Tuning Mess up with SPI Turbo

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Tuning Mess up with SPI Turbo

EUROSPIN

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Hello guys. Just wondering a SPI turbo conversion. A friend of mine just bought a white CCento, 1108cc SPI. We have a supercharger from 1.4tfsi vw and a turbo garrett from another FIAT. Before the work begins, just to be sure , there's a thing that is boggling my mind. I saw a lot of build where other people used to have 2nd injector with a MF2 or other controller to manage the fueling under boost , mantaining the original injector to manage fueling off boost. Apart from this, how did you manage the MAF sensor ? I know that above certain pressure the MAF will be "blind" telling the ECU how much air is sucked in so really don't know , how do you suggest or solve this ?

Thank you
 
Hi there Eurospin

What is the work you are going to start fitting turbo and charger or one of the 2?
you can build a boost injector for the turbo as to not create a lean conditon and burn a hole in a piston or 4
what is the setup for the original injectors ? the standard ECM?
how much power do you want to get from this mod?
give me some detail then I can give you some tips on how I did my TWIN CAM / turbo setup
 
Well back in the day when turbo spi were a bit more commonplace what was done was a diode is put into the map sensor wiring (its a map sensor not a maf, they are different things ;) ) so that the factory map sensor doesnt provide the ecu with a signal telling it that there is positive boost pressure and therefore the ecu doesnt throw a wobbly about it.

The 2nd injector that is controlled via mf2 or whatever other device used has a signal from a completely different map sensor from a turbo car so that it can see the real manifold pressure and apply fuel appropriately.

This does work, I have owned a cinq turbo and sei turbo with this exact setup - both had mf2 but different versions. One had an onboard map sensor so it had a vacuum hose directly to it and the other had a seperate map sensor in engine bay feeding it a signal. But, this is not really a good way to control fuelling, its really a bodge - the mf2 was never designed for this purpose really, its primary function is to control water injecton.

Really the better way of doing this would be to use an mpi head and fuel rail (either Punto 75 or from a later seicento/punto (basically any fire engined fiat after 2000 x-reg), uprate the injectors and get either a good piggyback system that completely takes over the fuelling and ignition. I recommend a ECU Masters DET3 or a Greddy Emanage Ultimate for this setup, both are very good piggybacks and can be properly mapped to ensure safe operation. I would add that the Van Aaken conversions not only had the mf2 but also the ecu chip changed which retarded the timing a little - but as this is a well engineered bodge rather than the proper way to do it the retarding of the timing was not really referenced against boost as it should cause the ecu couldnt see the boost. Been a long time since i read through all the Van Aaken paperwork but i think it was done by engine speed and throttle position.

Or you could go full aftermarket ecu but thats alot more expensive.

Also take into account how much boost you want to run, as you might want to consider lowering the CR. On a 1108 easiest option is a decomp plate. If you have a 1242 8v you can drop the 1242 16v pistons in and get a CR of 7.8:1 - cheap but bit low CR really. For reference stock CR on the 1108 is 9.5:1 and the Van Aaken high boosts were lowered to 8.5:1 - the Van Aaken low boosts didnt change the CR at all. But from experience even if you plan low boost you'll want to crank it up, its inevitable so I always suggest lowering the CR in the first place.

I have to say at this point, if i were to build another boosted cento i'd just get a tjet these days, seems silly not to.
 
aye, but even a 1108 8v spi turbo is significantly faster than a 1368 16v na - tried and tested ;) lol

a 16v swap does make a much better daily compared to a turbo converted spi though, nippy enough and doesnt use ridiculous amounts of petrol, easy get 100+ more miles from a tank with a 16v swap. But the boosted ones are way way more exciting (danger of death is much more present haha)
 
aye, but even a 1108 8v spi turbo is significantly faster than a 1368 16v na - tried and tested ;) lol

a 16v swap does make a much better daily compared to a turbo converted spi though, nippy enough and doesnt use ridiculous amounts of petrol, easy get 100+ more miles from a tank with a 16v swap. But the boosted ones are way way more exciting (danger of death is much more present haha)

Oh yes, but i also depends on how many MPHG (miles per head gasket) you can afford...

D
 
lol, my seei turbo did 43k miles and never popped a headgasket. It has since i sold it but that was just cause it overboosted due to driver error faffing with boost controller on the fly.
My cinq never popped a headgasket and that had like 3 or 4 owners before me while it was turbo. They only go cause people run too much boost or they arent fuelling properly..

Miles per head gasket though lol, thats classic, well done sir
 
Been a long time since i read through all the Van Aaken paperwork but i think it was done by engine speed and throttle position.

Most likely they modded the flat rpm only WOT ignition table (which I think is essentially what you said), effectively fixing the ignition for the whole boost range. [What I would do in any case, if I hadn't had any other means of dealing with the problem]. This is sub-optimal - you get not high enough ignition on low boost, and you cannot play with raising boost as it is easy to overstay your welcome offered by the fixed ignition table.

From time to time I am still pondering over the idea of doing pure SPI ECU based turbo mod design, that would give a nice stealth turbo setup, similar to what I had for my 1.2 MPI. Just don't see the point really anymore. I think the 2nd generation Novitec setup was close to that (no secondary injector).
 
I think i might have pics of all the paperwork Van Aaken supplied somewhere but i'd not know where to start looking to find it, was so long ago.

I did stick a wideband on my seicento to monitor and it just isnt possible to get it to run right, you can get it to run 'safe' but not right really with the 2nd injector controlled by an mf2. After much messing with mine it basically was ok on boost but running rich at idle and partial throttle conditions or it was running really nice out of boost and idling but leaning out on boost at high revs.

If you start from scratch there is little point it staying spi really in my opinion, if you open up any spi turbo engine its clear that cylinders 2 & 3 run rich and 1 & 4 run lean, wont matter how well its mapped the fuel distribution through the spi inlet is a bit pants when you throw boost through it - i've messed with quite alot of them now and they are all the same. For a nice stealth setup i think you need as a minimum the sei mpi head and mani etc - you could make it look almost stock.

Lad who has my old sei now has stuck a P75 head etc on it, we have tried running it with the spi tb so it should run as factory out of boost and the mf2 firing the p75 fuel rail injectors for boost, car doesnt run well that way at all and cuts out on overrun. Swapped ecu for a P75 and swapped it round so it runs mpi like a factory P75 and the mf2 fires the spi injector for the extra boost fuel - that kinda works but still doesnt want to run very well. Not really any worse than a normal VA setup but if i am critical of the VA setup it really doesnt like to not be going flat out, if oyu drive it fast its happy as larry but doesnt want to potter around and do traffic etc. Cars been parked for a while but the intention with it looking forward is to just uprate the mpi rail injectors and run a DET3.

I am a bit gutted I never got to have a go in Lees turbo when he bought all your stuff Woj, wanted to see how that ran, but i suspect it would have run better than all the 8v turbo conversions I've been in.
 
I never complained, in fact in some load regions it had better feel than my factory GP tjet (that is not factory anymore BTW, I went ECU crazy again :)). One Mr. Jack W. owns the setup, it's still out there :D
 
Hi guys. Sorry for late reply, I was having some health problems. Anyway I give you right. It was intended to be a turbo conversion for cheap, planning low boost and using parts off the shelf.

Anyway I decided to use classic 1242 8v, multipoint fuel injection. I have some injector from 1.4 tjet 120hp and 12hole Pico injectors from jeep 4.0 that should be around 257cc/min

For the ecu I think we will go through DET 3 or speeduino, by using original wiring harness with an harness adapter.

I'd like to know more about your conversion, even only just for my culture.

Thank you guys for all tips you giving me, I think you are truly the best community about turboed fiats.
 
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