924Board.org

[RC]

Since I know nothing about this expensive and poor substitute to basic EFI, I will make an educated guess as to the MAP bin values.

These MAP figures are ABSOLUTE values. One bar = 1 atmosphere = 100 KPa. 2 bars = 1 bar boost, or 200 KPa. 0.4 bar = 40 KPa or 18" Hg of vacuum. This is around where the engine will idle and is the lowest meaningful absolute pressure, or vacuum if you like, although values will get lower on closed throttle downhill.

Also possible that the MAP bin values can be user defined.

Didn`t you buy an EFI controller recently?
Wonder why you`re looking at this Morghen, instead of getting the EFI up and running?

Roger

[morghen]

for efi..i have to change the fuel pumps...the injectors...the wiring loom...the pressure ducts for the fuel delivery.....i have to source and engineer mountings for everything and i really just want to drive this car more not play trial and error with it....i've invested SOOOOO much time and money in this car(its been 4 years now and over 17.000 euros.)...it just cant eat more...its time for me to enjoy this one.
I work over 10 hours per day...the rest i try to relax and sometimes drive the car...i'm sick of soldering and arangeing stuff in the engine bay.

yea I want to upgrade it..make it better....but i need these upgrades to be as easy to make as possible and as reliable as OEM parts....so UT-CIS vs EFI....UTCIS wins !

yea i have an EFI controller...but i think i'm going to use it on my spare engine instead of making a mess of the currently quite nice car. I have another 931 with a curently NA engine wich i might supercharge/turbocharge on the long run....so the Emerald will probably go in that one.
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https://www.the924.com

[RC]

Fair enough. Can see where you are coming from. I agree, the hidden cost converting to EFI is the time factor, especially if you prefer to be on the road rather than in the garage.

This unit is definitely quicker to install and appears to be much easier to tune as there is only one table. Still not plug and play though. Does it come or can you download a default table to get running straight away? Shouldn`t be difficult to initially imitate the 931 CPR pressure chart. Really requires a WBo2 to safely and accurately tune. Obviously the ignition timing remains as it was always, pre-programmed by bosch.

Others seem to be happy with it so far anyway. If/when you do get one, be sure to post some pics and at least a basic write up. There is some interest here, however I think the price may be a deterrent to most.

Roger

[tconner]

My name is Tom with UnwiredTools, the company behind the UTCIS. We just finished installing a UTCIS-PT on our recently purchased 1980 931. For initial testing we are keeping the car completely stock except for the UTCIS-PT. However, in the future we will be modifying the engine for more power. Right now it is set up to stay at 3.0 bar of control pressure at all manifold pressures and rpm. We got some pretty interesting results already. For a lot more information and pictures of the install check out:

http://unwiredtools.wordpress.com/2008/11/26/utcis-pt-install-porsche-924-turbo-931/
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1980 - 931

[Grenadiers]

Hey Tom, thanks for the post, very interesting write-up. I'm in Sedona for a couple weeks, was wondering if I could stop by and get a ride in the 924? I would like to get a seat of the pants comparison versus my '81 931 with a rebuilt WUR. Dave.
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'83 944 Track car.
'88 924S Track car.
'89 944 Turbo
2004 Winnebago Vectra monster RV
2012 Jeep Wrangler
2014 Kia Soul
2001 Ford F350 powerstroke

[Rasta Monsta]

Hi Tom, thanks a lot for stopping by!

Can you tell us how you wired your AFR gauge?
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Toofah King Bad

• WeiBe (1987 924S 2.5t) - 931 S3

[morghen]

Thanks for the update Tom...i almost bought from you guys but got distracted by VEMS for a while and now i've put the projects aside for the winter...did you manage to get the prices a bit lower yet?
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https://www.the924.com

[tconner]

[Rasta Monsta]

Interesting. I would have thought that the splice would alter the resistance, and hence the reading going to the control unit. Have you verified the accuracy of the gauge with an independant measurement?
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Toofah King Bad

• WeiBe (1987 924S 2.5t) - 931 S3

[tconner]

That is a good question Rasta Monsta. I decided I better ask our electrical engineer about this one. He informed me the Oxygen Sensor is a voltage source that varies between 0 and 1 volt depending on the oxygen content in the exhaust. The lambda control unit measures this voltage and responds accordingly. When the AFR gauge green wire is spliced into the oxygen sensor voltage wire it does not affect the output of the sensor. It only measures the voltage similar to the way a volt meter would. By the way if you don't want to buy a gauge or install one you could simply hook up a volt meter to the oxygen sensor and measure the output voltage. The output of a narrow band oxygen sensor looks like this:





Just to be sure I did an experiment on the car. I started the car, let it warm up and looked at the frequency valve duty cycle using a scope. The duty cycle was right where it should be hovering around 50%. I then disconnected the AFR gauge green wire from the oxygen sensor wire and there was no change in the duty cycle. This assured me the AFR gauge was not affecting the output from the oxygen sensor to the control unit.
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1980 - 931

[ideola]

Tom, just a quick note to express a sincere and hearty "Thanks!" for working on the 931, and also for taking the time to post your results and info here. It is refreshing to see what you guys are doing for CIS-equipped cars. Personally, I find this to be one of the most compelling alternatives available.

I wish the turbo version wasn't more than twice the cost of the NA, but I totally and completely understand the R&D costs. The price point is the only thing that keeps me from taking the plunge on my 1980 931 right this very second! It's definitely on my radar for whenever my UWB project gets finished.

Thanks again, please don't be a stranger, and don't let the naysayers discourage you from posting here!
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erstwhile owner of just about every 924 variant ever made

[ideola]

P.S. Please let us know the minute you begin testing for E85 compatibility. I sent inquiries via the website regarding my 928 project and using this for E85. The 928 project is still available as a test mule if you guys change your minds!
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erstwhile owner of just about every 924 variant ever made

[Rasta Monsta]

Naysayers? Screw you, man!


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Toofah King Bad

• WeiBe (1987 924S 2.5t) - 931 S3

[tconner]

Thanks for the praise ideola. This forum seems especially open to new ideas and we very much appreciate that. As for your question on E85 we have a solution in the works. The new valve body design shown below completely isolates the electronic control pressure sensor from the media - gasoline, E85 or whatever. The only other issue is that the body is currently made of aluminum which is not compatible with E85. However, we would be willing to offer a stainless steel version for those interested in running E85.


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1980 - 931

[ideola]

Why not just anodize or powder coat the aluminum? It seems like that would be cheaper than stainless, and it's the technique used to protect other aftermarket items like fuel rails and filler necks on fuel cells, etc.

The other factor that would need to be taken into account, of course, is that the fuel distributor would need to be rebuilt with Ethanol-safe o-rings and seals, and the stock nitrile soft lines would need to be replaced with teflon-lined braided stainless. I've read a few threads where 944, 928, and BMW guys have converted over without modifying their fuel tanks and main hard lines, but at a minimum the fuel dizzy and soft lines to the injectors will need addressing. This is not necessarily Unwired Tools' concern, just pointing out that more than the WUR would need to be addressed to do a proper conversion...
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erstwhile owner of just about every 924 variant ever made