View Single Post
Alan L Alan L is offline
Registered User
 
Alan L's Avatar
 
Join Date: Apr 2006
Location: New Zealand
Posts: 2,809
In real life you do have a certain amount of inbuilt damping. I'm not sure quite how you have your test system set up, but the airplate in the CIS responds to these pulses by altering the internal volume.
In my system when things got real bad the pulses sent the airplate into spastic fits trying to follow the pulses. But your trace looks much finer than what I was getting - ie your responses seem much sharper. I will try and find some of my traces (on previous computer I think). from memory UT tried altering the response times (slowing them), but of course this had other consequences. We could get it to sit at a steady state reasonably well, but as soon as a change in CP was required it went into pulses again - this would happen during the warm up phase. It may have asked for say 2.5 bar and it would sit there steady as a rock, then when it asked for 3 bar it would go into spasms.
it seems slightly odd, but UT seemed surprised by the spiking response I had, when I first installed the injector system. I can only assume their bench test system was not doing this. Their conclusion initially was that my fuel head had less leakage (past the metering piston) than theirs. This would have the effect of compensating also, but made the system highly dependant on the fuel head. But it does make me think they had an initial unit that was not spiking so badly, mainly due to the damping effect in the fuel head.
regards
Alan
__________________
83 SC, 82 930 (track) - Stock except for RarlyL8 race headers, RarlyL8 Zork, K27-7006, 22/28 T bars, 007 Fuel head, short 3&4 gears, NGK AFR, Greddy EBC (on the slippery slope), Wevo engine mounts, ERP rear camber adjust and mono balls, Tarret front monoball camber adjust, Elgin cams, 38mm ported heads, 964 IC. 380rwhp @ 0.8bar Apart from above, bone stock:-)

Last edited by Alan L; 09-07-2014 at 12:27 PM..
Old 09-07-2014, 12:21 PM
  Pelican Parts Technical Article Directory    Reply With Quote #110 (permalink)