Performance Development of 4.2AJP
Discussion
after lots of spannering, mainly for electronic-defects, my car is now (after 2 years) finally roadworthy again.
so far so good. early 4.2AJP, 28.000miles, recent service with valve-clearances, new cats, emissions spot-on
now i had the chance to drive the car the first time since purchase and i was somehow disapointed about the power.
this said: before the Cerb i owned a westfield-seven with a tuned 3.5Rover V8 engine with 220BHP...lots of torque, straight from start, loud, noisy and no windscreen and a 4L Chimeara
the Cerbera feels like a car for my Grandma, compared to that.
precise steering, operational forces of steering and braking quite comfy, suspension as well...feels like a modern car
ok...not wanting so see things only negative: the only "gauge" i could see that there must be Power somewhere, was the Tachometer.
my feeling during driving / acceleration was "this must be 80mph" but in reality i was driving already 110mph.
i was viewing lots of videos, reading lots of reports in magzines about the cerbera before i bought it.....and it was decribed as brutal beast...but mine behaves more like a kitten. (imo)
so far so good. early 4.2AJP, 28.000miles, recent service with valve-clearances, new cats, emissions spot-on
now i had the chance to drive the car the first time since purchase and i was somehow disapointed about the power.
this said: before the Cerb i owned a westfield-seven with a tuned 3.5Rover V8 engine with 220BHP...lots of torque, straight from start, loud, noisy and no windscreen and a 4L Chimeara
the Cerbera feels like a car for my Grandma, compared to that.
precise steering, operational forces of steering and braking quite comfy, suspension as well...feels like a modern car
ok...not wanting so see things only negative: the only "gauge" i could see that there must be Power somewhere, was the Tachometer.
my feeling during driving / acceleration was "this must be 80mph" but in reality i was driving already 110mph.
i was viewing lots of videos, reading lots of reports in magzines about the cerbera before i bought it.....and it was decribed as brutal beast...but mine behaves more like a kitten. (imo)
Edited by LLantrisant on Tuesday 6th December 22:54
Hard to put power down in first - not too bad in second, but third gear is just dreamy, BUT suicidal to do it this time of year - please don't, please be careful.
Also, things have moved on in the last few years 0-60 in sub 6 or 5 secs is now quite common for affordable things like electric cars, Golf R etc, whereas 25 years ago it was rare or expensive.
It's deceptively quick though, especially for an 'old' car. Personally I like mine as a GT car, it positively eats distances
Have you put yours on a rolling road just to check it?
Also, things have moved on in the last few years 0-60 in sub 6 or 5 secs is now quite common for affordable things like electric cars, Golf R etc, whereas 25 years ago it was rare or expensive.
It's deceptively quick though, especially for an 'old' car. Personally I like mine as a GT car, it positively eats distances
Have you put yours on a rolling road just to check it?
what i want to say with my Post? that this so called "brutal beast" feels rather like a slow kitten, compared to my Rover V8 powered westfield. even my high mileage Chimaera400 felt torquier than my Cerbera.
i know, the cerbera needs to be rev-ed, but also beyond 5000rpm i could not feel any oomph, like i had in all my Rover Powered cars even fom lower rev´s. i´m missing somehow this oomph.
my mates 4.3 Chimeara feels quicker, not talking about the other mates 5L Griffith
rolling road? no...impossible were i live to find a rolling road.
as said, it seems that the car has some Power, otherwise the speed-increase would not be so noticable...but how this speed-increase happenes, feels rather unspectular.
maybe my expectations are too high?
i remember in the past my 4.2L Jaguar XJ/S....it was similar....no oomph..i also thought "how poor in power is that car" .but the power was equally distributed throughout the complete rev-range. you could only "feel" the power by viewing the speed-increase on the tachometer.
maybe its similar with the AJP engine as well?
it feels that the Cerbera would be well for motorways, driving long distances, eating miles without too much stress?
i know, the cerbera needs to be rev-ed, but also beyond 5000rpm i could not feel any oomph, like i had in all my Rover Powered cars even fom lower rev´s. i´m missing somehow this oomph.
my mates 4.3 Chimeara feels quicker, not talking about the other mates 5L Griffith
rolling road? no...impossible were i live to find a rolling road.
as said, it seems that the car has some Power, otherwise the speed-increase would not be so noticable...but how this speed-increase happenes, feels rather unspectular.
maybe my expectations are too high?
i remember in the past my 4.2L Jaguar XJ/S....it was similar....no oomph..i also thought "how poor in power is that car" .but the power was equally distributed throughout the complete rev-range. you could only "feel" the power by viewing the speed-increase on the tachometer.
maybe its similar with the AJP engine as well?
it feels that the Cerbera would be well for motorways, driving long distances, eating miles without too much stress?
Edited by LLantrisant on Wednesday 7th December 10:14
Assuming that your name is where you are from, there is a rolling road in Cardiff. That is about 16 miles away. Surely that isn't too far. That has to be your 1st port of call. If the Cerbera is producing the expected power but it doesn't feel fast, to you, then it is time to sell it and buy something else.
Any V8 Cerbera in good health, should feel mental fast in the first 3 gears at least.
That said, it will feel comfortable compared to a Lotus 7 type car for sure, and the suspension can feel soft and comfortable.
It is a unique engine, I love the power delivery but it's perhaps not for everyone.
That said, it will feel comfortable compared to a Lotus 7 type car for sure, and the suspension can feel soft and comfortable.
It is a unique engine, I love the power delivery but it's perhaps not for everyone.
It's an odd quirk of the human body that we are very poor at recognising acceleration. Instead, what we identify well is rate of change of acceleration (known as jerk) and often associate this with being acceleration.
In a car with a sudden change in torque delivery (i.e. lots of low down torque when you drop the clutch, a turbo delivering boost at a certain point in the rev range, VTEC kicking in
, etc.) you feel that non-linear acceleration - jerk - and associate it with acceleration.
In a car with a very smooth, linear power delivery (from personal experience a Mazda RX8 best showed this) you do not get that jerk, and so your body struggles to identify how hard linear acceleration is.
If you couple that with the (relative) comfort of a Cerbera isolating you from other indicators of speed (wind noise, exhaust sound, etc.) compared to the 7-style car you're used to, you end up with what I think you're experiencing. A car that gets to speeds very quickly, but doesn't give you the feedback you're used to while it's doing it.
I experienced similar when I bought my BMW E39 M5 - although only in the bottom half of the rev range. I'd be driving along wondering why everyone was driving so slowly on the motorway, then check the speedo and realise it was me doing 30mph more than I believed I was! My senses eventually recalibrated to a 'new normal' and everything was fine (no speeding fines in that car!).
In a car with a sudden change in torque delivery (i.e. lots of low down torque when you drop the clutch, a turbo delivering boost at a certain point in the rev range, VTEC kicking in
, etc.) you feel that non-linear acceleration - jerk - and associate it with acceleration.In a car with a very smooth, linear power delivery (from personal experience a Mazda RX8 best showed this) you do not get that jerk, and so your body struggles to identify how hard linear acceleration is.
If you couple that with the (relative) comfort of a Cerbera isolating you from other indicators of speed (wind noise, exhaust sound, etc.) compared to the 7-style car you're used to, you end up with what I think you're experiencing. A car that gets to speeds very quickly, but doesn't give you the feedback you're used to while it's doing it.
I experienced similar when I bought my BMW E39 M5 - although only in the bottom half of the rev range. I'd be driving along wondering why everyone was driving so slowly on the motorway, then check the speedo and realise it was me doing 30mph more than I believed I was! My senses eventually recalibrated to a 'new normal' and everything was fine (no speeding fines in that car!).
DuncanM said:
Any V8 Cerbera in good health, should feel mental fast in the first 3 gears at least.
That said, it will feel comfortable compared to a Lotus 7 type car for sure, and the suspension can feel soft and comfortable.
It is a unique engine, I love the power delivery but it's perhaps not for everyone.
watching the Tacho it looks really fast....but as said i´m missing this "oomph"...a kick in the ass when you push the pedal.....That said, it will feel comfortable compared to a Lotus 7 type car for sure, and the suspension can feel soft and comfortable.
It is a unique engine, I love the power delivery but it's perhaps not for everyone.
i have now made this expirience and it really might be, that this car is not for me....so it might be soon up for sale, i guess...lesson learned..
Edited by LLantrisant on Wednesday 7th December 12:10
Doesn't sound like it's running right? It's never going to give that huge kick in the seat, because it's geared long, but then what do you expect from a car that'll do 180mph plus. There's no way it's sluggish though if running right, although the delivery is smooth and deceptive.
However, not the time of year to be trying it out.
However, not the time of year to be trying it out.
my 2p for what its worth:
Comparing my 1998 4.2 with my 2002 4.5, the early 4.2 actually seemed to have a sense of urgency and almost a bit of mild panic when accelerating. I dare say this is a result of the 4.5's slightly obscure mapping out of the factory, in my case, and a comparative sense of slight sluggishness.
On that pretty groundless basis, maybe that's the answer - if you can get it somewhere and get it mapped properly? Might give you the grunt you're looking for? or, if not an early grave.
Comparing my 1998 4.2 with my 2002 4.5, the early 4.2 actually seemed to have a sense of urgency and almost a bit of mild panic when accelerating. I dare say this is a result of the 4.5's slightly obscure mapping out of the factory, in my case, and a comparative sense of slight sluggishness.
On that pretty groundless basis, maybe that's the answer - if you can get it somewhere and get it mapped properly? Might give you the grunt you're looking for? or, if not an early grave.
We don't know where you live, so don't know the weather, the types of roads, traffic conditions etc.
However, at some point, when and where it is safe and legal to do so, it cannot be that difficult to have a passenger time you from zero to a given speed. That should give an indication on whether the engine is healthy or whether there is something seriously wrong.
However, at some point, when and where it is safe and legal to do so, it cannot be that difficult to have a passenger time you from zero to a given speed. That should give an indication on whether the engine is healthy or whether there is something seriously wrong.
look...i´m 30y into automotive...so i should most likely recognize when an engine is not healthy.....
the valve-clearances are well set, camshafts look like new, once warmed-up the idle is smooth and mechanically reasonably quiet (for an early 4.2). compression is equal on all 8pots. emissions are spot-on.
as said....watching the tacho the car really goes forward.....but without the oomph i expected....and at the moment its not the best "season" to make any fancy road-tests in terms of acceleration.
what i can really tell is: that the engine really needs to be warmed-up well too change its behavour. the hotter it is, the better is behaves, the smoother it runs.
obviously, i dont now anything about the mapping....but with such a low mileage i guess its unmodified as it came from TVR...this said, the car was a model built for Japan (year 1997)....maybe it was mapped different from the factory for the japanese market?
the valve-clearances are well set, camshafts look like new, once warmed-up the idle is smooth and mechanically reasonably quiet (for an early 4.2). compression is equal on all 8pots. emissions are spot-on.
as said....watching the tacho the car really goes forward.....but without the oomph i expected....and at the moment its not the best "season" to make any fancy road-tests in terms of acceleration.
what i can really tell is: that the engine really needs to be warmed-up well too change its behavour. the hotter it is, the better is behaves, the smoother it runs.
obviously, i dont now anything about the mapping....but with such a low mileage i guess its unmodified as it came from TVR...this said, the car was a model built for Japan (year 1997)....maybe it was mapped different from the factory for the japanese market?
Edited by LLantrisant on Wednesday 7th December 13:41
Interesting thread. I was slightly undwerwhelmed by my 4.2. It was good, but didn;t seem as good as the hype.
I spent a bit of time trying to set it up as best as I could but it still seemed 'off'. Recently I decided to have a look at the catalysts, and discovered they were both in very poor condition, having been damaged due to a misfire allowing raw fuel down the manifold and had effectively melted them.
With decat pipes it's a changed beast. Markedly better. As Paul notes traction at this time of the year is poor, and I'm now finding it needs far more respect than it did before.
You mentioned electrical issues. Did you have misfires too?
I spent a bit of time trying to set it up as best as I could but it still seemed 'off'. Recently I decided to have a look at the catalysts, and discovered they were both in very poor condition, having been damaged due to a misfire allowing raw fuel down the manifold and had effectively melted them.
With decat pipes it's a changed beast. Markedly better. As Paul notes traction at this time of the year is poor, and I'm now finding it needs far more respect than it did before.
You mentioned electrical issues. Did you have misfires too?
Sounds strange. I had a similar thing once with a car I owned and we never look for the obvious do we? Everything I looked at was perfect except one thing, perhaps not so obvious? It ended up being that the throttle wasn't set up properly and the throttle valve was only opening 3/4 of the way at full throttle! Just an idea!!
Bogsye said:
Interesting thread. I was slightly undwerwhelmed by my 4.2. It was good, but didn;t seem as good as the hype.
I spent a bit of time trying to set it up as best as I could but it still seemed 'off'. Recently I decided to have a look at the catalysts, and discovered they were both in very poor condition, having been damaged due to a misfire allowing raw fuel down the manifold and had effectively melted them.
With decat pipes it's a changed beast. Markedly better. As Paul notes traction at this time of the year is poor, and I'm now finding it needs far more respect than it did before.
You mentioned electrical issues. Did you have misfires too?
Interesting you say that, my 4.2 was decatted and the 4.5 has cats. Perhaps thats it.I spent a bit of time trying to set it up as best as I could but it still seemed 'off'. Recently I decided to have a look at the catalysts, and discovered they were both in very poor condition, having been damaged due to a misfire allowing raw fuel down the manifold and had effectively melted them.
With decat pipes it's a changed beast. Markedly better. As Paul notes traction at this time of the year is poor, and I'm now finding it needs far more respect than it did before.
You mentioned electrical issues. Did you have misfires too?
I'd already discussed this with Joolz when chatting through emerald ecu and map options. To paraphrase Joolz very poorly, removing the cats makes next to no difference in performance gain, but there's no real hard and fast rule, as you can imagine with low volume production, hand built cars.
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