Does anyone know if carb spacers really work?

 

Depends on your definition of "work".

The part about adding space, is pretty dependable. You can count on one to "work" for that.

Of course, that feature also often means that your hood can't close, but that's just a minor detail I guess.

Beyond that, they're a tuning aid. Some engines they help, some they hurt, some they do nothing at all. 4-holers have different efects from 1-holers; a 4-hole one "looks" to the engine like an extension of the carb throttle bores which smooths and straightens the flow through the carb, whereas a 1-holer "looks" like an enlargement to the plenum, and in the case of dual-plane intakes, compromises the dual-plane-ness of it, which most often is a net loss to the engine's capabilities. Only way to know for sure in your particular combo, is to try one.

 

K ima chek out the 4-hole one thanks bro

 

I've seen a bunch of different dyno tests where they proved a gain, but only with the expensive $100 ones that they used... and even then they agreed that it wasn't worth the extra expense when you could easily apply that elsewhere. I want to say I saw it on the YellowBullet forums, but I can't recall for sure. It was like a 6HP increase on a fairly well built motor.

 

I seen a dyno article yesterday in an older magazine.

I dont remember much about it, but I do remember that it was a 350. 360ish hp max. Air-gap intake. An open 1 1/4" spacer made 4 more hp on the topend. On the bottom it lost 7 ft-lbs and 2 hp.

Cant remember much more details but they pulled it off saying that the motor didnt need the extra plenum volume.

 

I tried a 1" open spacer on my S10 yesterday.

350, Performer RPM Air-gap, 650 DP, Dart Pro1P 200 heads, 10.5:1, 244/249@50, .565/.543

I noticed a definate loss of bottom end. The truck didnt feel as responsive as it was. I couldnt tell any difference on the topend. I pulled the spacer back off pretty quickly.

Im not saying they arent worth it on some motors, but for mine, a 1" open spacer hurt performance.

 

The butt dyno isn't very reliable. Quantified, back-to-back data is the only way to know.

 

true.

I didnt really post to say positive or negative or spacers in general. Just to say that from my "butt dyno" I feel I lost performance. Which 98% of the people on here can relate to. Id love to be able to get on a dyno with time to tune and tweak things, but I dont have the money.

 

I put a 1" phenolic (sp?) 4 hole spacer on my 305 because I was having vapor lock issues and it def. keeps the carb and air cleaner A LOT cooler. That's the only reason I picked one up.

 

Same here, a 1/2 in phenolic 4-hole fixed my vapor lock.

 

They are a tuning tool that will change the air flow delivery and therefore the power curve for better OR worse (plus some cut down on carb heat).

So if the motor needs one it will help. If the motor does not need one it will hurt. Even for a motor that can use one to help, the wrong one will hurt...

Not the easy answer most are looking for but in short it all depends.

 

exactly.

and like five7kid pointed out, back to back comparison like on a dyno is pretty much the only way to tell what it truely is doing.

 

car craft did a comparison in spacers on a sbc, they got 10 more horse on the 4-hole and 12 or 15 on the expensive airfoil lookin one, with no loss on the bottom end, has anyone else done any tests like this?

 

I've done several tests. Bottom line is every engine combination is different. I've got a cabinet full of open, four hole, thick, thin, phenolic, wood, aluminum, tapered and straight spacers. Changing the spacer will almost always require a jet or air bleed change because they will drastically change the signal to the carb.

My info is from running and testing over 10 years on our engine dyno with <1% repeatability. Not a butt dyno.

 

Have you noted any significant changes between the phenolic and wood spacers? I'm curious how that would change things. Aluminum dissipates heat differently so that's a given, but I would imagine that the other two would be similar to eachother.

 

i would imagine as long as the shape is the same the material wouldn't matter that much? The incoming air temp change should be minimal, correct? i never really got what the different materials would do

 

Well, that's what I was getting at Different materials will make a difference, but I'm not sure how much of a difference between those two would be readily apparent.

 

Phenolic and wooden spacers are good because they isolate heat from the carb. They don't allow the heat to dissipate up through the intake manifold into the carb. If you have two identical spacers, one wood and one phenolic, you wont notice any performance difference. The advantage of a wooden spacer is that they're cheaper to produce. The advantage to the phenolic material is that it can be made into any shape imaginable.

 

I made 612fwhp with a 1" phenolic 4-hole spacer, then made 623 with a 1" aluminum 4-hole tapered spacer from Bo Law's, with no other change's.(did have to re-jet though.

 

Kinda curious, do you have any pictures on those 2 different spacers? Also what engine and carb was they on?

 

496 BBC, 1030cfm Jet Performance 4150 Holley HP. This is the only pic i have of the tapered spacer.
I dont know why the pic wont post?

 

I'd like to see that dyno sheet along with correction factor info, weather data, A/F, water and oil temps. HP numbers don't tell the story. What kind of dyno was it?

 

SuperFlow, SF-902. I have the sheet for the last pull, I'll post it. Trying to post a video on the dyno.

 

 

Chances are if you have a small carb yes, if it's big no. Also depends on the size/style of your intake.

 

I've tried spacers on nearly all of my carb engines (I keep a few 4 hole and 1 hole phenolic ones around), and my experience with them is that you generally shouldn't expect one to affect peak power drastically, but rather the curve.

I generally use the 1" 4 hole units to try to boost low-end performance on certain setups, and they generally work well for that purpose (or not at all, depending on the engine). My Olds engines seem to love them, but that may be because I'm using factory stock intakes (aftermarket Olds intakes are expensive).

They will also help keep the carb cool, like the vapor lock sufferers have noted.