gsmarrara

Dear all, I'm loving every minute with my 928. My car is a 1983 S, with an S4 engine swap. But here in Brazil, there's absolutely no availability of parts for those cars, and in terms of labor is everything DIY, maybe because we should have less than 10 928's in the whole country. Even oil filters and ignition wires need to be imported, an expensive and long process.

So...I started to seriously consider converting my engine to an aftermarket injection and ignition system. There are several local vendors of this kind of solution. This would allow me to replace/remove both the injection and ignition modules (seems that there is a lot of failure reports of those), MAF (a lot failures too), distributors, and have a very cheap interface to check the car status ( a usb port connected to a computer). Some of those systems also have the interface to activate the flappy at an adjusted RPM, and would allow for a easier adjustment of the redline, for track/street tunning.

I'm a little worried about fire in those cars caused by running with only 4 cylinders. So a integrated system would fix that too.

Do anyone have experience on aftermarket injection/ignition systems? Could you share your experience and roadblocks? Low lights and high lights of this conversion?

Thank you and my best regards, GM.

uncre8tv

I've started to convert my Scout to a MegaSquirt system. And I know there are a few people who have posted here about running MS on a 928. Open source and multi-vendor, probably one of the easiest to support from worldwide locations.
I took a long look at the 928 and decided that since the Jetronic system wasn't broke I had no need to fix it. But if I were I'd consider:
MS3 with the MS3X option board
Ford injectors
GM or other coil-on-plug adaptation (would need to find one that fit well)

But, this is a HUGE undertaking. I'm going to a simple TBI system on the Scout and it's already turned into a multi-year venture (partially because I've had it in storage across the country.) Going to the MS setup for injection and timing on a 928 would be a very heavy undertaking with probably more than a little development work from you. Could be very rewarding in the end, though.

gsmarrara

Hi Uncre8tv,
This is exactly where I am right now. My system is still working, so I'm still thinking about the cost to fix something that is not broken YET. At this time my motivation is more towards being able to know what is happening, since this is not an OBDII system and there's no scanners for this car in Brazil, so every problem make me investigate everything, replace everything...and of course the risks of fire caused by the double ign system.

Really appreciate the recommendation on the Megasquirt system, will go deeper on that. Previous study points to the use of double GM Vectra coils (local GM car, a version of Opel Vectra).

Why ford injectors? More flow, cheaper or some problem in the original Porsche injectors? My injectors are 100% right now.

Thanks and best!

gsmarrara

One more comment. This car is a mechanical wonder, the aluminum engine, the suspension and brakes, a good enough transmission. The weak points on the car are the electronics and the amount of key systems driven by vacuum, what adds complexity to a car that otherwise would is very reliable. The fact that there's no CAN, no electronic control of transmission, and a electrical system that is independent of the injection is system is definitely a plus.

123quattro

I second the megasquirt option. If you do convert to a stand alone install a dedicated wideband EGO in the exhaust and leave it. You can't tune the car without one.

Alan

is it like this?


I do think its a huge project to do this, could be fun maybe - but assume there is limited local support for and knowledge of these systems too?

If you could find one where there are local experienced folks and cheaper/easier local sourcing that would be a plus.

If the new system requires you import all the equipment and do everything yourself then you may not be any better off - in fact you could be worse off because at least with the stock stuff the config is known and you can get help here (etc) - with aftermarket you are likely more or less on your own for config, tuning, maintenance & repair for your particular year/config...?

Alan

DKWalser

928 Motorsports has a kit that replaces both the stock injection and ignition systems with the Electromotive Tec GT. It ain't cheap (which not the same thing as not representing good value). The nice thing about it is that it comes with a custom wiring harness, replacement sensors, and brackets needed to adapt the new ECU to a 928. You can, of course, use a different unit, such as the MegaSquirt, but then you'll have to create/find all the sensors, brackets, and wiring harness yourself.

Here's a link: http://www.928motorsports.com/parts/...management.php

victor25

Look at a VEMS system also

uncre8tv

Speaking from VERY limited knowledge here, so I am open to being corrected by other posters. But from my reading here and elsewhere, when you start tuning the 928 you find that the duty cycle for the injectors is fairly high. When looking at higher flow options there is a variety of Ford Mustang injector which is apparently a good fit and has a favorable spray pattern for our motors.

...take that with a grain of salt, it's just what I recall in my head from when I was looking at the MS 928 setups.

123quattro

The Ford injector works well for the 4v head. It has a split injection pattern that shoots on each intake valve. For a 2v head technically they would be worse as they would shoot at the walls rather than the one valve.

uncre8tv

Good to know. GM (OP) has the 32v so should be a good option.

gsmarrara

Dear all, thanks for the recomendations. Actually the systems you mention seems to be pretty good. But in order to keep things simple, cheap and reliable, when (if) I decided to execute this project I will use a local manufactured brand (fueltech, model FT 350). They are manufactured in Brazil, and they have a shop in the city I leave to install and support the system. May not be advanced as the other systems, but is widely used on races here, have the key features I need and they also manufacture a wide rande of sensors. Thanks for the recommendation on the ford mustang injectors, for sure they are already in the shopping cart, as my car is a 32V (previously tuned by a california shop called Andial by the PO). Question: anyone have a table with the resistance/tension of the most commom sensors in the car, such as O2, TPS, temp, oil and fuel pressure??? Thanks guys!

Hilton

What's running your S4 engine now? You mention MAF, so is it running the stock LH (fuel) and EZ-K (ignition) ecu's?

If it is, then just save your money and enjoy the car. By the time you do a full conversion to a different EFI setup, you'll likely have spent more than the cost of making your current setup "right". Especially if you go with a system that has individual cylinder retardation, knock sensors etc.

Sure, a rebuilt MAF and rebuilt LH will cost a lot, but thats about all you'll need to change, other than usual engine maintenance (replacing old rubber, broken sensors etc.), but the "usual engine maintenance" will be the same regardless of what EFI you run.

gsmarrara

Hi Hiton, I agree with you, and this is why I may only advance on this when something breaks. And yes, I'm running with a EZK and a LH, and they seem to be working ok. But in the cost perspective, the conversion may not be so much expensive than a new system. Looking to the 928 vendors prices, LH US$ 700, EZK US$500, MAF US$ 400...considering that I'll have to pay 50% more than the total as taxes on the value of part+shipping. So if I have to replace those 3 components, I'm already over US$2.5K. A new aftermarket injection and ignition with integrated MAP (instead of a MAF) will cost me around US$ 1k (for the model with touchscreen) or less, plus another US$ 1K in installation and new sensors, and than I have a brand new system that I have local access to cheaper parts. Of course, the car won't be original anymore, what could impact a future resale. In a perfect world, i wish my car keeps running and I don't HAVE to do this...The problem here are the importation taxes. My 1983 928S final cost after all taxes was US$32k, 3 times more than what I paid for it in US. Terrible, isn't it?

gsmarrara

Taking the opportunity to make a question. Someone here mentioned our cars uses the MAF as the E39 BMW M5. Reading the M5 board, I saw that several members migrated to the use of a VW MAF, code 06A906461A. In the poll they did about it, this new MAF seems to have worked for 85% of the users. So, as the teacher use to say in school, if A=B, and B=C, then A=C. Or, simply, does anyone ever tried VW MAF's in our 928's? I'm willing to give a try...