SPI Setup - Injection Characteristics
Turbo Mini Forums

Guys,

Does anyone know exactly how the spi injection system works, what I'm after is...

Does anyone know how many times per revolution (or engine cycle) the spi injector fires. Any idea on how/when that injection start point is timed?

Is a larger injector available to fit the spi manifold setup?

Anyone know what the flowrate of the spi injector is at 1bar (or any other pressure for that matter)?

I ask as I'm seeing up to 3.5AFR points variance outer to inner cylinders using my HIF44 carb setup. I'm wondering if the spi (modded to suit and using my MS) would be possible and worthwhile.

Cheers

Dan

Dont know how many times the injector fires per revolution, but id hazzard a guess at two considering there are two missing teeth on the crank reluctor one at TDC and one at BDC.

Standard SPi injector 0280 150 682 is stated at 511cc at 100%. Larger injectors are available from the Rover k8 1.4 part # 0280 150 683 and flows 602cc at 100%, k16 1.4 (seems to be an odball and not very common) part # 0280 150 657 and flows 671cc. Other injectors available from Seat/ VW, toledo/ polo, part # 0280 150 651 flows 611cc at 100%. There is a smaller injector on the VW Polo 1.1 part # 0280 150 667 and flows 352cc at 100%.

There are others but these are the ones i've identified, are a direct fit and seem to be fairly available ( i bought a brand new 0280 150 651 on ebay two weeks back for £12, bargin)Edit, make that £8 delivered)

Sometimes its a matter of buying the whole injection manifold just to get the injector, but the stepper motor if still working correctly is a good bag for a spare, well on the Rover ones anyway.

As for MSII and SPi, I'm working on it. Research before outlay

Edited by Sprocket on 20th Sep, 2006.

Thanks for the reply minisprocket.

I don't suppose you know if the injector operates reliably at higher pressures do you? I'm thinking another 10-14psi on top of the 1 bar. All my experience is with port style injectors and I have no data/experience with tb injectors.

I have ran my NA car with MS1 on a wet manifold setup, I have ran it with port injection on MS2 and have also collected data runnng just the HIF44.

I'm pretty clued up on the MS/MSII side of things but have never looked into the stepper motor control with either. Is this the potential "problem area" you are hinting at.

Have you perfected any spi stepper motor control with MS/MSII?

Cheers

Dan

Edited by Daniel on 21st Sep, 2006.

I dont know how the injector reacts under higher fuel pressures in N/A yet, though some one has turbo'd a Fiat SPi set up so i expect on that side of it, it works.

As for increasing fuel pressure to get more fuel through the injector oriface for a given Duty cycle, why bother when you can easily get hold of larger injectors and use standard fuel pressure. Im a bit like Turbo Dave in the fact that if manufacturers did or didnt do it, it was for good reason. As far as im concerned placing a washer under the spring of the pressure regulator is a ubber bodge of which some well known engine tuners happen to use.

The stepper motor is not realy a problem. MSII has drivers for a bipolar motor, these motors are available widely so a retrofit for the SPi's unipolar motor is easy. The other option is to re wire the unipolar motor as bipolar, but, i havent yet looked at the spec for the MSII drivers to see if the original motor is to 'big' for these drivers.

I cant see there being an issue running MSII on a standard SPi set up, it comes down to code in the end, though an extra tooth needs to be welded onto the flywheel reluctor for EDIS to work. other options are to use the original single coil and distribution with a direct fire from the MSII.

Like i said, im researching before outlay, that means that i dont yet have MSII and reading up on the hardware and capebilities of the MSII. Just not got much time at the mo to read quite technical information and my dyslexia doe not help one bit, takes me ages to read and digest.

Dont see the point going this rout if you have to start changing sensors, motors, weld manifolds and loose good control. Its always going to be difficult as the Rover MEMs Ecu is actualy quite a clever device all be it useless to remap.

Edited by Sprocket on 21st Sep, 2006.

All I was thinking of doing was dropping the spi manifold setup onto my existing motor. It's a 1380 NA in a mildish state of tune and I've using it as a research mule really.

The cars already setup for MS injection although is back running ignition only at the moment. So I've already got the MS (actually an MS1 and an MS2) in the car so the only outlay would be a s/h spi unit.

Fuel pressure raising would be a quick and dirty way to get enough fuel through for the 1380 (only about 100hp - not massive anyway).

If you assumed the stock injector of 511cc/min runs at max 80% that gives approx 410cc/min for a 65bhp motor.

Upping to a 671cc/min (100%) only gets you up to about 85bhp at 80%. Raising the fuel pressure to around 25-26psi should push enough through the 671 for 110bhp at about 80% DC.

Looks like I need to look into the stepper motor side of things - never used it before.

There is certainly a lot of info out there on the MS kit. I've been involved with it for years and have to keep going back to the literature for refreshers every so often. Plus there's always new features coming along to keep up to date with.

Good luck with your side of it - I'd be very grateful if you have any further stepper motor pointers to pass along to me in the meantime.

Taking the flow figures for the standard 511cc injector fitted, John Cooper Garages manage to get 87bhp this coincidently equates to 87% duty cycle and was warrantied by Rover at that time, so pushing duty cycles that little bit, does not follow convention, but also doesnt seem to cause any reliability of fuel starvation issues.

Thats what im going off anyway.

The same can be said for the MPi, once you start getting to the 100bhp mark, it starts to get real complicated, more so than the SPi.

Just for your information, I'm running 1399cc with the Kent MD274 injection cam, modified 44mm throttle body and 0280 150 651 injector. Power figures on a 1000 mile engine which is still a bit tight, no lightening, verto flywheel, cam timing 2 degrees out and the wrong ECU for the CR of 10.1, cat still fitted. I was getting indicated 78bhp at the flywheel.

There is plenty of room for improvement on that with the Kent MD274SP injection cam, dial it in those two degrees, lighten everything, gas flowed head, correct Cooper ECU and possibly 1.5 ratio rockers. 100bhp is not that far away even on the standard ECU.

What you have to remember is that the injection cam is a funy one, to compensate for the closed loop fueling, wild cams pass a huge amount of unburnt fuel through the engine, the lambda sensor pics up on this and leans off, plus it can be a bugger to get through the emissions test. AC Dodd of ML motorsports did a test with the MG cam and it was piss poor, Aparently. Bear this in mind

Stepper motor R&D http://www.turbominis.co.uk/forums/index.php?p=vt&tid=10807

Engine build http://www.turbominis.co.uk/forums/index.php?p=vt&tid=9481

Car Rebuild http://www.turbominis.co.uk/forums/index.p...5&p=vt&tid=8784

First power plot http://www.turbominis.co.uk/forums/index.php?p=vt&tid=10480

Edited by Sprocket on 21st Sep, 2006.

Any dimensions on that injector ??

The top looks slightly different, but overall its pretty similar to the side feeds as used in a lot of Jap cars.

I know you can get these as big as 1000cc.

9.85 @ 145mph
202mph standing mile
speed didn't kill me, but taxation probably will

MS2 wont run EDIS will it?

Alex

AlexF

Runs whatever you want i think, though im sure i read somewhere that if you use the stepper motor, one of the wasted spark outputs is used by this, so its run stepper with original single coil and distributor, or EDIS.

I say that, but im a little confused and overloaded with the various versions and capebilities so excuse me if i got it wrong, my brain is starting to boil over with so many different configurations

The thing with MS2 is that it has the capebility to control a wasted spark coil directly, doing away with the need for the Ford EDIS.

Edited by Sprocket on 1st Oct, 2006.

Hello,
I admire your content written in detail.

May I ask a question ?
Regarding fuel pump, Do you use stock Spi pump or Mpi pump ?

Please advice.