AustinT

I have a chance to buy a holley 900 Cfm TBI. The TBI is the pro- jection model. The number of the Injectors is 250r-123aa. I think this is holleys old injectors, Im not sure. How hard would it be to update it to new injectors, or are those the new injectors? Is 225 a good deal for the TBI? The guy says its new.
I want to run This TBI with my 305 ecm, using a prominator. I will build a injector driver to drive the other two injectors
Thanks

chevypower

Your factory ECM will run all four injectors. I'm going with a 700cfm Holley 4bbl TBI on my '91.

AustinT

thanks for the Post Chevypower, I think that the TBI that I would like to buy has the old style injectors. What would it take to swap them out for some Delhpi injectors?

Dewey316

i beleive holley sells the stuff to switch to the delphi injectors.

with a second injector driver board, the TBI computer should be just fine, but it is going to take alot of tuning. the biggest downfall is the slow refresh rate for datalogging. that makes the tuning process that much harder.

AustinT

Dewey316 could you go into a little more depth on the datalogging. I am new to fuel injection. Why would it be slow? I just thought I could use the Innovate wideband to help tune.

r90camarors

A WB would be excellent for tuning. What dewey was talking about is the extremely slow baud rate we have to deal with. It seems to be 1.1-1.2 seconds between each entry with winaldl-not winaldls fault, that's just what we get to deal with. Though if you do some research, I believe there are ways to get quicker readings. JPrevost did this when he posted his 0-60mph times if I remember correctly.

Also, I know holley sells the new style pod for the 2bbl units. It is around $80. So I would assume they would also have to sell them for the 4bbl units, though I would expect the price tag to be a little more.

When I purchased the 85pph injectors, they cost me $160 for the two of them (like I tell many people though, holley does sell a 670 unit with 85pph injectors, I just had to spend the extra because I bought it with 57pph injectors when I had the 305).

So if you figure in $320 for injectors, $225 for the 4bbl tbi, and say $100 for the injector pod, it starts getting a little pricey at $665.

I did at one point find a place that sells them for around $500 if I remember correctly, I will post a link if I can find it.

Best of luck


Roy

r90camarors

Here is the link I was talking about http://www.gtoracing.com/automotive/...d/throttle.asp

The picture shows the unit with the old style injectors though, so I'm not sure if the picture is outdated, or if maybe they had overstock on the old units and still sell them. Best bet would be to call them and find out. If they do come with the delphi injectors, that is a killer price, assuming of course that the $400 price is for the unit with injectors, and the $1,XXX price is for the entire setup, i.e. ecm, harness, etc.

AustinT

r90camarors, Thanks for the info and the link, I came across that same website yesterday but I didnt know if the 900 cfm unit was a TBI or just a TB. I see from your sig you are running a 383 with a tbi. Tell me a little about your setup please, thanks

AustinT

The TBI on ebay for 225 just ended. I did not bid because I didnt want to end up with something I didnt need. However I found these injectors http://cgi.ebay.com/ebaymotors/ws/eB...tem=2450307468

are they the new style? 20$ a injector!!

AustinT

Part numbers:

534-173 Holley 900 cfm TBI $740 from summit
534-169 4 Barrel injector pod update 108 from summit
522-43 Delphi injector 78 from summit



I still havent been able to get ahold of GTO racing on the holley TBI that they sell.

r90camarors

Those injectors on ebay are the old mopar style injectors. The way to tell the delphi's apart from the old syle is the connector. Delphis use a side mount with a housing around it, not too much different looking than the IAT sensor's connector (just for reference). The older style injectors are fatter and have the harness connectors exposed at the top.

Unforuantly, I am back to a very slow dial up connection, so I wasn't able to research all that much, but I ran a search for "500-16" on holley's website. That is the part number advertised on the gtoracing page. The search found a 500-16s, which is the polished complete 900cfm tbi. So I would think that the 500-16 is the cast complete version. So hopefully, come monday, the guys will be there and will be able to give us a sure yes or no answer.

My combo is in my sig. She runs very strong, but it has been 8 months so far, and I am still getting things straightened out. She is much faster than the times in the sig now. My main issue has been trying to work around the restricted airflow, which I think I have finally got around via intake manifold, extra plenum, and opening my adapter plate. Of course though, if you go with a 4 bbl tbi, you will not have to worry about that for the most part. If you have any specific questions, feel free to ask.

AustinT

Do you think you are in the 12's yet? How many barrels does the holley 670 have, 2?
I will post the info on the GTO TBI first thing monday when I call them, Thanks for the all the research r90camarors.

r90camarors

To be completely honest, I strongly feel I will be in the 11s once I get the suspension and traction hooked up. As it is now, I am sure I am in the 12s. Actually, I have a set of slicks now which will go on when the car is completely ready to handle them, and had I had before, I probably would have been right around 13 flat (in reference to the times in my sig). Since my 13.4 run, I have done some work, namely the rpm airgap intake that replaced the old performer style intake I had on there. I also finally adjusted my pinion angle (via torque arm) to -2*, had a little chip work done, added ram air, and cleaned up the tbi and adapter plate some.
My main concern now, as far as the track goes, is my 10bolt (currently whining like a b&^ch) and my lack of subframes. I am saving up for a 12bolt or 9", and not quite sure which subframes to go with. Unfortuantly, both are nice and pricey, but I will need them if I want serious times. The flex on the car has caused all kind of cracks in the paint, mainly on the driver's side quarter panel. So for the mean time, I will more than likely focus on my traps.

The holley 670 is a 2bbl tbi with 2" bores.

AustinT

K, I called Summit and jegs. With the 500-16 number, they said they are no longer available. However both companies can order the 500-16s for $710, ouch!!!

r90camarors

Man, that sucks. And I assume the 500-16s are overstocks and use the old style injectors. I priced out a new 900 cfm holley tbi a while back at O'riellys (special order obviously), and it was right around $800! If I remember right, the whole commander 950 system was only $500 more, and that includes the 950ecm, harness, tbi, pump, and a few sensors. Can't remember if it was with the software included or not though.

AustinT

Yeah its not looking good.