924Board.org

[Beartooth]

I'm really tempted to buy a Microsquirt, both for mixture trim and timing control, since I want to push my 931 up a notch or two (I may add water/methanol injection). I love old-school fully-mechanical tuning, and I might be able to get good results, but at some point it's working with one hand behind your back - without a dyno facility at your disposal anyway. That's all down the road though; if I can get my shop closed in one of these days, I'm going to tear into my motor and see what I can figure out for a budget rebuild.

Getting to what you're asking, @safe, it seems the question of "why not Microsquirt/FrankenCIS?" is a good one, and I think the answer (for average yokels with average expectations like us anyway) boils down to whether you've got a good working CIS setup. I'd say if someone has a poorly-functioning CIS setup, they'd be wasting their time and money doing anything with it until they get it working right - either find the problem and fix it before you do anything else, or convert to EFI (much easier now). About the only persistent issue I've got with my 931 is hot starts, and since that seems to be a problem of fuel vaporizing in the injector lines, I'm thinking of addressing that by re-wiring the cold start valve for manual activation.

Anyway, I hope this thread isn't getting off the rails. For Morghen, I'm curious how much you think you'll need to change around for the 931. Hopefully it's not too major a re-work, since the market is smaller with so much fewer 931s. On the other hand, if you've got a 931 that's not running well, you've got the further incentive to do something about it because of the much stronger possibility of blowing an engine, where it's probably just a nuisance on a NA engine. I've got no particular info on this, but I suspect some CIS setups get damaged or degraded over time in ways only someone set up with calibration and measuring equipment like Bosch has (or had), and that's why some run well and others won't behave no matter how much you tweak them. Obviously everybody's in a different position in terms of what they've got and their budget - for some, an EFI conversion may be using a sledgehammer to drive a nail - but I bet there are quite a few 931s out there that would benefit from this kit.
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1980 931 diamond in the rough

[safe]

[morghen]

I also bought one of those digital WUR things and it didnt work.
Software was saying it is doing something but in reality it wasnt.
I troubleshooted it a bit and seems that the position lf the wur is too close to the ignition system and it gets a lot of signal noise and that prevents it from functioning properly. I tried to get some customer support but they couldnt help much. So i just gave up on that and started on my own efi.
That thing wasnt cheap either with the controller for it.
If it had worked it would have somewhat solved the hot start and allowed for some fueling adjustment..but nowhere near what efi can do.
I really love the k-jet and for many years i didnt want to let go of it, however i believe that this system that we now have pays enough respect to the old k-jet, reuses some of it but works like a modern system.

I bought a 931 basically because several guys wrote asking for a 931 version of the efi kit.
And because i also love the 931 and it also deserves to be enjoyed along the 924.
My 931’s condition is still a mistery to me, the car hasnt been delivered yet, maybe next week or the one after. But from the pictures..it doesnt look too good, its a bit of an albino rat
I hope the engine is useable.

On the EFI kit, i’m making 8 kits in the first run, 6 are sold. 2 to Manny, 3 to Italy in their 924 club, and one to Spain. There are others lurking and asking about it so i’m sure that when it is ready the last two will be snapped quickly.
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https://www.the924.com

[safe]

As long as the kjet is working properly and you don't want to modify the engine to much, it's fine and reliable.
But if you have a troublesome kjet, something someone ha as tinkered with before... You will probably be better of with EFI, both in performance and money.
Not a lot of people who knows can fix it without a part's cannon...
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/Magnus, Stockholm Sweden
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Porsche 924 -79 NA, EFI and Turbo.
Porsche 931 -79
Porsche 911 -77, 3.2 Targa
Porsche 911 -69, 3.6, Coupe

[morghen]

Comparing CIS and EFI, i would say EFI is more consistent, meaning CIS had some conditions where it would not perform at its peak.

For example the warm up cycle wasn't always clockwork and that was noticeable with CIS.

Another quite important thing, i could never get the same performance coming out of a sharp turn to the right compared to a sharp turn to the left, this has to do with the position of the CIS metering scale and the momentum of the car.
Obviously this is not an issue with EFI.

Another aspect is along the RPM, with CIS at some RPMs i got good AFR and good torque, while at some RPMs wasnt optimum...and no way to adjust that.
With EFI the car pulls consistently from idle to redline.
Because of this the car is more capable in dynamic conditions.

So in real world with EFI you are faster because even more availability of the torque and power.

[Kenodog]

Man, if ONLY there was someone that made a kit like this for a 931. Dang, wouldn't that be nice


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1979 Euro 931, Olive
1981 931, Sabine
1991 Ford Ranger XLT 4x4, Ricky
1996 Ford E-350 ex-FedEx Van
2014 Mazda CX-5 (Kinderwagon)
2019 KTM 790 Adventure
2024 KLX300
2024 KLX140

[morghen]

[924RACR]

[Kenodog]

Oh, i read it. Just wanted to stir Morghen up a bit lol !


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1979 Euro 931, Olive
1981 931, Sabine
1991 Ford Ranger XLT 4x4, Ricky
1996 Ford E-350 ex-FedEx Van
2014 Mazda CX-5 (Kinderwagon)
2019 KTM 790 Adventure
2024 KLX300
2024 KLX140

[924-76]

[morghen]

The 931 mule is here.
Obviously doesnt run, hoping it is mechanically useable.




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https://www.the924.com

[Raize]

Shouldn't be much difference between a 931 and 924 really except the map.

[morghen]

Yes, and the crank pulley, the 931 uses a different offset crank pulley so in order to keep the same bracket, sensor position and trigger wheel i had to make a custom pulley.
I now have everything needed in order to start my 931, except some free time. I’m busy working on them kits..this is exhausting stuff. After this round, i’m taking a break until June.


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https://www.the924.com

[morghen]

Box-up time for the SC version first round.


931 kit ongoing development, hoping for a first start next week but realistically it will likely be within the next 2 weeks.

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https://www.the924.com

[barnwerks]

Looking great Morghen. Very exciting.