this thread, its been dyno'd at 360 or thereabouts by Autocar or whoever it was that was sceptical at the time.
You would probably destroy your clutch trying to achieve the the 0-60 time.
BCA. Yes, forgot about the decat. It had a standard exhaust though didn't it? I suppose it was typical of people who owned the cars that were trounced in that shoot-out to claim foul. I'm sure the rumours about a bored out race engine were bandied around just becuase they couldn't believe a car that 'smells like an old boat' could go that fast.
BTW, I'm yet to smell any hint of boat in mine!
Scott
BCA. Yes, forgot about the decat. It had a standard exhaust though didn't it? I suppose it was typical of people who owned the cars that were trounced in that shoot-out to claim foul. I'm sure the rumours about a bored out race engine were bandied around just becuase they couldn't believe a car that 'smells like an old boat' could go that fast.
BTW, I'm yet to smell any hint of boat in mine!
Scott
njw 77 said:
a decat... which gains no power unless using linked decat pipes.
.
Is that statement 100% correct?
That it was decatted or it gains no power??
The latter was said ages ago by PH'er "roop" who has connections with the factory IIRC. The former was general consensus since the days of the Cerbera egroups and all dyno comparisons that I have seen havent really been any difference, except one where there was a noticeable dip in mid range torque...
Ben, I was referring to the latter (the power gains). I was of the belief that a normal decat gave negligable increases (i.e. a couple of bhp, but agree not very well documented) as opposed to the 6 or 7 bhp from the linked decats which I believe Jools said were proven on a recent RR.
Its only nitpicking over a few bhp, I know. My decat and sports exhaust were done (or at least supplied by) Jools, before I had the car, so I dont have an axe to grind, just asking
Its only nitpicking over a few bhp, I know. My decat and sports exhaust were done (or at least supplied by) Jools, before I had the car, so I dont have an axe to grind, just asking
I've always been under the impression its no gain or even a loss in terms of power... the linked decats are the first time I have seen any back to back comparisons with a gain. Just going on what I read years ago - mind, back then not many cars ever saw the rollers so it wouldnt be easy to prove either way! If someone has any before and after graphs for normal decats I'd be interested to see how they turned out.
Even so, if a decat gave 1-5bhp it would be completely unnoticeable in any car like the Cerbera, so had no real effect on clarksons test I should think.
If a decat gave 80bhp+ we still wouldnt be able to have one
, the Cerbs just about as noisy as it can be in terms of noise regs for sprints/ the neighbours!!!
Even so, if a decat gave 1-5bhp it would be completely unnoticeable in any car like the Cerbera, so had no real effect on clarksons test I should think.
If a decat gave 80bhp+ we still wouldnt be able to have one
, the Cerbs just about as noisy as it can be in terms of noise regs for sprints/ the neighbours!!! NJW 77 said:
Ben, I was referring to the latter (the power gains). I was of the belief that a normal decat gave negligable increases (i.e. a couple of bhp, but agree not very well documented) as opposed to the 6 or 7 bhp from the linked decats which I believe Jools said were proven on a recent RR.
Its only nitpicking over a few bhp, I know. My decat and sports exhaust were done (or at least supplied by) Jools, before I had the car, so I dont have an axe to grind, just asking
I'm still not clear on why the linked decat pipes work and with a sample size of one, you'll have to excuse me while I wait to see what other results come in. I was under the impression you generally didn't link the banks on a flat plane crank V8 via the exhaust. Like I mentioned before, with the pulses from the opposite bank feeding into the system 75 degrees after the the current pulse, intuitively it feels like you'd get some odd wave forms in the exhaust system. Mind you that assumes the standard TVR system is in some way exhaust system is in some way tuned and doesn't already produce odd wave forms
.... who knows .... Steve.
I gathered all the test reports I could find on the 4.5 (pre-Red Rose) and NONE are as fast as the original 1996 4.2 reports from Autocar and Performance Car which they rolling-roaded at 350 bhp.
I changed from a '97 4.2 to a new 4.5 in 2001 and it felt and was slower - power output was only 335bhp with 312 lb/ft torque (4.2s max at about 290lb/ft), and the car was a bit heavier mainly due to aircon. Down a favourite country road the 4.2 could just get into 4th from a 40mph exit from a bend before the braking point, redlining in each gear. My 4.5 couldn't pull maximum revs in third no matter what I did. A real sickener.
The power delivery of the 4.5 engine doesn't help in these comparisons. It has more torque lower down in the rev range so it pulls harder, but it doesn't breathe as well in the upper range so the power tails off quickly after 6k or so. In comparison the 4.2 engine is top-end biased which gives it a white-knuckle quality with the throttled floored, and mine just loved whamming into the rev-limiter.
No idea about relative top speeds, but on the basis of the above, the 4.2 should be slightly the quicker as it produces more power at higher revs and has the same gearing.
A Red Rose conversion and shortening the intakes (plus ECU remapping of course) makes the 4.5 into the car it should be - 400+bhp and 360+ lb/ft torque, nice and top-endy and seriously fast…. Mine gets deep into 4th along that same piece of road - scary!
I changed from a '97 4.2 to a new 4.5 in 2001 and it felt and was slower - power output was only 335bhp with 312 lb/ft torque (4.2s max at about 290lb/ft), and the car was a bit heavier mainly due to aircon. Down a favourite country road the 4.2 could just get into 4th from a 40mph exit from a bend before the braking point, redlining in each gear. My 4.5 couldn't pull maximum revs in third no matter what I did. A real sickener.
The power delivery of the 4.5 engine doesn't help in these comparisons. It has more torque lower down in the rev range so it pulls harder, but it doesn't breathe as well in the upper range so the power tails off quickly after 6k or so. In comparison the 4.2 engine is top-end biased which gives it a white-knuckle quality with the throttled floored, and mine just loved whamming into the rev-limiter.
No idea about relative top speeds, but on the basis of the above, the 4.2 should be slightly the quicker as it produces more power at higher revs and has the same gearing.
A Red Rose conversion and shortening the intakes (plus ECU remapping of course) makes the 4.5 into the car it should be - 400+bhp and 360+ lb/ft torque, nice and top-endy and seriously fast…. Mine gets deep into 4th along that same piece of road - scary!
For an impression of power... i had either a 911 Turbo or a GT2/3 behind me-- and by the time we hit 160mph he was 30m behind... and he was up my ass till we got over 100, yes he was trying.....
I work next to a Jap Import garage and have made a whole lot of Rice look like sooped up Novas.
Wether the BHP figures are out or not-- the power to weight ratio is still enough to toast everything on the road including most sports bikes above 100mph
obviously all this took place either in my head or on a private runway....
>> Edited by garethgtt on Monday 28th November 17:49
I work next to a Jap Import garage and have made a whole lot of Rice look like sooped up Novas.
Wether the BHP figures are out or not-- the power to weight ratio is still enough to toast everything on the road including most sports bikes above 100mph
obviously all this took place either in my head or on a private runway....
>> Edited by garethgtt on Monday 28th November 17:49
c18ere said:
is there a red rose type conversion for all us 4.2 owners who want even more power?
yes, but it's expensive .. tvr power will upgrade to 4.5 litres and do their red rose conversion .. check their website for details.
i'm sure it's perfectly possible to do red rose style porting and compression hike to the 4.2 aswell .. chat to tvr craft though if you want anything out of the ordinary i think.
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