nathanUK '81 930 G50

Just to add, another great optional feature would be a weather sensor as it is known that CIS does not compensate for weather changes. This results in the AFR being different.
https://rennlist.com/forums/911-turbo-930-forum/432087-a-f-and-temp.html

e170drvr

Ok, I am real close to pulling the trigger on one of these digital wurs. Mine is bad. I noticed that the unit has been revised to pull the rpm signal directly from the tach signal wire. As I am bad with wiring stuff, how difficult is it to tap into this signal. do I need to wire it directly from the tach itself or can I pull the signal from the cdi box wiring. Just want to kow what i'm getting myself into don't want to wire the thing imcorrectly and blow the motor. Does the leask rpm solenoid work in a similar fashion, tapping into the tach signal wire?

Thanks Eric

Olli

I had Brian's WUR but not his RPM Solenoid. His WUR tapped into the tach wire that is the black with violet and comes out of the CDI box. I had no knowledge about wiring either and had to ask Stephen Kaspar who generously shared his time with my questions.

JBL930

I'm confused Olli, the WUR doesn't sense RPM, the only wire going to it is for the warm up of the bimetallic spring, the Leask adjustable unit is no different. What were you using the tach signal for if not for the RPM solenoid?

Olli

You're right Jonathan, my bad...I was looking into the RPM Solenoid but decided to do the EFI instead and never needed to go that route. Seems like such a long time ago....

nathanUK '81 930 G50

Eric, I would imagine you pick up the tach wire near the CDI in the engine compartment.

Ag02M5

How about some action here?

Some good debates at Pelican..wish we could merge the threads.

http://forums.pelicanparts.com/showthread.php?t=379783

UT_tech

We've been getting some great feedback from tuners on several fronts. A couple of our customers have reached the point of maxing out their stock fuel delivery systems. This isn't hard to do if the air capacity has been greatly improved, i.e. with an Ultimatemotorwerks turbo, cams, exhaust, etc.. This condition is easy to spot on the dyno. As the power level increases at some point lowering the control pressure will no longer decrease the AFR. One of our tuner customers called us with the result of a flow test of a stock 930 fuel system which indicated a max capability of about 400hp. The flow test was done because the customer's car was starting to lean out at peak power at about 400hp. We've heard from two other tuners on this same subject, with stock fuel systems flowing 420 and 460hp.

It occured to us that if an upgrade to the air handling is planned it would save a lot of time and cost to know ahead of time what exactly is the capacity of the fuel system. Bosch documentation gives the minimum specification for the flow test but not typical or max. In addition, it would be very helpful to know what the effect is of fuel system upgrades before the first dyno run. To address this problem we put together a simple tool to estimate how much power your fuel system can support given only the result of a simple flow test. We've also included all of the conversions and equations so that if you have a special case (like racing gas) you can easily tweak the results. Here's the document:

http://unwiredtools.com/manuals/cisflowtest.pdf

We've also had consistent feedback that using the control pressure pressure maps in the UTCIS is very helpful in the mid-range "hump" and at the high end. Please note the attached 3-D engine map which shows how to address the need for low AFR at the mid-range Volumetric Efficiency peak, then moving to slightly higher AFR at peak power. Note the open trough (green) in the mid-range. This is not a released base map yet so please use this as a starting point only. Please email or PM me if you want a copy of the map itself but you'll need the free UT software to open the map file.

WERK-I

Steve,
Thanks for the invaluable information. Regarding the pdf doc supplied, is there a way to trick the factory WUR circuit to get it to think it's at max boost instead of tweaking the system fuel pressure to get the theoretical HP? Or......am I missing the message in your document?

UT_tech

You've got it, it's a very legit question. In theory one could raise the control pressure at any given operating point and the effect on the flow out of the injector could be the same as rasing the manifold pressure that the injector is spraying into. That's fine for any operating point up to max flow. When max flow is reached the metering plate is all the way against the stop. At that point the control pressure has no effect. Since we're looking for a measurement of the maximum, the control pressure won't help. For any operating point below maximum, the digital WUR can compensate for humps and bumps in the AFR curve so gettiing to max power is no longer a limitation of the fuel system.

It isn't absolutely neccessary to lower the system pressure as described in the document. That's a good way to get an exact measurement of max theoretical power on the car. Is an exact measurement needed? If I were looking for 350HP, I would not want a max flow measurement exactly equal to 350HP. I would prefer a rough measurement of 400HP. You could easily leave the system pressure alone and just test with the system as-is, leaving some margin for your target power level.

JBL930

Would be interesting to see what the IA Fuel head flows, am i right in thinking that the IA Fuel head is basically a ROW style head or does it flow more than a ROW fuel head?

WERK-I

I believe it flows more than the RoW fuel head.

nathanUK '81 930 G50

Stephen assured me that even if both the usa and the euro heads are modded, the modded usa will flow more than the modded euro head.

nathanUK '81 930 G50

Steve, the hp figures you quote, are they at the fly or rear wheel?

nathanUK '81 930 G50

Steve, why don't you post a screenshot of the table where you tweak the pressures according to rpm and map? I think that will help people to understand what the utcis can really do and how it gets us the AFR we want.