TBi conversion on 3F - need more info

[Yspen]

Here in Africa we never saw the 3F-E .
We were given the 3F , and the EFI only reached out shores in the form of the 4500Efi in the 100 series .

I have done some searching and see the TBi conversion done to the F and 2F in the US using GM 4,3 V6 throttle body , harness and ecu.
It seems like a straight forward , easy conversion and certainly would be less expensive than converting the 3F to 3F-E using imported Toyota parts. ( or not ?)

a few questions :
1. Will the adaptor plate made by Downey for the 2F intake manifold also fit the 3F intake manifold ?
2. Are there any pitfalls to look out for ?
3. Is the components for the conversion easy to source in the US ( I have a friend who lives there and can ask him to try and get it for me if no hassle )
4. Where is the best place to get a kit ( I see a place TurboCity has a kit but very expensive )
5 . I have regeared the diffs to 4,56 - making the speed pickup over read . The kit has a speed sensor that will now see the wrong speed - is that an issue ?

We do not have emissions control here . I just some more performance and economy but not lose reliability during the "into darker Africa" excursions .

 

[Trollhole]

I'm pretty sure the carb bolt spacing is the same between manifolds.

Question on switching to 3fe would be. Does the 3f head have the cutouts for the injectors? If not then shipping a 3fe head would be quite expensive.

You could probably source the ECU and TBI in SA and save some money on shipping. Most TBI people will just want to know what ECU and TBI you have so they can sell you the right chip.

Problem I see is displacement of a 3f over a 2f. I don't know how different the programming would be. Something tells me it could get expensive shipping chips back and forth.

I'd make sure whoever you deal with understands the logistical issue and is willing to work with you.

Downey is a good company. I'd give Jim a call and talk with him. I know some others also.

 

[Bryan062087]

I do not think the 3f head can be fitted with injectors. But I could be wrong.

It may be easier to get a 3fe head from someone from the US with all the EFI equipment and install that. Not sure about the money side of it. I've heard that you can get 3f Carb heads in the US pretty cheap through various sources- sor and the cruiser place in Atlanta, GA (forget the name). But not sure about the other way around. Maybe some die hard carb fans will offer up their 3fe head and swap with you for a carb'd one for the simplicity and lack of electronics. Something that I'm interested in myself.

Here's a good thread comparing the 3f head and the 3fe head. https://forum.ih8mud.com/60-series-wagons/143089-3fe-vs-2-3f-carb-cyl-head.html


I really do not know anything about the chevy TBI set up, that may be a good route to go as well.. (or better)

 

[Downey]

Yspen, here's some info for you:
(a) I don't know if the Downey adapter will fit a 3F intake manifold or not, but I highly suspect it will since your engine is probably very similar to our 2F, carburetion wise.
(b) Regarding pitfalls, the only problems I can think of are encountered when customers use partial kits, or try to cut corners to save $$$$$.
(c) Regarding sources for obtaining an EFI conversion kit, the USA sources range from less expensive "partial" kits, to our mid-priced kit, to expensive kits that include new or used GM parts. It is probably best to check out each source.
(d) Regarding sourcing GM parts (throttle body,computor,harness), we still have you pick up those parts used from a wrecking yard. We can do this for the time being because they are (1) available, (2) inexpensive, (3) dependable. Five or ten years from now that probably will not be the case, at which time we will offer more expensive NEW parts. Your USA friend should have no problem whatsoever obtaining used parts from a USA wrecking yard for you.
(e) Regarding Vehicle Speed Sensor, you will find that the VSS signal for the computor will not be sensitive to deviations in tire size and gear ratio. This would only be a problem if you were running an electronic speedometer or electronically shifted automatic transmission. If you are absolutely determined to have a correct signal, you can always use our Frequency Module, but I really don't think you need it.
If I can answer anymore questions, just ask!!!

 

[Trollhole]

Yspen, here's some info for you:
(a) I don't know if the Downey adapter will fit a 3F intake manifold or not, but I highly suspect it will since your engine is probably very similar to our 2F, carburetion wise.
(b) Regarding pitfalls, the only problems I can think of are encountered when customers use partial kits, or try to cut corners to save $$$$$.
(c) Regarding sources for obtaining an EFI conversion kit, the USA sources range from less expensive "partial" kits, to our mid-priced kit, to expensive kits that include new or used GM parts. It is probably best to check out each source.
(d) Regarding sourcing GM parts (throttle body,computor,harness), we still have you pick up those parts used from a wrecking yard. We can do this for the time being because they are (1) available, (2) inexpensive, (3) dependable. Five or ten years from now that probably will not be the case, at which time we will offer more expensive NEW parts. Your USA friend should have no problem whatsoever obtaining used parts from a USA wrecking yard for you.
(e) Regarding Vehicle Speed Sensor, you will find that the VSS signal for the computor will not be sensitive to deviations in tire size and gear ratio. This would only be a problem if you were running an electronic speedometer or electronically shifted automatic transmission. If you are absolutely determined to have a correct signal, you can always use our Frequency Module, but I really don't think you need it.
If I can answer anymore questions, just ask!!!

Hey Jim will 3f displacement cause an issue with stock 2f tbi programming?

 

[Yspen]

I checked today : the inlet manifolds are the same in the 3F and 2F . ( according to my Land Cruiser specialist mechanic - and he knows his stuff )

No GM parts available in South Africa at all so I will have to import the lot .

Re the chipping - I'm sure that can be done here . But the TBi type engines are very much a rarity here. I'm really glad you regard GM stuff as dependable - in Africa it is an issue ( that is why we stick with Cruisers )

I will have to stick with a reliable source of parts and installation instructions - being so far away . Seems Downey has a new customer .

 

[Yspen]

I found a company here who imports products from HOLLEY . They claim they deal with Downey as well .

How does the Holley TBi universal kit - Holley Performance Commander 950 and Pro–Jection TBI Service Parts Products - compare with the GM setup ? ( using a Downey adapter)

 

[Yspen]

I already have an Petronix electronic ignition in my distributor and a upgraded coil - do I still have to get a new HEI distributor ?

 

[ntsqd]

My experience with the Holley EFI bits is in the early stuff. I would sooner go with the GM parts. Even though they may look the same, they are not the same.
Only advantage to the Holley is that it is user programmable. In one stroke that is both good and bad.

GM TBI's are not exceptionally smart. If you are close to the original engine's configuration then it'll be happy. If you stray too far away you're in the land of needing chips burnt. Search Colorado K5 and one of the GM F-body devoted forums for further info on this and ways to trick the ECU into behaving if the config is at the outer range of what the ECU can handle.

 

[Yspen]

Thanks ntsqd .
I'm not looking for smart - but reliable, so it seems GM is the way to go .

Can anybody answer this : will 3f displacement cause an issue with stock 2f tbi programming?

 

[Yspen]

adaptors

Picture of 3F with Aisin Carb

From the side of the carb

As you can see the throttle cable comes from the right side of the car as it is right hand drive version ,

Thus it seems the Downey adapter will be a better option as it will accommodate the cable better .

But it seems that the Dwoney adapter is higher than other brands that is milled from aluminum - will the air cleaner have enough clearance above ?

 

[ntsqd]

I figured that reliability was of highest importance, but thought that you should also know about the sources for the work-arounds for the potential pitfalls.

The throttle body on the 4.3 is very similar to the TB's used on the 5.0's, 5.7's, and 7.4's. They should all have the same mount flange to filter can gasket surface height, which was designed to fit where a Rochester QuadraJet carb fits. Holley 4 barrels have a similar such dimension. Does either of those carbs exist there? A quick measurement would give you a rough idea. From the looks of the carb in the above picture it should be considerably shorter.

Wow! I went looking for the third gen site and found it. Some of the info there on hot rodding is woefully wrong, but the EFI guys on cK5 used their ECU/programming info as a bible. A primer on programming the EPROM's can be found here: Programming PROMs for your Thirdgen Fuel Injected F-Body: Part I - ThirdGen.org

 

[Yspen]

A throttle body injection (single-point, SP) uses one (or more) injector at a central point before the gas is getting to the cylinders via the inlet manifold. A multipoint (MP) injection system uses one injector per cylinder; the injector is located at the end of the inlet manifold or the head.

The prime difference between the two systems is:

The SP system has a small hesitation between gear changes. This is the result of the manifold going "dry" when the throttle is taken back. This hesitation can be eliminated with a "throttle damper": A device which doesn't allow the throttle to close completely during gear changes.

Has anyone who fitted a TBi experienced the hesitation in the gearchanges that is mentioned ?

 

[ntsqd]

Only TBI that I've driven was an auto trans. I can't see how driving a manual behind one would be much different, in this regard, than driving a carb.

 

[Mace]

That hesitation is a non issue. You will never notice it.

 

[lehiguy]

I figured that reliability was of highest importance, but thought that you should also know about the sources for the work-arounds for the potential pitfalls.

The throttle body on the 4.3 is very similar to the TB's used on the 5.0's, 5.7's, and 7.4's. They should all have the same mount flange to filter can gasket surface height, which was designed to fit where a Rochester QuadraJet carb fits. Holley 4 barrels have a similar such dimension. Does either of those carbs exist there? A quick measurement would give you a rough idea. From the looks of the carb in the above picture it should be considerably shorter.

Wow! I went looking for the third gen site and found it. Some of the info there on hot rodding is woefully wrong, but the EFI guys on cK5 used their ECU/programming info as a bible. A primer on programming the EPROM's can be found here: Programming PROMs for your Thirdgen Fuel Injected F-Body: Part I - ThirdGen.org

Just a couple of corrections here. The throttle body assembly is identical from the 4.3, the 5.0 and the 5.7 but the injector flow rates are different. They are all 42mm throttle valves that flow 450 CFM. (good for 4.3 liters, lame for 5.7) The mounting pattern is entirely different from any other thing ever made, it uses three bolts, not four.

 

[ntsqd]

Sorry if I mislead, I was trying to say that the TBI bodies have the same mount flange to air cleaner flange height as the carbs, not that they mount the same as the carbs.
I suspected that the injector flow rates were different, but didn't know that the TB flow rates are the same. Ick!

 

[lehiguy]

Sorry if I mislead, I was trying to say that the TBI bodies have the same mount flange to air cleaner flange height as the carbs, not that they mount the same as the carbs.
I suspected that the injector flow rates were different, but didn't know that the TB flow rates are the same. Ick!

They need help, that's for sure. I am about 3/4 done installing a TBI setup on my otherwise KILLER running 350. (I had it bored out to 47mm which flows 600 CFM.) Obviously I had a custom E-prom made for the computer and I made my own adapter plate being the consumate skin flint. All in all it has gone extremly well, looking forward to driving it later this week. It will be interesting!

 

[WyattEarp1789]

Here in Africa we never saw the 3F-E .
We were given the 3F , and the EFI only reached out shores in the form of the 4500Efi in the 100 series .

I have done some searching and see the TBi conversion done to the F and 2F in the US using GM 4,3 V6 throttle body , harness and ecu.
It seems like a straight forward , easy conversion and certainly would be less expensive than converting the 3F to 3F-E using imported Toyota parts. ( or not ?)

a few questions :
1. Will the adaptor plate made by Downey for the 2F intake manifold also fit the 3F intake manifold ?
2. Are there any pitfalls to look out for ?
3. Is the components for the conversion easy to source in the US ( I have a friend who lives there and can ask him to try and get it for me if no hassle )
4. Where is the best place to get a kit ( I see a place TurboCity has a kit but very expensive )
5 . I have regeared the diffs to 4,56 - making the speed pickup over read . The kit has a speed sensor that will now see the wrong speed - is that an issue ?

We do not have emissions control here . I just some more performance and economy but not lose reliability during the "into darker Africa" excursions .

How did this turn out for you? I am looking at the same issue. I have an '89 3F and am in the midst of restoring the entire car. So I am wondering which direction to go myself.