Turbo charged MG Midget help please
Discussion
OK I have most of the bits took loads of photos of Simons car (1 of two midgets in the country that I know of with a turbo), remember where to put most of the bits bar
Where I connect the pipe to the fuel return pipe to the tank.
The turbo is an MG Metro turbo and carb, not using the ECU so I can get the 21psi rather than that silly 4psi limition at 4k for the metros gearbox.
Im fairly sure that the fuel return comes of one of the carbs pipes and I think its the middle one but im not 100% any ideas out there.
>>> Edited by boredpilot on Monday 5th July 20:32
Where I connect the pipe to the fuel return pipe to the tank.
The turbo is an MG Metro turbo and carb, not using the ECU so I can get the 21psi rather than that silly 4psi limition at 4k for the metros gearbox.
Im fairly sure that the fuel return comes of one of the carbs pipes and I think its the middle one but im not 100% any ideas out there.
>>> Edited by boredpilot on Monday 5th July 20:32
Are you using the full metro turbo block?
The blocks are very different to a standard a-series, If memory serves me correct the fuel return should be the one closest the dash pot but don't take my word for it.
The wastegate on the turbo defaults to 4 psi, the ecu bled air from the feed pipe to allow it to generate 7psi, if you want 21psi a) you will have to change the wastegate b) major reworking of the internals! and expect unreliability! thats the sort of psi the metro turbo challenge cars ran and they regularly blew engines!
The blocks are very different to a standard a-series, If memory serves me correct the fuel return should be the one closest the dash pot but don't take my word for it.
The wastegate on the turbo defaults to 4 psi, the ecu bled air from the feed pipe to allow it to generate 7psi, if you want 21psi a) you will have to change the wastegate b) major reworking of the internals! and expect unreliability! thats the sort of psi the metro turbo challenge cars ran and they regularly blew engines!
Thaks for the reply,
New the fuel return had to be around there.
The metro turbo is great, a friend runs it on his MG done over 60k now with it on never below 10 PSI and has run it at 21 psi which he said was scarey, even at 10 psi he has difficulty changing gears in time (Has a toyota 5 spd in like me)
Not using the full Metro kit, im using the turbo, carb, exhust manifold, using the inlet manifold of a non turbo metro so I dont hit the bonnet, (Simon did use this as therefore created a bonnet buldge for clearance.
Not using any of the ECU, have a fish tank valve (1.29 for 2) to control the wastegate boost to what I want it to be.
New the fuel return had to be around there.
The metro turbo is great, a friend runs it on his MG done over 60k now with it on never below 10 PSI and has run it at 21 psi which he said was scarey, even at 10 psi he has difficulty changing gears in time (Has a toyota 5 spd in like me)
Not using the full Metro kit, im using the turbo, carb, exhust manifold, using the inlet manifold of a non turbo metro so I dont hit the bonnet, (Simon did use this as therefore created a bonnet buldge for clearance.
Not using any of the ECU, have a fish tank valve (1.29 for 2) to control the wastegate boost to what I want it to be.
What did the oil spays do on the turbo?
Im only using a standard A series engine (1098 so expecting quite a marked torque improvment), im not going as mad as simon with his turbo, ive already decided that 10 psi is my limit unless I fit an intercooler and do some real work to lower the engine compression.
Im only using a standard A series engine (1098 so expecting quite a marked torque improvment), im not going as mad as simon with his turbo, ive already decided that 10 psi is my limit unless I fit an intercooler and do some real work to lower the engine compression.
An otherwise std metro turbo could not run 21psi. The turbo is too small, and it would blow up, if it did.
It has to high compression, and no intercooler. Even 10psi would be running close to detonation, unless moves were taken to combat it.
Since when do metro turbos have oil jets for the pistons ??
A metro turbo block is virtually identical to a normal A+ block.
Heads are the same also, apart from the sodium cooled exhaust valves. I think the turbo heads may even have smaller valves generally. ( Cant quite remember, its been about 10 years since I bothered with my turbo mini )
There should be no fuel return coming from the carb. The fuel is fed via the pump, to the fuel presure regulator, and returns to the tank via that.
Fuel is tapped off the FPR, to the carburettor, feeding the carb using the lower connection.
The one at the dashpot is part of an economy device. It should be conected to the inlet manifold, so at part throttle cruise, the vacuum will lower the pressure within the float boal, effectively weakening the mixture. There is also a drilling ( restricted ) which vents the float bowl into the plenum, bolted onto the mouth of the carb.
It has to high compression, and no intercooler. Even 10psi would be running close to detonation, unless moves were taken to combat it.
Since when do metro turbos have oil jets for the pistons ??
A metro turbo block is virtually identical to a normal A+ block.
Heads are the same also, apart from the sodium cooled exhaust valves. I think the turbo heads may even have smaller valves generally. ( Cant quite remember, its been about 10 years since I bothered with my turbo mini )
There should be no fuel return coming from the carb. The fuel is fed via the pump, to the fuel presure regulator, and returns to the tank via that.
Fuel is tapped off the FPR, to the carburettor, feeding the carb using the lower connection.
The one at the dashpot is part of an economy device. It should be conected to the inlet manifold, so at part throttle cruise, the vacuum will lower the pressure within the float boal, effectively weakening the mixture. There is also a drilling ( restricted ) which vents the float bowl into the plenum, bolted onto the mouth of the carb.
Thanks stevie, that explains why my photos dont show the return pipe, only took one of the fuel pressure reg.
I know the MG metro turbo can run up to 21 psi as ive seen it and its on simons MG midget see link below.
But yes he has modified his engine to cope with that. Im afraid im not going to that much expense so also not going to silly boost levels. Even simon these days is afraid of loosing his licence and only goes to around 10 psi.
www.turbomidget.connectfree.co.uk/nographics.htm
If anyone thinks of anything else that simon missed in his very old web page let me know.
He has since done another 30k so now upto 60k with the turbo fitted.
I know the MG metro turbo can run up to 21 psi as ive seen it and its on simons MG midget see link below.
But yes he has modified his engine to cope with that. Im afraid im not going to that much expense so also not going to silly boost levels. Even simon these days is afraid of loosing his licence and only goes to around 10 psi.
www.turbomidget.connectfree.co.uk/nographics.htm
If anyone thinks of anything else that simon missed in his very old web page let me know.
He has since done another 30k so now upto 60k with the turbo fitted.
Just a thought, Ive had both supercharged and 1700 Ford Mexico powered Midgets in the distant past and I found that much more power than stock tends to lead to snapped half shafts. Tried to get some strengthend ones still broke, in the end fitted a back axle from a Ford Anglia which was great.
mark
mark
well i've been looking in to turboing my 998 for a long time and i think there is no better a forum to ask about turbo questions on an A-series than [url]www.turbominis.co.uk/[/url]
Despite what he says, IMO, a std engine will not ever take 21psi. I also dont think the std turbo could pump 21psi without serious overspeeding. It is a very small turbo.
I am ( was, havent driven it for a few years ) running 1.5 bar on my mini, although it has a much larger turbo than std, and an intercooler. Welded dizzy, modified SU carb, head, cam, rockers, water inj.
the short motor is std though apart from the machined pistons I mention below.
Following from the weblink someone posted...
Other points to note. While any proper efi pump will do, make sure you also supply it with a large enough pickup from the tank. At least 10mm with a suitable gauze filter that will not restrict the flow. Any restriction here will cause pump cavitation and reduce pump life, and could also cause weak running because of the cavitation.
As for pistons, I dont know anything about the Marina van pistons he refers to.
While not ideal, I simply machined 6mm from the top of the std metro turbo piston. On an otherwise std turbo engine, this will reduce the CR to 7.5:1
Machining this amount does not reduce the crown strength in any way.
I only used original Rover head gaskets, or Payen equivalent. IMO Copper head gaskets are crap.
As he says, metro turbo cam is same as a normal metro cam.
An MG Metro cam is a worthwhile upgrade if you can locate one. Im using a Swiftune racing SW5 camshaft in mine now along with high ratio rockers. They work very well. No downsides.
High lift rockers are worthwhile on any turbo engine. Racy cams are not. I tried a 284deg cam in mine one time, and it totally destroyed the car. Lost all driveability below 3000rpm, for little if no gains top end.
My car is totally tractable, and actually very torquey from idle to 7k, with all the fun from 3500-7k ( It will rev to 7500 easily ) The laggyness is from my big turbo, but below 3500 it drive very very well.
Agree on bearings and rods etc. Ive never had a problem there, but do use turbo bearings ( latest A+ are same anyway, with the bottom main shell with no groove )
Oil...not sure what he means by Mobil. I would NEVER use Mobil 1 0/40w in such an old engine. It is far too thin.
Mobil 1 motorsport 15/50w, or Motul 300v 15/50w would be better if you insist on synthetic.
I actually mostly ran mine on a good quality 20/50 semi synth Valvoline, and never had problems.
I am ( was, havent driven it for a few years ) running 1.5 bar on my mini, although it has a much larger turbo than std, and an intercooler. Welded dizzy, modified SU carb, head, cam, rockers, water inj.
the short motor is std though apart from the machined pistons I mention below.
Following from the weblink someone posted...
Other points to note. While any proper efi pump will do, make sure you also supply it with a large enough pickup from the tank. At least 10mm with a suitable gauze filter that will not restrict the flow. Any restriction here will cause pump cavitation and reduce pump life, and could also cause weak running because of the cavitation.
As for pistons, I dont know anything about the Marina van pistons he refers to.
While not ideal, I simply machined 6mm from the top of the std metro turbo piston. On an otherwise std turbo engine, this will reduce the CR to 7.5:1
Machining this amount does not reduce the crown strength in any way.
I only used original Rover head gaskets, or Payen equivalent. IMO Copper head gaskets are crap.
As he says, metro turbo cam is same as a normal metro cam.
An MG Metro cam is a worthwhile upgrade if you can locate one. Im using a Swiftune racing SW5 camshaft in mine now along with high ratio rockers. They work very well. No downsides.
High lift rockers are worthwhile on any turbo engine. Racy cams are not. I tried a 284deg cam in mine one time, and it totally destroyed the car. Lost all driveability below 3000rpm, for little if no gains top end.
My car is totally tractable, and actually very torquey from idle to 7k, with all the fun from 3500-7k ( It will rev to 7500 easily ) The laggyness is from my big turbo, but below 3500 it drive very very well.
Agree on bearings and rods etc. Ive never had a problem there, but do use turbo bearings ( latest A+ are same anyway, with the bottom main shell with no groove )
Oil...not sure what he means by Mobil. I would NEVER use Mobil 1 0/40w in such an old engine. It is far too thin.
Mobil 1 motorsport 15/50w, or Motul 300v 15/50w would be better if you insist on synthetic.
I actually mostly ran mine on a good quality 20/50 semi synth Valvoline, and never had problems.
Thanks for the info stevie.
Simon I think says (But its been a long time since he did his web site) that the standard A series should cope with around .5 to 1 bar without to many probs, if your up at the 21 psi 1.4 bar he agrees that you need to do some work on the engine.
Thanks for the other info. Im hoping to get the couple of bits im short,
1 boost gauge
2 exhaust downpipe
in the next few days ill be able to crack on and finish the mad machine.
Ill keep everyone informed when done
Simon I think says (But its been a long time since he did his web site) that the standard A series should cope with around .5 to 1 bar without to many probs, if your up at the 21 psi 1.4 bar he agrees that you need to do some work on the engine.
Thanks for the other info. Im hoping to get the couple of bits im short,
1 boost gauge
2 exhaust downpipe
in the next few days ill be able to crack on and finish the mad machine.
Ill keep everyone informed when done
Finally finished.
The torque increase is great. Infact in 3rd, 4th and 5th its amazing the performace increase ive got.
Only thing thats odd had some people say this is correct and I cannot remeber on simons and hes still out of the country is what kind of oil pressure would you expect on an A series with a turbo on it.
I used to have about 30 idle and 40-45 when driving while hot.
I have taken the oil feed from the oil pressure gauge, I now have 10 idle and 20 when driving while hot. I cannot find any reference on the internet as to what the kind of psi the oil would be at in the turbo metro.
Im assuming the turbo metro is a high flow low pressure affair. Any ideas
The torque increase is great. Infact in 3rd, 4th and 5th its amazing the performace increase ive got.
Only thing thats odd had some people say this is correct and I cannot remeber on simons and hes still out of the country is what kind of oil pressure would you expect on an A series with a turbo on it.
I used to have about 30 idle and 40-45 when driving while hot.
I have taken the oil feed from the oil pressure gauge, I now have 10 idle and 20 when driving while hot. I cannot find any reference on the internet as to what the kind of psi the oil would be at in the turbo metro.
Im assuming the turbo metro is a high flow low pressure affair. Any ideas
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