Mpi supercharger inlet
Turbo Mini Forums

MPI mini --- Hi everyone , I've had an eaton supercharger laying about for a while , I've finally got round to doing my research , what is confusing me is the inlet manifold . it seems the normal set up is a modded inlet to mount the charger. Then the the injectors are mounted at the charger intake. All makes sense - the air and fuel gets sucked through . Now what is bugging the fuck out of me ... is the fuel going through the charger ? Surely it isn't designed to take fuel ? But my big question !!! Is the mpi inlet manifold has the injectors mounted on the inlet manifold just in front of the block ... why not modifying the standard mpi manifold for the charger to sit on top ???? So the fuel doesn't go through the charger ? Am I being totally thick ? Thanks everyone :) ps it's goood to back

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I don't think the blowers are designed to take fuel but lots of people do it so they must for the most part be OK. 90% of setups on minis are 'suck through' carb setups where fuel is indeed drawn through the blower. Some say passing fuel though them makes them more efficient as it helps seal the rotors. Some say the coating on the rotors of modern blowers can be damaged by fuel. Neither is clear cut fact so I conclude either is ok.

The main difference between the two injection setups you propose is one works essentially as an electronic carb with fuel injected and allowed to go where it pleases further down the induction system. The mpi setup however has a quite complex sequential map in the ECU to make sure fuel is distributed correctly. Its a quirk of the 5 port head design and niwhere near as simple as an engine using 7 or 8 ports There's alot if threads on here about it. if you did fancy going down that route you'd need to do alot of reading and understanding before committing.

What i might be inclined to do is go with the electronic carb option but by mounting the blower on the front of the engine with a throttle body before it but utilising a intercooler after it and injecting the fuel just before the inlet manifold. Ive nit seen this done before but I think it should work OK and will be greatly superior to a non intercooled setup imo.

Thank you for the reply , I just thought it was odd that nobody has tried the concept and concluded there's a reason .. ? I've been doing further research 'the yanks love their blowers' lol sate side the tuners go either way and after reading many American forums :( lol and returning here to see your reply - your bang on the fuel passing through the blower cools the charge temperature. Interestingly you can combine both - injectors before and after which would be an easy mod with an mpi . I'll continue with the research and hopefully my thread will build up with suggestions and advice

Edited by stevecoolerking on 2nd Dec, 2016.

Ps fab advice on the intercooler !

yep[ as mentioned fuel can cause issues going through the charger, the lobes have a teflon coating and this can flake off, i belive late chargers are less prone to this, and also as with all things it will no doubt depend on how hard your pushing the charger.

Draw through air only and intercooled is how the Bini was set up.

So being rather weirdly OCD and like rain man lol I didn't go to bed drawing up plans in my head. I'm definitely going to go with a front mount for the charger and run the air dry . My initial msg mentioned modding the current mpi intake as compared to DIY and professional charger intakes the original mpi one looks like it flows air a million times better ! so I was thinking how can I add a nice samco take off to it without bastardising it ... after staring at intake for ages it hit me ! The throttle body is plastic and has a lovely lip for a hose . I'm going to strip the gubbins off the throttle body and tidy it up filling any tiny holes then will add a new throttle body on the intake side of the charger lmao ! Bingo !

something worth considering if your running more than about 10psi is whacking some water injection on the inlet to the charger, it will scrub off some temp and make the charger more efficient and wont hurt the rotors like fuel.,

Hi slater I'm back after your suggestion on reading up on the mpi fuel mapping and yep it's complicated lol. Luckily my mates is a physics teacher I've just text him the following -

Perfect person to ask ... injection car ... if my car injects fuel into the engine 'squirts it' the fuel travels a short distance to the cylinders. The cars computer times the squirt so the fuel arrives just at the right moment - so basically the fuel is squirted the pressure of the fuel determines the fuels speed of travel ... if I added a turbo ... the air would also be moving !!! And under pressure 🙃 Would this affect the speed of fuel ?

I'll update his reply lol ! If the fuel velocity isn't affected I'm golden lmao apart from running lean from the extra air - any suggestions on overcoming this without a new ecu ? bigger injectors , how would I increase fuel pressure so more fuel is added when the ecu pulses the injector to open ?

the fpr is ported to the boost in the inlet, so fuel pressure and boost pressure rise synchronously .

therefore the fuel pressure will stay the same amount above whatever pressure is in the manifold ,and the speed will be the same, unless the higher density of the air in the pipe affects it .

Edited by robert on 3rd Dec, 2016.

Medusa + injection = too much torque for the dyno ..https://youtu.be/qg5o0_tJxYM

The pre 04 M45 chargers are ceramic coated and the 04 onwards are Teflon coated.

The pre Facelift ones would be better if runninf fuel across them but they do need servicing I had one fail on my bini sounded like somone playing the maracas under the bonnet. Also my inlet temps were 15ish degrees above what they should of been in the last few miles before it let go.

Thanks rob , so if if the fuel pressure regulator synchronises the mixture I shouldnt have any concerns of a lean mixture even with the extra air due to boost from the charger ?
Thanks again ☺️

Edited by stevecoolerking on 3rd Dec, 2016.

The only way to get the correct fueling for the entire engine range (load and RPM) is to program the correct fueling and injection timing for the setup you end up with. And you can't do that with the stock ECU.

http://www.jbperf.com/

I've done some shopping today I've ordered a decompression plate , a specific blow off atmospheric valve for chargers , it has a dial so you can blow off at a specific boost , although in the U.K It's deemed unessery for superchargers it's considered a sin not have one over the pond with the logic that when you throttle off - the boost pressure is still present and needs to go somewhere so releasing prevents damage to the charger. Obviously with a turbo a bov recicaltes for performance. 'Honest I don't want the tsshht noise' 😂 🙊 😇 I've also looked at the eaton inlet manifolds , my tig welding skills are non existent owing to the fact I don't own a tig welder 😂 And I can't be having a crude diy job and I'm certainly not paying 300 or 400 hundred bucks see pics attached this is a nice inlet from a rx 5 performance web shop - it only costs £479 wtf ? Luckily I'm pretty skilled and knowledgeable in composites , I've ordered some 'alufibre' cloth it will look much more goochy than carbon fibre , its mostly an astetic composite so I'll sandwich it with 'unidirectional glass' very strong and smooth glass fibre that's like carbon fibre cloth. I'll make the mold this evening and post pics :) pic attached of alufibre

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Yeah I know the mpi ecu is a nightmare and I don't mind getting a mapable one if I have to ... but the 5 port a-series must be a bastard to map ? I'm just thinking if the current ecu is bang on for fuel timing and all I want is a bit more fuel 'in' and fired at the same time and length as per the rover ecu - a larger fuel outlet 'pressure / jets' would be the easier option ? at least in my head - what do you think ? Is this viable ?

steve ,no , , if the supercharger is increasing the density of the air , but the ecu is injecting the same duration of inj as it was with no supercharger ,then the engine will run lean ,,,as stevie says, it needs remapping .

Medusa + injection = too much torque for the dyno ..https://youtu.be/qg5o0_tJxYM

Schrödinger's cat - so which one am I ???

The MPI MAP sensor is only an absolute sensor and wont measure much above 115kpa, I also seem to remember that the ECU cuts all fuel at about this pressure, so using the stock ECU in a boosted application wont work, never mind that it still wouldn't provide the right fuel or ignition

That said, I've seen people try to do this by place the MAP sensor on the inlet of the charger to get round the MAP sensor issue and just raise the fuel pressure, or use a bigger injector in an effort to get the fueling somewhere right, but the ignition timing is still way too high. They then try to retard the crank trigger to compensate, and loose idle control.

The fact is that fueling and ignition are different in a boosted application on the same engine. Fueling is not a linear response as you wrongly assume. Engine VE is significantly improved over a wider RPM meaning it needs a different fuel and ignition map, not just 'more fuel'

Sure you might be able to throw enough fuel at it to get it to run, but it wont be anywhere near right most of the time, and it'll probably detonate from too much ignition.

Don't rely on the MAT sensor to pull timing on boost as its response is sluggish compared to throttle response.

Very informative thank you guys ☺️ Ok new ecu it is 😂😭 I suppose if it was cheap and easy everyone would be boosting ! Lol ! I'll keep my thread going as the project is under full steam - I should get my composites tomorrow or Tuesday so I'll have my charger intake built mid week and my additional throttle body has come 👌 So I'll get round to stripping that - I think the new ecu is the way forward as I'm still keen to keep the injectors on the inlet manifold and have the charger dry 👍 Oh and I've got a pukka little intercooler on route off eBay 20 quid lmao ! It's off a smart brabus it's got a shroud and a fan ! goochy or what ? 😂

Edited by stevecoolerking on 4th Dec, 2016.

Intercooler - dunno how big it is or tech specs but 20 quid worth a looksy and I like the fan 😂 The kid in me 😂👍

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Random question , so when it's time for my ecu is my local rolling road tuner gonna get the weird mpi set up with the minis 5 port ?

Schrödinger's cat - so which one am I ???

Hi all , another 24 hours of being awake cooking the books on fueling ... did any of you ever come across a thread when a guy added 2 additional mpi injectors into the standard intake - fareplay to him fucking hell of an effort - if it's OK with the mods I'll post a link it's an absolute fab read ... there's nothing to pick apart but let's have a thumbs up for him 'legend'
http://www.theminiforum.co.uk/forums/topic...r-mpi-manifold/

Edited by stevecoolerking on 5th Dec, 2016.

Well....
There are legends and there are LEGENDS....
Paul on here put 2 x 3 injectors in one manifold..!

http://www.turbominis.co.uk/forums/index.php?p=vt&tid=307902
Shame the pictures are gone..

Dazed and Confused....