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911st 911st is offline
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Join Date: Jan 2004
Location: Sacramento
Posts: 7,269
Of course we can get more (at least I believe so)!

We can get more from any of the above by bumping System Pressure.

Along with lowering Control Pressure this is how most 930 tuners got more fuel in the past.

This seems to be supported with some info another turned up that when Volvo was racing its CIS Turbo motors it ran System Pressure (SP) in the 8 bar range. We run in the 6.2 bar range.

It seems, bumping CP from 6.2 to 8 bar should be able to bump fuel flow about another 14% +/-.

If so, this could allow us to possibly approach 700 fwhp range. It should be noted that this would require two higher pressure pumps in series.

Thus, I suspect about 700fwhp or so is about the fueling limit of a modified CIS system.

How much air we can get through it is another story. .

I understand there are other potential factors and I would be off on this but this is what I believe to date.

There is however, one more step that could be taken for the truly crazy.

Larry tells me the Bentley / Rolls V8 is the only FD’s that can flow as much fuel per cylinder as the 930. If one could source such a FD and have Larry modify it, we might be able to plumb in on or two extra injectors before the throttle body for maybe another 33% fuel and get to almost 1000hp fuel delivery potential but that is just crazy, crazy thinking.



Something I wish someone would explore is reshaping the AFR curve by reworking the cone area around the air sensor plate. The factory designed this to move quickly off idle and then to begin to stall at about stock peak TQ levels. With modifications we blow thought this pretty quickly and go fat to fast and then lean.

Changing the cone around the air sensor plate on the CIS Turbo Volvo race car was noted as a way to change their AFR’s for different tracks. We should be able to do the same and get a good AFR curve without add-on’s.

I think a stock looking WUR/CIS 930 cold be built with no electronic add on's that can support up to 700fwhp and have near ideal AFR's by reprogramming the metering cone so the air sensor plate advances correctly at higher air flows.

In further support of this the 1994 CIS Turbo has a different cone profile supporting that this is an effective way to tune ones AFR’s.


I am not a real expert but this is what I believe so far.

I appreciate any addition and corrections.

Last edited by 911st; 01-27-2010 at 08:24 AM..
Old 01-26-2010, 01:05 PM
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