TheSamba.com :: View topic - H20 injection naturally aspirated head temp test with results

Tue Apr 22, 2025 4:12 pm

This was rather exciting! First the results! Test setup is a bus with 2180cc all the bells and whistles, 9:15:1 compression. Test road completed in numerous back to back test pushing it 75mph into the wind up the same long hill to achieve a max CHT of 362°. Max h20 injection spray achieved 44° lower head temps. Half flow was nearly identical at 40-42° lower head temps. Minimum flow was 15° lower head temps. Ran -20 blue windshield washer fluid and saw a minimal increase on the air fuel gauge.

The setup is as follows: 300psi pump and two 30cc nozzles. Each nozzle is located dead center above the custom velocity stacks I had made for this experiment. I have a variable volt water pump controller and a variable voltage regulator in place of a TPS. This allows me to control pump output between 2 volts and 5 volts. It can be run with a TPS as well which I did on bench test but for now just testing manually. Went with the smallest nozzles available based on horsepower to water injection flow charts. Four nozzles would be too much water and two required the custom velocity stacks. The velocity stack assembly seals off the jet stacks but have a "snorkel" so they can breath without ingesting any water that may get past the bells. I have a couple small holes drilled into the base plates to drip off excess water also. The bells are angled inward to help catch as much mist as possible. Best atomization begins to occur around half flow, which probably explains the large gain in lower temps from min flow to half flow. More details later if I can think about it....

Tue Apr 22, 2025 4:18 pm

Wow!, once again thanks for taking the time to document and post your work!, now we have facts opposed to "stories". 8)

Tue Apr 22, 2025 4:30 pm

The first test run I thought I did all this for nothing lol. I did a lot of bench testing using tap water.....which made crusty deposits and goop which clogged the nozzles after sitting in my shop the past month while I've been traveling the globe. Went for the first test run, flipped the switch on and saw 0 difference. Took everything apart and cleaned all the gunk out and voilà, it actually worked as I had hoped. In fact way better! I was expecting MAYBE 30 degrees lower temps. It gets fussy if left on at idle, but can cruise continuously with it running without any hiccups. The purpose for this is I actually do a lot of cross country drives pulling a lot of crap up mountains in high summer temperatures.

Tue Apr 22, 2025 6:08 pm

The little 4mm festo ball valve hooked up to the cross bar , you can just see the aquamist nozzles in the manifolds . Just a 12v 80psi RV water pump and a 4 lt container for just filtered water under the back seat . I just switch it on in summer if working the engine hard .

works a treat as you have found out. why more bus owners don't do this leaves me puzzled . side effect is cleaner valves and combustion chambers .

better picture of the nozzle's on the Ghia .

Wed Apr 23, 2025 5:01 am

This is great stuff! Thanks, both of you!

It would be interesting to see if there is a difference between water/methanol and just water on it's own.

Also I wonder about a difference between injecting the water above or below the throttle plates. Below to me would be better from a corrosion in the carbs/throttle body standpoint if there is no temperature advantage to the above option.

Wed Apr 23, 2025 5:17 am

with carbs I think below the throttle plate is best , less chance of water vapour ending up in the float bowl area . (That was my theory anyway)
With injection ,I think above would be better for better atomisation .
no answer about the cooling difference between straight water ,verses WM .

Wed Apr 23, 2025 5:26 am

oprn wrote: This is great stuff! Thanks, both of you!

It would be interesting to see if there is a difference between water/methanol and just water on it's own.

Also I wonder about a difference between injecting the water above or below the throttle plates. Below to me would be better from a corrosion in the carbs/throttle body standpoint if there is no temperature advantage to the above option.

Each runner below the throttle body would have been ideal, but you get into a situation where it's too much water. You could of course increase methanol and then just reduce jet sizes. Timing 1 gallon of fluid with the pump on low setting gave an output of around 25cc on the 30cc nozzles. At high flow a 30cc nozzle was flowing about 45cc on bench test. I may try a 45cc nozzle today and see how it does. Mist patterns suffer on low with a 30cc nozzle, whereas a 45cc during bench test gave a good pattern on low. I think there's less likelihood of a clog too. A 30cc nozzle has a microscopic opening and tended to give inconsistent patterns among 4 different nozzles I was testing. The next issue is the water cell. I need to find a place to store at least a few gallons. More the better. 1 gallon won't last long on some of my drives if it's running continuously. Back and forth to my shop where there's 2 steep hills a few mlles long, or if you were drag racing, you don't need a lot of capacity. Another purpose for all this is I'm building up a 2387cc and will run a higher compression ratio than you might otherwise on pump gas. I intend to have these setups activate around half throttle or so. Since this actually works, I'm going to have my guy make another set of velocity stacks for idf44s that will go on that 2387. If anyone is interested in buying them I can maybe get a deal from the guy if there's enough interest.

Wed Apr 23, 2025 5:34 am

Wreck wrote: with carbs I think below the throttle plate is best , less chance of water vapour ending up in the float bowl area . (That was my theory anyway)
With injection ,I think above would be better for better atomisation .
no answer about the cooling difference between straight water ,verses WM .

Water getting into the float bowl area was the biggest challenge. These velocity assemblies seem to keep them dry. I used a gasket and a little smear of gasket maker between them too just in case.

"Snorkels"

The enclosed float area and the passages to the snorkels.

Top view. The goal was catch as much water as possible so it's not collecting below.

Wed Apr 23, 2025 8:26 am

I'm wondering if water injection could be controlled to come on only at high load and above a set CHT?

Max

Wed Apr 23, 2025 8:53 am

Max Welton wrote: I'm wondering if water injection could be controlled to come on only at high load and above a set CHT?

Max

You just need a way to get a reading of at least 2 volts to activate the system. A TPS is ideal because they're 0-5 volts typically and this pump controller can be adjusted to come on as low as 2v and be full pump output between 2 and 5v. I'm not at all an electrical guru, but there's probably some way to have an X temperature trigger an electrical signal within that volt range. You just wouldn't want it coming on at idle.

Drive to the shop this morning as follows: normal cruise speeds I do of 70mph. Rolling hills, calm winds, cooler ambient temps. Max CHT temps on the hills between 330-335 without h20. With h20 activated temps between 275-280. That's a hefty difference.

Another interesting thing is seeing how quickly temps respond to the spray. It's not instant like you see if you let off the throttle and engine brake down a hill. Takes a moment and then they slowly come down. Once they've gotten established, you can seemingly drive the piss out of it and temps don't move all that much. Turn the system off and they slowly rise back up. I don't feel any performance hits at cruise. Wouldn't be surprised if there's a slight gain just by how it feels seat of the pants.

Wed Apr 23, 2025 4:19 pm

If you want to add to your experimenting , instal an EGT gauge

Thu Apr 24, 2025 6:17 am

Max Welton wrote: I'm wondering if water injection could be controlled to come on only at high load and above a set CHT?

Max

More road testing yesterday. I did a "poor mans TPS" by fabbing in place an electric brake light switch onto the one webber arm. At the moment I have it so it activates the pump somewhere around 35-45% throttle if I had to guess. Basically anytime I encounter some load and begin to get into some throttle where head temps will rise. What this seems to have done is cap head temps to 335°. Approach a hill and where the temps begin to rise, the pump kicks in and temps stop rising and then begin to lower if it's a long enough stretch of hill. To answer your question, that's probably the best and easiest solution to have it curb temps.

I've put a couple hundred miles on it and have gone through about 2 gallons of h20, half of which has been on a level surface at very light throttle and full h20 flow just to see if I encounter issues like float bowl flooding or any kind of hesitation or power loss. So far there's been zero issues. I ordered 45cc nozzles since full flow on the 30s isn't causing issues. I anticipate a better mist pattern with the 45s as previously mentioned about the 30s being finicky. I also found water containers that will fit perfectly under my rear bench seat storage area (this is a camper converted bus). I can hold up to 12.5 gallons of h20 back there but will start with 6.25 gallons and maintain a 25% methanol solution, either running washer fluid or distilled water and adding bottles of HEAT. I don't want to be continuously filling it up on cross country drives. Albeit 12 gallons at a time would be a chore. I already reduce gas station stops because I fabbed an extended range slim 10 gallon tank dead center under the bus. I'll have to decide what's the best water capacity after this summers drives. On the to do list is get a bracket to fit an actual TPS. I'll gladly take ideas or solutions there as I haven't looked into fitting one. I will retune for the methanol solution and go down on the main jets. This may require to have it start injecting earlier throttle position and where the TPS is needed so that the pump controller can ramp up spray from low to high as I get into throttle. Ideally I have it tuned so air fuel ratios are perfect here at sea level, but as I get into mountains can just run straight water to lean the mixture back out, treating it like a jet change sorta speak.

Thu Apr 24, 2025 4:05 pm

be careful with how much volume , I learnt the hard way by turning up the flow at low throttle setting to clean the heads and valves before I was pulling the heads to do guides etc . It washed the bore , I had to hone the cylinders and re ring the engine . (the engine was missing because of the water volume)

Yes the small nozzles are a pain . I remove them and strip and clean them from time to time .

Snow performance had a muscle car WI controller , no longer available , it works off manifold vacuum and rpm .

Thu Apr 24, 2025 4:22 pm

Wreck wrote: be careful with how much volume , I learnt the hard way by turning up the flow at low throttle setting to clean the heads and valves before I was pulling the heads to do guides etc . It washed the bore , I had to hone the cylinders and re ring the engine . (the engine was missing because of the water volume)

Yes the small nozzles are a pain . I remove them and strip and clean them from time to time .

Snow performance had a muscle car WI controller , no longer available , it works off manifold vacuum and rpm .

Do you happen to know what AFRs you had in conjunction to the h20 and what volume of water you were spraying?

Thu Apr 24, 2025 5:20 pm

Do you happen to know what AFRs you had in conjunction to the h20 and what volume of water you were spraying?[/quote]

On the bus I used a small needle valve to control volume , then adjusted it to give good head cooling without affecting the AFR , I changed the O2 gauge to read lambda. aiming for 0.85 .

It's been a while but I don't think I had to change carb jetting . I've a Snow muscle car controller that I want to hook up and need to get back to playing with it .
I haven't used the bus for long trips for a while , the Ghia has been getting the love,sorting out EFI tuning etc .

The Ghia has everything there and is controlled by the ECU ,disconnected at the moment . I want to see if the WMI makes any difference at WOT on the dyno and track . hopefully a later this year .

Thu Apr 24, 2025 5:57 pm

Did you guys not math it for the proper “water” ratio to fuel consumption? I believe it’s supposed to be about 12-15% if i remember correctly , but its been several years since i set one up.

Thu Apr 24, 2025 7:35 pm

BFB wrote: Did you guys not math it for the proper “water” ratio to fuel consumption? I believe it’s supposed to be about 12-15% if i remember correctly , but its been several years since i set one up.

I did. Snows has a nozzle chart based on horsepower for naturally aspirated or for boost levels. It's basically 30cc per 50 horsepower on the naturally aspirated column. The chart starts at 200hp @ 116cc. That would put me down around 70cc-80cc of recommended spray if I had to ballpark what horsepower I make comparing to dyno charts posted on this website equivalent to my engine specs. This is why I went with a single nozzle above and dead center, as opposed to 4 individual nozzles of 30cc. 60cc total is on the conservative side, whereas four 30s @ 120cc would be entirely too much. Two 45s @ 90cc would probably work though too, as you figure I am able to reduce pump output as well as not all the spray enters the bells of the pipes. There's a percentage of fluid loss having it spray outside and above the ram pipes. I am even seeing some anti freeze dripping from the small weep holes I drilled on the base plates of the filters after a drive.

Thu Apr 24, 2025 9:09 pm

I went with the smallest nozzle aquamist did at the time .

just looking into how to trigger a system in the simplest automatic form .

Summit have a RPM window switch https://www.summitracing.com/parts/sum-830453

combined with an adjustable vacuum hobbs switch from eBay or where ever .
A bit of trial and error with the Hobbs switch to activate at what ever throttle setting .

A shut off solenoid is also handy to stop engine vacuum pulling in water at idle and backoff .

Fri Apr 25, 2025 6:50 am

they really aren't that complicated to build from scratch and I think the premade systems are way over priced, over engineered , and over pumped for the average person.
mine, because its boost related, is triggered by an adjustable hobb switch. its sprayed pre- carb on a draw through, so no vacuum to suck on the W/I nozzle. but even at that there can still be a drip or an "after trickle " as the W/I pressure drops, so installing a pressure valve inline is a good idea. some OEM use an inline check valve in there windshield washer lines, which works perfect.

Fri Apr 25, 2025 7:40 am

I have a pressure valve in line also, but as you said some still trickles out afterwards as the pressure bleeds off.