TBI Fuel Injection

-

Money Pit

Well-Known Member
Joined
Nov 13, 2017
Messages
153
Reaction score
8
Location
Pasadena CA
Can anyone recommend a TBI injection system. I was going to convert to a 4 barrel carb but decided to go fo fuel injection for reliability. I have a 70 225, stock. Will I need to change to a larger fuel line to the tank and get a new fuel pick up? Thanks
 
You won't need a larger line for a slant, but you will need something for a return line. You cannot use the 1/4" vapor line for a couple of reasons.......it's too small and IT IS THE VENT for the tank. You MUST keep it open, if you remove the evap vapor emissions controls

You can buy aftermarket senders with a second line. If you can fab, you could pull the filler tube out and weld/ braze a fitting into it.

I lean towards Holley. Megasquirt is something you might check out if you DIY a lot. Many people seem to like EFI tech, there are others
 
You won't need a larger line for a slant, but you will need something for a return line. You cannot use the 1/4" vapor line for a couple of reasons.......it's too small and IT IS THE VENT for the tank. You MUST keep it open, if you remove the evap vapor emissions controls

You can buy aftermarket senders with a second line. If you can fab, you could pull the filler tube out and weld/ braze a fitting into it.

I lean towards Holley. Megasquirt is something you might check out if you DIY a lot. Many people seem to like EFI tech, there are others
I think Classic Industries has a return line that fits between the filler neck and the tank. I'll look into the holley system. Thanks
 
look for an old Holley Pro-jection. I saw one for $100 at a swap meet, didnt buy it. Its all analog, little dials on the 'box' for idle, enrichment and a few other things. You can buy Mopar senders with return lines in them now on E-bag.
 
The Holley Sniper units are really nice. I have been studying up on them, because I think I am going to use one on one of my projects.
 
The Holley Sniper units are really nice. I have been studying up on them, because I think I am going to use one on one of my projects.
I'm waiting for the new FiTech 2 bbl system designed for between 150 and 400 hp applications, perfect for our slants! They should be available at the end of March. I will be running this on an M1 2 bbl intake with Dutra Duals with upgraded ignition. FiTech's Fuel supply kit (#4005) does recommend a 3/8" diameter pickup in the tank and they supply a return line as well NOT to be tied into the vent line. Should be a nice reliable system.
 
"2 bbl FiTech?!" Damn, I should have waited!

I installed a FiTech last month (slant 6). New offy 4 barrel intake. (Maybe wouldn't have needed that if they had the 2-barrel available!)

Return line: FiTech does not require one for my application, but I remember 90's TBFI cars would get vapor-lock issues! (I drove one with that vapor lock issue.) So I decided return-line was the way to go. I re-purposed the existing hard fuel line (5/16") and added a "3/8" (-6 flex-line zip-tied to the hard-line) feeder fuel line (unregulated). The FiTech instructions said I needed a 3/8" fuel line but I could use the 5/16 for the return. (WAY WAY overkill since I'll never flow that much fuel, but whatever, I was adding a fuel line either way.) One of the things I liked about the FiTech is that it will intelligently control the fuel pump speed. (Not sure about other brands.) I went with an in-tank fuel pump... allot of extra work. And the in-tank FiTech kit does not come with the fuel line, so that's a bit of a hidden extra cost versus the most basic kit. The most basic (least expensive) kit has an in-line fuel pump but in-line pumps must be mounted BELOW the fuel tank! I didn't want that thing being the lowest thing hanging under the car. The easiest option would be their fuel command center, but it's big and goes inside of the engine compartment.

The tech support guys were good and always answered the phone. The Holley rep I talked to said FiTech was known for not having support after the sale. Not my experience.

Oh, and this might apply to other brands, I had to install a bigger (3/8"? NTP?) "GM-style" water-temp sensor. This requires drilling and tapping a bigger thread into your head. I didn't like that. It might be possible to find a water-temp sensor that will screw right in the existing hole (1/4" NTP?). Anyway I found a water-temp sensor online that had specs that 'looked about right' but then when got it I did some resistance measurements. It was not as closely matched to the FiTech sensor that came with the kit, so I chickened out since I want the thing to work right the first time.

The Oxygen sensor hose-clamps that come with seemed way too whimpy so I found some good heavy-duty stainless-steal clamps on Amazon. (Eventually I plan to just weld the bung onto the exhaust.... but I figured I can do that later.)

Idles like a dream... I haven't had it on the road yet since it's been too sloppy (Minnesota). I'm hoping to take it for a maiden-voyage spin this weekend if the weather cooperates.

O-rings: the in-tank fuel pump has a built-in regulator and comes with a plug to swap out if you use the return-line configuration, as I did. (Again, you don't *need* a return-line for my application.) Anyway, the plug had pre-installed o-rings that were just wrong. I swapped those with those that came on the regulator that I was removing. Now it's fine. Though that was 'sloppy' of them to ship it that way. It would have been better to ship the plug with no o-rings so one would naturally grab the ones from the unused regulator...
 
I'm waiting for the new FiTech 2 bbl system designed for between 150 and 400 hp applications, perfect for our slants! They should be available at the end of March. I will be running this on an M1 2 bbl intake with Dutra Duals with upgraded ignition. FiTech's Fuel supply kit (#4005) does recommend a 3/8" diameter pickup in the tank and they supply a return line as well NOT to be tied into the vent line. Should be a nice reliable system.

The Holley Sniper 2300 is already out.

EFI 2300 Two-Barrel Fuel Injection Systems 550-849K
 

I considered that one. Very tempting! Since I'm a bit of an electronics hacker. The show-stopper for me was that, after talking with Holley tech-support, I learned that the only access to the data logs was through their proprietary windows-based software. Since I don't run Windows (I'm a Linux guy) and since proprietary windows software implies (sometimes frequent) upgrades (as compared to standard ASCII text file formats that allow me to use other software or even write my own) the Holley software usage model *might* annoy me. The last thing in the world I want is to have to perform software upgrades to continue to use a stand-alone piece of electronics that I purchased.

That said, for all I know the Holley software is wonderful and never needs upgrades! Does anyone have any experience with it? It looks cool. And can one dump data from the Holley proprietary software into a simple ascii file format (CVS, for example.) for analysis using 3rd party software?
 
I'm waiting for the new FiTech 2 bbl system designed for between 150 and 400 hp applications, perfect for our slants! They should be available at the end of March. I will be running this on an M1 2 bbl intake with Dutra Duals with upgraded ignition. FiTech's Fuel supply kit (#4005) does recommend a 3/8" diameter pickup in the tank and they supply a return line as well NOT to be tied into the vent line. Should be a nice reliable system.
I'm not familiar with the M1 intake manifold. I'm new to slant six's. Thanks. Great info.
 
"2 bbl FiTech?!" Damn, I should have waited!

I installed a FiTech last month (slant 6). New offy 4 barrel intake. (Maybe wouldn't have needed that if they had the 2-barrel available!)

Return line: FiTech does not require one for my application, but I remember 90's TBFI cars would get vapor-lock issues! (I drove one with that vapor lock issue.) So I decided return-line was the way to go. I re-purposed the existing hard fuel line (5/16") and added a "3/8" (-6 flex-line zip-tied to the hard-line) feeder fuel line (unregulated). The FiTech instructions said I needed a 3/8" fuel line but I could use the 5/16 for the return. (WAY WAY overkill since I'll never flow that much fuel, but whatever, I was adding a fuel line either way.) One of the things I liked about the FiTech is that it will intelligently control the fuel pump speed. (Not sure about other brands.) I went with an in-tank fuel pump... allot of extra work. And the in-tank FiTech kit does not come with the fuel line, so that's a bit of a hidden extra cost versus the most basic kit. The most basic (least expensive) kit has an in-line fuel pump but in-line pumps must be mounted BELOW the fuel tank! I didn't want that thing being the lowest thing hanging under the car. The easiest option would be their fuel command center, but it's big and goes inside of the engine compartment.

The tech support guys were good and always answered the phone. The Holley rep I talked to said FiTech was known for not having support after the sale. Not my experience.

Oh, and this might apply to other brands, I had to install a bigger (3/8"? NTP?) "GM-style" water-temp sensor. This requires drilling and tapping a bigger thread into your head. I didn't like that. It might be possible to find a water-temp sensor that will screw right in the existing hole (1/4" NTP?). Anyway I found a water-temp sensor online that had specs that 'looked about right' but then when got it I did some resistance measurements. It was not as closely matched to the FiTech sensor that came with the kit, so I chickened out since I want the thing to work right the first time.

The Oxygen sensor hose-clamps that come with seemed way too whimpy so I found some good heavy-duty stainless-steal clamps on Amazon. (Eventually I plan to just weld the bung onto the exhaust.... but I figured I can do that later.)

Idles like a dream... I haven't had it on the road yet since it's been too sloppy (Minnesota). I'm hoping to take it for a maiden-voyage spin this weekend if the weather cooperates.

O-rings: the in-tank fuel pump has a built-in regulator and comes with a plug to swap out if you use the return-line configuration, as I did. (Again, you don't *need* a return-line for my application.) Anyway, the plug had pre-installed o-rings that were just wrong. I swapped those with those that came on the regulator that I was removing. Now it's fine. Though that was 'sloppy' of them to ship it that way. It would have been better to ship the plug with no o-rings so one would naturally grab the ones from the unused regulator...
Sounds like you were really busy with this installation. It seem like this is a pretty complicated installation. I may wait to see if the two barrel version comes out soon and see what is involved in the installation. Thanks
 
The Holley Sniper 2300 is already out.

Yeahhhhhhh, maybe and maybe not such a hot idea. See here .

Also go head over to slantsix.org and pay attention to "Sandy in BC", who has a lot of experience and success retrofitting TBI using inexpensive, widely-available components. See here, here, here, here, etc.

(And in case you're thinking "Aha, I'll use the '88-'91 3.9 V6 parts!" — see this whole thread.)
 
I'm not familiar with the M1 intake manifold. I'm new to slant six's. Thanks. Great info.
The Mopar Performance M1 for the slant 6 was produced during the 80's & 90's. It's an aluminum 2 bbl intake much like the Super 6 and flows maybe 3 or 4 % better. They show up up on eBay, etc. These did not have the porosity problem as the 2 part 2 bbl aluminum intake had.
 
Yeahhhhhhh, maybe and maybe not such a hot idea. See here .

So according to YOU based on "twenty years ago" this is not a hot idea. Bullshit.

the Holley sniper stuff has a good following.

OP if you want cheap DIY wander over to "Binder Planet" which is a bunch of IHC (truck and Scout) guys who adapt old GM stuff to non EFI engines

"START HERE"--Fuel Injection FAQ--"START HERE"

Dan might be "surprised" to learn that Holley, just like any other tech bullshit including 8088 computers or anything else back then, has come a hell of a long way. The Sniper has a good following, and Holley makes a BUNCH of EFI stuff besides that. Biggest problem I have with the Holley HP/ Dominator computers is that they are not fixable. They are sealed in something resembling JB weld. This is not to say that most others ARE or that anybody WILL
 
Seeing a few vids on youtube of inlines running fitech units. And hear nothing but good things. There is a good thread on slantsix.org as someone is running it there. And now here!

I am all for tbi. A daily driver will see nothing but benefits
 
Cheapest might be a used Holley Commander 950, with the smallest fuel injectors that fit. Even better, get the ECU & harness alone and substitute Holley Pro-jection 2-D for the TB. The Pro-jection controller was poor, in its 3 variations. The original "by MSD" version had the most robust connectors. The designer of Big Stuff 3 originated it, then Holley took over. But not having a Pman sensor made it erratic. I think the last 4Di version was effectively the 950 design. They use GM TBI injectors (both early & late style). The Mopar Magnum V-6 TBI might be a better fit and cheaper, but will need to fab a custom adapter plate. All above need a 4-bbl intake manifold (Offenhauser or Clifford). I have most of the above for my 3 Mopars and bought one Commander 950 ECU for ~$50 on ebay.

But, MPFI would be much better on a straight six, since a TBI still has the fuel mal-distribution problem. For my slant, I am thinking of modding an aluminum intake for MPFI. One guy here (Pishta?) put MPFI holes in the head. Too bad Mopar didn't continue the slant into FI days, though the AMC 4.0L did (Jeeps).
 
But, MPFI would be much better on a straight six, since a TBI still has the fuel mal-distribution problem. For my slant, I am thinking of modding an aluminum intake for MPFI. One guy here (Pishta?) put MPFI holes in the head. ...

TBI on a slant? You can do better than that.....
20180302_212737 (1).jpg
20180302_212811.jpg


The injector wire loom is a hollow putter shaft. FORE!
 
No idea man.....its a journey for sure. Baby steps.....:rolleyes:
 
The fuel distribution issue is such a moot bs point for a street car. I dont drive with the car with my 1920 and think...."boy the fuel distribution issues are so bad"

Its usually. "Man this car runs smooth for being carbed" wish i had a tbi setup but im going through IVF with my wife and the money isnt necessary to spend.

The extra expense of a mpfi setup for a daily might be worth it to some. But if a tbi gets me to where i am now having a carb with better mileage and a bit more power. Im in !
 
But if a tbi gets me to where i am now having a carb with better mileage and a bit more power. Im in !


The TBI will excel in 1 area over the 1920/1945: All weather start up. A guy did a GM TBI retrofit on a slant and didnt gain anything (MPH/torque) except a easy to start slant! mind you there is little to tune on a stock GM unit but its not a bolt on +25% venture. MS/Holley/ETC will allow you to tweak many parameters and timing. I think the latter is the seat of the pants key to an improved conversion. Holley 1920 had great functionality, as it had a very small venturi and had very high velocity in the intake. Slap a 2bbl TBI with 2 1-3/8 or 1-13/16 non staged bores and your going to really drop velocity which carries the fuel in suspension. you may want to look into a 1bbl TBI off an 82-86 GM 2.0-2.4, as your looking for HP levels, not necessarily displacement. You can always adjust fuel pressure up to boost the injectors output to a point.

How to TBI - Slant Six Forum
 
Will I need to change to a larger fuel line to the tank and get a new fuel pick up? Thanks

you can run a surge tank: Feed a small tank with your stock pump/lines and run the HP pump off the bottom of this tank, run the return line back to the top of this tank. The fuel will just cycle through this tank and you dont have to upgrade your feed line but you will still need a return line to the supply tank unless you can rig up a float system in the surge tank inlet and a needle seat inlet valve. Benefits are there is no sump to uncover, and your high pressure fuel line is kept short, drawback is it is its in the engine bay and could be the size of a car battery once your done with it, but you were going to relocate your battery to the trunk anyway...right? :)
 
-
Back
Top