Modified MG Maestro Turbo

[Mike Brock]

This is my MG Maestro Turbo #385 as it was 9 years ago 2003. It had a self built 'Twincharged' system that developed 250bhp. It was a crude system but worked well and had massive potential. It was compound turbo/supercharged.

Supercharger removes all turbo lag - completely! Full power/boost from idle RPMs upwards! Stand on the gas and GO! The Rotrex initially provides the go - but this makes a lot of exhaust gas that spins the turbo up fast! Sudden boost too! If used as a "turbo lag remover" the Rotrex is turned off as soon as boost is achieved via a manifold pressure switch. This switch turns off the magnetic clutch pulley on the nose of the blower - then at a predetermined boost level - it bypasses the Rotrex via a special K-gate.

Fun and incredibly interesting to drive. Like all experimental engines it had its weakness and that was its ability to over rev very quickly! This happened once tooo often causing an exhaust valve to drop inside pistons destroying the engine in seconds. #385 has sat in my garage with a broken engine ever since 2003!

I now want to resurrect #385 - let the rebuild begin...

[Guest]

This is my MG Maestro Turbo #385 as it was 9 years ago 2003. It had a self built 'Twincharged' system that developed 250bhp. It was a crude system but worked well and had massive potential. It was compound turbo/supercharged.

Supercharger removes all turbo lag - completely! Full power/boost from idle RPMs upwards! Stand on the gas and GO! The Rotrex initially provides the go - but this makes a lot of exhaust gas that spins the turbo up fast! Sudden boost too! If used as a "turbo lag remover" the Rotrex is turned off as soon as boost is achieved via a manifold pressure switch. This switch turns off the magnetic clutch pulley on the nose of the blower - then at a predetermined boost level - it bypasses the Rotrex via a special K-gate.

Fun and incredibly interesting to drive. Like all experimental engines it had its weakness and that was its ability to over rev very quickly! This happened once tooo often causing an exhaust valve to drop inside pistons destroying the engine in seconds. #385 has sat in my garage with a broken engine ever since 2003!

I now want to resurrect #385 - let the rebuild begin...

Good luck with that.

Simon.

[Mike Brock]

Thanks Simon...

I will be asking lots of questions so I hope you lot wont mind too much as this thread progresses. Any help greatly appreciated as its been so long since i've done anything with maestros/montegos.

[countrydude]

how are you controlling the switchover? Do you still have standard management on atm or have you gone with emerald, etc? Im guessing you have a massive potential for leaning off early with your current setup?

Does sound like a good project though, I remember seeing some of your posts on Triple M now, I recognise the supercharger pic.

[Mike Brock]

hi - i use an exhaust diverter valve that is boost activated to switch between supercharger/turbo. It's like a big K-gate controlled by a boost type actuator. something like this....

No after market engine management system - just factory ecu / su carb and an fuel/air ratio gauge - i told you it was crude . I devised a simple system to toggle the supercharger on/off. I use a boost activated variable electrical switch. The Supercharger uses a simple magnetic clutch from an old air/con pump from a ford or something can't remember.

[Guest]

hi - i use an exhaust diverter valve that is boost activated to switch between supercharger/turbo. It's like a big K-gate controlled by a boost type actuator. something like this....

No after market engine management system - just factory ecu / su carb and an fuel/air ratio gauge - i told you it was crude . I devised a simple system to toggle the supercharger on/off. I use a boost activated variable electrical switch. The Supercharger uses a simple magnetic clutch from an old air/con pump from a ford or something can't remember.

My twin turbo Subaru had something like that but in a far more complicated way

Simon

[G51 NAV]

Wow Mike I really wasn't aware it had sat around unused so long!
It doesn't seem five minutes since you were talking us through the supercharge installation on the old forums.
I am getting old.
BTW all the best for the rebuild!

[countrydude]

Great stuff! I'm a big fan already! There must be a big power potential here, surely you could run a massive turbo as you have the charger to take care of low down, what do you currently have? You could go with some monster holset and still make boost off the line.

[Mike Brock]

Wow Mike I really wasn't aware it had sat around unused so long!
It doesn't seem five minutes since you were talking us through the supercharge installation on the old forums.
I am getting old.
BTW all the best for the rebuild!

Thanks for that John. Yes its been a few years when i first started going on about it lol. Back in the days of the old MG BBs forum - remember roger parker? The forums agony ant lol. Very clever chap indeed - must be 12/13 years ago now.

Great stuff! I'm a big fan already! There must be a big power potential here, surely you could run a massive turbo as you have the charger to take care of low down, what do you currently have? You could go with some monster holset and still make boost off the line.

This is true - I have a T4 that i will be using. look at the size in comparison to the T4 - T3 maestro turbo!



i don't no whats happened to the size of that last image lol.

[

[G51 NAV]

Thanks for that John. Yes its been a few years when i first started going on about it lol. Back in the days of the old MG BBs forum - remember roger parker? The forums agony ant lol. Very clever chap indeed - must be 12/13 years ago now.

Yeah I remember Rog very well and the old BBS. Seems amazing that it was all so long ago.

[Mike Brock]

This is a pic i took yesterday of #385 - this is how it looks today. I have a lot to do over the next few months with this project - so i will be looking for lots of advice tips etc. I have a three way dilemma at the moment on what engine to use - either the montego engine (pictured) that's already prepared to produce 270+HP - or the gold seal engine i have (pictured) that will need money spent on it modifying uprating etc. (at least i will know what has actually gone into the engine!) - or do i say to hell with it I'll go the T16 rout like everyone else (at least i could dial in some proven Hp - unlike the o-series 8v unproven 270+Hp!)?.

[countrydude]

I'd say keep it 8v, you won't get that kind of power from a t16 without either skulking around rovertech for months on end and buying a forged engine someone is selling, or spending a lot of money building a forged engine. You might be able to see 250bhp on a standard t16 with a t28 and front mount with 12psi but more reliably 230ish? Once you get into the engine 200 to 230 doesn't feel that quick in a maestro. It is, don't get me wrong but that is nothing compared to adding 4-5psi on top of the standard boost level!

If you were running 270-80 on 8v I'd guess for a t16 to compare you'd need a fresh rebuild with forged pistons as a minimum. I haven't seen a dyno of a 8v at that power level but it does create a lot more torque than the t16 in standard guise, I'm guessing that formula stays true in the higher power levels. I'd back the 8v to be quicker as long as you have the grip.

[Mike Brock]

From what i gather standard O-Series pistons/cons/crankshaft can handle up to 350Hp apparently - so well within my 300Hp goal. The weak area is the valve train. Like you say the cost of uprating the T16 is slightly overstated compaired with the all ready modified O-Series montego engine i have. How much would it cost building a Forged engine anyway? There's also the morel issue of removing the factory fitted O-Series turbo engine from an mg maestro turbo to consider. Not only that but the montego engine all ready has Forged pistons that lower the compression ratio - balanced lightened bottom end etc. Clutch could be a potential problem - the one that's in the montego is apparently rated to handle 300Hp - it doesn't feel like a paddle clutch as it has a smooth operation. I thought about the 400ft/lb torque rated one you have fitted to your car countrydude - but bedding it in seems like a lot of bother?

[countrydude]

Yes, a royal pain in the arse. I'd probably fit an organic clutch next time around. It soulds like you have a great engine ready to go, I'd not bother going to the T series if I had that setup. Realistically you'd be looking at circa £550 for forged pistons plus machining of the block and bearings, gaskets etc. So high hundreds unless you get something 2nd hand.

If you were thinking of a T series there is a forged engine coming up for sale on rovertech, if you look in the for sale section. Cableguy is the seller, he is a decent chap and builds engines so you can trust it will be well put together. Arias pistons on T series rods.

[Guest]

Mike, I've done both engines in the Gooon and I wouldn't use either now

Both have there pit falls at over 250bhp and there are much better alternatives available.

Audi TT engine is the simplest swap as Reyland sell an adaptor to fit the PG1 gearbox

Or

T4 Volvo engine and box which is the route I plan to use once our T16 is done for, or if someone buys it for 2k