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Rotary with water methanol, but little to no gain

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Hi guys

I would like to know what is the best way to yield result from a 5050 water methanol injection?

I can only see a marginal gain using a tiny 60cc/min nozzle up top, when the secondary 175cc/min nozzle kicks in there will be a big power drop and super rich AFR.

Is it safe to pull fuel out in cells where the large nozzle kicks in? or is it better to leave the fuel maps and advance ignition?

Thank you

The main gains with WI is from reducing the combustion temperature which raises the knock threshold and allows more boost to make more power.

Don't bother too much with leaning off the afr unless it is richer than 10.0:1 and make sure you have an upgraded ignition system so you don't get ignition misfire.

Also if you want to increase your boost and power level by a decent level you will need to increase your WI injection amount.

Thank you Boostn for the explaination :)

No worries :)

If you are looking to run decent boost using WI contact Green Brothers racing as they have alot of experience for setting up and tuning high hp WI rotaries in NZ.

Car was actually tuned by dynopower, but didn't make much power with EFR9180 full bridge port, only 410whp at 14psi with WI

They unable to make more than 14psi on my motor and said it was due to my porting... but end up I found a massive boost leak by their newly installed bov.

So I then went back to my other tuner, but we were unable to utilize the WI as I mentioned before, massive power drop on the top end when we bring in the second water nozzle.

So my current tune is only with the tiny 60cc nozzle begin spraying at 8psi and made 480whp with 20psi boost.

Should we advance the timing until power begin to drop, or until knock is heard and use more water to control knock?

Thank you :)

What sort of intake air temperatures are you seeing?

Andre done a water/meth injection webinar a while ago which might shed some light on your situation:


Thank you so much Chris, this webinar contains exactly what I needed.

I will re-tune in June and will post an update regarding to my gain, with advanced ignition and increased boost.

After watching the webinar, I have one more question regarding the actual water and methanol mix.

I purchase methanol in a separate container and mixing it myself, I can only do so much to make it a "50:50" mix, but unable to know the exact content.

Is it better to just run pure water, or slight difference in methanol content each time will not affect the tune as long as close loop fuel trim is on?

Thanks guys

Keep in mind the webinar was with a piston engine.

Don't get too hungry with timing on a rotary. Power is not as sensitive to timing as it is with a piston engine. Plenty have rolled off the rollers with no knock and have destroyed themselves on the first high load run due to the extra load experienced on the road / track.

Increasing boost will make the extra power for you, keep the afr around 10.5:1 and conservative timing so it holds together.

Not sure how much power you are after but I don't recommend increasing the boost until you install much bigger jets for your wi system.

I've upload a ignition map of my current tune, the problem is once we got the second water nozzle on we will get big power drop. The second nozzle is only 175cc/min.

I am running stock ignition with HKS twin power, should I unplug trailing leads and see if the leading plugs have any misfire at higher rpm?

Thank you

Attached Files

What are your charge temps with the small jets? you might not need the larger ones

~30 degrees C

60cc is nothing. You definitely need to increase it significantly if you want to run more boost. What is your hp target

How much power did you loose with both jets on?

Do you have a dyno sheet of both runs?

Was the ignition breaking down?

Hi Boostn

Im aiming 550ish whp on a dynodynamic,

I lost about 20-30hp from ~6000rpm with the second injector coming on at 18psi based on memory.

No misfire detected, but could be trailing hiding the problem, I will tune again in April with trailing disconnected first.

I will also.look into injection timing angle, ive heard that could affect top end power too. The current tune is the same as base map setting using 130degrees BTDC start of injection for the entire map. The haltech video mentioned something like 270-330degrees.

If your charge temps are only ~30oC then you can't be too far above ambient temperatures, what's the difference?

Ambient temp around 16ish C

I have not seen a twin power used with WI so I'm not sure how well it can handle it however I have heard of others who have used them successfully so it may be ok.

It's expected to lose some hp with WI but don't be concerned as it will allow you to increase the boost into the turbos efficiency area and gain much more power as a result.

Also injecting WI pre turbo will increase the efficiency of the turbo which is more effective as higher boost levels are used.

WI injection amounts typically are around 15 - 25 % of fuel flow. The ideal amount seems to depend on each specific engine and setup factors.

Not sure what system you have but as an example AEM recommend between 800 - 1200cc/ min for 550hp.

Hi Boostn

Thank you for the advice :) I am running snowperformance kit,, their nozzles are flow rated at 80psi but their pump is working at 250psi so the actual flow is much higher than what it stated. With the small jet alone we have to pull some fuel to maintain 10.5AFR. I will go into the 30psi range with water alone and hopefully I can report back with good result.

Even running both jets at 200psi will only be total of about 375cc/min.

Using water only requires less to be injected however it is also harder on the ignition system so you may find the limit of the twin power if it isn't strong enough.

Just take a cautious approach and slowly creep up on the boost.

I suspect you will reach 550rwhp with boost of around the mid 20's psi range.

How did you end up going Evil ?

My friend who runs mid-high 10s passes in a 13b 808 wagon was making 400hp at the wheels without the WMI.

With WMI, he's making 440hp at the wheels, it turns on at 5psi and sprays at full capacity, air inlet temp is very cold to touch after a pass on the strip.

The Nozzles are 2x 350cc with a 200psi pump, not twin staged. 90/10 V/V mix of methanol to water, which is more like 80/20 w/w.

I 60cc and 175cc nozzels are SFA imho, you need to pump that up to 700+ if you're going to 550rwkw, I would say 1000cc total. Larger CC is due to more meth being added, but that's what you want - more octane with still a cool intake temp.

He's done some testing and found that 90/10 v/v is the way to go with no ignition timing changes.

@Racetune I don't doubt that using a 90/10 mix of methanol with water would offer advantages to 50/50 however there is a risk to this since the mixture you're using is highly flammable. Since often the WMI tank is in the cabin, it could be a potential risk in an accident. 50/50 WM on the other hand is a little harder to ignite and hence a little less dangerous. Of course the risk is up to the individual but I just wanted to point out that there are some potential downsides.

Pretty much every serious AI rotary is running heaps more AI than thst when aiming for 550+. You really need to go to IGN01A coils, one of the new kits with R35GTR COP or aftermarket CDI to light it properly. Green brothers have been kind enough to document progression on their shop car here: https://www.rx7club.com/auxiliary-injection-173/my-pre-turbo-wi-974884/

A lot of guys in Australia running straight water, not as much density improvement but still massive knock suppression/total loss cooling allowing big boost on pump fuel.

I just glossed over this thread but I noticed that you dyno'd the 9180 at ~14 psi. From my experience that turbo doesn't really wake up on a 2 rotor until about 20-21 psi. Good luck!

Hey Andre,

Good point, Regarding in cabin and boost WMI setups. Some of the plastic bottles are a bit agricultural and would leak under slosh imho.

With the right tank spec, eg: metal - the risk would be similar to a boot mounted fuel surge tank arrangement.

Marcos is running a 1 gal ish tank in the engine bay near the pump. he swears by the 90/10 v/v mixture but I'll have to do my own testing at 50/50 v/v towards 90/10 v/v .

I'll get a picture of it and post.

Slides - Interesting point you raised there regarding boosting the ignition system to cope with a higher octane / air density.


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