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  #1  
Old 08-08-2016, 06:48 AM
djfourmoney djfourmoney is offline
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Default On the right track?

For the past three weeks I have visited the track as an alternative to dyno testing, plus I just like drag racing.

Since installing my AEM WMI system the car isn't performing as I think it should.

I tired the smallest nozzle the system comes with, which is 250 cc. It seems location is important because as you know Richard most Focus ST owners are installing the nozzle right behind the throttle body using a spacer.

It seems you don't need much squash knock but there is no cooling of the incoming air as a result, this is the same result as direct injection.

I've been plague with typical mid-summer heat in Southern California, meaning ambient temps of 30c + with corresponding inlet temps of would you believe 45c as recorded at inter-cooler exit.

The car is pulling timing obviously as my trap speeds between the 1/8th mile and 1/4 mile should be about 20-21 mph, I'm only getting 17-18 mph.

I started with the 250cc nozzle as I said before. Temps never dropped and only adding octane boost added enough timing to jump from 92 mph trap speed to 96 mph trap speed.

This weekend I tried 500cc after I got some air caught in the system. Better track conditions (closer to sea level) but same hot weather even as racing didn't start until 8 pm local time.

3 passes in a row, trap speeds never got over 94 mph with the system activated and it really didn't matter how much or how little was injected (in term of the linear curve by the progressive controller). The tune on the car featured a small trim of the fuel system and that didn't work at all.

I decided to let the car sit for about an hour to cool it back down to normal operating temps. At the same time I knew track conditions would improve as the night wore on it got cooler and cooler.

The car responded by going 98-99 mph in the 1/4 mile.The only other change was to revert back to the previous tune as it featured no fuel trims.

Here's where things might get confusing so hold on.

My current track tunes are based on blending ethanol with pump gas to get E30.

That means I would add 30% ethanol via 1-1.5 gallons of E85. It could vary but were in the summer now so I know it's E85.

Aquamist and others but not AEM apparently suggest 15-20% of 50/50 should be injected in relation to how much total fuel is being injected (cc).

My math may not be perfect as I don't have the stock flow numbers of the Focus ST. But based off 3rd party aftermarket direct injectors available for the car, I come up with 4760cc total at 100% duty cycle.

Sounds about right since the stock fuel system can easily support another 100-130hp at the wheels.

Now I fully understand yours and Wizard of Nitrous critique of US based manufacturers of water injection and nitrous systems.

I bought into AEM's simplicity of their system; Pump, Controller and Three Nozzles, no math to do.

According to AEM at 250hp, I would need 449cc. So starting with the 250cc nozzle was wrong. But when 500cc had similarly no effect I started looking for answers.

At 15% of 4760, I come up with 714cc, @20% 952cc.

I bought a second nozzle kit anyway because I thought I might use it.

So now I have -

(2) 250cc nozzles, (2) 500 cc nozzles and (2) 1,000cc nozzles

Right now I have the 500cc nozzle pre-turbo but it might as well be nothing because inlet temps remain high.

My theory according to things I have read, is that the turbo is turning the water to steam, so by the time it get through the inter-cooler and to the throttle body, it's not nearly as dense as it should be.

My tuner saw enough of a change with the 500 cc nozzle to trim some fuel, but that log was taken in much milder evening conditions. Even with it being cooler I am still not dropping below ambient and charger cooler temps still skyrocket until load/boost.

So I am going to install the second nozzle, starting with 500cc pre-turbo and 500 cc post inter-cooler. The MAP/Temp sensor is on the exit flange of the inter-cooler.

That would be just over 952cc required for 20% injection.

Not sure if I should install the nozzle in the exit end tank to make sure the sensor sees it or not. There's another MAP/Temp sensor in the intake manifold, might not be necessary.

How on earth AEM suggest such small rates of injection?
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Old 09-08-2016, 08:25 AM
Richard L Richard L is offline
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Default Re: On the right track?

We have spoken before on the st forum.

I will repeat: AEM system is very basic, the more boost it sees, the faster the pump rotates. This will lead to the following issues:

1. Non-linearity leads to more flow at low/mid load, not enough at high load
2. Poor atomisation at low/mid load.
3. Boost without rpm reference is not representative to true engine load.

It appears AEM's solution is "not" to inject too much to lessen the issues above. This is just my opinion.
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Old 15-08-2016, 01:30 AM
djfourmoney djfourmoney is offline
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Default Re: On the right track?

Quote:
Originally Posted by Richard L View Post
We have spoken before on the st forum.

I will repeat: AEM system is very basic, the more boost it sees, the faster the pump rotates. This will lead to the following issues:

1. Non-linearity leads to more flow at low/mid load, not enough at high load
2. Poor atomisation at low/mid load.
3. Boost without rpm reference is not representative to true engine load.

It appears AEM's solution is "not" to inject too much to lessen the issues above. This is just my opinion.
That makes sense.

I am actually 250cc Pre-Turbo and 500cc Post Inter cooler in the exit elbow of the IC right under the sensor. (750cc)

I took the car to the local 1/8th mile with this configuration. It ran 78.1 mph on my only pass.

If I[m reading the logs right, inlet temps are dropping below ambient, finally.

Last edited by djfourmoney; 15-08-2016 at 01:32 AM.
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Old 15-08-2016, 07:25 AM
Richard L Richard L is offline
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Default Re: On the right track?

This is good news, the spray is effective. What is the 1/8 mile before?
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Old 16-11-2016, 10:55 PM
djfourmoney djfourmoney is offline
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Default Re: On the right track?

I don't know, the WMI has been abandon for the moment.

I have been running first E30 tune and now an E40 tune. The car has gone quicker, now it's doing 79-80 mph in the 1/8th. For awhile the car wouldn't trap over 100 mph. I short-shifted 3-4 and it's been running 100+ ever since with no other changes.

Last month I did max out the preload on the stock wastage and that picked up 1.71 mph.

I want to stop mixing fuels but as long as the WMI is dead rich and I can't seem to get my tuner interested in it. He wants 3rd gear log pulls and I don't want to risk getting tickets.

No point in logging at the track really since he doesn't reply while I'm there with an update, he will reply after I get home.

I'm going to give him one more chance as I am now adding nitrous oxide to the mix and want to totally get off blending.

Besides I bought the system and did pre-turbo specifically to push the stock turbo which at the outer limits will push out low 300 hp with a Turbo Smart IWG.

This has annoyed me so much that I am going to start my own tuning business.
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Old 08-01-2017, 11:44 AM
Richard L Richard L is offline
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Default Re: On the right track?

It is annoying you have all the tools to make power but cannot find a tuner to use them. As far the the we are concerned, you have a very capable wmi system, there isn't much we cannot do.

It is a pity. Start to tune your own car in baby steps, plenty of options out there.
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