DO CARB SPACERS REALLY WORK? 4-HOLE VS OPEN (360 MAGNUM-HP & AF-FULL DYNO RESULTS)

[Music] hey guys richard here and welcome to the channel please before we get going make sure like share subscribe ring the bell but more importantly whether it's your first time here or you always come here take a look around look at all the playlists we've got stuff for ford chevy dodge all kinds of other guys stuff we've got turbo stuff and blower stuff and nitrous stuff even yes compound turbo stuff so go check it out use the search function go check out all the playlists i'm sure if you have a question i might have already tested it but today we're taking a look at a dodge magnum we have a direct back to back apples to apples comparison looking at a four hole carburetor spacer to an open carburetor spacer on our dodge magnum 360 mopar performance crate motor that's right carb spacers not only what it does to power but also what it does to the air fuel that's right changing the spacer changes the tune along with that i also have some tuning stuff what happens when we change the timing on our carbureted crate motor let's check it out before we take a look at our carb spacer testing testing the four hole carburetor versus the open carb spacer we need to take a look at our test motor and it is a dodge 360 magnum this particular one didn't come from the wrecking yard which is where most of my motors come from this one actually belonged to the guys at westec and it was a dodge magnum 360 crate motor which meant that it was basically a stock dodge magnum just like we would get in the wrecking yard but it had a few nice goodies on the first thing was i like the valve covers they're awesome the best part about the motor but to help it make power and run in a swap application dodge equip their crate motor with a carbureted induction system in this case it was a m1 mopar performance dual plane intake manifold and it had an msd distributor we installed a 750 brawler carburetor and this particular case we had run long tube headers but to get things started what we did was and this is the way that we approach any dyno test on any motor and this this one is a perfect example this motor hadn't run for 12 or 13 years so we put it up and set the timing and put a carburetor on it never even looked at the jets we just wanted to make sure that it would run in and it did so we started up and started our tuning we wanted to make sure that we had a good baseline and know how much power this thing made so what we do normally is set the timing low to make sure that as we're rolling into it it's not going to detonate and then what we'll do is add timing until the motor stops making power so this first thing i'm going to show you is what happened when we went through that sequence with timing on our dodge magnum crate motor so as i said we had our 750 brawler carburetor on there we had the timing set at a total of 25 degrees and the 25 degree number is with full rpm because you have to set a distributor that has a centrifugal advance in it you have to run at the rpm where all of the advances in in this case it was about 35 or 3600 rpm and the weights had allowed all the timing to be in so we set the maximum timing for 25 degrees and it obviously had less than that at lower engine speeds so run with 25 degrees of total timing of peak timing our 360 produced 283 horsepower peak torque was up at 385 foot-pounds of torque you can see the torquer is fairly flat down here from 2700 rpm all the way out to almost 33 or 3 400 rpm it's not a high revver we didn't run it any higher than 5000 rpm peak power occurred at you know 43 400 rpm here's what happened and after we'd run it at 25 degrees and saw that everything was okay that the air fuel was good we increased the timing this is a jump from 25 degrees up to 30 degrees and when we do that when we rotate the distributor obviously it adds timing everywhere now there's still less timing down low but there's a little more than there was and obviously the motor responded very well to this we were up to 398 foot pounds of torque and peak power was up to 299 horsepower so we've taken a pretty healthy jump just from the timing chain so since we got a good jump from this timing change we decided to add more timing and we did exactly that we went up to 32 degrees now if you look at the curve you start understanding what's happening we got a pretty good jump going from 25 up to 30 but a very small gain going from 30 to this is between 31 and 32 degrees and we know that there's really not much more power left because the peak power was only 301 horsepower peak torque was up to 403 foot-pounds of torque you can see we're not getting really very much after this timing level so now let's take a look and see what happened with our spacer test and the reason that we had to run the spacers as i said because we had a situation where we could not run that carburetor on that dual plane manifold because the linkage hit so the first thing that we did was i put a four hole spacer a half inch four hole spacer underneath the carburetor to kind of continue with the okay this is a dual plane theme so let's check that out and see what happens [Music] to run our carb spacer comparison all we had to do basically was take off the four hole throttle body or the four hole carb spacer that we had already had on the motor to initialize our test so we had our 750 holley then we had a half inch basically four whole spacer and then the dual plane intake manifold now we also had it's important to note that we also had a very small plate sandwiched in there that we used to connect the throttle linkage to and i'll go ahead and show you a photo of the throttle linkage here and so there's a little bit of opening there which makes it work a little bit like an open spacer but as we'll as we'll see from this comparison it did not like the open spacer and it shows you what a dramatic change not just in the power curve but we're also going to take a look like we did in the previous video if you haven't checked that out make sure you do take a look at what happened to the air fuel curves when we changed the exhaust going from the two different size stock exhaust manifolds to long tube headers had a dramatic effect on the air fuel curve offered by the carburetor despite the fact that we made no changes to the carburetor and this same thing happened with the spacers so with our four hole spacer we were making 301 horsepower a nice round curve you see it's falling off out at 5500 rpm and we were making 403 foot pounds of torque so the long runner or the the dual plate intake designed to enhance torque production so it was working fairly well on this fairly mild combination with a mild cam and stock hits this is with our four hole spacer here's what happened when we put an open spacer on here and all we did was replace the spacer we made no other changes and the open spacer is in red so the open spacer made less power than the four hole spacer basically everywhere it was kind of the same out here from 4300 or so out to about 47 or 4800 it kind of matched the power of the four hole spacer it got a little bit worse at the very top but the four hole spacer you can see down low was dramatically better i mean peak torque on the open spacer was 393 foot pounds so down 10 foot pounds compared to the four hole spacer peak power was almost identical both of them were 300 301 horsepower so we're kind of splitting hairs there but there was a dramatic difference between the low speed torque production and the response rate of the carburetor with the open spacer because what it does is when you put an open spacer on a dual plate intake it starts to make the dual plane especially down low start to operate a little bit more like a single plane you lose a lot of the signal to the carburetor and i'll go ahead and show you exactly what that looks like when we take a look at the air fuel curves of the two different spacers so let's check that out so this is the air fuel curve with our four hole spacer of our dual plane carbureted 360 dodge magna motor and it might look like that that's a little bit jaggedy and all the fuel injection guys are gonna be going man i could straighten that out and make it exactly perfect all the way through and yes you could and and when you did that you would have zero effects on horsepower because the scale of this is four tenths of an air fuel point and that's why it looks so this curve is actually very very smooth and flat for a carbureted combination especially on this dual plane but this is our four hole spacer again the four hole spacer made the dual plane continue to act like a dual plane and it had good um signal to the carburetor so we had a good air fuel curve but here's what happened when we installed the open spacer same carburetor same intake manifold take a look at the difference and now you can see what i'm talking about with the four hole spacer which is in black down low you can see how flat that actually is when you see it on a scale a realistic scale you can see hey look that's actually fairly flat but look at the difference on the four hole spacer and this is why it lost so much power or rather it lost so much power and this is the result of it losing power so you can chicken and egg the whole combination but if you take a look at this you'll see that with the open spacer the signal to the carburetor was greatly reduced and what that meant is because the signal was reduced it was not drawing nearly as much fuel and the result was we were all way up at 14 to 1 at wide open throttle on the load-in of this thing you know at 27 or 2800 rpm eventually it kind of came into its own and was still a bit leaner than the um four hole spacer but if you take a look at that it didn't make any more power so all the guys are saying well you need to run that thing leaner than 120 and leaner than 12 or 11.5 or 11.8 well we did that and we ran it up at 12 8 or 13 to 1 here with the open spacer but guess what it didn't like that now there wasn't hardly a change at all in most of this range in the 4 500 rpm range despite the fact that we have a full air fuel point change between the two different spacers but some of that is air fuel and we didn't see really a change in power and some of that is the difference in the signal to the carburetor between the different kinds of spacers it's doing different things and it's affected dramatically obviously by the spacer but the thing i want to show you and point out is this stuff down at the bottom below 3500 rpm the drivability with a four hole or with an open spacer compared to a four hole spacer on this kind of combination on a mild magnum motor like this with a dual plate intake i would not recommend the open spacer the drivability would be much worse the four hole spacer works good or just having the carburetor down on the manifold as long as the linkage works let's get to our conclusion okay guys this is the time we take to maybe talk a little bit about what we learned today and what did we learn today about our dodge 360 magnum couple things first off it does respond to timing like every other motor but that's exactly why we start off with low timing and then start adding timing until the motor doesn't make any more power and then we know that's enough timing same thing with air fuel a lot of times we'll start out rich lean it out until it stops making power and then we'll stop there because we know there's no more power to be had once the dyno tells us hey that's enough timing that's enough air fuel we are all good but the test today was about carb spacers and i thought it was pretty awesome to see the difference between the four whole carb spacer and the open carb spacer not so much in terms of power there was a little bit of a difference there but it was a dramatic change in air fuel ratio we made no changes to the carburetor all we did was do a spacer swap and found out what the change was if you look at the open spacer it completely changed the dynamics of that intake manifold it no longer thought it was a nice efficient low rpm dual plane with a great carb signal it turned it more to a single plane intake which as you can see was much much leaner at the bottom part of the rpm range and also would not drive as well because as we know power is one thing but there also has to be drivability armature holder please make sure to like share subscribe ring the bell check out those playlists lots of good stuff i'll keep testing

Channel: Richard Holdener

Views: 46,171

Keywords: HOW WELL DO CARB SPACERS WORK, 4-HOLE CARB SPACER, OPEN CARB SPACER, DO CARB SPACERS HELP, DUAL PLANE INTAKE, MI IINTAKE, MOPAR PERFORMANCE CRATE MOTOR, DYNO TESTING

Id: 8HWoxtkObuM

Length: 13min 42sec (822 seconds)

Published: Wed Aug 18 2021