esc

iTrader: (6)

I have an old 900 CFM Holley Pro-Jection4 TBI system. It has been on my Camaro for 20 years and I like it a lot. It is one of the early ones with the analog controller made by MSD and uses 85 lbs/hr injectors and is supposed to run at 15 PSI.

I actually have 2 complete systems but that is another story.

Original style replacement injectors are no longer available for these and I've had mine cleaned with limited success. Holley sells a replacement injector housing and new injectors for about $550. A lot to spend on such an old system.

Realistically, I'll probably just save up the $1800 for a new Holley kit. It will have a better ECU and the last one has lasted me 20 years so I can't complain too much about that.


But I'm considering having a new injector housing custom machined to hold some off-the-shelf injectors. But what kind of injector should I be looking at?

It would need to support at least 85 lbs/hr. A low pressure TB style injector would be preferred but high pressure would not be a deal breaker. Pricing, and current/future availability would be the most important factors. If it isn't much cheaper that what Holley is offering ($410 for 4 injectors) there is no point messing with it. I'm wondering if injectors from a BBC injection would work. Are injectors injectors for those still available new?

If it were compatible with my current TBI controller that would also be a plus. But I'm also looking at my options there. I may go with some sort of GM ECU or a mega squirt.

Finally, I'm toying with putting both of the 900CFM throttle bodies on top of an 871 blower and seeing what breaks first.

Any ideas or comments are welcome.

one92rs

iTrader: (5)

what do your injectors look like

esc

iTrader: (6)

Like this:

Ronny

iTrader: (1)

Would a GM pod bolt up to Holley TB ? I think I read that somewhere. Unlikely you can place a GM in Holley pod. I would contact FIC injectors. They have rebuilt/reconditioned flow matched TBI injectors and would know. Holley tech line was OK to when I called asking Q's.

I researched Holley back in 2006. I was told by a tech that Holley rates the injectors at 21 lbs FP(their pump). So that injector at 21 lbs = 80 lbs injector. Their online instructions state to set FP at 21 lbs. Maybe <2006 it was lesser FP?

esc

iTrader: (6)

I would be very surprised if that were true...maybe for a two barrel, but not a 4.

I'm considering a custom machined pod. If I can find injectors that make it worth while. I've got a buddy that owes me a favor and would probably do it for the cost of materials.

The older ones (I got mine in 1991) were run at a lower pressure (15PSI). When I last had mine cleaned they were flowing mid 90s @20psi, which is about what I run now anyway and it is still barely adequate.

Ronny

iTrader: (1)

Yes I was refering to a 2 barrell. I guess it did not pertain to the task at hand. My error.

there is some value in just the TB itself that OP has to be used with a single plane with port fuel. the 4 barrell Holley I saw at NHRA was sequential

esc

iTrader: (6)

The newer Holley 4 barrel TBI's are a lot nicer than mine...but I have two of them and don't really want to throw them away. They would work with port injection and that has crossed my mind more than twice. But trying to fab something up can get complicated...I would probably end up with a mega squirt to control it all.

The newer ones ($1750.00) have IAC, MAP and I expect (need to check) will work with a WB-O2. All things that mine will not do. So spending almost $600.00 to rehab the old system is not very appealing.

Ronny

iTrader: (1)

Is there room to drill body to allow IAC? If not one would need to machine an alum block for IAC, do a remote mount, and feed a 4AN threaded fitting at unit. Simpson 36 did just that. He had two dual TBI units with feed from one IAC.

esc

iTrader: (6)

I could do that, but I've gotten along well enough without IAC so far. It might be nice to have when the AC is cycling on and off. If I go with a MegaSquirt I might do something like that.

If I get a new FI system it will already have IAC.

But what I am really wondering about is if there is a common TBI unit (like the one off of a BBC) with big injectors that are available new for a reasonable price.

I would prefer something that would be available at a parts store, not special order. I ditched my old Mallory Uni-lite (which always worked perfectly) for a small cap HEI (which, in "limp home" gives me the perfect advance "curve") so that I would not have to mail order caps and rotors. That is why I am investigating alternative injector options.

Ronny

iTrader: (1)

EBay . New possibly but big bucks. best bet is refurbished. Or used from junk yard.

I think DC trumpet on this board rebuilds them and sells as well.

check this out as another alternative to MS. dynamicefi.com

esc

iTrader: (6)

I found out a little more about the newer style injector pod that Holley makes. They refer to the connectors on the injectors that it uses as "GM Maxi TBI style".

Here is a picture of one:


I wonder if this is a standard GM TBI injector. Anyone recognize it?

Ronny

iTrader: (1)

It appears the same. I have only had mine out twice. looks like a match to my rebuild kit. The connectors are different however.

Nowdoes the new style pod from holley fit the old version of 4 barallel TBI? Or is it available. I have heard neg comments on old style Holley injectors. GM was far superior.

esc

iTrader: (6)

Yes, the new pod is a service part for the old 4 barrel TBI's.
It is about $150.00 for the pod and a little over $100 for each injector...so close to $600 when all is said and done.

I ran the original injectors for 10 years, then replaced them and ran for 7 more, cleaned them and ran for 3 more. I have no complaints other than I can't get any more new ones.