Intake distribution issues

[statsystems]

Single 4 with a BLP B4X carb.

1 and 3 are rich at a cruise.

5 and 7 are almost perfect.

2 is rich at a cruise.

4,6 and 8 are almost perfect.

Is it possible I'm not running enough emulsion? I have emulsion in 1 and 3 and the rest blank. I have .024 holes in them.

Or am I going to have to use some dams on the rich cylinders?

Thanks

[ZEOHSIX]

Mopar? The popscicle stick & epoxy fix is right in the engine manual.....

[statsystems]

Mopar? The popscicle stick & epoxy fix is right in the engine manual.....

Yes. Small block.

I did get out the manual but that show different cylinders. If 1,2 and 3 are rich do they get the dams?

The book shows a dam on 2 and 4. I'd hate to put them in and get it wrong.

[Tuner]

You might get it with the tiewrap on the booster trick. They don't need to be as large as this one, it was just what was available at the moment. The smallest tiewraps will have significant effect. Point it where you want the fuel to go. Like Robin Hood, it steals from the rich and gives to the lean.

Other pictures here. http://racingfuelsystems.myfunforum.org ... ut230.html

[cjperformance]

You might get it with the tiewrap on the booster trick. They don't need to be as large as this one, it was just what was available at the moment. The smallest tiewraps will have significant effect. Point it where you want the fuel to go. Like Robin Hood, it steals from the rich and gives to the lean.

Other pictures here. http://racingfuelsystems.myfunforum.org ... ut230.html

Yep , DIY booster tabs!

[steve cowan]

this is on of the coolest things i have seen
what a neat trick
thanks for sharing tuner
PS i really enjoy the fuel systems website some real good stuff

[mag2555]

Are these aftermarket heads (i.e.) no Exh crossover?

[statsystems]

Are these aftermarket heads (i.e.) no Exh crossover?

No, just ported cast iron production heads.

I have W-2's sitting there. I may just say screw it and do those up. After I try tuners ty wrap trick. I forgot about that.

[statsystems]

You might get it with the tiewrap on the booster trick. They don't need to be as large as this one, it was just what was available at the moment. The smallest tiewraps will have significant effect. Point it where you want the fuel to go. Like Robin Hood, it steals from the rich and gives to the lean.

Other pictures here. http://racingfuelsystems.myfunforum.org ... ut230.html

Thanks tuner. I'll look through the link you posted.

Do I use the tie wraps on the booster over the rich cylinders to force fuel all the way back to the back of the intake manifold? For example, put the tie wrap over the 1-3 cylinder booster and point it map towards 5-7? It will move fuel that far?

[DaveMcLain]

If it is doing it at cruise I doubt that messing with the booster will help much if at all. I think its mostly just because of the way the fuel comes out of the idle discharge and the transition slot. Most of the time it isn't atomized very well and depending on the intake it can dump right into a runner. Sometimes the addition of a carburetor spacer will really dramatically help a problem situation. I had this one time with a Dominator on a big Chevy in a jet boat. It was a very good carburetor with excellent part throttle drivability with a 1 inch spacer on the intake, take that off and it would get so rich on the front two cylinders that it would hardly run, wide open was fine. That was with a Dart intake.

[Warp Speed]

Yes, it is a combination of the idle/transfer circuits and the blade angle directing what fuel is coming from the boosters. The ty wrap trick will have little to NO effect.

[statsystems]

Well damn davemclain and warp speed.

Do you think I should try dams at the plenum end of the runner or just live with it? I'm not yet ready to test WOT yet.

What about a 1/2 shear plate? I can't go much thinker than that?

[DaveMcLain]

Well damn davemclain and warp speed.

Do you think I should try dams at the plenum end of the runner or just live with it? I'm not yet ready to test WOT yet.

What about a 1/2 shear plate? I can't go much thinker than that?

It would certainly be easy to try the 1/2 inch plate and see if it helps. I think the problem is up high in the intake and not on the floor.

[statsystems]

Well damn davemclain and warp speed.

Do you think I should try dams at the plenum end of the runner or just live with it? I'm not yet ready to test WOT yet.

What about a 1/2 shear plate? I can't go much thinker than that?

It would certainly be easy to try the 1/2 inch plate and see if it helps. I think the problem is up high in the intake and not on the floor.

Ok. I'll get a shear plate ordered.

Thanks

[Tuner]

If it is doing it at cruise I doubt that messing with the booster will help much if at all. I think its mostly just because of the way the fuel comes out of the idle discharge and the transition slot. Most of the time it isn't atomized very well and depending on the intake it can dump right into a runner. Sometimes the addition of a carburetor spacer will really dramatically help a problem situation. I had this one time with a Dominator on a big Chevy in a jet boat. It was a very good carburetor with excellent part throttle drivability with a 1 inch spacer on the intake, take that off and it would get so rich on the front two cylinders that it would hardly run, wide open was fine. That was with a Dart intake.

Yes, it is a combination of the idle/transfer circuits and the blade angle directing what fuel is coming from the boosters. The ty wrap trick will have little to NO effect.

i know you guys are no dummies, but where did you get your experience with this?

The tabs on original 3310 primary boosters were for part-throttle distribution, on the other hand, the tabs on the L-88 R-3418 and ZL-1 R-4296 carbs were for WOT distribution with the factory intake with the divider opened between plenums. Combined with stagger jetting, larger jet on the boosters with the wing, the tabs steer fuel to 4 and 5 at WOT.

I have personal experience with the 3418 at part throttle in a flatbottom V-drive boat. 20 minutes at 2500 or so would put so much soot on #4 you could blow it off with your breath.

There were OE applications that had a tab or vane below the T-slot (or transfer orifices). A Buick or Olds (I forget) had a stainless steel shim below the carb, between the carb and manifold, with a 1/4" square tab projecting into the bore below the transfer orifices in the Rochester 4-Jet. I still have one of the shims.

3418 Tabs for WOT distribution


3310 Tabs for PT distribution


Another thing I can tell you from experience is the step or ridge in the primary bore (on the right in the pic below) of this 289 Ford spacer is important. Once upon a time in '69 a committee of experts removed that obvious restriction and the little Mustang suffered. Mileage went from 25 to 15, ET went from 9.50 to 10.70 (1/8 mi.). After much effort to fix everything else, a trip to the junkyard for another spacer (with the lip) it was right back where it was before we (I blame it on the other guy) 'fixed it'. That experience may be the single worst thing I know about carburetor tuning.