Carb 2.9

[rusty ol ranger]

I have no idea. I have never actually worked on a 2.8.

I was reading about carb 2.9s on a Sunbeam forum a while back, and someone actually did manage to get a 2.9 running with 2.8 intake and carb and such, but the end result was reportedly terrible. All the bolt holes and coolant jackets lined up, but the intake runners didn't line up with the ports at the heads correctly, and so it had massive vacuum leaks, no power, and sucked down fuel. Reportedly while the engine did run it has worse power and fuel economy than either engine in stock form and the idea was quickly abandoned.

I was always under the assumption a 2.8 intake wouldnt even bolt to a 2.9. Ive never really screwed with a 2.8 either.

P.S. I have an idea, from the way my 2.9 ran with the fuel injection, I bet it would accept a small 600 cfm holley with no problem. It would be one of my experiments if I ever got this idea started. If a stock crappy 302 with 140hp factory will wake up with a 4 barrel intake and a little holley 600, I would think a 2.9 high winding v6 that made 140hp stock could benefit also from the same carb. I can tell you having owned a 2.9, and now driving a 2.8, there is no comparison, the 2.9 cologne will run circles around a 2.8 cologne.

No way id put a 600 CFM on a 2.9. a Holley 390 would be about the largest id go.

You gotta think, the factory V8 2bbls (motorcraft 2150s) even on the 400 were only pulling 335CFM max.

A 600 on a stock 2.9 would probably run like shit unless you did some serious internal work.

 

[franklin2]

I am just talking here now with no actual facts to back it up, but I am betting the front 2 barrels on a holley 600 flow less cfm than the 2 barrels on a 2150. If the 2.9 did not need the rear barrels on a 600cfm vac secondary carb, then it would never open the rear barrels up. Not ideal I agree, but I don't think it would be the disaster that you would think it would be.

 

[rusty ol ranger]

I am just talking here now with no actual facts to back it up, but I am betting the front 2 barrels on a holley 600 flow less cfm than the 2 barrels on a 2150. If the 2.9 did not need the rear barrels on a 600cfm vac secondary carb, then it would never open the rear barrels up. Not ideal I agree, but I don't think it would be the disaster that you would think it would be.

Holleys arnt run the same in both sets of barrels right? I cant remember im an edelbrock guy.

Either way, a 600 CFM with equal bore sizing would run 300CFM off the first 2 barrels. Which is why i suggested a 390 Holley cause its stupid to have a 4bbl and only run 2 bbls.

 

[adsm08]

its stupid to have a 4bbl and only run 2 bbls.

Not always.

When I had my 78 Olds with a 3.8 I thought about putting a 4 bbl on it. I sat in traffic a lot and I wanted the smaller primaries.

 

[8thTon]

Make an adapter on the stock manifold that replaces the throttle body and mount a side draft Weber on it. Fuel distribution might be crap but it would probably run pretty good.

 

[1987ranger12394]

What about using the fuel injection "carburetors" they offer for you to swap over to fi in older trucks. With the carborated manifold and the fi "carb" you get the simple clean look and install with the benefit of fi and fuel monitoring

 

[rusty ol ranger]

What about using the fuel injection "carburetors" they offer for you to swap over to fi in older trucks. With the carborated manifold and the fi "carb" you get the simple clean look and install with the benefit of fi and fuel monitoring

You mean this?

Holley's "sniper" EFI?

I have zero experence with it.

Im not an EFI fan, i think a carb would do just fine on a 2.9 as long as you properly size it. Why dont you post over on the 2.8 board and/or do some googleing to see what guys are running for performance on those then that'll give you an idea of the right carb size for a 2.9.

My gut just tells me a 600 would be way to much for a 2.9. With the secondaries disabled youre basically running a 2bbl and you might as well save yourself some money, get a 2bbl adaptor and just run a 2150 motorcraft that even in its largest iteration (on 351M/400s) pulled 335CFM.

I think most of them on 289s/302s ran around 300CFM with the smalled 1.08 venturi.

 

[franklin2]

View attachment 38188

You mean this?

Holley's "sniper" EFI?

I have zero experence with it.

Im not an EFI fan, i think a carb would do just fine on a 2.9 as long as you properly size it. Why dont you post over on the 2.8 board and/or do some googleing to see what guys are running for performance on those then that'll give you an idea of the right carb size for a 2.9.

My gut just tells me a 600 would be way to much for a 2.9. With the secondaries disabled youre basically running a 2bbl and you might as well save yourself some money, get a 2bbl adaptor and just run a 2150 motorcraft that even in its largest iteration (on 351M/400s) pulled 335CFM.

I think most of them on 289s/302s ran around 300CFM with the smalled 1.08 venturi.

Secondaries would not be disabled. A vacuum secondary carb is sort of a "self sizing" carb, it only gives the engine what it needs or can use, if the engine doesn't need or can't use the secondaries, they will not open up. Of course this is all adjustable with different springs and such.

I am contemplating this, #1 because the 390cfm carb is so expensive compared to the 600cfm, which I happen to have several of already. That and the fact that when discussing the 2.8 carbs, that some people are having success with the larger 2150's made for v8's on their engines. I am thinking if anything is going to be too large or off, it's going to be the idle air bleeds and stuff like that which is a little bit difficult to change out and modify.

I would love to try one of those aftermarket fuel injection systems. I am sure they would work, they even have them that run the factory 8 injectors for LS conversions and such. There must be a way to make one of those run a v6 engine with 6 injectors, so no need to modify the intake at all, just keep the 6 injector system. What would you have with this? A tuneable injection system that you can actually troubleshoot and communicate with unlike the EECIV. What's the problem with this? The money problem rares it's head up again.

If I go the MSD route, I am going to have to save up for a little while, that unit being close to $400 refurbished is still a lot of money for me.

And one final note; I don't like comparing the 2.8 to the 2.9 as far as fuel requirements. I can't believe the power difference between the two engines. The 2.8 is pretty sick compared to the 2.9. I have never had or driven a 4.0 for comparison to it.

 

[Paulos]

@franklin2
Check out this YouTube video on the 4-barrel sniper. It looks like you could select either 4, 6, or 8 cylinders and displacement during the setup.

 

[rusty ol ranger]

The 2.8 is pretty sick compared to the 2.9. I have never had or driven a 4.0 for comparison to it.

Ill catch hell for this but the OHV 4.0 IMO doesnt feel nearly as strong as it should compared to a 2.9.

The SOHC seems to feel good, but truthfully the 4.0 OHV's ive driven while faster and more torquey then a 2.9, just still feel disappointing given the extra displacement.

 

[Snoranger]

Ill catch hell for this but the OHV 4.0 IMO doesnt feel nearly as strong as it should compared to a 2.9.

The SOHC seems to feel good, but truthfully the 4.0 OHV's ive driven while faster and more torquey then a 2.9, just still feel disappointing given the extra displacement.

I was talking to PetroliumJunkie yesterday about power differences between the 2.9l, OHV, and SOHC...
I was saying that I’d rather have a OHV then a SOHC. There’s not enough difference to have all those timing chains. But the 50 lb-ft of torque between the 2.9l and the 4.0L OHV is noticeable.

 

[adsm08]

Ill catch hell for this but the OHV 4.0 IMO doesnt feel nearly as strong as it should compared to a 2.9.

The SOHC seems to feel good, but truthfully the 4.0 OHV's ive driven while faster and more torquey then a 2.9, just still feel disappointing given the extra displacement.

Yes and no. It largely depends on your driving style. From day one, when I was 15, I could not stand the noises that the 2.9 and the FM145 were making when I'd wind the gears out into the peak of the 2.9's power band. It just sounded strained like something was going to break, so I shift the 2.9 way too early, and I loose a lot of it's potential. I know I'm doing it, but I can't bring myself to do it differently.

On the other hand the 4.0's torque curve peaks very low in the RPM band, and so the engine isn't as rev happy, and I can get enough power to keep a load moving in 4th gear through curves and small hills without going past 2K RPM and having her screaming like a demon.

Now the HIPO 2.9 I had did love to be cracked wide open though. If I'd been able to find why it was running so poorly I might not have swapped it, but I found the issue while working the wiring for the 4.0.

 

[rusty ol ranger]

Yes and no. It largely depends on your driving style. From day one, when I was 15, I could not stand the noises that the 2.9 and the FM145 were making when I'd wind the gears out into the peak of the 2.9's power band. It just sounded strained like something was going to break, so I shift the 2.9 way too early, and I loose a lot of it's potential. I know I'm doing it, but I can't bring myself to do it differently.

On the other hand the 4.0's torque curve peaks very low in the RPM band, and so the engine isn't as rev happy, and I can get enough power to keep a load moving in 4th gear through curves and small hills without going past 2K RPM and having her screaming like a demon.

Now the HIPO 2.9 I had did love to be cracked wide open though. If I'd been able to find why it was running so poorly I might not have swapped it, but I found the issue while working the wiring for the 4.0.

Ive never had an issue with power anywhere in the 2.9s powerband. I dont have a tach but i doubt mine ever goes much over 3000 even if im taking off with a decent load.

The 4.0 is more powerful, and ive never towed with an OHV one and maybe thats where they shine, but empty vs empty in a stomp the pedal bash, they just dont feel as good as one would think based on how the 2.9 feels.

 

[rusty ol ranger]

I was talking to PetroliumJunkie yesterday about power differences between the 2.9l, OHV, and SOHC...
I was saying that I’d rather have a OHV then a SOHC. There’s not enough difference to have all those timing chains. But the 50 lb-ft of torque between the 2.9l and the 4.0L OHV is noticeable.

Once again im not saying the 4.0 OHV isnt more powerful, just not as much more powerful as someone would expect given 1.1L more of displacement.

If the OHV 4.0 was as good as the 2.9 inch per inch it would be making 193HP and 234ftlbs.

Thats what im getting at. The SOHC 4.0 is more on par with "this is what the OHV shoulda been".

 

[adsm08]

Ive never had an issue with power anywhere in the 2.9s powerband. I dont have a tach but i doubt mine ever goes much over 3000 even if im taking off with a decent load.

The 4.0 is more powerful, and ive never towed with an OHV one and maybe thats where they shine, but empty vs empty in a stomp the pedal bash, they just dont feel as good as one would think based on how the 2.9 feels.

I agree that unloaded a 2.9 will scoot much quicker and freer than a 4.0

Towing truly is where the 4.0 shines. I have hauled off loads big enough to break my clutch disc with the 4.0. Engine didn't mind it one bit, but I doubt a 2.9 would have gotten that trailer rolling in a few spots I had to stop.

While it's not in the works this minute, one day I want to port polish and supercharge the truck.