Help!! Underpowered

[javi1892]

Hi all!

I had a problem with my 4.5 clutch two weeks ago (seals gone) and the dealer replaced the seals and some other worn parts (maybe one of the cylinders) all under guarantee.

The problem is that after I picked the car I have notice a sensible drop in the power output. Could it be something related to the clutch? I am not very good in mechanics and I would appreciate any suggestions.

Best regards,

Javier

[javi1892]

OK! I am going to tell the full story.

The seals of my clucth broke a couple of weeks ago and my dealer changed the seals, slave cylinders and release bearing, all under the warranty. They had to remove the gearbox to perform this job.

Meanwhile, before collecting the car from the dealer I agreed to bring the car to Austec to fit the induction kit, do a remap and fit AVO shocks. I knew the car was lacking some power at that time and I could hear the cats rattling all the time.

When I collected the car from the dealer, I noticed a certain power drop. The car felt much slower than before the clutch failure. However, I brought that same day the car to Austec for the other jobs.

When they put the car on the rollers it only gave 170BHP . I am sure that the car was giving much more than 170BHP before as I could feel the power when overtaking and when living other powerful cars for dead in the road. I am also sure that it was not close to 300BHP.

Austec told me that the cats were in very bad condition which I already knew and fitted bypass pipes and started to tune the engine. At the end, the current figure is only 290BHP at the wheels (induction and some remap already done) which is really poor. They are trying to identify the reason for this poor performance and are waiting to perform the final adjustment to the fuel mapping.

That's why I was wondering if it is possible to fit a gearbos or clucth in a way that about 60BHP are lost in the process. I would appreciate any help as at the end I was not expecting to spend a lot of money to bring the car to a performance much lower than a standard 4.5.

Regards,
Javier



>> Edited by javi1892 on Saturday 6th August 18:45

[GreenV8S]

javi1892 said:

That's why I was wondering if it is possible to fit a gearbos or clucth in a way that about 60BHP are lost in the process.

Ruling out obvious damage such as a flattened exhaust pipe, can't see any way for it to cause this other than damage to wiring or sensors for the engine management system. And I expect this would be picked up pretty promptly by anyone doing a rolling road setup.

[2 sheds]

The question is, have you road tested it since the Austec work with 290 bhp ? if so is it still down on the power it had before, or is it possible that it has always been low even before the cats let go.
290 at the wheels is about 330 ish at flywheel, low for a car with mods but to put it into perspective at the Cerbera RR day last year at Surrey there were a few standard cars that made similar figures.

[javi1892]

2 Sheds,

You are right to comment that quite a few cars in the Surrey RR session gave figures close to mine but I doubt that any of them were already tuned and checked as mine. Therefore, I think there is something wrong with my car and I hope Austec will find it (the car is still there). IMHO all cars should be able to be brought to standard figures (+/-10 or 15BHP) w/o induction kits and remaps.

Regards,
Javier

[2 sheds]

javi1892 said:

2 Sheds, You are right to comment that quite a few cars in the Surrey RR session gave figures close to mine but I doubt that any of them were already tuned and checked as mine. Therefore, I think there is something wrong with my car and I hope Austec will find it (the car is still there). IMHO all cars should be able to be brought to standard figures (+/-10 or 15BHP) w/o induction kits and remaps. Regards, Javier

My point was has your car always been down on power, you can only conclude this by driving it now after the Austec work.

I totally agree with you in that it should do much better with the tuning kit.

[GreenV8S]

javi1892 said:

IMHO all cars should be able to be brought to standard figures (+/-10 or 15BHP) w/o induction kits and remaps.

Agreed with most of what you said but not so sure about the above point. The factory figures were based on engine dyno readings rather than estimated from a rolling road, measuring the power by different methods in different places under different conditions gives plenty of scope for the numbers to vary hugely. Additionally, you don't know how optimistic the TVR figures were in the first place. Figures for the recent models seem to be less optimistic than for the earlier ones, even so I wouldn't necessarily take them at face value.

In my opinion the best way to look at these figures is how does the car compare before and after a change, and how does the car compare to other similar cars measured in the same place under similar conditions.

[Cyclone1]

javi1892 said:

When they put the car on the rollers it only gave 170BHP . I am sure that the car was giving much more than 170BHP before as I could feel the power when overtaking and when living other powerful cars for dead in the road. I am also sure that it was not close to 300BHP. Austec told me that the cats were in very bad condition which I already knew and fitted bypass pipes and started to tune the engine. At the end, the current figure is only 290BHP at the wheels (induction and some remap already done) which is really poor. They are trying to identify the reason for this poor performance and are waiting to perform the final adjustment to the fuel mapping. >> Edited by javi1892 on Saturday 6th August 18:45

Strange one this. It could just be a coincidence that you noticed a power drop after the clutch was sorted? After having your car RR'd and getting figures of 170bhp, the last thing I would have been doing is having the engine remapped and adding various mods. At 170bhp you clearly have something amiss that needs rectifying prior to a remap etc, admittedly the cats were identified as a restricting factor, but was the car RR'd after adding the decat pipes?.

The question I would ask is what has been done to get the car from 170bhp to 290bhp (both at the wheels?), apart from the cats I can't see how just a remap and mods would achieve this, there must have been either a mechanical or set up issue with your car??

You may know a liitle more after Austec have completed their work on your P&J.

[javi1892]

GreenV8S said:

javi1892 said: IMHO all cars should be able to be brought to standard figures (+/-10 or 15BHP) w/o induction kits and remaps. Agreed with most of what you said but not so sure about the above point. The factory figures were based on engine dyno readings rather than estimated from a rolling road, measuring the power by different methods in different places under different conditions gives plenty of scope for the numbers to vary hugely. Additionally, you don't know how optimistic the TVR figures were in the first place. Figures for the recent models seem to be less optimistic than for the earlier ones, even so I wouldn't necessarily take them at face value. In my opinion the best way to look at these figures is how does the car compare before and after a change, and how does the car compare to other similar cars measured in the same place under similar conditions.

Sorry, maybe I didn´t explain myself properly. What I meant as "standard figures" was what standard cerbs are really giving in the rolling roads, not the factory claimed power.

At the moment, any standard cerb in good condition will give substantially higher performance than mine (mine is giving 290BHP at the wheels so about 30BHP more I reckon) and mine has already the induction kit fitted and some adjusts to the mapping done. Therefore, something is wrong with it.


>> Edited by javi1892 on Sunday 7th August 13:31

[javi1892]

Cyclone1 said:

javi1892 said: When they put the car on the rollers it only gave 170BHP . I am sure that the car was giving much more than 170BHP before as I could feel the power when overtaking and when living other powerful cars for dead in the road. I am also sure that it was not close to 300BHP. Austec told me that the cats were in very bad condition which I already knew and fitted bypass pipes and started to tune the engine. At the end, the current figure is only 290BHP at the wheels (induction and some remap already done) which is really poor. They are trying to identify the reason for this poor performance and are waiting to perform the final adjustment to the fuel mapping. >> Edited by javi1892 on Saturday 6th August 18:45 Strange one this. It could just be a coincidence that you noticed a power drop after the clutch was sorted? After having your car RR'd and getting figures of 170bhp, the last thing I would have been doing is having the engine remapped and adding various mods. At 170bhp you clearly have something amiss that needs rectifying prior to a remap etc, admittedly the cats were identified as a restricting factor, but was the car RR'd after adding the decat pipes?. The question I would ask is what has been done to get the car from 170bhp to 290bhp (both at the wheels?), apart from the cats I can't see how just a remap and mods would achieve this, there must have been either a mechanical or set up issue with your car?? You may know a liitle more after Austec have completed their work on your P&J.

As you say maybe it was just a coincidence but I am quite sure that a month ago the car had much higher power than this (maybe much lower that optimum). The problem is that after collecting the car from the dealer I only drove it for 40 miles before leaving it at Austec and didn't push it hard, but it felt a bit underpowered. Anyway, I really didn't pay much attention to this fact at that time to be honest.

To bring the car to 290BHP (both 170 and this are at the wheels) they have decatted it, cleaned the injectors, adjusted the fuel mapping and fitted the induction kit (I will confirm tomorrow if I have missed something). Austec told me not to panic and were going to run the car for about 200 miles (mix of rollers and road driving) to re-adjust the fuel mapping afterwards and see if further improvement can be reached. On tuesday I will call them to know how things are going.


>> Edited by javi1892 on Sunday 7th August 13:44

[GreenV8S]

javi1892 said:

What I meant as "standard figures" was what standard cerbs are really giving in the rolling roads, not the factory claimed power.

I'm with you now, yes I agree that as standard your car should have produced similar power readings to other standard cars the same spec, when measured on the same rolling road under similar conditions.

[SXS]

Hey Javi, you havent been having much luck with your car since you've bought her. Ever thought of selling her on and just picking up a sorted one? Might work out cheaper in the long run??? (just a thought)

[javi1892]

SXS said:

Hey Javi, you havent been having much luck with your car since you've bought her. Ever thought of selling her on and just picking up a sorted one? Might work out cheaper in the long run??? (just a thought)

You're right to some extent but up to now I haven´t spent a lot of money because almost everything was covered by the guarantee. I expect to have the car well sorted after the visit to Austec (fingers crossed).

About selling it to buy a sorted one, when things go wrong you even think of selling her and escape from TVR forever but this feeling disappears as soon as the engine starts . I think this question has been asked by all us TVR owner at some point during our ownership.

[GreenV8S]

javi1892 said:

About selling it to buy a sorted one

Aside from any difficulty you may have selling a car which you know has problems, what you're really doing is trading it for another which has no known problems as far as you know. 'No known problems' isn't the same as 'no problems'. You can spend a lot of time and money buying an average car, half-fixing it and then moving on to the next one.

[SXS]

javi1892 said:

SXS said: Hey Javi, you havent been having much luck with your car since you've bought her. Ever thought of selling her on and just picking up a sorted one? Might work out cheaper in the long run??? (just a thought) You're right to some extent but up to now I haven´t spent a lot of money because almost everything was covered by the guarantee. I expect to have the car well sorted after the visit to Austec (fingers crossed). About selling it to buy a sorted one, when things go wrong you even think of selling her and escape from TVR forever but this feeling disappears as soon as the engine starts . I think this question has been asked by all us TVR owner at some point during our ownership.

You're in good hands with Austec, but theres only so much a mechanic can do, the car might leave perfectly fine, but what if more problems pop up literally down the road?

Ok, its a given that my attitude was a little pessimistic, but knowing how things can be, there are quite a few good ones going for sale at the moment, I was merely just opening the doors to that option.

Fingers crossed Jav, but if you come back in a week or two with more problems, I'll be doing my 'told you so' routine Goodluck mate.

[Mark Adams]

Hi Javier

Was your car the one at Austec on Monday/Tuesday 25/26 July? If so, then I was there the next day (and dyno'd a 4.0L Chim with 185BHP at the wheels). I saw your cats when they came out, and they were completely blocked.

When the cats were illuminated with a very bright torch, you could not see any light coming through at all. However they had broken free in their cans, and there was about a 12-15mm gap around the outside. The reason they get like this is because they have had unburnt fuel through them, which causes them to superheat and expand - thereby crushing them.

Once the cat has broken free in its casing, it will then move backwards under high load to cork up the exhaust

Maybe it was still attached to the casing before you had the clutch done, and removing/refitting the exhaust just set them free?

Again if that was your car, IIRC there were two very dud injectors. The jets went sideways, and one of them dribbled when not operated. The rest of them were pretty manky too, and I think that Austec wanted to make sure that none of the others went screwy before mapping it. Hence the suggestion of putting a few more miles on it before serious mapping. The injectors will be tested again before mapping. Experience tells us (tested several thousand of them now) that where this type of injector shows a high flow rate (for the type), it will often fail quite soon.

So don't be too despondent about your figures - they are probably not the final ones

[javi1892]

Mark Adams said:

Hi Javier Was your car the one at Austec on Monday/Tuesday 25/26 July? If so, then I was there the next day (and dyno'd a 4.0L Chim with 185BHP at the wheels). I saw your cats when they came out, and they were completely blocked. When the cats were illuminated with a very bright torch, you could not see any light coming through at all. However they had broken free in their cans, and there was about a 12-15mm gap around the outside. The reason they get like this is because they have had unburnt fuel through them, which causes them to superheat and expand - thereby crushing them. Once the cat has broken free in its casing, it will then move backwards under high load to cork up the exhaust Maybe it was still attached to the casing before you had the clutch done, and removing/refitting the exhaust just set them free? Again if that was your car, IIRC there were two very dud injectors. The jets went sideways, and one of them dribbled when not operated. The rest of them were pretty manky too, and I think that Austec wanted to make sure that none of the others went screwy before mapping it. Hence the suggestion of putting a few more miles on it before serious mapping. The injectors will be tested again before mapping. Experience tells us (tested several thousand of them now) that where this type of injector shows a high flow rate (for the type), it will often fail quite soon. So don't be too despondent about your figures - they are probably not the final ones

Hi Mark,

I appreciate your reply as you have given me in these few lines much more information than what I knew (Paul is on holiday, you know). Yes, it was my car the one at Austec on Monday and Tuesday (still there now).

It´s is a good appreciation the thing you say about the cats free after refitting the exhaust system. I knew the cats were in bad condition because of the rattles and because I had noticed a bit of power drop during the last months.

I have had news today from Austec and it seems that there is something wrong with the rolling road setup because my car has given only 170BHP today. They were very surprised and tested a Cerbera with a known power output and in good condition and it only gave 120BHP. Therefore, it is clear that there is something wrong with the rollers. The engineers are going to have a look at it during the weekend.

I will collect the car on saturday (a new car looking at the amount of components replaced including full new suspension) and will put some miles on it before returning the car for the final setup.

Regards,

Javier

>> Edited by javi1892 on Tuesday 9th August 17:42

[javi1892]

OK, latest news!!

I brought the car to Austec on Saturday to finish the re-map. In the first run the car only gave about 276BHP at the wheels (the car is already de-catted, injectors have been cleaned) which was really strange.

Nevertheless, Paul quickly detected a problem with the the throttle cable. It was not properly aligned and there was an undesirable friction while pressing the accelation (sorry, I know it's not very technical).

Once the problem with the accelerator was sorted, the re-map of the MBE ECU could start. At the end these were the final figures:

Environmental Conditions: 33.3degC; 35.84''Hg, so a bit hot in the workshop

Power output:
- Flywheel: 395 BHP estimated (at 6368rpm)
- Wheel: 327 BHP

Torque output:
- Flywheel: 388.4 lbft (at about 4000rpm)
- Wheel: 335 lbft

I'm very happy with the results as it drives much better and it's clearly much faster than before (+51BHP after changing throttle cable and re-map).

I'll try to post the graphs later on.

Regards.

[gazzab]

congrats.
what has happened to the front of your motor? Those lights are a bit 'unusal'. Might also impact airflow.

[Cyclone1]

Ditto the congratulations, I bet you are relieved!!!

Amazing that something as simple and undetectable as a throttle cable can hide so many ponies.

Enjoy............