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Cedric  



Joined: 27 Aug 2004
Posts: 2160
Location: Sweden

PostPosted: Fri May 14, 2021 9:12 pm    Post subject: Reply with quote

It would be interesting to see if the us distributor with the valve could lower control pressure more than a regular euro one at full load. That could in theory mean a bit more fuel flow than we can achieve with the euro stuff.

Yeah since you tune the car yourself any dyno should work as long as they have someone to run the dyno itself. Maybe you just need to make that clear. Especially if its a braked dyno you could reach every possible part of the table and perfect the tuning. The power number itself is not so easy to compare to any other dyno, a roller dyno is for tuning, not a measurement device. But it could give an indication.
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Carrera RSR  



Joined: 08 Jan 2010
Posts: 2226
Location: Somerset, UK

PostPosted: Sat May 15, 2021 2:44 am    Post subject: Reply with quote

Exactly that, the power runs are there to prove your modifications and tuning is heading in the right direction and it’s a +/- guide to the level of improvement. Quoting a number dyno in U.K. versus US is not a direct comparison. But helps us all to know what we are all achieving with our mods.
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Then www.924board.org/viewtopic.php?t=31252
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Fasteddie313  



Joined: 29 Sep 2013
Posts: 2315
Location: MI

PostPosted: Sat May 15, 2021 8:54 am    Post subject: Reply with quote

CIS Basic (euro) has 2 fuel pressure tuning demensions.
System pressure and control pressure..

CIS Lambda (US) has 3 fuel pressure tuning dimensions..
System pressure, control pressure, and inner chamber upper/lower differential pressure..

CIS-E (latest CIS) ditches the concept of control pressure altogether and has only 2 pressure tuning dimensions.. System pressure and chamber differential pressure..

System pressure doesn’t do much..
Control pressure changes the airplates resistance to movement, changing airplate/FD plunger position for any given airflow past the metering plate..

Chamber differential pressure changes flow through the FD for any given airplate/plunger position.. (euro models do not have)

You can only change control pressure to get more fuel until you max out the airplate travel..

CIS Lambda and CIS-E, by changing the chamber differential pressure, you can make them flow rediculous amounts of fuel even at say 50% airplate travel..

CIS-E does not even use adjustable control pressure. It is internally set to control pressure = system pressure, about 100psi, and all tuning is done with chamber differential pressure..

In theory the same could be done with Lambda, raise control pressure very high and lock it steady (no WUR), and do all the tuning from differential pressure including warmup..
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Last edited by Fasteddie313 on Sat May 15, 2021 11:35 am; edited 2 times in total
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Fasteddie313  



Joined: 29 Sep 2013
Posts: 2315
Location: MI

PostPosted: Sat May 15, 2021 8:56 am    Post subject: Reply with quote

See #5 in diagram.. CIS Lambda..


(See 3 fuel pressure zones, speckled around 7 is control pressure, in most of body from 8 medium grey is system pressure, very dark around 5 is lower chamber pressure)

10 is “out to injectors”

The more pressure you let out of 5, the more you open the path to 10, increasing flow, or vice versa..

Pressure is let out of 5 with CIS Lambda by dumping it back to the return to tank circuit through the frequency valve..
Increasing the duty cycle of the frequency valve dumps more fuel/pressure from the lower chambers, reducing lower chamber pressure, increasing the flow through the upper chamber out to the injectors..



CIS-E diagram..

(Key to the 2 pressure zones in bottom left corner)

Works on the same principle of dumping more or less fuel pressure out of the lower chamber, but instead of using a frequency valve to do so, it has an integrated DPR (differential pressure regulator)..


The 3 measurements I took from the US Lmabda distributor were all at 100% plate travel, but with changing lower chamber pressure..

(Maximum lower chamber pressure)
Frequency valve full closed/unplugged
76.5 grams in 30 sec

(About 50% lower chamber pressure)
Frequency valve plugged in and running as default (can measure actual duty cycle later)
102.53 grams in 30 sec

(Minimum lower chamber pressure)
Frequency valve full open, +12v constant
163.97 grams in 30 sec

Showing the drastic changes in flow, given the same airplate position, with only changing the lower chamber pressure..
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Last edited by Fasteddie313 on Sat May 15, 2021 11:36 am; edited 1 time in total
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Fasteddie313  



Joined: 29 Sep 2013
Posts: 2315
Location: MI

PostPosted: Sat May 15, 2021 11:31 am    Post subject: Reply with quote

CIS Basic is quite difficult to control via electronics because you only have control pressure at your disposal to manipulate your AFR with, basically the same way the boost sensing WUR works..

Tuning via control pressure has a slow response and the lower you make your control pressure the faster you run out of airplate travel, as all lowering control pressure does is effectively make the airplate travel further for the same airflow, reduces the plates resistance to the force of the air flowing past the plate..

The resistance controlled by control pressure is the pressure applied to the top of the plunger..
The higher the pressure on top of the plunger the more difficult it is for the airplate to force the plunger up to expose more metering slits.. Reducing control pressure reduces the force required to lift the plunger, therefore letting it lift further given the same force, and opening up more of the metering slits..
You only have so much metering slits to open..


With CIS Lambda and CIS-E, you can reduce the pressure in the lower chambers, therefore letting more fuel flow given the same metering slit opening..
With this method you can increase control pressure so you don’t run out of metering plate travel.. (CIS-E runs 100psi control pressure)

Say you have 50psi of control pressure and your metering plate will run out of travel at say 100cfm of airflow past the plate and give 10lb/min of fuel at full plate travel.. (even numbers)

By lowering the lower chamber pressure you can make the distributor flow the same 10lb/min of fuel at 50% plate travel instead of 100% travel, and you can double your control pressure to 100psi instead of 50psi so 100cfm of airflow will only move the plate to 50% instead of 100%, and then you can flow up to 200cfm of air past the plate to reach 100% travel, and now at 100% plate travel flow 20lb/min of fuel instead of only 10lb/min because you lowered the lower chambers pressure..

In a nutshell..
Higher control pressure for more CFM capacity before 100% airplate travel..
Lower lower chamber pressure for more fuel flow given any plate position..
Turns your 200HP capable system into a 300HP capable system..

Lower chamber pressure is also very easily manipulated via electronics, and responds fast, so you can raise control pressure and lower your lower chamber pressure as a baseline to increase air and fuel flow capability of the system as a whole, and then you can finely manipulate the lower chamber pressure easily via electronics to push your AFRs around where you want them, from around 15 at cruise down to around 11 at WOT/boost, is just a small change in lower chamber pressure..
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jacobroufa  



Joined: 18 Nov 2016
Posts: 359
Location: Rockford, IL

PostPosted: Sun May 16, 2021 12:39 am    Post subject: Reply with quote

C�dric wrote:
Fasteddie313 wrote:
Hey Cedric, would some $$ get that lower charge tube printing faster?
Probably should make atleast 3..

I also have a tunable US fuel distributor with most of the frequency valve setup for you if you want it..
Known working and will bolt right on.. Just add a microsquirt..
Will tune exactly the same way as my V8 one, except it doesn’t need any other external DPR controller, but won’t do complete fuel cut..
(I’ll talk someone into trying it eventually)


The design is more or less done on that, took some help from a friend who worked for years designing cast boost pipes to finish om my design. The thing im not settled on is the assembly options, at the moment the plan is to integrate steel nuts in the print. But its a risk that it will never work with only 2 screws for the flange, thats the biggest challenge i think

I probably don have time to take my car appart and experiment, at least not for a while. Would you want to try one if i print it?


If you had another stateside guinea pig would that help...? This post has put me over the edge as far as IC approach.
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Fasteddie313  



Joined: 29 Sep 2013
Posts: 2315
Location: MI

PostPosted: Sun May 16, 2021 8:01 am    Post subject: Reply with quote

jacobroufa wrote:
C�dric wrote:
Fasteddie313 wrote:
Hey Cedric, would some $$ get that lower charge tube printing faster?
Probably should make atleast 3..

I also have a tunable US fuel distributor with most of the frequency valve setup for you if you want it..
Known working and will bolt right on.. Just add a microsquirt..
Will tune exactly the same way as my V8 one, except it doesn’t need any other external DPR controller, but won’t do complete fuel cut..
(I’ll talk someone into trying it eventually)


The design is more or less done on that, took some help from a friend who worked for years designing cast boost pipes to finish om my design. The thing im not settled on is the assembly options, at the moment the plan is to integrate steel nuts in the print. But its a risk that it will never work with only 2 screws for the flange, thats the biggest challenge i think

I probably don have time to take my car appart and experiment, at least not for a while. Would you want to try one if i print it?


If you had another stateside guinea pig would that help...? This post has put me over the edge as far as IC approach.


The lower charge tube print we are talking about is to print a new one with better interior flow characteristics..
Smoother interior designed to have a hose clamped onto it, rather than it be designed to sit onto a turbo outlet and have that big step in it..

Cedric, are you planning those in 2” or 2.5”?
2” would be a bit of a difficult change for me to make down there..
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Cedric  



Joined: 27 Aug 2004
Posts: 2160
Location: Sweden

PostPosted: Mon May 17, 2021 5:43 pm    Post subject: Reply with quote

The first design at least will be 2", it fits the rest of the area in the pipe best, and it makes for better space down there. Its very very tight and i have all the pipes chafing against each other there, and the ARB mount. Even though i had put alot of effort to build the very special oval pipe down there i rather just use downsize from 2,5 ->2"

I hopefully will make a test print this week in regular PLA, then we will probably do some changes and chose a more suitable material, like ABS-CF, Nylon-CF, PC, PC-CF or any other high spec material..

Some small changes might have been done after these pics, but they show the problem

[img]https://www.bildtagg.se/file/thumb/niq88pde66qet3vb35lr51kj[/img]

[img]https://www.bildtagg.se/file/thumb/ytehtqqt2v8c4z0cu6w41xdk[/img]

[img]https://www.bildtagg.se/file/thumb/mom4oignht1s160l74xhmo5s[/img]
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Fasteddie313  



Joined: 29 Sep 2013
Posts: 2315
Location: MI

PostPosted: Mon May 17, 2021 11:39 pm    Post subject: Reply with quote

Mine turns to rubber just before passing up the compressor..
2.5” 90, quite long toward the IC side, cut very short probably to like a 70 or 80 in the bend there by the comp..


(Ancient pic but still the same except t-bolts)

I kinda figure.. If it ever rubs enough to blow, I’ll have gotten my money’s worth out of that hose?

I think going to 2” there would have me redesigning some stuff, unless I could find a long 2.5-2 reducer to make the span..
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Cedric  



Joined: 27 Aug 2004
Posts: 2160
Location: Sweden

PostPosted: Wed May 19, 2021 6:08 am    Post subject: Reply with quote

We re now done with the first version, with slot in nuts. I might use embedded nuts in the flange if this isnt enough. Printing a battery box for my lithium battery at the moment, so it might jump into the printer tomorrow


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Cedric  



Joined: 27 Aug 2004
Posts: 2160
Location: Sweden

PostPosted: Mon May 24, 2021 9:40 pm    Post subject: Reply with quote

Okay, whos up for some testing? I dont have time to pull my engine apart, i need to go the opposite way to actually get my car out since the season is short. But if anyone want to help out with the testing ill gladly ship pipes This is a very rough print to see how it would work out to print, how the slot-in nut works etc, we are changing some small stuff and then it will get a more serious print.




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Fasteddie313  



Joined: 29 Sep 2013
Posts: 2315
Location: MI

PostPosted: Mon May 24, 2021 11:08 pm    Post subject: Reply with quote

I’ll try one.. When I can..
Can’t guarantee I’ll get around to it anytime soon..

PM you my address..
Well.. I would but it won’t let me because of your “e”..
I’ll try it from a not-a-phone tomorrow..
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Fasteddie313  



Joined: 29 Sep 2013
Posts: 2315
Location: MI

PostPosted: Mon Jun 14, 2021 11:55 am    Post subject: Reply with quote

Bought that red “941” car...





Oops!!
OMG my fat fingers!!
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Cedric  



Joined: 27 Aug 2004
Posts: 2160
Location: Sweden

PostPosted: Mon Jun 14, 2021 9:07 pm    Post subject: Reply with quote

Fasteddie313 wrote:
Bought that red “941” car...





Oops!!
OMG my fat fingers!!


This will be very interesting to see, how much and how good the control ability is with the MS+frequency valve.

Though I think it might be time for you to start a new thread for the new car !
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jacobroufa  



Joined: 18 Nov 2016
Posts: 359
Location: Rockford, IL

PostPosted: Mon Jun 14, 2021 9:55 pm    Post subject: Reply with quote

Fasteddie313 wrote:
Oops!!
OMG my fat fingers!!




This will be good.
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