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Discussion Starter · #1 ·
Hello!

I've got an '88 Saab 900 non-turbo with an 8v CIS injection motor. It's a great car, and I'd like to restore it (do you already restore an '88?) and use it as a daily driver. The car runs fairly well, but I'd like to convert it to electronic injection to give it more power, better miliage, and smoother operation. Has anybody tried this?

My idea was to retain the K-jet ignition control, and use MegaSquirt to meter fuel. The intake manifold looks like it could be easily redrilled for electronic injectors, and the 5th injector port could be plugged. The wiring should be pretty basic (this is as simple as EFI gets...), but I'm wondering how best to do the TPS. Anybody have any idea whether a 16v TB will fit an 8v manifold? I'd also like to eliminate the EGR, does anybody make a header that can help? Can anybody think of a good reason not to do this?

Thanks!
-Aaron
 

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Discussion Starter · #3 ·
I'm new to Saabs, but I know what I've got. Its definatly an 88, and its definatly a k-jet rig. There were no 8v turbos that year, but the base model still used the n/a 8v (I'm gathering this from the owner's manual...)
 

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Ummm yeah...NA 8vs were available up to at least 88, maybe 89, but I forget. And available even after that in Europe..?

I'm not familiar really with Megasquirt, but I have installed SDS (www.sdsefi.com) on both my SPG and my 8v 99 rally car. If Megasquirt requires a potentiometer TPS, then you can snag one from a 91+ nat-asp 2.1L 900S. These are the only Saabs available with pot type TPSes. Further, you can't really retrofit a pot TPS onto the older cars because the mounting points are slightly different.

You will need to fab up a fuel rail, but this is easily done with some square tubing. You'll need a fuel pressure regulator from an EFI car too.

I didn't redrill my 8v manifold, but found that the Bosch EFI injectors fit right into the existing holes. However, my engine builder removed some material from the manifold to ensure that the EFI injectors were closer to the head to ensure a good spray pattern into the head.

Headers - MSS makes an 8v header. There was a post recently about nat-asp 16v headers, MSS' contact info in there.

As for reasons not to do this...if you're going to all the hassle of installing an aftermarket EFI system, then why not get something that does ignition too? Factory ignition is archaic now, not very precise control.

And if it's power you're after...8v Turbo hardware will retrofit easily. With a bit more work, so will 16v Turbo hardware.

Oh, and here's a link to building a fuel rail:

http://sdsefi.com/techrail.htm

Check out the rest of the SDS site for lots of good EFI info. And no, I don't work for or with them, but they've treated me extremely well over the years! ;)
 

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Discussion Starter · #5 ·
Megasquirt fits my needs really well. First off its really cheap, like less than $300 for an assymbled fuel only ECU. If you know how to put together circuit boards and fit them into a universal case, it can be done for as little as $110. I agree that the ignition is archaic, but its tough, and easy to fix. Honestly, I'm not really looking for much more power, although I'm sure that removing the air meter is going to free up a decent bit. This is just going to be my daily driver car, so I'm mainly looking for fuel economy and throttle response. Megasquirt is widely used in the Volvo community, and is reported to deliver amazing gas milage. Oil hit $65 a barrel today... How long until the ECU pays for itself? As a bonus, it will pollute a hell of a lot less. I drive the car every day so I'd like it to be reasonably clean.

I like underpowered, overbuilt cars. The chassis on this car will see a good amount of wrench time. Aside from the EFI conversion, the motor won't.

Maybe a junkyard solution is best for eliminating the EGR... What year was it fitted to the 900? I bet an early manifold could be retrofitted with a little work to hook it up to the cat.

Vince T,any idea what the part # was for those Bosch injectors was? Will that 91+ TB bolt up to my manifold? Will I need to fab up an adapter plate? The ECU can use basically any tps input. Its open source code, so theres a patch for anything...
 

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Hi!

Megasquirt will work with TPS or MAP. Why not using the MAP sensor and using a WOT switch at the throttle body, only? Might be a better solution.

I think the throttle bodies are pretty much the same for all 8V and 16V Turbo and NA engines. 55mm Throttle plate and a body with three hole bolt pattern.
You can compare your throttle body with the pics of my (enlarged) T16 throttle body:
http://www.akakraft.de/bilder/saab/DSC00042.JPG

Your can upgrade MS to MSnSExtra (Megasquirt'n Spark Extra) and use it for ignition control with the appropriate code at any time after you have the FI running. AFAIK this does not require any modifications of the MS ECU, it is only the code that has to be changed.

Good luck with this project. I plan to convert to MS, too, but I'd like to control ignition and boost as well.

Cheers,

Tadek
 

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You can use megasquirt without a tps but it limits functions like flood clear, overrun, tps accel enrichment, idle control. The MS can be repgrogrammed to function with the OEM Throttle switch. This is part of what I've done. Inaddition to programming an PWM Idle control algorithm (b/c existing code is insufficient) and other things.. but the 8v uses an on/off valve so that'll work easy enough.

That reminds me, now that I'm finished with the code, I need to get in contact someone on this board.

Megasquirt will integrate into the oem ignition system, so no problems.
 

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Don't know the part number off hand, but I had them kicking around from my 88 SPG (16v Turbo). SDS can control whatever type of injectors, so in my rally car application (8v NA) I just put in what I had on hand - but my SPG runs 55# units. I suspect Megasquirt will be similar in what it can control? Only thing to be slightly wary about is whether you have high or low impedance injectors.

The 91+ throttle body will bolt up no problem - I've done it. Oh, the one mod I had to do was to slightly hammer out the supporting arm that goes from the block to the TB. Not a big deal.

ATX-Alchemist said:
Vince T,any idea what the part # was for those Bosch injectors was? Will that 91+ TB bolt up to my manifold? Will I need to fab up an adapter plate? The ECU can use basically any tps input. Its open source code, so theres a patch for anything...
 

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Discussion Starter · #9 ·
Thanks for all the info!

I'm pretty sure I don't want to mess with the ignition (there is a certain elegance to it's simplicity), just replace the k-jet with a very simple EFI set-up. As far as I can tell, the k-jet doesn't have an equivilent for tps-enrichment, is this true? I.E., will a set-up using the MAP and a WOT switch be equivelent to what I've got? Does the OEM TB already have a switch I can use? I wouldn't mind leaving the tps for later...

BTW, will I need to upgrade the fuel pump to a higher pressure unit? Can one be fitted from a 16v?
 

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I can't remember if it was the CIS cars or not that actually had a higher fuel pump pressure than the 16v cars. At any rate - once you run a regulator, I think it's kind of moot how much pressure the pump puts out. CIS needs continuous pressure, right, but EFI is regulated anyway....

But someone else please correct me if I'm wrong.
 

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Ubipa said:
Y
That reminds me, now that I'm finished with the code, I need to get in contact someone on this board.
got it, I'll get back to you shortly on that. at the moment I have a bit of a rig job set up for my idle control because as you noticed- none of the idle codes people have made for megasquirt work properly, at least on our cars. right now mine will idle at 1000 RPM's when hot, slightly less when cold. with increased load (like running the A/C) it will drop to around 650, but never less than that. small detail to sort out but it seems like you have it all figured out with the stock idle valve from the PM you sent me. I was up at SOC last weekend running on megasquirt and let me say it's just awesome :D Going up the mountain to stretton (a good 4 mile run) I left a lightly tuned 9000 CSE compleetly behind and kept right with a stage 4 SQR tuned 9000! Lets see a LH jetronic C-900 do that! between 2000-and Max RPM's my car just rips. no rev limiter what so ever, so you have to look out and not over-do things RPM wise. I am still getting it to work on a good cold start to warmed up switch over, a good idle code, and non sputtery low RPM opperation when cold. anyone looking for an affordable stand alone ECU, this is the one to go with... pre built for $300? how can you beat that :D my next upgrade is going to be a set of trionic injectors, TD04HL 16G and a Jon W. stainless steel header. I am really going to have to go easy on it then, as I just have a stock rebuilt 5 speed.
 

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The EGR system can be removed easily by crimping over the metal pipe at the head (between cylinders 2 and 3) and at the intake manifold end, do the same. You can, of course, remove the unit from under the intake manifold and make a template to weld on. Run a short vac hose, looping between the two ports at the head.

PDA has some part numbers of bolts to neaten up the whole job - SAAB actually made an "EGR removal kit" :eek: PM him for the details.

T16 throttle? ... Yes! I have one on my T8. Direct fit.
 
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