tbi injection

[racer88]

Hi Guys

I am starting to gather parts to buid a gm tbi for my 2.8/260. I am planning on using two one barrel tbi units off of early 90's 4 cyl chevies. A programmable gm ecu. My question is this. Can anyone see a problem with turning the tbi's from horizontal to vetical. I would like to attach them the same position as my su's are now. Machining adapters, linkage and such are no problem, my only concern is to the function and poss atomization probs and or fuel dribbling at slower speeds. Any help or opinions would be great.

thx

bob

[Tony D]

Been done.

Check out Patton Machine for GM TBI Injector-into-SU Body adapters.

Rick Patton's Page

 

There is a gent in france using custom flashed GM ECU with the Patton Adapters to great effect.

 

 

Good Luck with the conversion. For the cost, the Patton Pieces make the conversion so much easier than adapting the bulky stock GM Bodies---all you really want is the injector...right?

[racer88]

Hi Tony

Yep just looking to inject the z without getting into the work and expense of multi port.Thought it might be just as easy to use an exsisting tbi as it already has the tps attached to it The SU's carbs run ok but I would like a little more control over the A/f with the thought of putting a catalytic convertor to try and get rid of some of the exhaust smell. Yes I have done every mod to the car (door rubbers seam sealer etc.) but it still stinks a little bit at idle and low speed. When I start it up at the cruise nights my buddy's are amazed at how it smells. I have worked on the carbs untill I am blue in the face. I did find those Patton adapters in one of you previous posts, where you also mentioned about using a spacer with injectors in them and short air doors. I found that interesting but do not know enough about injector placement to pursue it further.

Thx

Bob

[kiwi303]

or Extrudabody make a bolt on kit... just remove the SUs, bolt up the ITBs in the SUs place and add an ECU.

 

 

http://www.extrudabody.biz/servlet/the-299/Kit-cln--Datsun-L6-Twin/Detail

 

"45mm/1.75 or 48mm" Twin SU Kit: Includes 2 ITBs (45mm or 48mm bore, clear anodized), 13" Fuel Rail (clear anodized with Red Anodized Hardware and -6AN Fittings), Base Plates for SU Pattern, Throttle Cam & Stop, TPS with subharness, 2 Air Horns, 2 Air Filters, and all required Stainless Steel Bolts. NOTES: Manifold is not included. Fuel rail comes drilled for injectors. - Fuel Injectors, Manifold, and hoses are not included, Injectors are available in the injectors Dept."

[strotter]

To answer the original question, no, there's no problem with turning them on their side. W/r/t reprogramming them, check out the 3rd Gen "DIY PROM" board here. There's a very good "Intro to Programming" stickied there as well. Also, the guys that did all the original PROM hacking have a library of PROMs at the DIY EFI site. Finally, some of the hardware you'll need for on-the-fly tuning is available at Moates. Very good gear, quite reasonably priced. Any questions message me, I done a fair amount of this stuff with GM components over the years.

[racer88]

Thx everyone. I am gonna start cruising to local auto wreckers for tbi's that look like they might do the job. I am gonna use as many stock type parts as I can Will posts pic as the project moves forward

Bob

[Tony D]

Please keep in mind a catalyst doesn't do anything most of the time, it's for scrubbing the exhaust during transients!

This is a common misconception. A catalyzed car runs clean through precision fueling, not by virtue of a post-combustion scrubber! When you accelerate quickly you pump extra HC's out from lean and rich transitions...when you misfire a plug...when you have a sensor failure---THAT is when your Catalyst is working and working hard. Places like WOT and partial throttle cruise---it's doing nothing for HC Reduction.

 

I ran my 73 through a California Smog Check when I originally came to the state, and it tested clean to 83 catalyzed standards using an AIR pump and not much more than properly tuned timing and SU's. Amazingly clean.

 

The EFI will allow a wider range of 'correct' mixture, but don't think a catalyst will help if you don't have that proper mixture control. The BIGGEST thing you will notice will be decel fuel cut. THAT ALONE will noticably increase your fuel economy and almost totally eliminate the 'eye watering experience' inside the Z...

 

Keep us posted on the updates. Myself, I just found the DIY PNP Setup for the Megasquirt for my Rat-Motored Tow Rig and was considering it, knowing full well the old ECU's were fully back-hacked. I now have to thank or curse strotter for giving me quick access to the information I need to do it without changing my ECU. I have always liked the GM ECUS, and having been trained in them at their inception I'm comfortable with their subroutines and durability. Hacking makes me more comfortable than total replacement. It's worked flawlessly for 20+ years, why change it when I can just tweak it! (And the fact that the original Turbo City VW stuff was all GM ECU based EFI as well, and I worked on that now for 20+ years as well... damn I'm getting old...)

[racer88]

thanks guys all great advice. i am going to do the gm ecu and try to find some type of single tbi. one to replace each su. any ideas as to what size i should look for? My engine is an n42 block with an e31 head that has been ported, large valves added and decked 60 thou. cam is a regrind 245 @ 50 thou lift 470 lift with custom lash caps to move the pattern as close to the pivot as possible to maximise lift and duration. Ported intake, zx dizzy with hei module and lightened flywheel. 6-1 header with 2 1/2 exhaust with a single magnaflow muffler. Sounds like a ferrari at 6800 rpm. i would like to see some sort of performance improvement. I was thinking of finding the same size tbi as the su's. any ideas or tips would be great. I have access to milling machine lathe surface grinder etc, so adapters are a piece of cake

thx in advance

bob