thanks Ted

you just stopped me from making another mistake

stuey

That a Yes.  The pictured spacer is shown upside down.

I’ve experimented with the iron intakes in dropping the center divider down and those efforts end up hurting the lowend torque values regardless of the spacer design being used.  The Mummert aluminum 4V intakes have a preference for a measure of open plenum between the intake and carb and that’s what the tapered spacer provides.  On the other hand, the Blue Thunder intakes tend to prefer a carb spacer that is more segregated in design or has less openness between the sides.  Said another way, the BT intakes prefer a spacer that keeps more true to the dual plane design.  Doug’s observation mimics what I also see with the BT intakes.

 

With both intakes being so similar in overall design, then that begs the question “Why the different spacers?”.  Here’s my observation.  The Blue Thunder intake has a crossover slot at the secondaries while the Mummert aluminum intake does not have that slot.  Unless proven otherwise, this would be a contributing factor why the two intakes prefer different spacer designs when all else remains equal.  The verification for this would be to test the Mummert intake with and without the aforementioned slot and verify that is indeed what is driving the carburetor spacer difference.

 

Here are a couple of pics of some of the spacers that were recently tested on a variety of Y intakes.  The left picture is the carb side of the spacers (top) and the right picture is the intake manifold side (bottom).

  

Lorena, Texas (South of Waco)

The plastic being used on those particular HVH carb spacers deforms with any kind of prolonged heat.  They eventually deform enough that a gasket seal becomes an issue.  A different composite material would likely solve the deformation issue as there are no heat related problems with the Moroso brand plastic spacers.

Lorena, Texas (South of Waco)

very interesting thread

been looking at HVH website,  surprised they say plastic/phenolic spacers not for street only drag/marine use!

ally for street/strip use  why ...any coment please. i would have thought plastic would have been a better heat blocker

stuey

Well I put a Mummert 2 slot spacer on the Blue Thunder, and while it may not be optimum neither is the BT manifold without some exhaust help.  The machinist who milled the back of the manifold also fit and polished the spacer with the BT which did have some edges he said had to go.  I'm not racing but I'll take what I can get and it runs real nice.

Ted, Redding, CA

I had a  1" thick square hole spacer on my engine for a while but recently changed to this slightly modified 1" tk 4 holer. This is the surface that contacts a Blue Thunder manifold. The purpose of transitions is to provide smoother flow out of the bottom of the spacer reducing turbulance in the plenum allowing the A/F mixture an easier time turning to the horizontal runners.  It also should help A/F reach the back of the engine when running on the front barrels.  Remember the front and back of the BT manifold is curved to the radius the carb throttles. 

 I drive mostly on the street and this spacer is somewhat more forgiving at Idle and off idle. I didn't notice much loss in acceleration but I have not tried it on the track. The BT has a medium size "window" between the oval holes, if that window was not there the idle would probably be even better. 

Doug T

The Highlands, Louisville, Ky.

Ted -

(1) Is the above picture inverted to the way the spacer goes under the carb and shown this way for clarity?

(2) Assuming so, would it then simply discharge onto the the carb mounting surface of the manifold (slots in particular)? Does the center divider get reduced - removed to certain depth  - "sharpened" edge - what sort of manifold match?

 
 Steve Metzger       Tucson, Arizona

Rono.  You’ll need to slot the four hole gasket so that there is no unsupported gasket material under the carb or over the intake opening depending upon which way you install the spacer.

 

Billy.  Boosted applications are completely different when it comes to air flow requirements.  While I’ve reams of data for naturally aspirated carb setups, I’ve only a smattering of information on some of the various blow-thru applications in regards to spacer demands.  Because many of the engines I test with superchargers already have fixed carburetor setups, there’s not much opportunity to test a variety of carb spacers on those.  There are undoubtedly some learnings to be had in that area but the complexity of many of those setups prevents their owners from spending the time on the dyno to test some of the variations in those setups.

 

Chuck.  Here’s a picture of the tapered spacer and looking at it from the bottom side.  The general idea is to have the four hole portion at the carb base which eliminates some of the flow eddys that form which in turn inhibits flow through the carburetor.  These spacers work really well on the smaller sized carburetors in that the flow through the carb is increased simply due to the reduction of the turbulence that occurs under the carb.

 

 

There is not a carburetor spacer that is a ‘catch all’ for all applications.  For the Y, I find that the Mummert aluminum intake prefers one design of spacer while the Blue Thunder intake prefers another.  And then the ECZ-B iron intake seems to be up in the air on which spacer works best depending upon the intake and engine modifications themselves.

Lorena, Texas (South of Waco)

Chuck, I think he meant try them the other way around with open end together, but a try both ways may show some interesting results.



Frank, I don't think the idea is to slow the mix down anywhere down the line, slowing it down is what causes the molecules

To fall out of suspension, too smooth a port job will also cause this when not in wide open throttle. I recently installed the 1.08 carb I got from Glenn and my car does not bark as load as it did Exhaust wise with a 1.12 but it is a lot smoother power all around, can't tell if it has more power but definitely smoother with the increase in velocity from the smaller bores of the carb!

55 Vicky & customline

58 Rack Dump, 55 F350 yard truck, 57 F100

59 & 61 P 400's, 58 F100 custom cab, 69 F100, 79 F150, 82 F600 ramp truck, 90 mustang conv 7 up, 94 Mustang, Should I continue?

Now I'm really lost. Ted, are you talking about using 2 tapered spaces small holes in the center and large holes on the outsides? So you have a large opening under the carb AND at the maniflold, sort of an hourglass setup? I know I'm getting old but I'm completely lost in this thread. Chuck

Y's guys rule!
Looking for McCullouch VS57 brackets and parts. Also looking for 28 Chrysler series 72 parts. And early Hemi parts.

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