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cole930 cole930 is offline
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Join Date: Mar 2000
Location: Auburn,In. U.S.A.
Posts: 2,449
I'm going to really confuse you here as I truly believe the 930 Euro fuel head will flow more than enough fuel to support 375- 425 Hp. Steve Weiner of Rennspor Systems says the issue is not a lack of fuel but the lack of air. The amount of air pushing on the metering plate determines the amount of fuel to the injectors. Steve had raced the old 934 and 935's when the 934 still used CIS. He has built high Hp 930's and worked on CIS for 28 years. He is also the first to tell you if your going to do a 930 build with 400 Hp + you want to go with EFI period.
I have an 80 ROW 930 and am in the middle of a getting the old sled back together after a tear down and repaint. I have been looking at the CIS threads for years. I personally believe you need to know what you have and what you want before you start dumping big bucks on fuel head mods. All the normal 930 updates, cams, headers, turbo upgrade, ignition system, larger intercooler, boost springs, etc are logical bolt on improvements that give you predictable, proven, instant performance results. The fuel system is a whole separate issue and needs to be approached from a complete systems point of view. CIS is an antiquated mechanical system thats 36 years old and has a bi metal strip as its only electronic facsimile. Air goes in an arm goes down a piston goes up and fuel goes out but not quite as simple as it sounds. Check filters, accumulater, pump pressures, return ck valve, system pressure, control pressure, fuel lines, WUR operation, AAV operation, and spray flow and pattern. All these things need to be in correct working order before you take another step. Next and most importantly what are your afr's from idle to full rpm and boost. This can only be done 2 ways; a dyno run or installing an O2 sensor and some lm1 type logging device. Now if you are running lean and can not adjust the system to safe afr levels you might want to look at a fuel head mod. There are a lot of guys out there running fuel mods that are washing the cylinders and running pig rich constantly and can only jack with the control pressure to try and get it under control. I don't know how much it costs to weld up and recut the metering slots but a new fuel head is probably cheaper.
I'm 66 have a junk pump and cancer, in 66 years I've made every mistake you can make and if you learn a little from each mistake the one that always comes back to bite you in the ass is I wish I had gathered all my facts before I did that.

Cole - 80 930 "The Old Sled"
Mods: TurboKraft Custom IC, 934 Headers, GSX 61, Zork, Port Work, SC Cams, Air Mod Fuel Dist Relocated, Water Meth Injection, BL WUR, MSD 6530, Greddy EBC, Synapse Bov, Short 2nd & 3rd with 8:37 R&P, Wevo Shifter, Coupling, and Mounts, MTX-L SSI-4, Big Brakes, Rebel Coilovers, Bilstein Sports.

Last edited by cole930; 04-28-2009 at 07:00 PM..
Old 04-18-2009, 01:10 PM
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