Thumper Max II 12 Volt Air Compressor Mod: Boosting Performance with Porting?

Get your Thumper Max II here: amzn.to/3F8Cs66
In this episode of Lock your Hubs 4WDing, we're porting the heads of the Thumper Max I 12 Volt Air Compressor.
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[@LockyourHubs4WDing]

Where do we got from here? Don't forget to hit that "like button" to see how the Thumper Max II runs on 24 volts!

[@SirFuseable]

I'm also interested in how long it will run on 24v.

[@my98wagonoid]

Love the way you use an evidence based approach to your videos. Particularly enjoying the Thumper Max videos, hope to see you solve the valve timing issues.

[@LockyourHubs4WDing]

I've gotta say, it's a real thorn in my side at the moment. With no camshaft, it's going to be tricky to work out what the actual stock timing is, let alone how far I've shifted the timing from stock with the mods. Though I have a couple of ideas.

[@Scicluna83]

Same can’t wait to see the results

[@michaelbowman7398]

I really appreciate that you share these mods whether it improves performance or not. Helps us to know what is worthwhile.

[@LockyourHubs4WDing]

Good with the bad I guess!

[@sirstevo]

Love to see a timing video 👍👍

[@damonstone3790]

These compressor videos were awesome to watch. I would like to see if the highly modified Thumper is running any cooler after these changes!

[@LockyourHubs4WDing]

Good question! I may test that.

[@benmorrison9004]

Yes I want to see valve timing and yes I want to see the magical smoke from 24v 👍👍👍👍

[@LockyourHubs4WDing]

Getting closer to the smoke show!

[@scottjacobs7522]

Great testing so far even though the results aren’t getting the results we were hoping for , keen to see if the timing makes an improvement , and hopefully 24volts of power will fix it lol

[@LockyourHubs4WDing]

24v should fix everything right? 😁

[@nordic5490]

Nice. A great series of mods and testing so far. I have one of thse pumps, only 1 month old. I will definitely upgrade the wiring. You are doing the good work / hard yards so the rest of us wont have to. Thanks

[@LockyourHubs4WDing]

Thanks, I just wish the work got better results!

[@SirFuseable]

I reckon that's a good idea for any brand of pump. Even the wiring supplied with my ARB is a lot less substantial than I reckon it needs, so I wired it using a much heavier cable, at least up to the pump's connector plug. I'll probably do it all the way to the motors the next time have it out, seeing as it's now out of warranty anyway.

[@LockyourHubs4WDing]

@@SirFuseable that's never a bad idea, you can never have too little voltage drop!

[@joekirklin]

I love it, man. Very scientific approach, and I TRULY APPRECIATE you showing us the mods when they don't work (or even make things worse). New subscriber!

[@LockyourHubs4WDing]

Thanks mate I appreciate it!

[@1987FX16]

5:53 I think the reduction in performance was from the port taper removing material and lowering the compression ratio, lowering it's volumetric efficiency. Also the exhaust tubes possible could have introduced exhaust scavenging which would lead to the valva timing problem you mentioned. It is like you said a 2 stroke and the exhaust chamber volume/shape matter for proper exhaust scavenging.

[@benhitchcock3057]

Great content, I'm loving this series. Like you I also went through a similar process when I got a new compressor, however all I did was upgrade the hose that connects between the compressor and the tyre (much shorter, higher diameter, better gauge, better tyre valve fitting). This made enough of a difference that I didn't need to upgrade anything else. I don't think the extra mods have caused it to be slower, I think you're just seeing artefacts - normal experimental deviation. Looking forward to the rest of the series.

[@LockyourHubs4WDing]

The air chuck upgraded, or the valve stem upgraded?

[@benhitchcock3057]

Just the air chuck, I didn't change anything on my tyres. The hose that came with my compressor was terrible, it restrictions all the way along it. My upgraded version is straight through all the way from the compressor to the tyre.

[@LockyourHubs4WDing]

@@benhitchcock3057 sounds a lot better. When you reach high levels of flow, like when you have tanks, removing the Schrader valve improves flow no end. It's just the time it takes to remove and then replace it after inflation.

[@1987FX16]

​@@benhitchcock3057I noticed this even on my Smittybilt 2781. The original tire chuck and yellow coil hose would show 25psi of back pressure from running open air through the tire chuck and with the deflator pressed down open it showed 15-20. The whole yellow coil and chuck and very restrictive.

[@79series]

How does this not have more likes. 10 likes from me.

[@LockyourHubs4WDing]

😂😂 thanks!

[@faawks]

Hey mate, love the video series, I have a few of these compressors, one of the things I noticed is when using them for long duty cycles they get extremely hot due to the fins on the heads not actually making contact with the cylinders, I'm planning on doing something to get the cylinders to cool better. But even as it is, I've been using mine with a 90psi switch as an onboard air system and it works pretty well with a 4L tank, I have another feeding a 10L tank but it's way too big, that's the one that needs extra cooling. Also, something to think about, your times might be increasing/decreasing as the grease inside gets pushed to areas where it's not doing much.

[@LockyourHubs4WDing]

I was thinking about using some thermal heat transfer compound to get the heat into the head, though I haven't tried it yet.

[@MegaDirtyberty]

@@LockyourHubs4WDing Use a thermal compound like they do in computers, something like Arctic Silver should do it.

[@1kontrabida]

Love the comparisons, thanks for doing this tests...if i may suggest for the next test is to have a small air tank, this will open a lot of possibilities for this compressor.

[@LockyourHubs4WDing]

I've done plenty of testing with vs without tanks for the ARB and TJM twin compressors, there are massive gains to be had!

[@andrewcox710]

It would be interesting to take another stock compressor and just fit the plumbing. Then remove it and just do the ports. To see which variable has the best impact in isolation instead of compounded mods.

[@LockyourHubs4WDing]

You're right, I'm almost tempted to pick up another compressor to do exactly that!

[@baileycocks]

@@LockyourHubs4WDingthey’re on sale atm $139! May as well 😉

[@trd4x429]

Great video! Cannot wait for the next version. Thank you!

[@joellewis8320]

Gone this far, can't stop now.

[@LockyourHubs4WDing]

That's what I'm thinking!

[@maddan_78]

^ @@LockyourHubs4WDing this... lol about to start a similar journey myself... to try improve performance to fill a tank and then pump 4 tyres at once through an arb pressure module (auto set n forget pressures) interesting to see the decrease in performance, so keen to see the next vid

[@LockyourHubs4WDing]

The automated systems I tried (Jamec Pem Auto1000 etc) have really slowed down the flow (this includes the ARB digital inflator as a manual option). Especially an issue when you're filling multiple tyres. I assume the issue is using solenoid diaphram valves in the products as opposed to full flow automated ball valves.

[@maddan_78]

@@LockyourHubs4WDing with the arb only having an 1/8th inch manifold block, absolutely thats why i'm making my own valve set, with a 1/2 inch manifold and valves ;-)

[@evil17]

I’ve been enjoying this series with great interest & I am not an engineer, but my immediate thoughts as u were porting out the inside of the head was that you are decreasing the compression ratio in the cylinder area by removing that material & I wonder what difference u would see if that material (or more) was added as a formed shape up into this exhaust valve area on top of the piston, to fill this gap between piston & valve as the piston forces the last bit of air through the exhaust valve. IDK, maybe try a bit of 2 pack metal putty to form into this area. I’d make this a last mod after other tests in case it gives way. (Otherwise it may have been better not to have touched the inside area of the exhaust port other than making a tiny bit wider hole so as not to effect the internal ratio as much.) This may cause some other ill effects, vibrations or imbalances effecting its overall life, but in theory would increase ur cylinder area ratio maybe drawing in a little more air sooner on the downstroke, & then compressing it that little bit more at the top dead centre of stroke as well, could have a real effect on the output. Here’s something else to ponder, at 11,500 rpm that piston is pushing air through the exhaust valve at about 191 times every second. At least this compressor has o’rings for valve seating, on Dirt Lifestyle channel, his compressor had shitty non-seating valves with no o’rings. Thinner reads may allow for a quicker valve response & more airflow, but that would also be experimental & finicky to get right, maybe you could try using a thinner piece of a feeler gauge to experiment with this idea. I was also wondering if the copper manifold was maybe a bit large for this compressor, & if 3/8” copper tube may actually be better than 1/2”, putting a little more back pressure on ur exhaust valves. Q. What lubrication are you using? Because I heard a commenter on another channel say he had trouble with his compressor when he used a silicone based grease & compressor wouldn’t run right, so he removed it and applied a little gun oil and it has been running good ever since. Good job, lets keep modding this thing, & see if u can get any more real performance improvements before u try and let out the magic smoke, but it definitely needs a dose of 24v at some time in the name of science & because you can. If you don’t blow it up first you will have a great compressor. Cheers

[@LockyourHubs4WDing]

I did think about "lumpy top" pistons, to increase the compression ratio, though being die cast aluminium, though I probably wouldn't have too much luck TIG welding it. Firstly for lube, I tried a little lithium grease, then dielectric grease after that. I didn't notice an unloaded rpm difference between the two, so assume the frictional differences are negligible.

[@rjm7168]

Very thorough and scientific testing. Amazing thst all mods excep electrical made it worse. I'm wondering if the ambient air temperature played a part in that. Also, would like to see thd electrical mods testing duplicated. Hard to believe that just disassembly and cleaning would make such a big difference - which is what you seem to be suggesting when you discount the huge improvement from the electrical mods.

[@Innov8cnc]

Those reed valves can be a bit awkward to seal after re assembly, you may have a valve leak.

[@LockyourHubs4WDing]

Quite possibly, I initially thought that as well after the first 3 tests, so pulled the heads off and checked everything, then ran the test a couple more times and got identical results.....

[@craigclarke1628]

Simon, you referred to an inlet to outlet port ratio, is this for a four stroke engine or for a compressor? Could the ratio be different for a compressor due to the work of a compressor is entirely on the compression stroke whereas an engine does its work on the expansion stroke. Great video and great use of measuring equipment to verify results.

[@LockyourHubs4WDing]

Internal combustion engines are essentially air pumped with a little combustion thrown into the mix! Even standard, the Thumper (and other) compressors always flow more on the inlet side than the outlet.

[@craigclarke1628]

I was thinking of the pressure difference between a compressor reservoir and atmosphere. There is little work on pushing exhaust gases out by comparison to compressing air to 100 psi plus.

[@craigclarke1628]

Probably not relevant in this instance with port size being limited by the head gasket etc.

[@rjm7168]

Not sure what you nean about valve timing but would like to see what can be done for even faster inflate times. Also, would like to see the effect of inflating from 20 psi to 50 psi, which is more realistic (for a full size truck).

[@biagiopasseri6189]

Send it mate

[@LockyourHubs4WDing]

I think 24V is in it's very near future!

[@Quarantined_AU]

I recall the original baseline time of 113 seconds was, in your words (more or less), probably due to something wrong with that particular Thumper Max II (faulty?). Are you planning to re-test another one, out of the box? Just to compare if it is more or less similar to those 44 seconds after the electrical update (solenoid) or the horrible 113 seconds. It will be quite useful to find out if it was a dud one or such relatively simple mod gives such a massive improvement. Thanks mate.

[@LockyourHubs4WDing]

If I can get hold of one, yes.

[@stiles3711]

I want to see you test this thing at 24v. You said it will run like gangbusters or let out the magic smoke, but i think there are two other probable outcomes. One would be it runs under load just fine at ~ half the current, but the motor runs cooler cause of less copper losses. Or it runs at a higher loaded rpm, with an increase in current over half the 12v test. Pump performance should increase if volumetric effeceny isn't taking a nose dive at this rpm. With more power being generated you could see an increase in mechanical failure rate. If you xould measure the difference in no load rpm 12v vs 24v, but you probably have to put a halls sensor on the motor shaft. I have 2 napa branded pumps that I am going to run on 24v, i was thinking of running them in series but the packaging may become an issue so i want to test running one at 24v with pwm square wave triggering a ssr. I want to see what pump performace does at lower RPM or current limited. I'm wondering if the pump is efficiency limited at high RPM. Are you concerned about the motor's insulation not taking 24v. My guess is IR being too low is the least likely of my speculated outcomes. Maybe I'll borrow a megger and figure out how to test a DC brushed motor, naw I'll just send it.

[@LockyourHubs4WDing]

You can measure no load rpm using a current clamp and oscilloscope, just measure the duration of the current peaks and divide by 2! No need for a hall effect sensor. Using PWM to vary speed is interesting, the SSRs generate a decent amount of heat, so heatsinking will be mandatory. The insulation should be fine at 24v not worried about that at all.

[@craigtomkinson2837]

Cool Ep

[@LockyourHubs4WDing]

Thanks mate!

[@LimestoneCoastCustoms]

It's quite funny re the mods, but it sure proves the electrical side is very often overlooked. I'm sure most of the mods we did on our cars in the 80's actually made them slower (they just "sounded" fast 🤣🤣) So not just the timing, but how about the friction on the bottom end? I wonder what kind of bearings are used??

[@LockyourHubs4WDing]

Being not a pressurised lubrication system, I would be surprised if it was anything but ball bearings.

[@nathanielpulling]

Increasing the size of the lines is generally counterintuitive on these smaller compressers. Now you have to fill that massive line. So air moves slower than if it was in a smaller line. Hence taking longer times. There's several videos of people using 4-way tire inflation systems on KZbin comparing 3/8 to quarter inch lines. 1/4 inch flows more are cuz it doesn't have to fill up as much space. And your valve stem is a choke point. The compressor moves too much air to push through one valve stem.

[@LockyourHubs4WDing]

You're possibly right, I think the larger tubes are hampering the performance.

[@Timb077]

you can open your intake, open the exhaust, but you need a cam to find that HP and a better time down the track.......

[@LockyourHubs4WDing]

Exactly!

[@crom29a]

😎👍

[@LockyourHubs4WDing]

👍

[@heavymonty]

did you notice a difference in how loud it was between any of the tests?

[@LockyourHubs4WDing]

Only when I accidentally put the heads on the wrong way and plugged the pressurised tyre into the (now) inlet! Other than that, no.

[@einfelder8262]

The problem with reducing your airing up times is all the other gerbils you're off-roading with will still take the same time they always did, being 15 minutes slower than you. Then they'll want you to pump up their tyres too. You can refuse, and make yourself a brew while they're at it, but you become unpopular for that too, unless you make them all a coffee to have while they're lazily pumping. It all seems such a waste of ingenuity when you factor in all those downsides. Yes - a slight piss-take, haha. My take from this is to upgrade the electrics because the gain is the biggest and easiest, but I'll wait till the warranty runs out since Kings won't replace it if it's modded.

[@LockyourHubs4WDing]

Mine was modded the second day out of the box, it's probably cheap enough especially when on special, to have a little fun and the warranty be damned! My preoccupation from air up times comes from the fact I run bigger tyres than my mates, and even with the ARB twin, was always one of the last to finish airing up.

[@user-fw6eg3hc8f]

@@LockyourHubs4WDing So run a second compressor :) Just make sure you rev the engine a bit to like 1000rpm to get good power from the alternator

[@MiniLuv-1984]

That was surprising...take away, put the solenoid in and leave it alone? Well, you got your 500 likes...24V please! ( 172 @ 15:37 + 328 clicks of mine) - For crying out loud, you released this on Saint Bathurst day...do you really think you can compete with that? :)

[@LockyourHubs4WDing]

I launched the video at 6am because the telecast started at 7am!

[@Bigcountry_littlelegs]

The problem is the smoke is still inside the motor you need to remove it for increased performance and less drag.

[@LockyourHubs4WDing]

I'm thinking maybe around 28v from a 24v electrical system may be able to help out there! We'll see how many likes the video gets, though I have a hankering to throw near 30 volts into the Thumper and stand well back 😁

[@michaelsimpson9779]

Wouldn't the magic smoke have a lubricity factor?

[@Bigcountry_littlelegs]

@michaelsimpson9779 only the devils smoke does, non devil smoke just creates drag

[@whiteyeti6687]

Your video is awesome but it feels like your throwing shades at another youtuber🤦‍♂️im no pro but i think the plumbing can be improved; maybe a couple of check valves on the Y may improve it's performance.

[@LockyourHubs4WDing]

You think there could be reversion ? I've never seen a check valve used in an air manifold though.

[@user-fw6eg3hc8f]

@@LockyourHubs4WDing I'd say most even halfway decent home compressors have a check valve at the tank.

[@LockyourHubs4WDing]

@@user-fw6eg3hc8f I'll have to check out the compressor in the garage.

[@majed901]

The results are completely unexpected

[@LockyourHubs4WDing]

And disappointing!

[@aldoortega2170]

Lost me with all the giggly do…. So all the non electrical modifications made it worse…. Got it

[@LockyourHubs4WDing]

Pretty much!

[@corey797]

It also doesnt even look like the electrical modifcations made a difference... at the end of the video you stated that you removed the shrader valve between the original test and the electrical test, it makes more sense that that was the only thing that made a difference

[@corey797]

You would have to test a completely standard one with the valve removed to make any of this testing useful