Discussion
I'm having the engine of my Tuscan 4.0 rebuilt (for the third time 
) by the lovely people at TVR Power and whilst it was with them I was thinking of having the car decatted. I've heard that doing so will improve the performance, very slightly, and give the engine note a harder edge, much like the difference between pre and post CAT Griffiths. However, I also have the TVR Centres sports pipes fitted and I was wondering if the combination of the two would mean I'm going to be hated by the neighbours and will need ear defenders to save what little hearing I have left.
Has anyone else decatted their car with a sports exhaust and if so, is it unacceptably loud?
Also, I've heard that TVR Power are doing their own EPROM which improves drivability and power. Does anyone have any experience of this?
) by the lovely people at TVR Power and whilst it was with them I was thinking of having the car decatted. I've heard that doing so will improve the performance, very slightly, and give the engine note a harder edge, much like the difference between pre and post CAT Griffiths. However, I also have the TVR Centres sports pipes fitted and I was wondering if the combination of the two would mean I'm going to be hated by the neighbours and will need ear defenders to save what little hearing I have left. Has anyone else decatted their car with a sports exhaust and if so, is it unacceptably loud?
Also, I've heard that TVR Power are doing their own EPROM which improves drivability and power. Does anyone have any experience of this?
Do not de cat!
It's illegal.
All cars registered since about 1994 have to have a cat as law to be used on the road.
The car would be automatically unMOTed and therefore uninsured for most driver's policies.
Respect the construction and use regs even if you thinjk its crapp. The consequences otherwise could be disasterous.
It's illegal.
All cars registered since about 1994 have to have a cat as law to be used on the road.
The car would be automatically unMOTed and therefore uninsured for most driver's policies.
Respect the construction and use regs even if you thinjk its crapp. The consequences otherwise could be disasterous.
Thanks for the advice guys. I was wondering about the legality of taking the cats off, but I'm assured that it's not a legal requirement to have cats on the car, merely that the car must be able to pass the emmission tests. The other modifications that are being done at the same time i.e the new Eprom, will solve this little problem apparently.
Tuscan Thunder, I take it you think the car is going to be VERY VERY noisy. It's true I really only use it on weekends, but I also go touring in Europe with it, so perhaps it's not a good idea, but then again, if it gives me more power it might be worth sacrificing the hearing
.
>> Edited by disappointed on Tuesday 1st June 20:37
Tuscan Thunder, I take it you think the car is going to be VERY VERY noisy. It's true I really only use it on weekends, but I also go touring in Europe with it, so perhaps it's not a good idea, but then again, if it gives me more power it might be worth sacrificing the hearing
. >> Edited by disappointed on Tuesday 1st June 20:37
disappointed said:
Thanks for the advice guys. I was wondering about the legality of taking the cats off, but I'm assured that it's not a legal requirement to have cats on the car, merely that the car must be able to pass the emmission tests. The other modifications that are being done at the same time i.e the new Eprom, will solve this little problem apparently.
Tuscan Thunder, I take it you think the car is going to be VERY VERY noisy. It's true I really only use it on weekends, but I also go touring in Europe with it, so perhaps it's not a good idea, but then again, if it gives me more power it might be worth sacrificing the hearing
>> Edited by disappointed on Tuesday 1st June 20:37
I'd check up on those facts carefully... as far as I'm aware it's illegal to drive a car that is knowingly in breach of MOT requirements. If you're in an accident with the cats off and anyone notices, you'll probably have a nasty fight on your hands with the insurance company. Not sure of the legalities on the continent at all.
Regarding performance, it depends on the back pressure in the exhaust system on the car. With the Cerbera, for instance, the change with it de-catted in theory meant losing a few BHP through most of the rev range and gaining a couple up near the redline. Sure, if you de-cat a car, get someone to spend some time on it and get the airflow out of the back tweaked you'll gain some power, but don't expect miracles (or anything) from a set of bypass pipes.
To be honest, I wouldn't expect anything other than it to be a lot louder. Quite a few people don't like the type of sound the combination of a de-cat and sports 'zorsts creates... with "hollow" cans already on a Tuscan it'll be a fairly raspy, max-power sounding affair, nothing like the gorgeous V8 burble.
Regarding the ECU, any idea which ECU this is? The standard RR one, a custom one, or the "dThrottle chip"? (The latter'll actually reduce performance but increase driveability on cars with worn throttle bodies, etc). Not sure about any other "just ECU" upgrades they do at moment... will hopefully be chatting to TVR Power in the next day or so, anyway, so will no doubt ask them what upgrades they can do to my car, seeing as it's looking like ending up at a 2-3 month wait for a rebuild.
If you really want a faster car, the best upgrade (besides driver training) is to replace the suspension. The standard TVR shocks are awful. A set of Nitrons makes a huge difference.
J_S_G said:
[quote=disappointed]
....the "dThrottle chip"? (The latter'll actually reduce performance...
I don't think it reduces performance. It samples the throttle position better so smooths out the jitter so won't effect the actual power being produced. The worst it could do is soften throttle response but I've not noticed any difference. For all we know all the ECUs could have this feature now - which would explain why only the early cars need this "chip".
Cheers,
Andy.
I appreciate what you say JSG, and certainly I wouldn’t want to drive a car that is unable to pass the MOT test and therefore be uninsured. However, I don’t believe it will be in breach of the MOT requirements as I’m told the new chip will allow the car to pass the emission test of the MOT. After all, wasn’t there a lot of attention being focused on ‘lean-burn engines’ at one time - engines that gave low emissions without the expense and harmful effects of CATs?
I think I'm going to have to check the legal requirements more closely and find out whether it's CATs that are a requirement or just the need to have the correct emissions, no matter how that's achieved. It may be both of course, as cars with CATs can still fail the MOT if the CATs have passed their useful life!
With regards to power increases, I’ve rather assumed the new chip sorts out the new fuelling requirements that decatting will give, but having typed that I’ve realised the contradiction. How can the new chip meet the MOT requirements and still give the engine the fuel it needs to get more power hmmmm! If you’re speaking to TVR Power later I’d be grateful for any feed-back you get as it all seemed very straightforward when I was talking to them and now it’s rather hazy.
P.S. As far as increasing performance - I've already got the Nitrons fitted and I've had the caster and camber settings revised and that's improved the handling beyond belief. I've also had some driver training, but I don't profess to be a good driver, just average, as I always think there's room for a lot of improvement. It's just that the Tuscan doesn't feel anywhere near as quick as my old Cerbera, so I wanted to wring a few more bhp out of it.
>> Edited by disappointed on Wednesday 2nd June 10:23
I think I'm going to have to check the legal requirements more closely and find out whether it's CATs that are a requirement or just the need to have the correct emissions, no matter how that's achieved. It may be both of course, as cars with CATs can still fail the MOT if the CATs have passed their useful life!
With regards to power increases, I’ve rather assumed the new chip sorts out the new fuelling requirements that decatting will give, but having typed that I’ve realised the contradiction. How can the new chip meet the MOT requirements and still give the engine the fuel it needs to get more power hmmmm! If you’re speaking to TVR Power later I’d be grateful for any feed-back you get as it all seemed very straightforward when I was talking to them and now it’s rather hazy.
P.S. As far as increasing performance - I've already got the Nitrons fitted and I've had the caster and camber settings revised and that's improved the handling beyond belief. I've also had some driver training, but I don't profess to be a good driver, just average, as I always think there's room for a lot of improvement. It's just that the Tuscan doesn't feel anywhere near as quick as my old Cerbera, so I wanted to wring a few more bhp out of it.
>> Edited by disappointed on Wednesday 2nd June 10:23
I believe it's the emmisions that are the requirement, however I'm 99.9% certain that you'll never pass the emmisions test without a cat.
If it could be done without a cat, someone like Toyota or Honda would have done it by now so I can't see TVR managing what Honda haven't.
Certainlt I had to put the cats back on both my Elise and Caterham to get them through an MOT, pain in the arse particularly on the Elise, not so bad on the Caterham.
If it could be done without a cat, someone like Toyota or Honda would have done it by now so I can't see TVR managing what Honda haven't.
Certainlt I had to put the cats back on both my Elise and Caterham to get them through an MOT, pain in the arse particularly on the Elise, not so bad on the Caterham.
andyvdg said:
I don't think it reduces performance. It samples the throttle position better so smooths out the jitter so won't effect the actual power being produced. The worst it could do is soften throttle response but I've not noticed any difference. For all we know all the ECUs could have this feature now - which would explain why only the early cars need this "chip".
It won't reduce the power at any revs as such, but it will give a delayed throttle response, whether it's noticeable to an individual or not. By it's very nature, it is sampling over a greater period of time, hence the lag it introduces... that's the difference between it and a standard chip. It's basically dealing with symptoms rather than the cause; personally I'd rather pay to cure the real problems... up-rated throttle bodies, etc.
disappointed said:
I appreciate what you say JSG, and certainly I wouldn’t want to drive a car that is unable to pass the MOT test and therefore be uninsured. However, I don’t believe it will be in breach of the MOT requirements as I’m told the new chip will allow the car to pass the emission test of the MOT. After all, wasn’t there a lot of attention being focused on ‘lean-burn engines’ at one time - engines that gave low emissions without the expense and harmful effects of CATs?
I think I'm going to have to check the legal requirements more closely and find out whether it's CATs that are a requirement or just the need to have the correct emissions, no matter how that's achieved. It may be both of course, as cars with CATs can still fail the MOT if the CATs have passed their useful life!
With regards to power increases, I’ve rather assumed the new chip sorts out the new fuelling requirements that decatting will give, but having typed that I’ve realised the contradiction. How can the new chip meet the MOT requirements and still give the engine the fuel it needs to get more power hmmmm! If you’re speaking to TVR Power later I’d be grateful for any feed-back you get as it all seemed very straightforward when I was talking to them and now it’s rather hazy.
P.S. As far as increasing performance - I've already got the Nitrons fitted and I've had the caster and camber settings revised and that's improved the handling beyond belief. I've also had some driver training, but I don't profess to be a good driver, just average, as I always think there's room for a lot of improvement. It's just that the Tuscan doesn't feel anywhere near as quick as my old Cerbera, so I wanted to wring a few more bhp out of it.
Not sure on the details of the legalities... would be interested to know if you find out if it is just the emission level that matters. However, you'll still (technically) have to notify the insurer that you've modified the car from standard (Tesco didn't seem to mind about the Nitrons for me
) I spoke to TVR Power today about getting more power from mine when it's in for its annual rebuild... They suggested de-catting it, too, so maybe the breathing on it is sorted for that. I'm still not convinced about having it done, myself, though. Didn't chat to them about ECUs, but I'd be interested in which chip it is they'd put in. I can see the RR spec one doing a better job (or better still - get an Emerald, etc. one done).
Have you had the car on a rolling road session? What's it putting out? I'd say that my Tuscan feels about 50BHP up on the Cerb, which is probably about right. What spec Cerb did you have?
If it's TVR Power that've told you they can do all this, I can't see any reason to doubt them at all... They'll give you far more knowledgeable advice on the engine than I or almost anyone else on here ever will!
Just don't take up too much of their time... I've got to wait another month before they can fit mine in as it is
I haven’t had a chance to check the regulations regarding the emissions yet, but as soon as I have, I’ll post what I find.
I haven’t had the Tuscan on a rolling road, to be honest the engine has never lasted long enough for me to feel confident that it was run-in sufficiently to take the punishment I feel a rolling road gives. This is the third time the car has gone back for a rebuild, but now it’s being built to 2004 spec and considering what TVR Power have told me, I feel confident that it’ll be a lot better.
I got the impression the chip I was being offered was a new one they’d just developed. It wasn’t the RR one ‘cos I asked, but whether it’s the one that sorts out the worn throttle bodies or not I’m not sure. I hope not, as I like a very quick throttle response and I was going to get the dreadnaught conversion as soon as funds allowed.
The Cerbera I had was a late ’98 4.2 and it was by far the best Tiv I’ve ever owned. It only let me down twice. Once because the dealer forgot to refill the radiator completely when it was serviced….doh and once the battery went flat when I hadn’t used it for a month, which was my fault entirely, so no complaints there!!! I know there is a lot of controversy about which Cerbera was quickest, 4.2 or 4.5, but I think I must have had a ‘good one’ as it pulled like a train and took me to 160mph at the end of the straight at Duxford, which was amazing
I haven’t had the Tuscan on a rolling road, to be honest the engine has never lasted long enough for me to feel confident that it was run-in sufficiently to take the punishment I feel a rolling road gives. This is the third time the car has gone back for a rebuild, but now it’s being built to 2004 spec and considering what TVR Power have told me, I feel confident that it’ll be a lot better.
I got the impression the chip I was being offered was a new one they’d just developed. It wasn’t the RR one ‘cos I asked, but whether it’s the one that sorts out the worn throttle bodies or not I’m not sure. I hope not, as I like a very quick throttle response and I was going to get the dreadnaught conversion as soon as funds allowed.
The Cerbera I had was a late ’98 4.2 and it was by far the best Tiv I’ve ever owned. It only let me down twice. Once because the dealer forgot to refill the radiator completely when it was serviced….doh and once the battery went flat when I hadn’t used it for a month, which was my fault entirely, so no complaints there!!! I know there is a lot of controversy about which Cerbera was quickest, 4.2 or 4.5, but I think I must have had a ‘good one’ as it pulled like a train and took me to 160mph at the end of the straight at Duxford, which was amazing
disappointed said:
I haven’t had a chance to check the regulations regarding the emissions yet, but as soon as I have, I’ll post what I find.
I haven’t had the Tuscan on a rolling road, to be honest the engine has never lasted long enough for me to feel confident that it was run-in sufficiently to take the punishment I feel a rolling road gives. This is the third time the car has gone back for a rebuild, but now it’s being built to 2004 spec and considering what TVR Power have told me, I feel confident that it’ll be a lot better.
I got the impression the chip I was being offered was a new one they’d just developed. It wasn’t the RR one ‘cos I asked, but whether it’s the one that sorts out the worn throttle bodies or not I’m not sure. I hope not, as I like a very quick throttle response and I was going to get the dreadnaught conversion as soon as funds allowed.
YHM
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