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TBI setup on a B18/B20

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spock345

Well-known member
Joined
Nov 3, 2016
Location
Livermore, CA
I am curious. Has anyone rigged up one of those newer TBI units to their B20 or B18? Seems like a two barrel one would fit on a weber manifold.

I will be sticking with carbs for now while I try to sort out my beaten up SUs but thought I would ask.
 
I'm actually very curious about this myself.

I'm not sure which throttle body you're referring to, but the retroject 38/38 comes to mind.

ATB400_1_hr.jpg


They're not very cheap though, and I'd imagine an old K-jet/D-jet manifold would be better for actual EFI.

Does anyone have any opinions on TBI vs MPI in the case of the B18/B20s? I feel like the runners are short enough on most manifolds that it wouldn't matter between the two (except for having less injectors in a TBI setup), but I know next to nothing about EFI.
 
The Weber TBI looks promising and easy to install, until you realize that it is not a complete system. No fuel pump, no computer, no O2 sensor, no wiring.
Ive been looking at the Holley Stealth TBI which comes as a kit with nearly everything necessary. There are two 2BBL models, both seem to have the same specifications but different body configurations. You would need an adapter for certain and since the built-in computer is enclosed in the TBI body I would want a phenolic spacer to insulate it from the manifold.

https://www.holley.com/products/fue...l_master_kits_with_fuel_system/parts/550-849K

https://www.holley.com/products/fue..._2gc/sniper_efi_2gc_small_bore/parts/550-864K
 
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They came with multi port EFI from the factory that’s better in every way that guys in white lab coats figured out?

Late F Heads probably are the best flow potential of all the B20 heads anyway, D-jet barely sips fuel?

D-jet in an Amazon is pretty well documented on vclassics.
Fuel tank maybe could use a bucket/baffle in any case.
D-jet to MS is pretty well documented too?

Throw the D-jet dist trigger points, map granade, TPS etc in the trash.
Install Standalone electronic idle control from k-jet car, Dist od your choice, profit and profit again?
 
Megasquirt owner here. I was averaging 31mpg hwy with a somewhat conservative tune and V70xc brown injectors (335 cc/min IIRC), now its running 950cc Siemens Deka's from Yoshifab, along with full sequential ignition and injection, and starting the fine tuning, but I was still getting 27-29 if I could keep my foot out of it.

F head, k-jet injector holders, custom fuel rail, aftermarket FPR, megasquirt 2, modified 850 tps, 2L surge tank with 40 gph lift pump and a 255lph high pressure pump, -6AN EFI fuel lines, and last I checked I was all in at like $1k for everything as is now with the upgrades.
 
In previous posts I’ve been trying to add fuel injection without an E or F head. I tried several things and this is what I came up with. I know that the injectors aren?’t at a ?“proper?” angle. If I had more than a drill press and a bandsaw with a metal cutting blade I could have gotten fancier.
The set-up works reasonably well, though my tuning skills are non existent. I can switch between FI and carbs in about 15 minutes.

X0Kb55n.jpg


yl3Gldi.jpg
 
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In previous posts I’ve been trying to add fuel injection without an E or F head. I tried several things and this is what I came up with. I know that the injectors aren’t at a “proper” angle. If I had more than a drill press and a bandsaw with a metal cutting blade I could have gotten fancier.
The set-up works reasonably well, though my tuning skills are non existent. I can switch between FI and carbs in about 15 minutes.

X0Kb55n.jpg


yl3Gldi.jpg

Thats awesome! I had run my megasquirt with the 335cc browns in the head, and the SU's on the manifold. For a while I left the lines for the SU's all attached up to the firewall just in case..

I think that even though your angle isnt the best, it should run just as well as the SU's did.
 
I've got a beautiful GM/Rochester 2BBL TBI from a 4.3l Chevy we took off of the Jeep when we went Redblock that I will make a hella deal on.
New FPR, cleaned and flowed injectors, could be just what you need!
 

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I've got a beautiful GM/Rochester 2BBL TBI from a 4.3l Chevy we took off of the Jeep when we went Redblock that I will make a hella deal on.
New FPR, cleaned and flowed injectors, could be just what you need!

I am sitting here with a B18 so stuff like this has my interest. That and cwdodson's setup are creative and unique. I like it. There is a thread I read where someone put GM TBI on a Mercedes 220 motor which caught my interest.

I am guessing the SUs are just there to be throttle bodies. Even with the carb bodies still there it is a very clean setup.

If I had an F head and a B20 I would be looking at D-jet. I also like hacking on electronics. The analog D-jet system has a level of elegance that you don't get in this era of micro-controllers.

Does D-jet need a fuel return line? I would assume it does. I am not sure how I would hook one up to the stock amazon fuel tank.
 
I am not sure how I would hook one up to the stock amazon fuel tank.

There are probably a couple of different ways. On the estate there's a nice long pipe connecting the filler neck to the tank that something like this will fit into.
<a href="https://ibb.co/RSKy167"><img src="https://i.ibb.co/RSKy167/IMG-20190513-144334.jpg" alt="IMG-20190513-144334" border="0"></a>
 
There are probably a couple of different ways. On the estate there's a nice long pipe connecting the filler neck to the tank that something like this will fit into.
<a href="https://ibb.co/RSKy167"><img src="https://i.ibb.co/RSKy167/IMG-20190513-144334.jpg" alt="IMG-20190513-144334" border="0"></a>

The sedan is much shorter on the fill tube side.

I used a "Bulkhead" style hose fitting for my return. Drilled an appropriate size hole in the fuel level sender. So far, no leaks, and it also makes for easy tank draining.
 
rigged up one of those newer TBI units to their B20 or B18?

With a carburetor or TBI setup, the intake manifold must have enough heat to prevent icing internally. Volvo's PV544 manifold had intake/exhaust sides "bonded" together (B18D SUs), so exhaust heat warmed up intake side.

Looking at the "Weber" DGV intake manifold for Volvo B18/B20, I don't know if icing happens in colder environments. Years ago, I recall a person with an aftermarket intake manifold having this icing issue in a PV544.

Pilot's tip of the week...Carb Ice In Summer?
It is possible for the temperature drop in the carburetor to be as much as 70 degrees Fahrenheit, meaning that ice could form on a day where the ambient temperature could be as much as 100 degrees Fahrenheit. However, carburetor ice is most likely to form when temperatures are below 70 degrees Fahrenheit and the relative humidity is more than 80%

Using a Weber Retroject 38/38 downdraft Throttle Body is a nice idea, but icing would be a topic to consider.
 
I never saw icing as an issue with GM or Ford TBI. Neither had a stove hose. The ice changes the shape of a carb venturi, making it more sensitive, and run rich. I would think it would take a huge chunk of ice to change the airflow enough for a TBI to go rich. Not saying it never happened, but I never saw it.
Around here the majority of icing was caused on cool, foggy days. The fog was turning to ice, and I would use a coolant test bulb to suck hot coolant out of the radiator, then put drops on the venturis to melt the (water) ice on the venturis. This was a small base Rochester 2-jet cobbled onto a 73 Corolla 2TC.
I did a search and found some old F-Body guys arguing that the fuel was turning to ice. That hurts my head.
Some early EFI (ford, nissan) had small coolant hoses attached to the throttle body to stop the discs from sticking, though. YMMV.
 
Wiki - Carburetor icing

2000 Saturn LS - There is a technical service bulletin (TSB) on the V6 engine dealing with throttle icing upon start up in cold weather. The cause is water droplets that condense out of the vapors carried from the crankcase to the throttle body by the PCV system. These can then freeze at the bottom of the throttle plate causing it to stick. The TSB describes a fix where the pcv vapors are re-routed to the intake manifold after the throttle body.
 
With a carburetor or TBI setup, the intake manifold must have enough heat to prevent icing internally. Volvo's PV544 manifold had intake/exhaust sides "bonded" together (B18D SUs), so exhaust heat warmed up intake side.

Looking at the "Weber" DGV intake manifold for Volvo B18/B20, I don't know if icing happens in colder environments. Years ago, I recall a person with an aftermarket intake manifold having this icing issue in a PV544.

Pilot's tip of the week...Carb Ice In Summer?
It is possible for the temperature drop in the carburetor to be as much as 70 degrees Fahrenheit, meaning that ice could form on a day where the ambient temperature could be as much as 100 degrees Fahrenheit. However, carburetor ice is most likely to form when temperatures are below 70 degrees Fahrenheit and the relative humidity is more than 80%

Using a Weber Retroject 38/38 downdraft Throttle Body is a nice idea, but icing would be a topic to consider.
Icing wouldn't be an issue with the B18/20 downdraft manifolds. You are supposed to route coolant through a channel on the underside of the manifold. That warms up the bottom of the thing. The downside I noticed is that it makes them a bit more susceptible to heat soak. A spacer block turned out to be the solution for that.
 
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