Definitive Foam Gun Ratio Charts

There was a thread here recently asking about the correct ratio of soap to water to use with a foam gun. I was interested in this topic because I just bought a Gilmour gun with a 32 oz. reservoir and I like to use CGs Citrus Wash Clear shampoo. My concern is that although this shampoo is made as a daily wash (meaning it will not strip your wax), it will indeed strip LSP if applied in a more concentrated ratio. It is easy when using a bucket wash to get it right but the foam gun dilution settings make the ratios a bit more complicated.

I just came across a ratio chart for the Gilmour using several well known and popular foam gun shampoos and I thought I would pass it along for your information. A fellow by the name of "denzil" at another forum put this together several years ago. Although it is rather long it makes perfect sense if you take the time to read it and it is the best chart and mixing explanation on this subject I've seen. If you wish to skip the mathematical explanations, just go towards the bottom for the charts. The following was prepared by "denzil":

"Since Gemini suggested that we have a thread dedicated to foam gun ratios, I figured I'd volunteer my time for it (hey I'm on summer break and I love helping everyone at DB). However, I'll only be offering what I know for my Gilmour Foamaster II #95QGFMR.

The particular Gilmour model I have has a multi-ratio dial with 5 mixing head settings. All these settings/specifications can be seen at the Gilmour website for your own personal reference.

The most common used setting, at least for me anyways, has always been the C setting with an output volume of 4 oz./gal. In most cases car wash shampoos suggest having 1 oz of car wash shampoo added for every gallon of water. Initially you might ask, why not just keep it simple and use the A setting where its output volume is 1 oz./gal? The answer is the foam gun is not capable of sucking such a viscous liquid through its siphon tube. Now I can not attest to whether this is true or not but I don't dare try it myself. However, there is the exception with some of those cheaper car wash shampoos in which they are pretty watery (and probably not great car wash shampoos altogether).

There's also the B setting (2 oz./gal.) which can be used as well but just remember that your shampoo mixture may still be too viscous for the foam gun to handle. One nice thing about the B setting though is that you will not be required to refill as often as you would as the C, D, or E settings.

Since I mentioned the D and E settings, I will say that these settings are definitely not ideal. Their output flow, 6 oz./gal. and 12 oz./gal. respectively, is just too fast and will require a lot of refilling! For me, these are simply not an option almost all the time but perhaps maybe it is for others. I won't even bother with the E setting as it's just not practical for me but I will mention the one occasion in which the D setting is actually useful later. Anyway, on to the hard numbers!

We'll start with the most common dilution, 1 oz of car wash shampoo to 1 gallon of water. The 95GQFMR is a quart container which is the equivalent of 32 oz. At the C setting, we have an output flow of 4 oz./gal. Now in essence, we want 1 oz of that 4 oz./gal. flow to be car wash shampoo and in order to achieve that, we must have a 3:1 ratio in the 95GFQFMR container. So how do you do that? It's pretty simple. You add 8 oz of car wash shampoo and 24 oz of water so that your ratio comes out to 3:1. So what if you want to use the B setting? Sure, that can be done. Your ratio will then effectively be 2:2 or 1:1 and you will be adding 16 oz of car wash shampoo and 16 oz of water. The only concern with using the B setting is whether or not your mixed solution will be soluble enough to be sucked up through the siphon tube and provide the proper volume output. Of course as I mentioned before, the B setting will require less refilling than using the C setting which is nice.

Ok, so what about car wash shampoos such as Chemical Guys Citrus Wash & Gloss? Well, they have 2 different dilutions for separate applications. There is one dilution that is ideal for the weekly wash in which 1/2 oz of CWG is required for every 2 gallons of water or 1/4 oz of CWG for every gallon of water. There's also the paint cleanser dilution which is 2 oz of CWG for every gallon of water.

In order to achieve the proper dilution for CWG as a weekly wash, we need 1/4 oz of car wash shampoo for every gallon of water. Now this gets a little tricky with the 95QGFMR and I may lose you in its translation. Since our previous dilutions have been 1 oz of car wash shampoo to 1 gallon of water, we need to figure out what setting we'll be using before we dive further into the numbers.

If we want to go with the most common C setting, the short answer is we divide by 4. Now if we divide our original 8 oz of car wash shampoo by 4, that gives us 2 oz of car wash shampoo and leaves us with the remaining 30 oz of the 95QGFMR to be filled with water. To fully understand how this calculates out, we have to remember that at the C setting we are outputting at a rate of 4 oz./gal and we want 1/4 oz./gal. If you think about it, 2 oz of car wash shampoo to 30 oz of water is simply 30:2 or 15:1. However, we are still at a ratio to 1 and what we really want is to 1/4 or .25 in order to understand the numbers in a simpler form. To keep it fairly simple, we divide both sides of the ratio (15:1) by 4 which gives us 3.75:.25. Well what do you know, these two numbers add up to a total of 4, meaning 4 oz, which also meets our requirement of 4 oz./gal. output flow.

So what if you want to use the B setting? It's pretty simple. Just use 4 oz of CWG and 28 oz of water, with the ratios working out as follows (keep in mind these are all equivalents): 28:4 -> 14:2 -> 7:1 -> 3.5:.5. -> 1.75:.25.

Okay, now that's out of the way. What if you want to use it as a paintwork cleanser? So it's 2 oz of car wash shampoo to 1 gallon of water. Ok, simple enough but it's doubtful that you'll be using the B setting for this one. Essentially if you do decide to use the B setting you'll have to fill the entire container with solid CWG, non-diluted. As I mentioned before, the 95GQFMR will not be likely to successfully suck this viscous liquid through it's siphon tube. So C setting it is and it's simple. You need 2 oz of car wash shampoo for every gallon of water and at the C setting we have an output flow of 4 oz./gal. Essentially, we just need a 1:1 ratio here, 16 oz of CWG and 16 oz of water. Now if that mixture may be too viscous still (I haven't tried it myself yet), this would probably be the only occasion in which the D setting would be feasible, IMO. At the D setting we have an output flow of 6 oz./gal. which would mean that in order to achieve a 2 oz of car wash shampoo for every gallon of water, we'd need a 2:1 ratio, which roughly comes out to 11 oz of CWG and 21 oz of water (the ratio isn't exactly 2:1).

Ok so that was a lot of reading (if some of you actually read it all) but below you will find the short and sweet version for your reference. I'll continue to add to it if need be. I hope my English was structured well enough to understand, LoL. Either way, I hope it helps out some of the fellow foam gun users who are still new to its dilution ratios or just need some refreshing of their memory. Enjoy!

Gilmour Foamaster II #95GQFMR
Any car wash soap at 1 oz per gallon of water
C setting - 8 oz of any car wash soap + 24 oz of water
B setting - 16 oz of any car wash soap + 16 oz of water

Chemical Guys Citrus Wash & Gloss at 1/4 oz per gallon of water (weekly wash), also applies to Citrus Wash & Clear and Maxi Suds II
C setting - 2 oz of CWG/CWC/MSII + 30 oz of water
B setting - 4 oz of CWG/CWC/MSII + 28 oz of water

Chemical Guys Citrus Wash & Gloss at 2 oz per gallon of water (paintwork cleanser)
C setting - 16 oz of CWG + 16 oz of water
D setting - 11 oz CWG + 21 oz of water

Detailer's Pride Xtreme Foam at .4 oz per gallon of water
C setting - 3.2 oz of DPXF + 28.8 oz of water
B setting - 6.4 oz of DPXF + 25.6 oz of water

Detailer's Pride Xtreme Foam at .5 oz per gallon of water (for simplicity and/or rounder numbers)
C setting - 4 oz of DPXF + 28 oz of water
B setting - 8 oz of DPXF + 24 oz of water".

Great stuff and very helpful

Hey there Shortspark, great thread! If I have DPXF, when should I follow the 3.2oz of formula over the 6.4oz?
Thanks!

Great writeup and contribution!! :props:

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Originally Posted by BobbyG

Great writeup and contribution!! :props:

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Thanks Bobby! But all I did was copy it from somewhere else.

Quote:

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Originally Posted by ARizzle

Hey there Shortspark, great thread! If I have DPXF, when should I follow the 3.2oz of formula over the 6.4oz?
Thanks!

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You should follow the 3.2oz if you use the C setting on the gun. You should follow the 6.4oz if you use the B setting on the gun.

Now, why the difference? Well, everything is diluted in the jar, that is a given, then it is shot out of the gun at a certain water ratio, depending on the setting of the gun. The author of this article seems to think C would be best for most applications and is the most common setting. It requires a certain dilution ratio such as he has provided (for the specific shampoos he mentions). It makes sense since it is in the mid range which should give you plenty of suds and foam and yet not waste the product and make you keep filling the gun.

The real reason to adjust settings is to get the foam out of the gun in the first place at the rate that both works and also that suits your personal preference. Just like the real reason (again, as the author intimates), to dilute the product in the jar is so that the product will be "thin" enough to leave the gun in the first place. Some shampoos (especially CG shampoos) are really thick, even thicker than the thickest I formally used which was Griot. Without proper dilution in the jar, these shampoos could not escape. Maybe they would in a more powerful cannon with a high power gas sprayer but not through a house water hose like you use with a foam gun.

The truth be known, the best thing to do is understand the math principal involved that the author of the article gave us. That is a constant and never changes in principle; however, the figures change constantly because of differences in soaps and your personal preferences. But then get the shampoo of your choice and experiment on your own with different dilution ratios and different gun settings. I personally like a little more "runny" foam while many people prefer a thicker or "shaving cream" kind of foam, something like you might get in a cannon. After a few times you'll know just what works best with your favorite car soap.

My gawd thats a ton of soap for cw&g for the stripping setting on C. I thought it was 1 oz per gallon to strip. I guess 2 oz is guaranteed to strip lsp for sure. You must buy cw&g by the gallon or you'll be spending a lot buying the 16 oz.

That's a main reason why I abandoned foaming products years ago...you have use a lot to get any kind of decent results compared to other methods available. Plus I'm in the minority when I say I don't want foam and soap all over my driveway running out into the street. Not cool in my book although most may think its somehow cool or impressive.

If I have to use 4 or more ounces of any soap to wash my car I'm looking for a better way no matter how cool it looks to some.

I just checked the label on cg cw&g. It's 1 oz per gallon for paint cleanser dilution. On C setting that would be 8 oz of soap to 24 oz of water correct? That's still a ton of soap and is that enough for only one car or is it good for multiple washings?