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can I get these to idle right?
Posted: Fri Feb 03, 2006 4:07 pm
by Drac0nic
I've got a chance to pick up a 454 TBI unit with 85# injectors, I'm wanting to use this with a basicly stock 4.3L V6. (no cat, no EGR, MS-II unit) I was wondering if I could get these injectors to idle decently, perhaps even going as far as using a vacuum regulator, which will apparently drop FP by about 5# at idle comapred to WOT or make them about 67#s by the MS calculator. The reason for this is the eventual addition of a turbocharger.
Posted: Fri Feb 03, 2006 4:32 pm
by Bernard Fife
Drac0nic,
When I had a Holley TBI, it had 4 85 lb/hr injectors on a 6.7 liter engine. The idle was around 1.7 milliseconds and 35 kPa. However, 1.7 milliseconds at idle is borderline.
Your engne is 64% as large, but only has half as many injectors, so that's good. On the other hand, if it is stock it might idle with a lower vacuum kPa. I'd say that it will work, but not perfectly with MS-I.
MS-II has 100x the pulse width resolution, so it would be a better match, and should be fine. For example, I have 8 72 lb/hr injectors on my engine now with MS-II, and idle isn't a problem at all.
Lance.
Posted: Fri Feb 03, 2006 5:41 pm
by Drac0nic
Yes, I was sort of wondering about that. I mean, a stock Syclone comes with 30# injectors I believe, as do Buick GNs. 6X30# injectors is about 180#, which is more then the 170# from the TBI injectors. I'm just not sure that with the way the TBI system works if I'd bog the engine down horridly or not.