The Big Fuel Test: Meth Injection Adds 42 RWHP

big fuel test header image

This article is the third of our “Big Fuels” test series (Article 1–Introduction, Article 2–Boostane), which spans 13 different test fuels, octane additives and injections. During this article, we will be reporting on the testing of three different injections head on: water injection, a traditional favorite of the Ford side and widely used in World War II to boost power output and longevity of fighting planes, Boost Juice injection, which is a mix of water and methanol you can buy from Snow Performance and have shipped to your door, and the traditional GM tuning crowd’s mainstay – straight methanol.

Meth injection has always been one of my personal favorites, and before methanol, we used Isopropyl or Denatured Alcohol (from our days back in the ’90s when tuning Buick Grand Nationals) to provide the cooling and/or octane needed to run more boost and spark advance. In the old days, we transformed our turbocharged Grand Nationals from mid-13-second cars on 93 pump gas at 14 psi of boost to mid/low 12-second cars at 20-22 psi because of these alcohol injections, so you can understand my fondness for meth injection kits. This was before E85 was available as well. This time around, we will compare our three injections against one another, and then to our existing tests of 93 octane pump gas and BOOSTane.

During the endless debates inside our offices, our instructors banter about the pros and cons of meth injection, but the debates cannot deny one thing–they make power and they do it well.

The meth injection kit used in our testing came from Snow Performance, and was their Stage 2 kit with the VC-50 controller, which serves as a boost gauge as well as the controller. The controller also displays fault codes for the system, as well as pump duty cycle, on and off points, and more. It also allows for easy prime testing of the system with one of three pushbuttons, as well as configuration of two stages of injection should you need it.

When asked about pump longevity, Snow didn’t recommend any particular mixture of methanol percentage to avoid, noting that their pumps are also used in the BMW M4 GTS as factory equipment; which means they are of the highest quality possible and have passed OEM-level durability testing.

One specific variable that Snow did mention was about spark plug gap. According to Matt Snow, one of the most common problems that people experience when tuning this type of injection is having set their plug gap too wide. When the plug gap is set too wide, the tendency is for the spark to be unable to jump the gap–and thus gets blown out or drown in the fuel mixture. This is commonly felt as a misfire during wide open throttle, and can be cured by gapping down. Most tuners advise .025-inch to .030-inch gap under these conditions.

The kit included everything needed to get up and running, from the methanol-specific pump (to protect against corrosion from long term use) to the hoses, nozzles, and progressive controller needed to make the whole thing work.

This introduces us to two specific points I like to make to customers considering buying meth injection kits. First, whatever you buy, be sure it’s progressive; and second, be sure it’s of the highest quality you can afford. Yes, you can buy a cheap meth kit, but speaking from experience, quality kits cost less money in the long run than cheap kits cost you in damage over the short run. Cheap kits have cheap parts, cheap connectors and hoses, and that makes for danger; and danger invariably creates broken parts and a lightening of your wallet. The last thing you want is some cheap kit failing when you’re making full power. Been there, done that, and lost a piston from it (circa 2000 with my old Grand National, using an off-brand, non-progressive kit).

So, what is progressive and why is it important? A good progressive meth injection kit has the ability, through a MAP (Manifold Absolute Pressure) sensor typically, to sense how much pressure is present (boost) and spins up the pump to provide more injection as boost increases. Providing an increasing quantity of injection with boost in this manner is key to a system that functions correctly in conjunction with the engine’s needs.

One last question remains – nozzles. Everyone thinks more is better, but in the case of meth injection, if your nozzles are bigger than you need to support your power level, you end up fighting a drowning engine. Too much meth / water from oversized nozzles and you cool the chamber too much, making for poor power. You can’t do that if your combustion chamber is a wet puddle, which the tuner can easily establish when doing his/her job. So, as the tuning goes, we start with one nozzle and a small or medium sized one at that, or a dual nozzle kit with 2 small nozzles. It’s better to start small and work your way up as needed for additional cooling.

Our test car, a 2016 Chevrolet Corvette Z51–6.2L LT1 engine with direct injection, equipped with a Vortech V3 supercharger and intercooler, blower spec’d camshaft, long-tube headers and high flow exhaust–was the recipient of a Snow water-meth injection kit. Our friends from 360 Customs, Inc. in Brandon, Florida were kind enough to provide the installation expertise.

If you haven’t seen our previous tests, you should familiarize yourself with our test results of pump gas and BOOSTane. You can see the previous articles Introduction and baseline results, and BOOSTane results over here.

The car produced 574-rwhp on pump gas, and 599-rwhp safely when BOOSTane was added – thus making BOOSTane our reigning champion to date, but read on to see how the injections stacked up.

Each test performed was done with the same 4th gear pull, the same test range of 3,000-6,200 rpm. For all tests we held the boost the same, but used spark advance, as well as adjusted the air/fuel ratio to find the best safe power each fuel would make. We used HP Tuners for the tuning. So, let’s get to the head to head comparison of the injections and see how they made power.

Performance Numbers

Let’s begin with Snow Performance’s Boost Juice. This was the surprise of the tests for me, and for our team as we had placed our bets on what we thought would make really good power.  boost juice

Boost Juice actually consists of 50-percent methanol and 50-percent water, and because of that, we thought it had no chance of making anywhere near the power straight methanol would, but the law of diminishing returns slapped us around a bit here. We found Snow’s Boost Juice to be within 8 rwhp of straight methanol, making a peak of 608 rwhp (up from 574 rwhp with just 93 pump gas), compared to 616 rwhp for straight methanol, both of which making new records for our tests at this point in the testing. Below are the results for Boost Juice on our Mustang Dynamometer.


You’re probably asking yourself why we find that to be good – leaving 8 rwhp on the table. Well, normally you would be right, and we would want all the power, but in this case, there’s a few positives to leaving that power on the table a shop owner or enthusiast should consider.

In favor of Boost Juice, you get the non-flammable aspect. This means that when the car leaves your shop, you installed a product that wasn’t another flammable fuel. Why is this important? If the customer has an accident, Boost Juice won’t light up and create fire. In fact, testing has actually shown that when Boost Juice was sprayed directly onto an open flame, it extinguished the flame. So if there happens to be a leak or break in the system from trauma, the safety margin is there to prevent fire (methanol burns clear, incidentally, but won’t burn with a 50-percent or higher mix of water). Also, you can supply Boost Juice easily to the customer. It ships straight to your customer’s door. Much easier than finding and storing straight methanol.

Lastly – most people only look at peak power – and yes, methanol makes 8 hp more there; but looking at average rear wheel torque and horsepower, we see exactly the same average torque and only 5 hp more on average when straight methanol was used. These factors helped us see a niche when Boost Juice is appropriate, such as when safety is a primary driving concern, such as street vehicles.

Next up are the results for straight methanol. As mentioned earlier, the methanol made best peak power–616 rwhp was a huge leap over the pump gas results of 574 rwhp. Taking 24.5 degrees of advance safely with no knock, it was much more than the 15 degrees tolerated by pump gas. This extra advance served two purposes for us in this test, allowing the added spark advance the engine wants to make power and also consuming the extra fuel added by the methanol injected.


Normally, this is the part where we talk about the octane rating of the fuel or injection we are discussing – but this time we cannot do much more than generalize – and say a generally accepted value for the octane of straight methanol is about 100-110. Why is this?

The methods used to judge the octane rating of all fuels use a carbureted test engine prescribed by the ASTM (American Society for Testing and Materials). The problem is that the air/fuel ratio adjustment ranges of a carbureted engine are limited and cannot truly achieve the ratios pure alcohols like methanol require to meet air/fuel testing ranges and properly judge the octane rating.

So how is the testing done? Alcohol fuels are blended with normal fuels, and improvements are then estimated/extrapolated into octane values. An excellent article from Sunoco on the subject can be found here.

Results of the methanol injection show more spark tolerance (24.5 degrees advance with no knock) and excellent power production, as well as reduction of intake air temperatures by 25-40 degrees Fahrenheit.

methanol final pull

Lastly, we have the results of the water injection. Normally, we save the best for last, but we really didn’t see huge gains using water. The water injection performed the job of reducing intake air temperatures but since we do not increase boost (only spark advance) during these tests, we could not see if this reduction would have helped further if adding boost. We do know that without the addition of methanol of any kind, water injection on its own is at a disadvantage because there’s no additional energy being injected.

Below is the chart of all three tests compared. You can see the water injection as the solid lines, and the Boost Juice and methanol making much more (dashed lines). Power output for the water injection was 577 rwhp / 514 rwtq, versus 608 rwhp / 535 rwtq for Boost Juice, and 616 rwhp / 542 rwtq for straight methanol.

injections compared


Results Summary
peak rwhp through meth injection

After testing the injection products, here’s what we think:


  • Meth injection kits are about $500-$750. The gains we observed (574 rwhp on pump gas 93 octane versus 616 rwhp with methanol injection added) are large. Gaining 42 rwhp for $500-$750 is as economical as adding a good aftermarket camshaft to a typical LS engine.
  • Boost Juice is a great choice given its safety margin and 34 rwhp gains (6-percent power gain on 574 rwhp), or 82-percent of the gains that straight methanol made.
  • Straight methanol is the overall injections winner given its overall best power gains of 42 rwhp, (7.3-percent power gain on 574 rwhp).
  • Water injection is the least favorable, as it has no added energy from a fuel such as methanol.


  • Stay away from cheap meth injection kits, they can cause damage to your engine and wallet.
  • Most customers/enthusiasts can understand their added power comes from the methanol, Boost Juice or water in the reservoir tank, but a select few may ignore the low level warnings and can cause damage to their engine.
  • Screen your customer base accordingly before recommending a methanol injection kit.

We rank the tuning difficulty for water injection as 7 out of 10 – “Difficult.”

We rank the tuning difficulty for Boost Juice as 6 out of 10 – “Difficult.”

We rank the tuning difficulty for straight methanol as 6 out of 10 – “Difficult.”

We ranked them all difficult because dialing in the tune calibration not only required offsetting gasoline for methanol, which was simple, but we had to switch to Speed Density from our preferred MAF tune. This was required because the Gen V vehicles (such as our test car, the C7 Corvette) have a very sensitive MAF sensor (unlike previous generations), which wanted nothing to do with any of the above injections being sent across its element. This forced us to start our tune from scratch and go to a completely VVE (Virtual VE) tune, which we performed using HP Tuners.

In order to avoid this, we would have had to fabricate the MAF sensor tube and place the nozzles further upstream from the MAF sensor – but due to time constraints we could not perform this in the time we had available. Also, in the interest of fairness to all the other fuels, we performed this test like we assumed the average shop would, and knowing they would be least likely to fabricate a new MAF tube, we went that route and the required Speed Density (Virtual VE) tune.

Driveability is very good (no cold start issues, like you see when running ethanol based fuels, for example).

Tuning Notes

Typically, when tuning a car for meth injection we recommend the tuner find the limits without the meth injection first. For example, if the car will tolerate 8 psi of boost on the fuel you plan to use, but knocks at 9 psi, you have found the limits without the meth injection. There’s no need to start the injection as soon as boost comes in, but you will need it in sufficient quantity by the time 9 psi comes in; so we set it 2-3 psi before that point and let the progressive ramp-up work in our favor. If boost is not easily adjusted (such as in our case, with a fixed boost system from the Vortech supercharger – unless we were changing pulleys) the same process is applied to adjusting spark advance upward until knock is found; which is exactly how we performed our testing for this series.

It should be noted that when tuning with Boost Juice and straight methanol, there is a distinct change to the fueling of the car. Since methanol is also a fuel, it is necessary to reduce the gasoline injected to offset this in order to achieve best performance results. We typically see that if you do not do this, it will richen the engine by one full point in AFR or more. This can mean that if the engine was running 12.0:1 AFR at full throttle before adding meth, it will be 11.0:1 or richer if you do not compensate by commanding less gasoline in the tune. We command less gasoline to allow the methanol to do its job of cooling and enhancing octane; thus allowing more boost or timing to be run. Some tuners do not do this, and run very rich (but have no power gains, only cooler intake air temps); but we do not advise this method.

Power was safe at a reasonable 12.0 -12.5:1, keeping in mind that direct injection cars tend to prefer .5 AFR leaner than port fuel injection cars.

What’s next? Our tests lead us to the race fuels (non-ethanol-based) next. These fuels include VP Racing’s C9, MS103, MS109, and C16. Will these race fuels have enough to dethrone our newest champion, methanol injection? Can they beat 93 octane pump gas and methanol injection’s best of 616 rwhp? Watch out for the next article, and find out for yourself!

Article Sources

About the author

Bob Morreale

Bob Morreale is the author of several tuning related books and courses for The Tuning School. Bob began programming using BASIC in the mid-'80s in 2nd grade; and progressed to other languages, including HEX, self-taught. While Bob can program, he prefers to do tuning related R&D on new vehicles, writing courses and then teaching the tuning process. Bob has over 18 years of tuning experience, starting with the legendary turbocharged 1987 Buick Grand Nationals to modern LS/LT and Ford powered vehicles. Bob has also written numerous technical articles for industry-standard magazines and conducts “Tech Tuesday” video interviews for The Tuning School. Bob enjoys road-racing and drag racing.
Read My Articles

Late Model LS Power in your inbox.

Build your own custom newsletter with the content you love from LSX Magazine, directly to your inbox, absolutely FREE!

Free WordPress Themes

We will safeguard your e-mail and only send content you request.

LSX Magazine - The Late Model GM Magazine for Camaro


We'll send you the most interesting LSX Magazine articles, news, car features, and videos every week.

LSX Magazine - The Late Model GM Magazine for Camaro


We will safeguard your e-mail and only send content you request.

LSX Magazine - The Late Model GM Magazine for Camaro


Thank you for your subscription.

Subscribe to more FREE Online Magazines!

We think you might like...

Classic Chevy Magazine
Drag Racing
Engine Tech

LSX Magazine - The Late Model GM Magazine for Camaro

Thank you for your subscription.

Subscribe to more FREE Online Magazines!

We think you might like...

  • chevyhardcore Classic Chevy Magazine
  • dragzine Drag Racing
  • enginelabs Engine Tech

LSX Magazine - The Late Model GM Magazine for Camaro


Thank you for your subscription.

Thank you for your subscription.

LSX Magazine - The Late Model GM Magazine for Camaro

Thank you for your subscription.

Thank you for your subscription.