Carb air cleaners, thermacs, and spacers

[SirRobyn0]

I probably should mention when I got my truck it had a little tiny air filter maybe on 8" around, barely bigger than the carb top opening. Yes it cleared the distributor, but that's honestly a terrible setup. It's just to tiny and the only company making replacement filters for that was edelbrock, and damn near $20. I'm sure that small of air filter is restrictive, plus they get dirty so much faster due to less surface area. Since my factory air filter housing is gone I bought a generic chrome air cleaner that's 14" around 3" tall and wix makes a replacement filter for it. The only thing is the new filter housing wouldn't clear the distributor so I bought one of these. https://www.oreillyauto.com/detail/...mount/6411g/4514351?q=air+cleaner+riser&pos=8 Picked the one that worked best and that is that. I would like to go back to the factory air filter housing before winter comes so I can have the thermac back.

 

[AuroraGirl]

I probably should mention when I got my truck it had a little tiny air filter maybe on 8" around, barely bigger than the carb top opening. Yes it cleared the distributor, but that's honestly a terrible setup. It's just to tiny and the only company making replacement filters for that was edelbrock, and damn near $20. I'm sure that small of air filter is restrictive, plus they get dirty so much faster due to less surface area. Since my factory air filter housing is gone I bought a generic chrome air cleaner that's 14" around 3" tall and wix makes a replacement filter for it. The only thing is the new filter housing wouldn't clear the distributor so I bought one of these. https://www.oreillyauto.com/detail/...mount/6411g/4514351?q=air+cleaner+riser&pos=8 Picked the one that worked best and that is that. I would like to go back to the factory air filter housing before winter comes so I can have the thermac back.

Yay good thinking. My truck is just generally gonna be running a LOT better this winter and that was a huge improvement itself over the previous year. And having better driveability when cold blooded will for sure help it's main function it's used for lol. Not often I get up and need to go quickly tho, but definitely helps if I have the option. Like if it's clear windshield and I need to move some snow to get in somewhere etc. Find it lot easier to stall when cold.

 

[Battlac40]

Sounds like a problem with a dropped base air cleaner. It has been proven that dropped and raised base air cleaners reduce HP/TORQ/CFM. Food for thought...

 

[AuroraGirl]

Sounds like a problem with a dropped base air cleaner. It has been proven that dropped and raised base air cleaners reduce HP/TORQ/CFM. Food for thought...

tell me more o wise one

 

[Dutch Rutter]

Guess I've never had this problem. I've always ran at least a 1" spacer under the carb. Gains clearance for the filter base to dizzy. Also helps prevent vapor lock issues.

 

[82sbshortbed]

Guess I've never had this problem. I've always ran at least a 1" spacer under the carb. Gains clearance for the filter base to dizzy. Also helps prevent vapor lock issues.

Adds better performance too

 

[Dutch Rutter]

Adds better performance too

This is what I hear. I was able to tell more of a difference when I ran a open spacer on top of my dual place rpm performer and under my old 1406 even though edelbrock says not to (something about carb signals or something)

Now I'm using a 4 hole spacer onto of that same intake and a 1405 edelbrock that i concerted over to an electric choke. Seems to be running well. Can't really complain about either setup.

 

[SirRobyn0]

Sounds like a problem with a dropped base air cleaner. It has been proven that dropped and raised base air cleaners reduce HP/TORQ/CFM. Food for thought...

Torque I'm not sure if it would really change torque much on a low revving V8, where peak torque is at relatively low RPM. Horsepower maybe a tiny bit, if the drop is enough to effect air flow. On a built engine producing high HP & TORQ I can see why you'd want to avoid it, but I'll tell you I can feel it in the seat of my pants.

Guess I've never had this problem. I've always ran at least a 1" spacer under the carb. Gains clearance for the filter base to dizzy. Also helps prevent vapor lock issues.

Adds better performance too

Of course I've put spacers under carbs for various reasons most commonly for peculation problems, I'm just thinking if there isn't a perc or vapor lock issue that it wouldn't be worth while to remove the carb to add a spacer when a carb to air cleaner spacer will do the trick and it goes on in about a minute. Do you guys think a 1" spacer increases performance enough to feel it on the road?

 

[Dutch Rutter]

@SirRobyn0 I totally understand the simplest fix is the best 99.9% of the time. And in that regard agree whole heartedly.

However, the other added benefits (not including any power gains) of a carb spacer are pretty desirable alone. Some people do say that they needed to mess with the carb settings when adding a spacer. If your not too familiar with adjusting the carb it can be a pain.

I personally did notice the performance gain mainly in responsiveness. But more importantly the drive ability. All of this can be personal taste and or feel. Adding a spacer to a otherwise stock engine. I have no idea. My small blocks have never been factory.

People who know more then I do, say adding a spacer is essentially the same as adding larger intake runners. Having a spacer which doesent have a squared off exit would be ideal for fuel vaporization (or whatever its called). And the normal rule of thumb is open spacer for single plane intake, and 4 or two hole spacer for dual plane intake.

Like I said above, I had good results with a open spacer on a dual plane intake. Don't know how or why but it worked. Kind of the same principle of shaving some of the upper division plate on a dual plane intake.

 

[82sbshortbed]

Here's two different spacers for 2 different carbs. The one on the top is a 3/4" adapter plate for a Quadrajet. Bottom is a .830 thick plate for an Edelbrock carb.

You must be registered for see images attach

I have the adapter plate for it on my BB because I swapped out the half a POS eddy carb for the Quadrajet.

You must be registered for see images attach

Had it on my sbc Edelbrock performer eps intake before putting it on the BBC and it had way improved throttle response that I could actually feel.

I think I'm gonna do this when I rebuild the sbc. Haven't decided yet.

That's with the spacer under it.

You must be registered for see images attach

Plates are cheap and come with gaskets and are easy to install. I'd get one but, that's me. I think you can tell enough improvement to warrant the plate or spacer. Whatever you want to call it. Lol

 

[Dutch Rutter]

Alot of different styles available. Mine is even different then the ones 82shortbed listed. This is the one I'm using now with good results.

https://www.summitracing.com/parts/sum-g1412

Before I had just an open aluminum one. I've read that the aluminum ones are not as great with insulating the heat as a wood or plastic one. I really didn't notice any difference between the two materials though. I also second the cheap enough for the benefits. Just make sure to sandwich it in gaskets. Don't want any leaks.

Mine being squared off holes i imagine I am leaving some gains on the table. Ideally you want the intake holes rounding out to a larger diameter as it gets to the intake.

 

[SirRobyn0]

@SirRobyn0 I totally understand the simplest fix is the best 99.9% of the time. And in that regard agree whole heartedly.

However, the other added benefits (not including any power gains) of a carb spacer are pretty desirable alone. Some people do say that they needed to mess with the carb settings when adding a spacer. If your not too familiar with adjusting the carb it can be a pain.

I personally did notice the performance gain mainly in responsiveness. But more importantly the drive ability. All of this can be personal taste and or feel. Adding a spacer to a otherwise stock engine. I have no idea. My small blocks have never been factory.

People who know more then I do, say adding a spacer is essentially the same as adding larger intake runners. Having a spacer which doesent have a squared off exit would be ideal for fuel vaporization (or whatever its called). And the normal rule of thumb is open spacer for single plane intake, and 4 or two hole spacer for dual plane intake.

Like I said above, I had good results with a open spacer on a dual plane intake. Don't know how or why but it worked. Kind of the same principle of shaving some of the upper division plate on a dual plane intake.

I understand the principle of the spacer plate, or adapter riser. I think part of the idea is increased fuel atomizing. What I question is if for example one is added to an existing engine whether it is stock or built no other changes made will it be enough to feel. I'm not asking anyone in particular to answer the question, it is more one of those curiosities I have.