Can a caveman do DIY EFI? Nothing ventured, nothing gained...

[A/Fuel]

It's kinda hard to make out the pic iof the filters, but there is the notch.

[BKBridges]

I've seen what Randal talks about, TBIs are mindboggling in how they idle... finely atomized fuel spraying directly into a... throttle plate?

I later learned, it's the small pocket of low pressure air just beneath the throttles that will allow even a large droplet of fuel to expand into a well-atomized intake charge...

looking closely at the MSD "Atomic EFI" you can see they are using the same theme (as a carburetor) where a venturi creates a low pressure pocket, and they spray the injected fuel directly into that pocket. Coincidentally, their injectors seem to have a 90-degree orifice (fuel sprays 90 degres in relation to the injector body) - the only other place I have seen those types of nozzles is on the new ZR-1 engines, they have 90 degree orifices. The injectors mount in the intake almost horizontally, but still spray parallel to the vertical, incoming air charge. They are not happy creatures when you upgrade the injectors with bigger units that do not have the 90 degree tips...

And the 90 deg injectors sure make one think about some cool EFI blower hat scenarios...

The good thing about above-blade TBI is that you can get away with sleeve bearings instead of balls or rollers on the shaft due to the constant lubrication (gas).
The FAST TBI injects below the plates into small simply machined and plugged cavities that create a nice fan pattern, even at low pw.
BKB

[TheSilverBuick]

This is the TBI on my Thunderbird.


Notice the injectors are different? No gasket part in the middle. These set in with O-rings.



I found the kit in the basement, unfortunately two things came to mind when I pulled it out. One is you have the bigger bores, so the base gaskets don't work, and I'm not sure if the injector and regulator gaskets are the same or not. But the other thing that crossed my mind is that I'm getting a 4.3L TBI in the mail next month, and I know this kit will work with it. Sorry for the excitement, was hoping to get you out of $27



I'll just continue supporting you with tech advice and insistence of the 4-6-8 conversion

[seanm]

Glad to see you back to the cadstang. I'd do like DG says and do fuel then ignition. Or start with Carb then switch one system
Then the next. If I can help let me know.

[STINEY]

Here comes the first hijack, hope you don't mind. What are the dimensions of the HHR fan shroud? And the picture looks like dual fans is that correct? Thanks.

Took measurements last night. The HHR fan is 22.5" wide at the actual shroud - there are some funky ears/tabs on each side that make it 25" wide overall, but those ears are smallish and easily trimmed off with a razor knife, or could be used as some kind of mount.
Height is 18", no funky ears/tabs on those sides. Oh, and its a single fan not twins.



Thanks for checking Randall.......no biggie on the $27, would have been cool to use it if you couldn't. What is your T-bird TBI from? The aircleaner mounting is significantly different too.
Your pointers will surely be of extreme usefullness, I'm sure. Many stumbling blocks to come, I am sure to encounter. Much assistance to need, I will. (Yoda voice here)
If you stumble across a 4-6-8 system cheap enough, grab it and I'll buy it from you if you are willing. Be sure to grab those high-rise valve covers with it! Be careful, they are plastic and like to break.

Glad to see you back to the cadstang. I'd do like DG says and do fuel then ignition. Or start with Carb then switch one system
Then the next. If I can help let me know.

Hey Sean. How's work on big, black and evil progressing? Good to hear from you, ever consider a thread on Bangshift on it? I'll take you up on that offer, especially if boost ever enters the picture.


I have a nice extra Edelbrock here, may just toss that on and do some data logging with it. Would that benefit me later to "build" a fuel and/or ignition map by data logging a carb/hei setup first, then I would have that for this particular engine to tweak?
Good idea or waste of time?

[TheSilverBuick]

Thanks for checking Randall.......no biggie on the $27, would have been cool to use it if you couldn't. What is your T-bird TBI from? The aircleaner mounting is significantly different too.
Your pointers will surely be of extreme usefullness, I'm sure. Many stumbling blocks to come, I am sure to encounter. Much assistance to need, I will. (Yoda voice here)
If you stumble across a 4-6-8 system cheap enough, grab it and I'll buy it from you if you are willing. Be sure to grab those high-rise valve covers with it! Be careful, they are plastic and like to break.

The TBI is an aftermarket Holley 670cfm GM unit, which replaced the 600cfm Autolite. It has 85lb/hr injectors in it, which should work up to WOT with a worn out stock 428. However, it leans out real bad at high throttle and I'm fairly certain my 12psi (on a good day?) pump wasn't keeping up, so I just recently picked up a higher pressure pump that'll be going on this weekend. The air cleaner is a out of the spectre/edelbrock aisle at the parts store. The small filter, then at some point I wanted to change the air filter and couldn't find the right sized one so it's a bit narrower. I also have the lid hammered concavely because it was just tall enough to hit the hood. This way it doesn't. I have a Q-jet to squarebore spacer under the TBI adapter plate, which added height. Even with the larger rear spreadbores on the adapter I had to grind places of the adapter plate to get the larger throttle blades to clear. I would of also preferred to run the stock air cleaner housing, but where it sits on the carb is not round, it has a notch for the fuel bowl vent and to center the air filter housing.

This won't really apply to you, but on the throttle linkage, Blulightning Bob here sent me an Autolite carb base that I removed the throttle arm off of and with a bit of dremel grinding to make a rectangular hole it bolted right to the TBI nicely for the stock kickdown, throttle and cruise control linkage.

[STINEY]

Some info on the DNE2 Doug Nash Enterprises overdrive unit. Turns out none of these are supported by US Gear anymore, regardless of serial number. Some other company bought US Gear (retaining the name) and has nothing to do with these now.

But I've scrounged up a installation manual, and a owners manual with diagrams, exploded parts diagrams, ect. Some neat identification information too.

ID information: "I have three of them...two underdrives and one dismantled overdrive. I also have one U.S. gear Dodge underdrive, and a new adapter for a chevy tranny. The DNE's were ultimately produced and bought out U.S. Gear. U.S. Gear changed the tooth pitch on the planetaries for quieter operation which makes the currently produced models incompatible with the DNE units (for the gear set only, the rest appears the same) and they will not service the DNE units. The U.S. Gear adapters will work with the DNE units but be aware that the actual units must be matched for the make of tranny it is mounting to..i.e. Ford with ford adapter, Chevy with chevy adapter....Look at the input of your unit (the part that slides over the output shaft of the tranny) and if it has no grooves circling it it is a GM 32 spline overdrive, 1 grove ford 31 spline overdrive, 2 groves GM underdrive, 3 grooves Ford underdrive, 4 groves dodge etc. I prefer these units to the GV units for two reasons....1, inherently stronger (and heavier); 2. No clutches and no free wheeling planetary that engages/disengages on its own. They do "clunk" and need a slight release of engine load to shift so not for quick shifting for time but whatever position they are in they stay there until you tell them to shift and engine braking is always there. I also prefer the underdrive models for my lightweight (Ranchero and Crown Vic) because a 2.75 posi (CV) becomes effectively a 3.25 and the 3.25 DPI (Ranchero) becomes a 3.90....both good ratios for towing 460 BBFs. The CV will get over 20 mpg on freeway and the Ranchero did get 18mpg
with 460PI and 2.75 but it is in the process of being upgraded to 533, manual shift c-6, with the 3.25 rear so don't know what it will get when it is done. If I had it to do it over again though I would go with a maxed out AOD or E40 for the simplicity. Since there is no sliding spine you must use a truck driveshaft and you must KNOW which GM400 output shaft you have i.e. 1330 or 1350 universal type to get it properly matched up. If in underdrive I don't usually shift until 2 gear is used up, then upshift..use it up, then 3rd assuming heavy load...less load be lazy go 1-2-3 then shift unit. The ability to shift down .8 while in high is great on tough hills and smoking tires at speed in 2nd. I also think the underdrives are quieter while in direct drive and if you need the torque multiplication of the underdrive the engine is usually wailing anyway."



1st manual (I'm going to post this up here as it is nowhere else on the Internet and should give Bangshift a decent amount of traffic)

[milner351]

That overdrive looks cool!

Thanks for taking on EFI before me too - one more guy I can call when I'm ready to put a carb back on...

[STINEY]

Dne2 doug nash overdrive

2nd manual:

[smiti99]

Those aux transmissions are neat finds when you see them.

I don't know if you've already heard of this trick, but you can double- or triple-up the injector body gaskets with longer bolts to get the injectors up out of the throttle bores for a little more airflow. The injector body gasket is the Y-shaped one in the picture, and it's over 1/8" thick. I doubled them up in my TBI converted Cutlass.

[STINEY]

That overdrive looks cool!

Thanks for taking on EFI before me too - one more guy I can call when I'm ready to put a carb back on...

Suprisingly simple in design too. Still deciphering the wiring, the Factory Doug Nash switch I have seems to have overheated and is missing the relay (Timed relay?) and plugs, so I'll be getting creative with the controls on this bad boy. Hopefully I can just control it with a DPDT switch? Momma and Grandma aren't going to be driving it so "User Friendly" isn't way up on the priority list.

If I get EFI running before you, I'll be leaning hard on you to put dual TBIs on that high rise intake.........

[milner351]

Aarons "push pull" cable actuated over drive in his 68 F100 was an interesting set up - it was similar in over all design to yours, but was all factory installed - hung off the back of the 3 speed manual trans. As I recall you had to "unload" the power train by letting off the go pedal, then pull the cable to engage the OD, and then pour on the coal again. I don't remember if you were supposed to push the clutch in to engage or not...... you won't have that option on yours being an automatic. The delay switch is interesting - that will take some research to duplicate..... but maybe you can just do the same thing with two single throw switches - as long as the switches are thrown in the proper order - you'll be the delay box instead of the electronics.... I'm sure you'll figure it out!

DIY EFI on the 302 is just too easy with the factory intake, throttle body, sensors and fuel rails - I'll go that way if I do it, I have all the stuff sitting on the shelf. Hood clearance may be an issue - then I'd have to rob a set up off a 94/95 mustant or 92/93 tbird cougar, or get an aftermarket intake.

[STINEY]

Funny you should bring up a cable actuated system.......THAT plan is my fall-back position. I'll gut the electric actuator and jury-rig a manual engagement system if it comes to that.

By the way, look like a trip to MI is in the works for this weekend. Love last minute stuff - but anyways, might be going past you Saturday or Sunday, or both. Just FYI.

[hauen]

you had to "unload" the power train by letting off the go pedal, then pull the cable to engage the OD, and then pour on the coal again. I don't remember if you were supposed to push the clutch in to engage or not

nope, no clutching shenanigans. There should be a switch on the floorboard under the accelerator pedal too so the overdrive kicks out at WOT.

[squirrel]

It was a pretty well automated system on the old BW overdrives, but when it went wrong, people "fixed" them creatively