[Davenow]

But if you are getting a clogged nozzle or leak the failsafe is going to activate (speaking about the AM kit specifically), and you will know about the problem even without the DDS3 gauge thing. And if you dont run garbage through your system, there is no reason you should every get a clogged nozzle. Run pure distilled water, and straight meth (or denatured alch), and NOTHING else. The bottom line is that if you get a clogged nozzle, its your own fault. Leaks, yes they can happen. But again, in most cases, leaks are the result of a mistake made when the kit was installed. If the kit is in your trunk, and the leak happens back there, you will smell it REALLY fast. Even a small leak puts out a pretty noticeable odor, even from inside the trunk. (I had my gas can that I used to carry extra mix in my trunk, it leaked a LITTLE bit, and the whole car reaked of alcohol.)


As for knock on 91 ca gas, if you are running meth, you arent on 91 anymore. So you shouldnt have knock. Actually, if your car is tuned properly, you shouldnt have any more knock issues than anyone else on 93. You simply map the car accordingly. 91+meth=over 100octane in the cyl. So you shouldnt see any knock on a decent tune. Hell man you shouldnt knock on a decent tune even without meth. 91 doesnt make the car knock. A poorly mapped EM system causes knock. You can tune a car to not knock on 87 octane if you do it right (dont expect much joy from that map though lol). And honestly, I know a lot of people in CA that arent having knock problems even without the meth. Just tune the car properly. You cant run the same timing and boost on 91 that you can on 93, so dont try, or you get knock, then eventually, you get a new shortblock when the motor lets go.

A high knock level indicates a serious problem with the car. Either a motor that is already on its way out, or a tune that is VERY dangerously mismatched for the car and gas that you get. High levels of knock are absolutely not acceptable under any circumstances, ever. On any gas. Knock is the number one killer of subaru motors.

[halfelite]

On the stock tune it will knock on 91 occasionally Not really knock but enough for the em to think there is and dumb the tune at that point. I dont know very much about tuning yet still learning.

[Richard L]

Davenow,

RE: ... I have had no caffiene and was up WAY to late last night, so I probably jump around a bit in this, please read the entire thing before replying because I would bet my life I say a couple things that seem off if you dont read the entire thing to find an explanation of one statement or another elsewhere in the post…

I have read your reply with great interest and anticipation. No I am not going to nit-pick since you were not loaded with caffeine when you compiled the post.

Accuracy:
When you have picked a PPS system, you have to live with the constraint of accuracy. The choice is not up to you, it is governed by the law of physics. Without going into too much into technical details that may bore you to death, I will use a non-mathematical model to illustrate what I am trying to convey.

Explanation:
A PPS (progressive pump speed) system is liken to a heavy lorry with limited steering movement and fitted with a RPM limiter.

Lorry weight vs Pump inertia: It is perfectly fine to drive around on a straight-ish highway and a reasonably steady modulation of speed without too much problem. On a twisty road at speed, it will experience difficulty in following the road accurately. Similarly, the PPS system will experience the same.

Limited steering movement vs dynamic range: Tracking a twisty road accurately requires a good steering angle. A PPS system’s flow change relies on pressure change. In order to double flow, the pressure change needs to be varied by 4x times.

RPM limiter vs On-Demand (OD) switch: With the exception of a very few PPS systems, an on-demand switch is fitted to limit over pressure in the event of a clogged nozzle. Over pressure is dangerous if 100% methanol is sprayed all over the engine bay should a hose bursts.
An “on-demand” switch poses a real problem on a PPPS system every time it is triggered by a pressure ripple as the motor ramps up. Once triggered, a drop of 20psi+ drop is common. This hysteresis loop plays havoc on flow accuracy. The most likely place where the trigger takes place is during wide throttle movement during gear change. Inlet tract pressure can raise upto 3-4 times of normal boost pressure if a BOV is not fitted.

Some systems remove this OD switch to avoid the hysteresis loop but in the expenses of stressing the pump mechanism and risk of burst hose. Some maker tries to advise their users to lower the duty cycle. That would mean a 150psi based system is only operating just above 100psi in order to avoid the cycling. It is comonly knows as "pulsing".

I will make appropriate reply of other topics on your post later. I am terrible at typing too much as a time.
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[Davenow]

Originally Posted by halfelite

On the stock tune it will knock on 91 occasionally Not really knock but enough for the em to think there is and dumb the tune at that point. I dont know very much about tuning yet still learning.

Oh on the stock map definately. Heck you will see knock on 93 on the stock map (once in a while anyway). Light knock once in a while is a given. Its knock problems that dictate the need for tuning. Ideally, no knock, ever. Reality=some light knock, once in a while. Not enough to say that its "knocking on XXoctane gas" though. Does that make any sense?

I am going to hit submit reply and close the window right now, I HAVE to get my car ready and on a truck to the shop this afternoon so time is 100% of the essence. I am not even reading Richards reply just yet, because I will almost surely spend the next 20 minutes in some long winded reply back to it, as I am an obsessive when it comes to such things

Anyway, gotta go.

[C.J.]

so AEM for $350 or SMC for $500?

Also what kind of tuning does a person need to do to make it run properly?

I would like to try this instead of mixing race fuel everytime I fill up, how is the car going to run if you just run an SMC kit without tuning it?

[Davenow]

Again, in a hurry. Didnt get a chance to respond to everything I wanted to yesterday. Hopefully will today.



How will it run untuned? bad. Horrible. Actually, dangerously bad. WAAAYYYY too rich. You need to pull a ton of fuel in the areas of the map where it is spraying.

Richard, I have a bunch of comments. Hopefully I get a moment later today...

[Richard L]

Davenow,

There is no hurry, I haven't quite finished replying to your first email yet - pity we have many other things to do in a day - fyi, this discussion is far more interesting.

[halfelite]

I cant wait for Davenows reply this is the best discussion i think i have ever seen on the topic.

[gabedude]

Originally Posted by C.J.

so AEM for $350 or SMC for $500?

Also what kind of tuning does a person need to do to make it run properly?

I would like to try this instead of mixing race fuel everytime I fill up, how is the car going to run if you just run an SMC kit without tuning it?

Like Dave said, the Meth injection adds fuel on top of your fuel coming from your gas tank. So you end up going rich no matter what and losing power without a tune. You could run the smallest nozzle and have the pump not push to its full capacity if you wanted. That would cure knock, but make you a tad richer (and slower).