Apex MCX 310 kit with water/meth inj engine stumble

[cadmo]

Ok so my new to me 06 Apex mcx 310 with snow performance water/meth injection variable rate from start around 10 psi boost to full flow by 18 psi, ran amazing last ride at Golden,

Runs 18psi
With 94 octane and the water/ meth injection, knock box didn’t go off once

But this ride out at Revy it had a horrible mid-range mis/backfire, and kind of drown out, when out from full throttle. Once and a while it would do it top end as well.

During the last day i dumped out the 50/50 water methanol to windshield washer fluid (about 35% meth), then to strait water. Symptoms didn’t change all three times.

Does anyone have ideas?

Also what is the max boost psi I can run on strait 100LL stock engine with head shim, as the previous owner neglected to mention that it uses a TON of water meth during the day.

 

[roughrider99]

Stock internals on engine? After 17-18 psi you are pushing the limits of the rods but run 16-17 on a mix of pump and av and go play all day, everyday.

 

[apex08]

Had a stumble last year and it was the fuel filter. Change it and it was all gone.


Was also asking myself the same question about 100LL. I just remap my mcx 290 to 310 and want to know the minimum gas to run.

 

[boost mod]

boost calculator

 

[Menace1]

Over fuel?

boost calculator

Correct me if i'm off here but after looking the quartz vs revy elevations could it be possible that his apex is running to rich in revy and just over fuelling causing the engine to stumble? When I rode his apex it seemed to be flooding itself out when you got hard on the throttle but would clean up and run great if the throttle was brought on steadily. It would be nice if the fuel box was adjustable and there was an a/f gauge to dial it in better.

 

[hornydevil]

Correct me if i'm off here but after looking the quartz vs revy elevations could it be possible that his apex is running to rich in revy and just over fuelling causing the engine to stumble? When I rode his apex it seemed to be flooding itself out when you got hard on the throttle but would clean up and run great if the throttle was brought on steadily. It would be nice if the fuel box was adjustable and there was an a/f gauge to dial it in better.

I had the same issue with my Apex in quarts, bump up the boost and it ran perfect.

 

[cadmo]

even adjusting the boost still the same condition

 

[Habich76]

I run a H20/meth system on my Nytro from Dave at Hurricane Performance with excellent results. 18 psi on 92 octane and stock compression with a mixture of 50/50 BY WEIGHT! (2.25 gal distilled water and 2.84 gal Methanol) Dave is an excellent source for direction on the subject.
It took a while to get the right combination of nozzles and controller settings but it sounds to me like your nozzle(s) are slightly too big and with the system at full capacity it is flooding the engine with too much meth mix. I'd try bumping your max setting up to 22 to 25 so the system doesn't get to maximum flow at your 18psi boost setting. The ideal plan is for a span of water delivery between 25% at the highest load (not the highest rpm) and tapering to a point not below 12.5% at peak rpm and load. If lowering the max setting helps your problem then I would buy the next smaller nozzle and drop the setting back down to around 18-20 psi. In my experience you want the smallest nozzle you can get away with for the best atomization. A nozzle that is too large will form droplets of water and cause all kinds of difficult to diagnose characteristics.

 

[cadmo]

I run a H20/meth system on my Nytro from Dave at Hurricane Performance with excellent results. 18 psi on 92 octane and stock compression with a mixture of 50/50 BY WEIGHT! (2.25 gal distilled water and 2.84 gal Methanol) Dave is an excellent source for direction on the subject.
It took a while to get the right combination of nozzles and controller settings but it sounds to me like your nozzle(s) are slightly too big and with the system at full capacity it is flooding the engine with too much meth mix. I'd try bumping your max setting up to 22 to 25 so the system doesn't get to maximum flow at your 18psi boost setting. The ideal plan is for a span of water delivery between 25% at the highest load (not the highest rpm) and tapering to a point not below 12.5% at peak rpm and load. If lowering the max setting helps your problem then I would buy the next smaller nozzle and drop the setting back down to around 18-20 psi. In my experience you want the smallest nozzle you can get away with for the best atomization. A nozzle that is too large will form droplets of water and cause all kinds of difficult to diagnose characteristics.

Thanks for the tips, now that i just looked at the Snow performance controler, it engages at 12psi and is full by 19psi.

its also susposed to have "60" nozles if that helps, what size do you run?

 

[Habich76]

I am running the Devil's Own D03 (189ml/min) outside mount nozzles, one in each port spraying right outside the butterfly with the controller set to come on at 8PSI and the max setting at 25PSI with 17 pounds of boost. Also, I pull my nozzles out every year, clean the filters and make sure they are flowing correctly with a fog pattern and not a stream of fluid. I just connect a regulator to the pressure line on the controller and slowly increase the pressure until it turns on and then raise it up to my max boost pressure and make sure all three are flowing evenly. IT MAKES A MESS so do it into a cut off milk jug nor something to collect most of the fluid. This is also a great way to verify the controller is operating correctly. And yes, I go through a lot of boost juice. The two quart tank that came with the kit would run out at around a half a tank of fuel so I fabbed up a larger one and she works lovely now.
I tried smaller nozzles (60 ml/min) with the controller set lower on the top number but it wasn't enough to eliminate detonation a the highest load point of the pull so I changed it back and just deal with consuming a lot of meth mix. I have 11.1:1 compression so my engine does require more meth than yours but those nozzles seem small to me for that much boost (60 X 4 = 240ml/min versus mine at 189 X 3 = 567 ml/min) Could you be short on meth instead of too much like I was originally suggesting? Detonation will kill the engine instantly so I'd try too much meth first by lowering the top number on the controller to maybe 12 or 14psi (or buy larger nozzles) and see if it helps before taking meth away like I originally suggested.

Here's the nozzles I am using: http://www.alcohol-injection.com/en/49-nozzles

 

[cadmo]

I am running the Devil's Own D03 (189ml/min) outside mount nozzles, one in each port spraying right outside the butterfly with the controller set to come on at 8PSI and the max setting at 25PSI with 17 pounds of boost. Also, I pull my nozzles out every year, clean the filters and make sure they are flowing correctly with a fog pattern and not a stream of fluid. I just connect a regulator to the pressure line on the controller and slowly increase the pressure until it turns on and then raise it up to my max boost pressure and make sure all three are flowing evenly. IT MAKES A MESS so do it into a cut off milk jug nor something to collect most of the fluid. This is also a great way to verify the controller is operating correctly. And yes, I go through a lot of boost juice. The two quart tank that came with the kit would run out at around a half a tank of fuel so I fabbed up a larger one and she works lovely now.
I tried smaller nozzles (60 ml/min) with the controller set lower on the top number but it wasn't enough to eliminate detonation a the highest load point of the pull so I changed it back and just deal with consuming a lot of meth mix. I have 11.1:1 compression so my engine does require more meth than yours but those nozzles seem small to me for that much boost (60 X 4 = 240ml/min versus mine at 189 X 3 = 567 ml/min) Could you be short on meth instead of too much like I was originally suggesting? Detonation will kill the engine instantly so I'd try too much meth first by lowering the top number on the controller to maybe 12 or 14psi (or buy larger nozzles) and see if it helps before taking meth away like I originally suggested.

Here's the nozzles I am using: http://www.alcohol-injection.com/en/49-nozzles

I spoke to Dave 2 Hurrican Perfromance, he seem's to think the 60ml/min are good for my elevation (5000), boost and head shim. But who know's before i change nozzles ill play with the start and full settings.

Without having a AFR guage its hard to really tell what the engine is doing, but at least the knock box is not going off.

Is it possible that when the water/meth starts and then fully spray, the mcx box gets confused over or underfuling?

 

[Habich76]

I am not familiar with how the MCX box measures engine load but I don't think the meth should effect it at all.

Did you get it running better?

 

[cadmo]

No I was waiting on parts from Snow Performance, just came in.

One of the threads was stripped and buggered up, hope to have it back together by the weekend.

 

[TBird]

Is it possible that when the water/meth starts and then fully spray, the mcx box gets confused over or underfuling?

I don't believe so, i run it on my sled, a kit i bought from Dave this summer with 2 nozzles to my Apex Engine with MCX controller, and i no stumbles what so ever, MCX controller doesn't care about meth @ all.
My suggestion is to install an AFR, should be in every turbo application.