[chili36]

Here's another bit of info..

Originally Posted by Terry @ BMS

PWM is the means by which they are progressive.

[N54_Fan]

Originally Posted by Focus

Interesting...

Now why couldnt shiv post this, lol. Either ways very good read and info for someone like me who's a novice of this stuff.

Because sometimes I think it takes a layman to explain it to a layman. I think Shiv, Clap, themyst are so advanced on this stuff that they almost assume everyone knows and understands what they believe is tuning 101.

NO disrespect to any of them as I have learned volumes because of them.

[OpenFlash]

Originally Posted by Focus

Interesting...

Now why couldnt shiv post this, lol. Either ways very good read and info for someone like me who's a novice of this stuff.

lol... i wish I did. Props to N54_Fan for illustrating the differences so effectively

Sometimes a picture is worth a thousand works.

[Jeff@TopGearSolutions]

I'm not sure the .3 second between WOT shifts is really too much the purpose of the PWM kit.

I like how another guy mentioned to seek other sources outside of this forum and the BMW community altogether about more information.

Once you understand how the PWM kit works, you can then understand its benefits and flaws VS the benefits and flaws of traditional systems.

[Jeff@TopGearSolutions]

Although possibly biased being from a manufacturer I thought maybe I would share this.

For the record I have no dog in this fight as I mentioned earlier. I run the same exact setup as Clap and themyst. (with minor differences that are negligible IMO).

The differences between a

PWM -V system (same as OE fuel injection system)
and
PPS system (Progressive Pump Speed).




Who manufactures what?
- Devilsown, Snow, Coolingmist and Labonte make PPS systems.
- Aquamist and FJO are the only manufacturer making the PWM-V system.



Delivery method:
- PPS system: controls flow by changing pump speed.
- PWM-V system: controls flow by pulsing an inline valve (same principle as the OE fuel injection system)



Atomisation:
- PPS system: low flow = low pressure = poor atomisation. (video)
- PWM-V system: constant pressure at any flow = constant good atomisation. (video)
Consequences:
Poor atomisation results in large droplets resulting in uneven fluid entering each cylinder.
Modern manifolds are not designed for transporting fluid loaded air.



Response time:
- PPS system: slow response due to rotational inertia of the pump. typically between 0.1 to 0.5 second.
- PWM-V system: Fast response time. typically within 0.003 second.
Consequences:
In consistency in Air-fuel ratio under transient load due to the pump's inability to change speed.
A rotating mass has ample inertia resulting in after-spray dribble. (video)



Dynamic range:
- PPS system: only produce 2x between 50-200 psi. (A typical PPS system operating pressure range)
- PWM-V system: comfortably manages x10 minimum flow range between 0-100% duty cycle
Consequences:
Without the dynamic range, PPS system can only operate in a narrow power range of 2x. Not really ideal for Daily Driver.



Linearity:
- PPS system: A linear "pressure" increase does not produce a linear "flow" through an atomisation nozzle. Error can be as much as 120%+.
- PWM-V system: Flow linearity is in the region of 5%, can be improved by a custom designed valve on request.
Consequences:
Wacky AFR under different load and engine speed is common - nightmare to tune.



Cost considerations:
- PPS system: It is basically a motor speed controller, design cost is low. Regardless of how many gizmos are included.
- PWM-V system: Each PWM valve individually calibrated by technicians to ensure flow consistency
under harsh engine bay environment. Cost is higher.
Consequences:
PWM-V system production cost is high. PPS systems are normally 30% lower to produce. But overall performance is 5x poorer.

-Aquamist

[OpenFlash]

Originally Posted by chili36

Here's another bit of info..

Please read this the links that N54_Fan posted. Especially the bit about dynamic range and injection linearity. You will see that being progressive by PWM'ing a solenoid with constant injection pressure (like an actual fuel injection system) has many benefits over being progressive by adjusting pump speed from 0 to 200psi.

shiv

[themyst]

Originally Posted by N54_Fan

I do,..but it is about .3 sec or so,...with each shift. How many shifts does your daily driver do in a day? Add up all that meth in your engine unnecessarily over the course of a year...

You realize that many on here have only had small amounts of oil in their IC when installing a new one or in their OCC but we still exhaustively debate the best way to care for our IC and engines by preventing the "small" amount of blowby to reach the IC. It adds up.

Not trying to start any fights but I think this is pretty convincing for me.

Actually, the boost hitch is a by-product of how Progressive meth works. Also if you take a look at the shifts themselves, they are almost one second, hardly what would happen in a race. If you look at how meth stops and recovers, they are within milliseconds of each other. if you think that's worth it, by all means, Shiv is more than happy to sell you a kit.

My timing and IATs on that 6MT log were perfect, running more boost than Shiv did on his PWM meth kit, with slow ass 1 second shifts which is the ONLY reason I posted that log.

In realistic terms, who is actually going to keep their car north of 100k miles where the accumulation of all these issues may even begin to surface? I don't think there are too many who can admit that.

[OpenFlash]

Originally Posted by themyst

In realistic terms, who is actually going to keep their car north of 100k miles where the accumulation of all these issues may even begin to surface? I don't think there are too many who can admit that.

So that is a reason not to control meth injection more correctly?

[kjrulz]

Originally Posted by Jeff@topgearsolutions

Although possibly biased being from a manufacturer I thought maybe I would share this.

For the record I have no dog in this fight as I mentioned earlier. I run the same exact setup as Clap and themyst. (with minor differences that are negligible IMO).

-Aquamist

JP, if all of that is not marketing bs from Aquamist, it may very well be the selling point for me to jump to PWM. Especially since my first evo thread I jumped into was this: http://forums.evolutionm.net/evo-eng...o-cracked.html

[N54_Fan]

Originally Posted by themyst

Actually, the boost hitch is a by-product of how Progressive meth works. Also if you take a look at the shifts themselves, they are almost one second, hardly what would happen in a race. If you look at how meth stops and recovers, they are within milliseconds of each other. if you think that's worth it, by all means, Shiv is more than happy to sell you a kit.

My timing and IATs on that 6MT log were perfect, running more boost than Shiv did on his PWM meth kit, with slow ass 1 second shifts which is the ONLY reason I posted that log.

In realistic terms, who is actually going to keep their car north of 100k miles where the accumulation of all these issues may even begin to surface? I don't think there are too many who can admit that.

Guilty as charged,...41K miles so far and plan to drive it into the ground. So for me,...a PWM kit is worth it. Everyone must make their own decisions as to which best suits their needs.

[themyst]

Originally Posted by shiv@vishnu

So that is a reason not to control meth injection more correctly?

Just speaking from a real world point of view.

And as myself and Clap have asked from you NUMEROUS times, show us logs of your PWM meth kit in action at part throttle and compare to say your old Labonte-based meth kit at part throttle. Other than IATs which may be kept lower in comparison, I bet there is no significant difference.

You argue that keeping the IATs low proactively by injecting fine amounts of meth at low boost levels will keep the car happier, but the car is hardly stressed NOR ARE THERE ANY SIGNIFICANT BENEFITS OF LOWER IATS at the 4-7psi boost levels you are touting as making a huge difference. You know how I keep IATs low? Go WOT

I actually liked your old Labonte-based meth kit and when I priced the kit out individually, it was competitively priced for what it included. The only sore point was that POS flow sensor.

[themyst]

Originally Posted by N54_Fan

Guilty as charged,...41K miles so far and plan to drive it into the ground. So for me,...a PWM kit is worth it. Everyone must make their own decisions as to which best suits their needs.

Congrats.

[Jeff@TopGearSolutions]

Originally Posted by kjrulz

JP, if all of that is not marketing bs from Aquamist, it may very well be the selling point for me to jump to PWM. Especially since my first evo thread I jumped into was this: http://forums.evolutionm.net/evo-eng...o-cracked.html

Who knows....

AS you mentioned people should seek out other sources. I can hardly get a word in edgewise anymore since I become a vendor. Everyone thinks I have some ulterior motives to "trick" people. Whereas that is hardly the case. I'm just as interested in finding any benefits to PWM as anyone else.

[cn555ic]

Originally Posted by themyst

Just speaking from a real world point of view.

And as myself and Clap have asked from you NUMEROUS times, show us logs of your PWM meth kit in action at part throttle and compare to say your old Labonte-based meth kit at part throttle. Other than IATs which may be kept lower in comparison, I bet there is no significant difference.

You argue that keeping the IATs low proactively by injecting fine amounts of meth at low boost levels will keep the car happier, but the car is hardly stressed NOR ARE THERE ANY SIGNIFICANT BENEFITS OF LOWER IATS at the 4-7psi boost levels you are touting as making a huge difference. You know how I keep IATs low? Go WOT

I actually liked your old Labonte-based meth kit and when I priced the kit out individually, it was competitively priced for what it included. The only sore point was that POS flow sensor.

+1 I am completely happy with the old system, and I am sure this new system will be just as effective, better performance I am not quick to say yes....When my meth system is turned on if I am triggering the meth to spray from 6-7 psi, more than likely I am going at least 3/4 to WOT...

[EastBayE90]

Found these two videos I hope the links work. Just click the videos. Please watch both videos. I hope this helps.

Progressive kit


PWM kit


Clearly a difference

[themyst]

On other platforms with a closed/open loop system, I would be more than happy to vouch for the benefits of an aquamist meth kit, as if you're tuning for meth there, fueling needs to be spot on or it will be a relatively short-lived exercise for your motor.

On this system where BMW effectively idiot-proofed fueling with that amazing DME and closed loop system to the point users can spray 900-1000 ml/min of pure meth at 6-8 psi and not bog the motor, the advertised benefits of this PWM meth kit are WORTHLESS. Still waiting on logs, Shiv. I don't bother or give credence to testimonials from customers who never ran a meth kit before.

[kjrulz]

Originally Posted by Jeff@topgearsolutions

Who knows....

AS you mentioned people should seek out other sources. I can hardly get a word in edgewise anymore since I become a vendor. Everyone thinks I have some ulterior motives to "trick" people. Whereas that is hardly the case. I'm just as interested in finding any benefits to PWM as anyone else.

I completely understand, and by the by, you've always been one of the most level headed people, so I wouldn't let it get to me if I were you.

[N54_Fan]

Originally Posted by themyst

Congrats.

Sarcasm??...I tried to show respect to you and try to show proof in datalogs which eveyone was asking for and all you can do is make a sarcastic remark "Cograts" and say "who is going to own their car that long anyway".

Seriously you sound like the fox in Aesops fable "The Fox and the Grapes". He kept trying to jump and reach the grapes on a tree and when he tried and tried and could NEVER reach them he just said "well they are probably sour anyway"...

I currently have no dog in this fight and I'm only trying to make an educated decision and hopefuly help others do the same,..but unfortunately this forum seems to degrade to high school BS like that.

[N54_Fan]

Originally Posted by (-(ellblazer420

Found these two videos I hope the links work. Just click the videos. Please watch both videos. I hope this helps.

Progressive kit


PWM kit


Clearly a difference

I have posted those and the Aquamist info as well in the past but I guess no one saw them. Hopefully people will get informed and make an educated decision.

You guys that are interested should go back and read the links I have placed throughout this thread. There are numerous videos and good educational discussions from STI, VW, and EVO forums on them. Nearly everything I have read supports PWM as the way to go.

Many of this stuff is also on Shiv's site...

[themyst]

Originally Posted by N54_Fan

Sarcasm??...I tried to show respect to you and try to show proof in datalogs which eveyone was asking for and all you can do is make a sarcastic remark "Cograts" and say "who is going to own their car that long anyway".

Seriously you sound like the fox in Aesops fable "The Fox and the Grapes". He kept trying to jump and reach the grapes on a tree and when he tried and tried and could NEVER reach them he just said "well they are probably sour anyway"...

I currently have no dog in this fight and I'm only trying to make an educated decision and hopefuly help others do the same,..but unfortunately this forum seems to degrade to high school BS like that.

No sarcasm intended. You stated you made your choice based on the information provided, so congrats? I don't see how that's a sarcastic reply.

[N54_Fan]

Originally Posted by themyst

No sarcasm intended. You stated you made your choice based on the information provided, so congrats? I don't see how that's a sarcastic reply.

Then accept my apology if that is the case,...as it sure came off that way to me,...Like "what do you want a medal" type response.

[Jeff@TopGearSolutions]

Originally Posted by kjrulz

I completely understand, and by the by, you've always been one of the most level headed people, so I wouldn't let it get to me if I were you.

Thanks