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Topic Review (Newest First)
04-03-2011 10:01 PM
Leoman I run a Moroso drop-base cleaner. I tried switching to a chrome Holley and found myself with two little gouges in my hood after things expanded from operating heat! The Moroso is back. It's painted Rustoleum grey. It uses a 3" filter and seems to get plenty of air. It really is about 1/8 to 1/4" shorter than the Holley, which one would think was plenty short. It is, but not for me I guess.
04-03-2011 07:29 PM
ericnova72
Quote:
Originally Posted by Rineholio
As long as we're talking carb spacers, how about this? Has anyone run a drop base aircleaner so they could keep a 3" or larger filter and still add a carb spacer? That's a lot of curve for the air to follow.
Yep, and it's not a problem if you use a correctly designed dropped base. I use a 4" filter with a 1" open spacer and a950 holley on a Super Victor and it fits under the stock hood of a '72 Nova.

The very best is the original GM/Chevrolet design for the L-88 Corvette. GM did a bunch of testing to insure no power was lost in this air cleaner. This base is available from several resto parts suppliers. There are also a few good ones made for the Circle Track market.

Many of the generic chrome drop base air cleaners are not as good however.
04-03-2011 02:12 PM
Rineholio
Carb Spacers

As long as we're talking carb spacers, how about this? Has anyone run a drop base aircleaner so they could keep a 3" or larger filter and still add a carb spacer? That's a lot of curve for the air to follow.
04-03-2011 10:14 AM
04SilveradoMykk
Quote:
Originally Posted by Leoman
04Silverado, I bet the Vortech or Procharger or whatever that is feeding the carb helped a lot too Nice photos!
No force feeding here, naturally aspirated. The carb hat & tubing you see were part of the ram-air set up grabing air from the front of the truck
04-03-2011 08:39 AM
boatbob2
Carb Spacers...

Hi,years ago,i had a HOLLY carb,that would run fine when it was cold,when it got warm,it would die,(heat soak) an old man told me to make a carb spacer out of wood,i laughed,tried it,and no more heat soak,the wood spacer acted as an insulator.
04-02-2011 11:19 PM
Leoman
Quote:
Originally Posted by JCurry
so do the open spacers not work well on a dual plane manifold?? should i go with a 4 hole spacer for my rpm air gap?
Dual planes are something of a mystery to me I must admit. I would think that either style might help depending on the motor. I never did like having to tune the two halves of my carb like a pair of 2-barrels, so a short (1/2") open spacer would be the first thing I'd try. But I don't see why a 4-hole wouldn't do the same thing theoretically that it does on a single plane, i.e. lengthen the barrel for better flow, etc. I realize that the plenum floor on one side of a dual plane is deeper down than the other. This stuff can drive you nuts. I'd try both! Why not? It's such an easy and generally cheap mod, and it's fun to experiment. 04Silverado seems to have a good hint above with his tapered spacer that has the properties of both open and 4-hole (plus more).

04Silverado, I bet the Vortech or Procharger or whatever that is feeding the carb helped a lot too Nice photos!

Inspector, thanks for that cool test. I'll try that before I try the tapered spacer.
04-02-2011 02:03 PM
JCurry so do the open spacers not work well on a dual plane manifold?? should i go with a 4 hole spacer for my rpm air gap?
04-02-2011 11:01 AM
04SilveradoMykk I played around with spacers for a while. The tappered four hole still get's my vote, and it will stay on my setup.


I tried this gimmick four hole once, great for off the line torque and it even cured a few cruising issues too. It also helped with MPG. This spacer would be great for your car show cruiser that never see's above 3k rpm going from the garage to the cruise in. It made the higher rpm fall flat, and it lost some ***.





I even double stacked a 1" four hole on top of a 1" open on a RPM Air-Gap. It worked fine, felt like it really picked up the acceleration above 3500rpm



But, so far the tapered spacer flowed into the dual plane in my previous post is providing the best results. It even feels faster on the street than the big runner single plane I ran for almost a year.
03-31-2011 09:02 PM
Leoman
Quote:
Originally Posted by 001mustang
cool.

how did you measure hood clearance? play dough?
Couple pieces of cardboard. It was that close. I originally measured it by getting a couple of gouges in my hood. I now have two little bumps in the middle of it, visible only in the right light (or from the driver's seat) to remind me never to take anything for granted

Play dough is a good idea!
03-31-2011 03:00 PM
techinspector1
Quote:
Originally Posted by Leoman
I have a lot of overlap, no idea about reversion
In a very dark area, remove the air cleaner and fire the motor. Shine a very strong flashlight across the top of the carb. The standoff you see as a fog lurking around the top of the carb is standoff (reversion) caused by the long cam timing. The piston coming up the bore with the intake valve still open will push the mixture back up the intake tract and you can see it this way.
03-31-2011 02:45 PM
04SilveradoMykk
Quote:
Originally Posted by 001mustang
nice mykk.

can't figure out why your taper spacer has threaded mounting holes.
Thank you. I think it's just rough tooling marks by whatever bit was used to drill the carb stud holes. Like I said, cheap EBay spacer. But it works, and well.
03-31-2011 02:39 PM
001mustang cool.

how did you measure hood clearance? play dough?
03-31-2011 02:29 PM
Leoman Ok, just to update my earlier comments on the thread.... I'm limited to a 1" spacer on my setup due to hood clearance. I'm running a low-profile Weiand single-plane on my 350, with an old Cam Dynamics 'super-3/4' cam with a lot of overlap.

I already had a 1/2" phenolic open spacer. I added a 1/2" 4-hole phenolic on top to basically fab a 'combo spacer' (which Wilson recommends for motors with a lot of overlap since they say the tapered variety might amplify reversion on such motors).

The results were quite good as far as throttle response and idle smoothness. I have yet to try anything really hairy as the roads here still have some salt on them, but preliminary tests have been very encouraging! My first test (in my driveway when the roads were still totally grubby) went like this: I backed out, pulled to the back of the driveway, put the th350 in D, took my foot off the brake and punched it about 3/4. I thought I had skidded in sand, but a look revealed two 4-foot patches on bare asphalt. I run 275/60R15s at 20psi in back, so the patches were pretty wide! Also, the tires are taller than normal and knock down the effective gear ratio from 3.73 to about 3.50, hardly holeshot material. I was quite pleased, especially since my little 350 isn't at all cammed for torque.

I did hit the throttle-binding problem My gasket has bigger holes than my spacer, so I dremeled out the top of the spacer just a tad, since the bind wasn't very strong (a tap of the gas pedal cured it). It's gone now, but I'm still not sure if I was binding or if I just had the carb torqued down too hard since I was paranoid of vacuum leaks with 2 spacers and 3 gaskets. I may have warped the baseplate a bit, but if so it has sprung back with my latest (and less torquey) installation.

Conclusion: I'm interested enough to pursue this further, that's for sure!
03-31-2011 12:10 PM
001mustang nice mykk.

can't figure out why your taper spacer has threaded mounting holes.
03-31-2011 11:39 AM
oldbogie
Quote:
Originally Posted by 84Caprice57
I figured I'd start a thread discussing the different types of carb spacers out there. I currently run the 1in edelbrock Phenolic black plastic style with my Holley Commander 950 TBI setup. I was wondering what effects all the different styles have? Ive seen the open style, the 4 hole style, and the 4 hole tapered style. Are there pro's and cons to each? If I were basing price to match what might be best - it seems that 4 hole tapered costs the most.

Just wondering everyone's thoughts on this was.
Too a large extent it's a tuning device, some engines respond to them some do not, some require extensive retuning to find anything.

If you get an immediate positive response it usually means there was a tuning problem which the extra plenum volume helped solve or hide.

Nothing against their use but expect a cut and try. I do think the cost of these things is outrageous. Most designs you see can be duplicated at home with a chunk of plastic or aluminum, a hole saw, electric drill, some files, a die grinder and cutters, and a saber saw for a lot less money and a little sweat equity. But then I come from a generation that had to make parts rather than buy them 'cause they weren't available to buy. So my money went into tools and machines to make parts.

Bogie
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