2-2 Induction idea

69gmachine · Dec 3, 2007

Some of you may have seen the new Barry Grant inline 4 barrel carb that's coming out soon (if not already). With the barrels better spaced relative to the intake ports it has much better fuel distribution picking up more HP and Tq. Unfortunately it's so unique in design that you only have one manifold to chose from, and that's of course for the small block Chevy. But that made me think that an easier way to accomplish the same thing would be to arrange a couple of two barrel carbs sideways, so the barrels are spread out longitudinally. Of course that still requires a custom intake, so the next best thing to do would be to use an existing 2-4 manifold and use adapters with 2 2 barrels. It may be a lot of work to go through for little gain, but I wonder if it would be more driveable than with 2 4s?? I have too many experiments going on already, so I need to leave my engine alone, but if someone already has a 2-4 set up, maybe you could throw a couple of Autolite 2100s on it and do a test drive?.

ratio411 · Dec 3, 2007

It's not unique!
When is the last time BG had a product it didn't copy from someone else?

That carb is a copy of the Autolite (Ford) inline 4v carb from the late 60s.

There are plenty of Ford intakes out there for that carb.
Expensive, but out there.

ratio411 · Dec 3, 2007

Dug up a pic...

69gmachine · Dec 4, 2007

ratio411 said:
It's not unique!
When is the last time BG had a product it didn't copy from someone else?

That carb is a copy of the Autolite (Ford) inline 4v carb from the late 60s.

I meant unique in that it doesn't have the same dimensions as anything else out there, including the Autolite inline.

ratio411 said:
There are plenty of Ford intakes out there for that carb.
Expensive, but out there.

Plenty? 2 for the Boss 302 and 1 for the 351 Cleveland doesn't rate plenty to me.

It may be the same in concept, but unfortunately Ford didn't bother to develop the potential of the inline whereas BG has spent considerable effort on it. Regardless of who made it first, what's important is who can make it work. IIRC, the Autolite inline was pretty unreliable and most if not all the TA teams went back to the Holley before the season was over. Also, Ford never attempted to make it work on a street car, and in that sense too, the BG is unique.

I wish BG success with the idea.

mikethebike · Dec 4, 2007

Webber IDF.....need I say more? I doubt there is much 'new' left to do in carbs. BG has never IMNSHO done anything 'new'....only an expensive model of someone elses good idea.

As posted by others all he is doig here is a copy of the Autolite In-Line 4-barrell from 1969 that was for BOSS 302 and 429 engines. Difference is the Ford units used as many parts i.e., accell pumps, jets, booster venturies from a stock Ford carb as possible. I don't think BG will do that.

mikethebike · Dec 4, 2007

69gmachine said:
I meant unique in that it doesn't have the same dimensions as anything else out there, including the Autolite inline.

Plenty? 2 for the Boss 302 and 1 for the 351 Cleveland doesn't rate plenty to me.

It may be the same in concept, but unfortunately Ford didn't bother to develop the potential of the inline whereas BG has spent considerable effort on it. Regardless of who made it first, what's important is who can make it work. IIRC, the Autolite inline was pretty unreliable and most if not all the TA teams went back to the Holley before the season was over. Also, Ford never attempted to make it work on a street car, and in that sense too, the BG is unique.

I wish BG success with the idea.

It would have been VERY difficult for the Ford unit to be used on the street with any degree of success...success being defined as making good sense for the street....and any non-progressive, 1 accell pump per venturi and no chokes carb makes NO sense on the street. It didn't matter that I and others were willing to live with the beasts back then. Lots of power and throttle response and about 6-8 mpg in town and fouled plugs so often we made an adaper plate so we could put a stock Holley in place of the Fords, drive the car during the week and then bolt the 2-4 top plate and carbs on for Saturday night fun.
The carb was a race-only piece that according to published reports added 5-10 mph to a BOSS 302 on top end.
I still say if you want the best fuel distribution, tunability, power, torque, AND mpg you neen only vist your local Webber web site and spend about 1800 bucks and you're in.
The 305 Gurney-Weslake gave me about 19-21 driving back and forth fro Burlington to reensboro, N.C. back in 1968 and right at 15 in town.

D.Hearne · Dec 5, 2007

I was thinking on doing a 2 x 2 setup also, but with twin Holley 500's on an Edelbrock 2x4 intake. I have the adapters and one carb so far. I'm going to mount them conventionally though. As for better fuel distribution, you can get that right now using the repop 3x2 setup Mustangs Unlimited sells. I have this set on my 331. Works fantastic on the street. It's got three Holley 250's with a progressive linkage. It's like having a 750 cfm mech secondary spread bore carb but with better distribution.

Helmantel · Dec 5, 2007

I believe the SCCA didn't allow the inline four barrel to be used, so that's probably where development came to a halt.

I doubt that a dual quad intake with dual two barrels would work better than with dual four barrels. Say you need around 750 cfm. That's 375 cfm per carb. However, two barrels are rated at 3" Hg. To convert to the 1.5" Hg at which four barrels are rated, you need to divide by the root of the pressure ratio (= root of 3/1.5 = 1.41). So, two 500 cfm 2V carbs are the equivalent of one 709 cfm 4V carb.

I think you'd be better off with in terms of driveability with two 390 cfm 4V's. At low load/speed, you run on the primaries, so you basically have two 275 cfm 2V carbs (390/2 x 1.41 = 275), which are probably a lot more responsive than two 500's down low.

bnickel · Dec 5, 2007

as far as carbs go about the closest you're going to get to the distribution of an EFI system is the weber setup, which truly is just four 2 barrel carbs just with wider seperation between the venturis, it's really closer to eight one barrel carbs in the way it's setup but is actually just 4 2 barrel carbs mounted sideways. in all actuality the fuel distribution of the weber steup is really better than a port EFI system just not quite as efficient in controlling the amount of fuel being used. i think honestly, probably the best efi system would be eight individual injectors mounted so they spary the fuel through the venturies of a weber style carb body (similar to the old BG VFI system) with an air intake plenum monuted on top of the throttle bodies and controlled by a mass air computer. the momar injection system that Roush uses is about the closest i've seen to this type of system but it still mounts the injectors in the same manner as any other port efi system

D.Hearne · Dec 5, 2007

Helmantel said:
I believe the SCCA didn't allow the inline four barrel to be used, so that's probably where development came to a halt.

I doubt that a dual quad intake with dual two barrels would work better than with dual four barrels. Say you need around 750 cfm. That's 375 cfm per carb. However, two barrels are rated at 3" Hg. To convert to the 1.5" Hg at which four barrels are rated, you need to divide by the root of the pressure ratio (= root of 3/1.5 = 1.41). So, two 500 cfm 2V carbs are the equivalent of one 709 cfm 4V carb.

I think you'd be better off with in terms of driveability with two 390 cfm 4V's. At low load/speed, you run on the primaries, so you basically have two 275 cfm 2V carbs (390/2 x 1.41 = 275), which are probably a lot more responsive than two 500's down low.

Holley 500 2 bbls are exactly half of a 750 DP. Same throttle bore size, same venturis. In any case, the flow ratings are moot as far as what the motor will draw thru whatever you bolt to the intake. The rated flow is only to be used as a guide in choosing a carb. What it actually will flow at WOT on the engine is not what the rated flow listed is. For the rated flow to be duplicated, the engine would have to be pulling the same 1-1/2"HG at WOT (4 bbl rating) And that will virtually never happen, there's too many variables involved (cams, heads, intake, exhaust,etc) When I had the 331 in my 89 Ranger it would top in at 90mph on the center carb, at that speed, the motor at 100% VE would be drawing 386 cfm thru a 250 cfm rated carb. This motor more than likely pulls 100%VE with Canfield heads, and a Z303 cam using 1.7 rockers to increase the lift. The whole point of doing two 2 bbl carbs is purely as an experimentation, and simply doing something different, so you may as well forget talking us out of it, cause your not going to If I did want more throttle response, in a 2x2 setiup, then I'd go with twin 350 cfm Holley 2 bbls.

Helmantel · Dec 6, 2007

OK, I was off 41 cfm, but the point I wanted to make is that two 500's are not the equivalent of a single 1000 cfm carb.

I agree that you should not stare yourself blind at the flow ratings. It's not a pump that stops delivering at 750 cfm (or whatever the rating is), nor is it dumping 150 cfm too much into an engine that is only sucking 600 cfm. That's obvious to us, but some people seem to think of it that way.

If you want to experiment with two 2V's, by all means, go ahead, but it's doomed to fail miserably

3 x 2V setups on the other hand, are sweet

D.Hearne · Dec 6, 2007

Never said two 500's were 1000 cfm. Only reason I'd do it with 500's is I already have the one carb and the two adapter plates. The only cash outlay would be for the intake. I can get another 500 for $50 easy. As for it failing miserably, that I doubt. It'll be like taking a 750 DP and cutting it in half and mounting them farther apart. Nothing tricky about it, just doing something different.

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