PSH
PCGB Member
Hi guys
I thought that I would share my experiences of late trying to track down an issue with the car, in fact, I had a number of issues which were conspiring together to throw me off the scent. I may have mentioned before a problem with holding boost due to hoses popping off, this helped to fool me into thinking that this was all that was wrong. My car is nothing like a standard 951, when mine was standard loosing boost through a loose intercooler coupling would make the car undrivable, forcing you to stop and investigate what was what. Not so today, I wouldn't notice until pushing the car hard, say over 0.9bar, only then would I notice that the car wasn't getting over 1 bar and that the usual warning bleep when using more than 1bar hasn't sounded, I have the stepped boost gauge set to warn me at 1 bar. Why this is the case I'm not sure, perhaps something to do with where the MAF is placed, much, much further from the turbo than standard or even with other modified cars that I've seen. So that's the boost side and one of the side effects which didn't always happen was a slight hesitation, it wasn't always there but when ever I felt this I would check the hoses and retighten even if no sign of any movement, usually when the hose had moved it would slip off the alloy pipe but still be forming some sort of seal until I assume I asked for more boost? The funny thing is that 9 times out of 10 retightening the hoses would solve the hesitation? and why I was convinced that this was the main problem...
Well, I lived with this for a while until I could get a longer hose and move things around a bit.
BTW a very good friend of mine has offered to 3D print a set of hard pipes for me and then get them cast in alloy, I may investigate this in due course. I had worked with him for many years in films and know his work is second to none, today he's making good money building vintage Bugatti's from scratch, currently building the massive Royal and when I say from scratch that includes everything, engine, gearbox, clutch etc etc.....he is a true master at his trade.
Anyway, back to the car, things came to a head a few weeks ago when traveling home from my grandson's baptism, at times it was a struggle just to keep moving and then all would be fine again but at one point I struggled to get over 30mph, yep she was most certainly a sick girl and so once home I decided that I had to find out what was wrong. Alas this time I couldn't call on my son, he was far too busy with work and just didn't have the time to diagnose a modified car when it could have been something very bad such as burnt valves, slipped timing etc....I was convinced though that it was not mechanical, a sensor perhaps. A few other gremlins had occurred just before, fans staying on, possibly sticking thermostat being some of them.
I decided to do the sensible thing and change the normal service parts first, plugs, air filter etc... not having a jack at home I couldn't change the air filter (my number 1 suspect) as it's behind the inner wing liner and would require the car being jacked up to replace. I ordered a new K&N (wrong one I'll explain after), new NGK Iridium BPR7EXI plugs and as a temp solution bought a cheap mushroom air filter (the only one with a chance of fitting under the bonnet) from Halfords just to see if it helped the symptoms. Now the engine symptoms as she sat on the drive, when started refused to rev, well it would rev but was very hesitant up to around 4k, after that it cleared and behaved normally, idle had been perfect at all times which was the main reason why I had ruled out any mechanical issues. Fitting the temporary filter helped but not a cure, I could drive but the response was harsh on throttle close and not very quick on opening, clearly, the filter was far too small but it got me on the road, there was still some signs of hesitation but mild. The plugs arrived very quickly from Amazon, I wasn't sure what to expect with these as the advertised price was only a third of what I was expecting to pay at a cost of less than £40 instead of anything up to £130, there were similar high prices on Amazon for the same plugs (my son usually pay's around £100 at trade) so it was a very pleasant surprise to see that they were indeed the correct plugs when delivered. I fitted the plugs and the engine moved a step closer to her normal running. The K&N arrived (again from amazon) a few hours later, clearly I had got the size wrong, it was the correct 3" ID but this thing was massive and I knew that there was no chance of it fitting under the wing, however curiosity got the better of me and I removed the mushroom filter and put this massive filter in it's place sticking a good 6" out of the engine bay, I have to say that somehow I'm going to find a way to fit a much larger filter to the car, the response from the engine with this filter was very impressive, the taco needle just goes mad from zero to 6k, much quicker than before, I always knew that the current K&N filter fitted was too small for the output but it was the best that I could find at the time even if only rated for 350bhp, I need to find a way to fit a much larger filter, that will be a task for the future. I have now sent the filter back to Amazon so no real loss but it did open my eyes to a future mod.
Next step was the MAF, this has been on the car for many years now and not really had any attention given to it, having done a little googling I discovered a product from Halfords that can clean the MAF with supposedly good results, it's just an electrical cleaner but it did make a big difference and all signs of hesitation vanished. Last job was to get at that air filter, one of my other boys popped over with his jack and we removed the wheel and inner liner, it was then that I discovered just how much bigger the large filter had been, there was no way that it would have fitted without cutting into the plastic liner, not a good solution. On reaching the old K&N filter I could see that this had been the main problem and everything fell into place, the filter was very clogged and had been badly distorted by the air being sucked in, I wish that I had taken a picture to share, it had been pulled in around it's middle section to nearly half it's diameter and also badly twisted, such is the induction on this engine, something I should have realised having nearly had my arm sucked in during sourcing this problem. For now, I cleaned the filter, pulled it back to shape and reoiled the outer surface, it works great again but needs to be replaced for something larger, a job for the future, I'll add that to fitting those 80lb injectors and getting the car mapped by Wayne.
I thought that I would share these experiences as they may help others, for the future I will change plugs more often and the air filter too and also try not to get so paranoid when things don't seem quite right....
Pete
I thought that I would share my experiences of late trying to track down an issue with the car, in fact, I had a number of issues which were conspiring together to throw me off the scent. I may have mentioned before a problem with holding boost due to hoses popping off, this helped to fool me into thinking that this was all that was wrong. My car is nothing like a standard 951, when mine was standard loosing boost through a loose intercooler coupling would make the car undrivable, forcing you to stop and investigate what was what. Not so today, I wouldn't notice until pushing the car hard, say over 0.9bar, only then would I notice that the car wasn't getting over 1 bar and that the usual warning bleep when using more than 1bar hasn't sounded, I have the stepped boost gauge set to warn me at 1 bar. Why this is the case I'm not sure, perhaps something to do with where the MAF is placed, much, much further from the turbo than standard or even with other modified cars that I've seen. So that's the boost side and one of the side effects which didn't always happen was a slight hesitation, it wasn't always there but when ever I felt this I would check the hoses and retighten even if no sign of any movement, usually when the hose had moved it would slip off the alloy pipe but still be forming some sort of seal until I assume I asked for more boost? The funny thing is that 9 times out of 10 retightening the hoses would solve the hesitation? and why I was convinced that this was the main problem...
Well, I lived with this for a while until I could get a longer hose and move things around a bit.
BTW a very good friend of mine has offered to 3D print a set of hard pipes for me and then get them cast in alloy, I may investigate this in due course. I had worked with him for many years in films and know his work is second to none, today he's making good money building vintage Bugatti's from scratch, currently building the massive Royal and when I say from scratch that includes everything, engine, gearbox, clutch etc etc.....he is a true master at his trade.
Anyway, back to the car, things came to a head a few weeks ago when traveling home from my grandson's baptism, at times it was a struggle just to keep moving and then all would be fine again but at one point I struggled to get over 30mph, yep she was most certainly a sick girl and so once home I decided that I had to find out what was wrong. Alas this time I couldn't call on my son, he was far too busy with work and just didn't have the time to diagnose a modified car when it could have been something very bad such as burnt valves, slipped timing etc....I was convinced though that it was not mechanical, a sensor perhaps. A few other gremlins had occurred just before, fans staying on, possibly sticking thermostat being some of them.
I decided to do the sensible thing and change the normal service parts first, plugs, air filter etc... not having a jack at home I couldn't change the air filter (my number 1 suspect) as it's behind the inner wing liner and would require the car being jacked up to replace. I ordered a new K&N (wrong one I'll explain after), new NGK Iridium BPR7EXI plugs and as a temp solution bought a cheap mushroom air filter (the only one with a chance of fitting under the bonnet) from Halfords just to see if it helped the symptoms. Now the engine symptoms as she sat on the drive, when started refused to rev, well it would rev but was very hesitant up to around 4k, after that it cleared and behaved normally, idle had been perfect at all times which was the main reason why I had ruled out any mechanical issues. Fitting the temporary filter helped but not a cure, I could drive but the response was harsh on throttle close and not very quick on opening, clearly, the filter was far too small but it got me on the road, there was still some signs of hesitation but mild. The plugs arrived very quickly from Amazon, I wasn't sure what to expect with these as the advertised price was only a third of what I was expecting to pay at a cost of less than £40 instead of anything up to £130, there were similar high prices on Amazon for the same plugs (my son usually pay's around £100 at trade) so it was a very pleasant surprise to see that they were indeed the correct plugs when delivered. I fitted the plugs and the engine moved a step closer to her normal running. The K&N arrived (again from amazon) a few hours later, clearly I had got the size wrong, it was the correct 3" ID but this thing was massive and I knew that there was no chance of it fitting under the wing, however curiosity got the better of me and I removed the mushroom filter and put this massive filter in it's place sticking a good 6" out of the engine bay, I have to say that somehow I'm going to find a way to fit a much larger filter to the car, the response from the engine with this filter was very impressive, the taco needle just goes mad from zero to 6k, much quicker than before, I always knew that the current K&N filter fitted was too small for the output but it was the best that I could find at the time even if only rated for 350bhp, I need to find a way to fit a much larger filter, that will be a task for the future. I have now sent the filter back to Amazon so no real loss but it did open my eyes to a future mod.
Next step was the MAF, this has been on the car for many years now and not really had any attention given to it, having done a little googling I discovered a product from Halfords that can clean the MAF with supposedly good results, it's just an electrical cleaner but it did make a big difference and all signs of hesitation vanished. Last job was to get at that air filter, one of my other boys popped over with his jack and we removed the wheel and inner liner, it was then that I discovered just how much bigger the large filter had been, there was no way that it would have fitted without cutting into the plastic liner, not a good solution. On reaching the old K&N filter I could see that this had been the main problem and everything fell into place, the filter was very clogged and had been badly distorted by the air being sucked in, I wish that I had taken a picture to share, it had been pulled in around it's middle section to nearly half it's diameter and also badly twisted, such is the induction on this engine, something I should have realised having nearly had my arm sucked in during sourcing this problem. For now, I cleaned the filter, pulled it back to shape and reoiled the outer surface, it works great again but needs to be replaced for something larger, a job for the future, I'll add that to fitting those 80lb injectors and getting the car mapped by Wayne.
I thought that I would share these experiences as they may help others, for the future I will change plugs more often and the air filter too and also try not to get so paranoid when things don't seem quite right....
Pete
