Mailing List flyrotary@lancaironline.net Message #13501
From: Russell Duffy <13brv3@bellsouth.net>
Subject: RE: [FlyRotary] Re: Spare injectors? (RWS feature requests)
Date: Mon, 6 Dec 2004 10:06:06 -0600
To: 'Rotary motors in aircraft' <flyrotary@lancaironline.net>
Message
 > If I'm not mistaken, I have 2 of the 88 NA injectors listed below, as well as 4 of the 89-91 NA injectors.   
I'm not sure on the part numbers. My primaries are purple 550s, fed from the side. The secondaries are also purple 550's, but they're top fed. They all have square connectors. If you could send me two of each I'll send them back if they don't fit.
John 
 
You're primaries sound like stock 3rd gen injectors, so you're going to be out of luck swapping them with any 2nd gen parts.  If your secondary injectors are as you describe, they must be 88 model turbo injectors, in which case the 88 model NA injectors I have should fit.
 
If you want, I will send you these, but I can tell you right now that it's not what you want to do.  Going to 460's only on your secondary won't make enough mixture difference to even be noticeable.  The only time you'll notice that you changed injectors is when you try to tune around the transition point with mismatching primaries/secondaries.  You'll also notice when you disable primaries at low power, because you'll have to fiddle with the mixture.   I cursed having mismatched injectors, but if you want yet another problem... :-)
 
BTW, where is your mixture problem occurring?  The only place a "too large" injector will hurt you is at very low power, such as idle.  In that case, it can't accurately open/close with the very narrow pulse width.  At any higher power setting, there should be no problem with larger injectors.   I never had any problems with 550 size injectors, except for idle, and the 460's didn't help that either.  Lot's of 3rd gen RX-7 guys are running with 4- 1600 size injectors. 
 
If you still want to try them, I'll grab them the next time I go to the hanger.  Actually, I need to get a storage building, and start moving stuff out of the hanger.  The county is starting the eviction process to allow for repairs of the hangers. 
 
Rusty (too much crap to move out)
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