Thanks for the encouragement. I gave some thought to having the Fuel Tech controller use only the center throttle body until an off idle RPM to be determined, but then I'd need a progressive linkage for the throttle plates to avoid lean condition.
Abe
sounds like a neat install, picture?
X2 for pictures!
You're likely to run into trouble with that application and the stock injectors. At some point the ecm will be commanding pulsewidths smaller than the injector can reliably and consistently deliver. Installing six injectors from single four cylinder applications will make the issue worse. The fours were only slightly less hp than the 2.8 but the injector provided more fuel since only one was used. There may be an option, though but I don't know if it can be done solely with junkyard parts.
GM used two different styles of injectors in their TBI. Most of the V6 and V8 vehicles received injectors physically the same as your 2.8 TBs. But the big block medium duty trucks and some G vans used physically smaller injectors. Holley makes a pod that will attach to your TB which uses the smaller bottom feer injectors Once you move to that style injector you can source new injectors from 92-94 2.2 PFI engines which can be found in Cavalier and S10 among others. Flow for these injectors ranges from 16-17 psi @ 43.5 psi. Obviously you could drop pressure slightly if needed.
The TB on the medium duty trucks has a governor and looks different. They don't show up on Ebay very often and they usually go cheap. You could try your luck by buing one and trying to switch the pod to a "regular" TB .
http://yabe.chudov.com/TBI-ROCHESTER.../ebayhist.html
Multec Bottom Feed injector data:
http://www.gearhead-efi.com/Fuel-Inj...6&d=1344522961
A little discussion about Holley TBI and Holley injector part nos:
http://www.gearhead-efi.com/Fuel-Inj...feed-injectors
A picture of a Holley injector pod.
http://www.ebay.com/itm/Holley-TBI-I...d057d6&vxp=mtr
OK, I'm interested. But how does a multitek injector designed for 70 psi fuel pressure work at 13 psi? Would be good for a 60% reduction in flow rate. Or do we need a new high pressure pump. Looks like Holly eliminates the internal regulator.
Thanks
Abe
18 lbs/hr at 43.5 (stock pressure) is more than enough for 180 hp. Most TPI systems run at 43.5 psi or higher. Holley does put a regulator on the injector pod.
But I don't know if the replacement pod I linked to has one. There are more complete kits, I believe. Or possibly the four bolt pattern for the Holley regulator matches the GM regulator dimensions. There's one of the Holley parts on Ebay for $50 right now... Seems cheap enough for a test fit. If the GM regulator fits you can replace the spring with one for a 30 psi base and make the regulator adjustable to make up the difference in pressure.
Posting Permissions
Reply With Quote
Bookmarks