Chimaera 450 SC Problem
Discussion
Hi All, I'm almost at the end of a very long and extensive build. Last week we took it to a rolling road for final set up and a power run and were rewarded with very disappointing results. I wondered if anyone had any thoughts as to what could be the problem/s that we are experiencing? Firstly I'll give a very basic overview of the work carried out. We fitted an SC Power 500 Supercharger kit with C38-91 Blower Upgrade, I also spec'd a 20% larger Intercooler. The engine had a full tear down and was rebuilt using all new and upgraded parts including V8 Developement BV Heads, 45mm inlet manifold with a ported trumpet base and flared trumpets, Bosch injectors and an 044 fuel pump. It's running an Omex 710 ECU and coilpacks and has Zircotec coated decat manifolds.
The problem, and it is kind of a major one, is that we are only getting 0.6PSI at the plenum. We can't find any restrictions in the pipework and even went as far as re routing the K&N but nothing has made a difference. Aside from the lack of boost the engine is running beautifully.
If anyone out there can offer any advice as to why this might be it would be very much appreciated. Having missed all of last Summer, I am determined to get back on the road before this Summer is over and am now at the point where I wish I hadn't started this project as the car was previously nigh on perfect. Ho hum, best laid plans and all that!
The problem, and it is kind of a major one, is that we are only getting 0.6PSI at the plenum. We can't find any restrictions in the pipework and even went as far as re routing the K&N but nothing has made a difference. Aside from the lack of boost the engine is running beautifully.
If anyone out there can offer any advice as to why this might be it would be very much appreciated. Having missed all of last Summer, I am determined to get back on the road before this Summer is over and am now at the point where I wish I hadn't started this project as the car was previously nigh on perfect. Ho hum, best laid plans and all that!
Edited by maxxander on Wednesday 30th April 14:51
chris watton said:
I cannot help or give advice - but just wanted to add that those pictures are pure TVR porn! Astounding work and attention to detail!
Hope it gets sorted PDQ!
Thanks for the positive comments, I'm hoping it will drive as well as it looks once we've sorted the problem.Hope it gets sorted PDQ!
450Nick said:
Check the supercharger is getting a proper supply of traction oil - if it does not have enough oil, it will not produce boost. If it is getting oil then check your re-circ valve spring. If it is giving out too early then it will dump boost back to the charger plenum. Lovely looking build though by the way - you've got almost exactly the same spec engine as mine (even the same colour car!)
Hi Nick, just checked your profile and they are virtually identical but don't worry I haven't pinched yours, mines in Rolex Blue (purple). By the way, love your car. In answer to your questions, traction oil was pressurised to 15PSI and levels checked pre start and after running up - all seems good on that front. Your concerns about the re-circ valve are definitely worth checking out.macdeb said:
Have the suppliers of the supercharger any idea?
Looks fantastic by the way, I like this stuff [but beware that the manifolds wont look that good for long, and who did them will not give a s
t, I know!]
So far the only comment is that they have supplied 80 plus so far and haven't had a problem and that it must be an installation error. Time will tell! Looks fantastic by the way, I like this stuff [but beware that the manifolds wont look that good for long, and who did them will not give a s
t, I know!]portzi said:
BarnFind said:
450Nick said:
Check the supercharger is getting a proper supply of traction oil - if it does not have enough oil, it will not produce boost. If it is getting oil then check your re-circ valve spring. If it is giving out too early then it will dump boost back to the charger plenum. Lovely looking build though by the way - you've got almost exactly the same spec engine as mine (even the same colour car!)
What is the colour ?
mark
450Nick said:
maxxander said:
Hi Nick, just checked your profile and they are virtually identical but don't worry I haven't pinched yours, mines in Rolex Blue (purple). By the way, love your car. In answer to your questions, traction oil was pressurised to 15PSI and levels checked pre start and after running up - all seems good on that front. Your concerns about the re-circ valve are definitely worth checking out.
As well as pressurising the oil and checking the level, I would remove the return line from the reservoir and make sure it it returning oil into a container. If there was a blockage in the line, or in the oil filter or cooler then you may have pressured it and have a good level but it may not be circulating. To check the recirc valve, ideally you would make up a method of getting shop air into the system post charger. At max boost level (around 15psi at a guess), the recirc valve will dump and you'll hear it rush into the secondary plenum.
Mr Supercharged said:
Nick is correct, you need to make sure there is a flow of oil through the blower. I replaced my oil bottle filler cap with a sump plug fitted with a tyre valve so that you can pressurise the the bottle with a bike pump, crack open the banjo fitting on the oil out side of the blower and observe oil coming out to confirm that the system is correctly bled right through.
If the blower is bled and is spinning it will produce boost. The next thing to check is to remove the inlet hose to the blower and visually confirm that the impeller is turning at speed. Maybe there is interference between the snail and the impeller. I believe that when the threaded boss is welded onto the snail it has been reported that distortion has occurred and this caused the impeller to foul with the snail and not turn!
If you have oil moving through the blower and the impeller is turning the next thing to do is to check for air leaks. But I must say you would hear these! If you want me to look at your car for you let me know and I will pop round if you're not a million miles away, regards....
Thanks for your thoughts, this all sounds very plausible. The car is currently in Wellington, Somerset so this may be a little too far to ask you to travel but I really appreciate the offer. Just as a matter of interest, if I ever get it running properly, what would you consider to be a reasonable power output? If the blower is bled and is spinning it will produce boost. The next thing to check is to remove the inlet hose to the blower and visually confirm that the impeller is turning at speed. Maybe there is interference between the snail and the impeller. I believe that when the threaded boss is welded onto the snail it has been reported that distortion has occurred and this caused the impeller to foul with the snail and not turn!
If you have oil moving through the blower and the impeller is turning the next thing to do is to check for air leaks. But I must say you would hear these! If you want me to look at your car for you let me know and I will pop round if you're not a million miles away, regards....
450Nick said:
So how did the fault finding go? Has your engine builder managed to get it running correctly yet?
Sadly we don't seem to be any further forward. I spoke to him this morning and he's taken on board all the suggestions and is working through them. The dump valve was supplied with two springs, one yellow and one blue, I'm assuming these were for different pressures and he is going to swop them over. He is also going to drain down the hydraulic system and re pressurise it. Fingers crossed that one of these works. In an ideal world I would like to be able to measure the pressure direct from the supercharger before it makes its way into the intercooler but I have no idea how to do this. First thoughts were to make a bung to go in the end of the pipe with a tyre valve screwed into the end but on second thoughts this would probably give completely spurious readings. Any suggestions as to how I could get an accurate reading would be very gratefully received.Having trouble with the forum and get an error message every time I try to quote anyone, hoping that I can post without quoting. I've just got back from visiting the engine builder and we've decided to take a really basic approach to the fault finding. We are going to start by checking the boost as best we can at the SC outlet, if we are getting sufficient boost there we will move onto the next link in the chain and check boost at the intercooler outlet. If that's all good we will reconnect everything and go on to check the boost at the dump valve. I know this sounds very basic stuff but at least it will enable us to rule out the obvious.
KateV8 said:
Thread bump. Did the OP find a solution? Our car is currently having the SC Power kit so would be interesting to know if it was component failure.
Sadly still a lot of head scratching going on and no conclusions as yet. At the weekend a gauge was rigged up to measure the pressure leaving the supercharger, it registered 25 PSI at 2500 RMP and is this is a new engine build we were reluctant to take the revs much above 3000RMP with no load. I can't believe these figures as other people have quoted between 6 and 10 PSI as the optimum boost, having said that the suppliers are being very helpful and we are working through possible scenarios. I must admit at this point I'm feeling very much out of my depth and have to rely on the expertise of others. Having now been without the car for 15 months, I wonder if I'm ever getting it back and can honestly say I wish I have never started the project. 16 months ago I had a car that ran beautifully and eighteen grand later I have a very pretty engine bay which at some undefined time in the future will hopefully run as it should.Hi guys, thanks for all the support, I'll pass on your suggestions Nick450 but as mentioned previously I am now a little out of my depth. Just hoping now that I can get this all together in time to attend the Caring With Cars meet, I had intended this to be its first outing this year but that's now starting to look unlikely. As soon as I've got any updates I'll be sure to let you know. Thanks again, Tony.
Hoofa said:
Out of interest what size pulley are you running ?
Hi Hoofa, just got the measurements off the builder, the supercharger is running an 85mm pulley as supplied by SC Power and the crank pulley is 175mm. Just as a matter of interest for those of you that are already running a supercharger, what spark plugs are you using? Mine kit was supplied with B7's. But I have been recommended to use B8's. 450Nick said:
B7s are fine, 85mm pulley is the high boost pulley and should give you approx 10psi max boost with a rev limit on the charger of 6600rpm
Thanks for that mate one more question, for the supercharger to run at 6600rmp to produce 10psi, what would the engine be revving at? Sorry, I feel like I am interrogating you, the advice is very much appreciated. 450Nick said:
B7s are fine, 85mm pulley is the high boost pulley and should give you approx 10psi max boost with a rev limit on the charger of 6600rpm
Thanks for that mate one more question, for the supercharger to run at 6600rmp to produce 10psi, what would the engine be revving at? Sorry, I feel like I am interrogating you, the advice is very much appreciated. Gassing Station | Chimaera | Top of Page | What's New | My Stuff