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Bad LT
 
Uncle's Avatar
 
Join Date: Dec 2008
Location: Newcastle Australia
Posts: 675
Yep. Below is from Brians site.

Quote:

RPM control of the enrichment circuit has been developed in an effort to eliminate the absurdly rich mid-range condition exhibited by modified CIS Turbos. This condition is particularly noticeable on cars that are running a modified fuel distributor, aftermarket turbocharger, short-tube headers, 0.9+ bar of boost, and the Adjustable WUR. In order to have enough fuel for a proper 12.0 AFR at high RPM, the mid-range will typically be incredibly rich at the onset of boost. This is because the WUR enriches based upon boost pressure alone, regardless of engine speed.

The RPM Controlled Solenoid Valve (CSV) remedies this problem by allowing you to select when the enrichment circuit is enabled. This is achieved by swapping "chips" on the RPM controller. By controlling when the WUR receives its boost signal from the intake manifold, a much flatter Air/Fuel Ratio (AFR) curve can be achieved. This results in improved throttle response and more mid-range torque and horsepower. A side benefit is improved gas mileage and extended engine oil life, as the oil is no longer diluted with any fuel laden blow-by at the onset of boost.

The dyno chart below shows typical gains at only 0.9 bar of boost. The blue curve represents a dyno run with a precisely tuned Adjustable WUR. The red curve has the enrichment delayed until 4200 RPM. These runs were made back-to-back with no other changes between runs. You might be wondering what happened to DYNORUN_006. DYNORUN_006 was made with a 4400 RPM module installed which caused the AFR to peak at nearly 13.0 just before the enrichment was enabled. This was deemed to be too lean. A 4200 RPM module was installed and the car was re-run yielding the following results:
I've taken out the dyno graph as it was a little big.

Link.

http://www.930wur.com/


Last edited by Uncle; 11-18-2014 at 01:34 PM..
Old 11-18-2014, 01:32 PM
  Pelican Parts Catalog | Tech Articles | Promos & Specials    Reply With Quote #21 (permalink)
Bad LT
 
Uncle's Avatar
 
Join Date: Dec 2008
Location: Newcastle Australia
Posts: 675
So I did as I said on the dyno tonight. Wound down the warm control pressure and hey presto better AFR's. I'd still like more fuel at higher RPM but I am being fussy. AFR at 5,500 is now 11.9 or 12.1.
I've seen a 50rwhp increase from my base line so that's not too bad.
Old 11-19-2014, 12:30 AM
  Pelican Parts Catalog | Tech Articles | Promos & Specials    Reply With Quote #22 (permalink)
Crotchety Old Bastard
 
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Join Date: Jan 2000
Location: Huntsville, AL
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It is all teeter-totter effect so any change in one plane will affect the others. If you lower the warm control pressure you must compensate with the mixture setting. How much the WCP can be lowered is determined by the cold pressure range and the boost pressure range. All the while the Lambda system will fight these changes to bring it back to 50% duty cycle. By defeating Lambda you eliminate that issue and are left with the base settings of the fuel head.
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RarlyL8 Motorsports / M&K Exhaust - 911/930 Exhaust Systems, Turbos, TiAL, CIS Mods/Rebuilds
'78 911SC Widebody, 930 engine, 915 Tranny, K27, SC Cams, RL8 Headers & GT3 Muffler. 350whp @ 0.75bar
Brian B. (256)536-9977 Service@MKExhaust Brian@RarlyL8
Old 11-19-2014, 04:08 AM
  Pelican Parts Catalog | Tech Articles | Promos & Specials    Reply With Quote #23 (permalink)
Bad LT
 
Uncle's Avatar
 
Join Date: Dec 2008
Location: Newcastle Australia
Posts: 675
Yep, that makes sense.

Old 11-19-2014, 11:13 AM
  Pelican Parts Catalog | Tech Articles | Promos & Specials    Reply With Quote #24 (permalink)
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