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MG Midget and Sprite Technical - Metro turbo engine
| Hi folks. A friend asked me how easy or otherwise would it be to turn a metro turbo engine to inline ? For a Rochdale Olympic with an A series in place. I said fit a V8 instead ! |
| na munn |
| Arguably it's easier to swap parts - use midget block and crank, new LC pistons, turbo head and fabricate / frig the induction and exhaust. Fuel system and dizzy will need mods too. It's all in Daniel's book. |
| David (davidDOTsmithAT stonesDOTcom) |
| Keep as much as possible from the metro. fuel pump, regulator, carb, exhaust, turbo, as well as the engine. It is easier to rebuild a Midget engine, than convert the Metro to inline. But it is better to use metro pistons, metro head, be nice to use the metro rods also if you could find a Marina crank with 1 3/4 big ends. Mine is now performing briliantly, just playing around with 20PSI of boost and thinking why did I not do this 15 years ago???? If he needs any advice/help then give me a shout. Just helping a young lad now with a Mini who had been spoonfed with all the myths and no facts, cost him £1000 so far for nothing. He has now parted company with the conmen and hopefully we can sort his car for about £100. It is very easy to get suckered. |
| Robert (Bob) Midget Turbo |
| Bob, when are you going to add nitrous? |
| Trevor Jessie |
| Not ready for Nitrous yet Trevor Cos I continually sing the song I enjoy most at the moment, by Queen ""Don't stop me now, I'm havin such a good time, I'm havin a ball."" see "hear" ..........play on words Prop! http://www.youtube.com/watch?v=58CJih1iYC0 |
| Robert (Bob) Midget Turbo |
| Bob, This is a bit of a fluffy question but how much brisker does your set-up feel now, than your previous normally aspirated engine (which I assume was pretty highly tuned). Not having driven a turbo'd A series I've got no idea how the power delivery feels compared to a well sorted big bore A Series. Is it something that you can easily compare or describe? |
| Gary Lazarus |
| Bob 20 psi boost?! That must be giving something in the region of 160 lb-ft?? Do you use an intercooler? Do you have any kind of boost retard? How's the gearbox holding up?! A |
| Anthony Cutler |
| The power from the turboed engine is very smooth and would not break a halfshaft. But it is a wondeful feeling because as the pressure rises (and it rises very quickly on full throttle) the engine power multiplies up like it is going out of fashion. A normally aspirated car I think feels slightly better for about 1/2 a second perhaps :-) Ant yes I have an intercooler, it is quite staggering the difference in temperature before and after the cooler. After a run putting you hand on the pipes (Stainless steel) before and after the cooler shows a marked difference in temperature. I have programmable ignition and all I will say is that the ignition curve is a straight line when on full throttle, high pressure (As is a normal dissy) and when the throttle is released low pressure the timing is advanced (as in a normal vac advance dissy) My gearbox is a Toyota :-) |
| Robert (Bob) Midget Turbo |
| But if you had nitrous assist the NA car will not even have a 1/2 second advantage. ;) |
| Trevor Jessie |
| Bob, how much differance did the intercooler make, any dyno curves? Also where did you get the intercooler bits from? I'm still in two minds to go either suck or blow for my SC conversion. The suck thro way is easier, but if i'm going to lose some HP then it would be worth taking the longer route on the design, after all the extra oomph is the whole reason for fitting the SC. cheers Brad |
| Brad (Sprite IV 1380) |
I agree with Bob,the intercooler is really important especially if you're running normal pistons and CR.The blow through route is well developed,been done with s/c and allows intercooler fitment.This is mine.
 |
| steve cowling |
| Steve, I *like* that aluminium tank that I presume is the radiator's header tank now? Did you fabricate that or is a commercially available part? I'm using a VW plastic tank on my car now...not quite as handsome as your tank! |
| C L Zeni |
| Yes I bought it from an ebay (uk) shop.Seems ok so far.Most of the coolant pipework is copper tube from B&Q (Home Depot). |
| steve cowling |
| Hi Brad I do not have the figures for the intercooler performance improvement. I have still to get onto a rolling road since some major upgrades to the system. However I do know a little bit about physics and unless I am wrong (this is off the top of my head without reference to data, so could easily be wrong) a 20 degree C reduction in inlet temperature should equate to a 9% increase in air density into the engine with you would expect some kind of increase in power. My estimation of temperature drop in the inlet is in the region of 20 degrees but I intend to get a real measurement of that within the next few weeks. Here is my small intercooler as it was when I was modifying the car.  |
| Robert (Bob) Midget Turbo |
| Steve, most of my heater circuit is copper as well...I don't even have that metal tube that runs along the top of the manifolds back to the heater box and have done that for years. Thanks! |
| C L Zeni |
| Bob, i was wondering where to mount the intercooler as i already have an oil cooler fitted. Looks like a bit more metal work than i would ideally like. Any idea what size intercooler would i need? |
| Brad (Sprite IV 1380) |
| I can add some info on intercoolers. I use a Lancia Delta Integrale Intercooler. Before I use to have inlet air temp of 85-90C now max 40C. That is a HUGE power gain, also higher inlet air temps lead to pinging See also http://www.kmnet.demon.co.uk/arnold/ I run at the moment only 0,3-0,4 bar boost and that only is an enormous power gain. Bad enough my injector (coming from a Opel Astra single point injection) is too small, now I going to use 4 injectors..... Don't forget the blowoff / bypass valve. I my case this was a huge inprovement  |
| a.o. arnold |
| Hi Brad my oil cooler is down the opposite side to the intercoolerand balances up the front. I think there is scope for using say on a standard fronted midget to use a F/G bonnet and mount the intercooler across the front of the engne high up and make a scoop for it something like the Scooby dooo. I sometimes wish I had gone down that direction. The intercooler needs to be as big as possible, mine I think is just big enough. :-) Yesterday I was doing some testing and I put my foot down at 80MPH and it was too much for the clutch which began slipping big style :-) I think I will take it easy for a while and concentrate on making my bigger alloy fuel tank. :-) Arnold surely there is scope for making your intercooler pipes a little neater. ;-) |
| Robert (Bob) Midget Turbo |
| Bob, i'm still pondering the intercooler placement, a top mounted one with a bonnet scoop seems do-able. My grill is a bit full with the oil cooler & electric fan. Arnold, i have a POV from the blower shop in the states. I also have an evacusump system on my car which works well from about 1200rpm but not too great at idle. |
| Brad (Sprite IV 1380) |
| I too want a pov? how do you actuate yours Arnold, or anyone? I will also have to try the evacusump! |
| Robert (Bob) Midget Turbo |
| I think that should be a BOV.... :-) |
| Robert (Bob) Midget Turbo |
| http://www.theblowershop.com/homepage The one i bought is sprung. |
| Brad (Sprite IV 1380) |
I located the intercooler in the grill and cut a big hole below it to direct air past the oil cooler to the radiator.I have a fibreglass bonnet held by pins so didn't need strength in the slam panel.
 |
| steve cowling |
| Steve, Wheres your air intake? |
| Brad (Sprite IV 1380) |
| Steve Those small bumperettes are they frogeye (rear)ones or from something else ? its difficult to see in that photo. I want to do similar on the next car I am building up. Ian |
| Ian Webb '73 GAN5 |
| The air intake is low down on the near side behind the grill,with a hole to get air to it. The overiders are classic mini ones,with homemade brackets onto the bumper mounts. |
| steve cowling |
| Bob, i was interested in trying an evacusump. I e-mailed David vizard and got a prompt reply. He said that while they seemed to work on the dyno, he had had no luck at all when installed in a car. has anyone considered the small Audi intercooler. This mounts vertically in the Audi. |
| Shawn |
| Flippin heck Steve thats what I call an intercooler!!!! Nice one!! Shawn Thanks for that info, however at idle I think the vacuum in the inlet manifold is more than adequate for sucking out the crankcase. Then as the revs build and the manifold depression ceases I would want to take advantage of the extra speed of the exhaust gases. So hopefully with a non return valve on the manifold for idle and an exhaust evacusump for higher revs, perhaps it could work, I hope so. I think the exhaust side would also want a non return valve so that the suction at idle sucked from the engine and not from the exhaust. |
| Robert (Bob) Midget Turbo |
| Bob, the evacusump comes with a non-return valve for the exhaust, i have also put in one way valves & breathers much as you said. I still get a few drops of oil at idle, but nothing to worry about. |
| Brad (Sprite IV 1380) |
| Well, I wouldn't recommend to put the intercooler in front of the rad... One can pretty easily modify the surrounding of the rad to put an intercooler. |
| a.o. arnold |
| Arnold, have you any recent pictures of your set up, cheers Brad |
| Brad (Sprite IV 1380) |
| Hi Bob, Sorry for late reply,been away. Glad you like the intercooler.The coolant rad is a thicker core than standard and I have a leccy fan,but it all seems to work,even at 30C ambients and giving it some.Best so far was 14.3 seconds quarter mile but still lots of wheelspin.Need to put bigger tyres on over winter! |
| steve cowling |
| once more, http://www.kmnet.demon.co.uk/arnold/ anyway, for who are interested, I am still working on the EFI. I do not have too much time and the car is 100 miles away from where I live so progress is little, BUT there is progress. car is really quick, but I need larger injectors which I just got. Gonna remove the TBI unit of the astra and will use 4 injectors of an Alfa twinspark. I'll keep you informed |
| a.o. arnold |
| Arnold, I like the position of your intercooler, may go that route myself. Have you enough flex in the intercooler piping for engine rock? |
| Brad (Sprite IV 1380) |
| Steve wheelspin... My clutch can't take that much power even with the uprated friction plate. This winter I will need to take it out and replace the pressure plate I think. |
| Robert (Bob) Midget Turbo |
| Arnold, they seem to be quite expensive! http://www.carperformanceuk.co.uk/lancia-delta-integral-evo-16v-alloy-intercooler-pr-31089.html was it because of the 90degree unions that you choosed the Lancia one or just availability? |
| Brad (Sprite IV 1380) |
| Hi Bob, No clutchslip as yet,using the Peter May 7.5 in setup.What's in yours? |
| steve cowling |
| Brad A friend of mine gave it to me, it just fits and the 90 connections are fine. I also looked at the Renault 5 Turbo Intercoolers, they are o well, but the connections are not ideal in my point of view |
| a.o. arnold |
| Arnold, i had a gaze under the car today when i was rewelding the ARB mounts, it seems a bit tight for the 90 degree hoses, have you a close up of your intercooler installation? cheers Brad |
| Brad (Sprite IV 1380) |
| Picked up a R5 turbo one yesterday at an autojumble for 20 quid so not too expensive. |
| Brad (Sprite IV 1380) |
This thread was discussed between 08/09/2009 and 04/10/2009
MG Midget and Sprite Technical index
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