Advanced CIS Turbo Tuning Discussion Thread. Ultimate?

[911st]

Cole,

If you are going to race your car is is worth making sure you have even fuel deliver to each cylinder. Having the injectors flowed is part of it. Having the head flowed or rebuilt is the other half.

One guy here pulls his injectors in place, puts beakers under them, and pushes his metering plate down all the way after disabling the safety. I like!

We can be running 11/1 AFR and still have one cylinder go lean.

[zcoker]

Anyone know how far the metering plate on the CIS travels at full throttle? Or where the stall point is? How much more fuel is available when the metering plate is wide open? Perhaps a few might know this; I sure don't.

[zcoker]

There must be something to this CIS system that we are missing because this is directly inline with the 'CIS Monster' thread that I started whereat that guy is getting over 600hp out of CIS. I don't claim to know this system a whole lot like I do EFI. Just how much fuel can a CIS system put out?

[911nut]

Originally Posted by 911st

Why do we want early movement? Is that for accel fuel? That could be a goal.

I was focused on complete movement for more fuel up top.

To overcome inertia; improved throttle response and to increase force on the plate to eliminate the stall.

[911st]

Originally Posted by zcoker

There must be something to this CIS system that we are missing because this is directly in-line with the 'CIS Monster thread that I started whereat that guy is getting over 600hp out of CIS. I don't claim to know this system a whole lot like I do EFI. Just how much fuel can a CIS system put out?

I think he has found the limit with out major changes like drilling out the two other blanks on the fuel head for more flow. For all I know, he may have even done that. I think Porsche took that approach with one of there 924 race cars.

He also knows how to build a motor that will not lift and leak at the heads, that will stay together, and breaths very well. He also has a very efficient turbo.

His biggest trick is he is managing boost much differently that we are and goes much higher than 1 bar in the mid range. I believe he keeps pushing boost until he reaches the total fuel deliver capacity of the fuel head. Then, when the motor can not push anymore fuel, he starts pulling boost back fitting the boot level to the fuel deliver limit to achieve stable AFR's to red line.

His peak TQ is artificial and where he first starts to manage and reduce his boost level. His peak HP is where his motor is at its peak VE which is the same place we hit our peak HP. I bet he is pushing somthing around 1.5 bar in the mid range. That is just over 22 lbs. Many run boost into the 30's.

With our motors, our TQ curve is steep until we reach our target boost level. Then the TQ curve takes a turn as we hold our boot goal and we try to hold this to red line. This puts our TQ and HP at there natural points much as if our motors were normal aspirated.

He seems to be using a stock set of euro heat exchangers and probably a turbo with a bigger compressor wheel than we are even with the larger HF's.

This is repeatable with some effort but buget for rebuilds based on hours instead of miles if you track it.

I made some posts near the end of that thread.

[911st]

Originally Posted by zcoker

Anyone know how far the metering plate on the CIS travels at full throttle? Or where the stall point is? How much more fuel is available when the metering plate is wide open? Perhaps a few might know this; I sure don't.

I suspect around 425-450 rwhp if full travel can be achieved in a way we can use it.

I spoke to the builder of the Rice Fueler many years ago. He modified WUR's to be vacuum sensing and for more fuel on boost. He told me that even with much lower control pressure (like the Andial Fueler gets) that he ran a motor at peak HP on the dyno once and was still able to push down the metering plate with a screw driver and flood the motor.

That is why I have been so interested in getting full travel our of the metering plate all these years.

Again, I believe full travel will get us to around where the IA head is getting us now. However, adding the IA on top of full travel should get us further yet. Say upto 500hp.

Thus, fuel dose not have to be the limit. It becomes more like sealing the heads, managing heat, keeping the motor to together, and making it breath well.

Boost and fuel are just part of what makes HP.

[911st]

Originally Posted by cole930

Keith,

2. Just talked with one of the original developers of the velocity cone
for Porsche CIS. He confirmed exactly what we were assuming.
He said it accelerated the metering plate faster from rest through
full movement of the lever and eliminated the plate stall inside
the venturi allowing full movement of the control plunger.
He said this was originally seen on an old Mercedes CIS and
they did some testing and then had one made for a 930 metering
plate and it worked so well they used them on their race motors
had them made locally and sold them through various Porsche
aftermarket suppliers.
Cole

Just had to see this again because it rocks!

[JBL930]

I'm like a kid at school

[911st]

Below is an interesting uTube video on that Compressor Boost Valve mentioned above compared to a normal blow off valve.

I found that taking this approah along with fast reduction in conrol pressure upon acceleration and the righ AFR's made a big differance.

The BOV only opens to release boost on overrun to keep the compressor from dammage.

The other valve stays open letting boost past to keep the turbo spinning in reserve at idle and cruse and closes when boost is needed.

This is simmiler to wha I did on my C2T by changing the orientation of an adjustable CBV and playing with the spring tension. Mine was actually much faster. The advantage to the new system is the amount of air if may flow. My set up fit the standard Bosch CBV fittings.

http://www.youtube.com/watch?v=gvnBDlXyheI

[cole930]

Cole,

If you are going to race your car is is worth making sure you have even fuel deliver to each cylinder. Having the injectors flowed is part of it. Having the head flowed or rebuilt is the other half.

One guy here pulls his injectors in place, puts beakers under them, and pushes his metering plate down all the way after disabling the safety. I like!

We can be running 11/1 AFR and still have one cylinder go lean.

Keith,

No more racing for "The Old GUY"

I'm 66 have a Junk Pump and Cancer I'm doing all this just to see if acceleration
can set my defibrillator off, I'm considering this a Physics Experiment.

Steve is doing the fuel head now, injectors are soaking in a jar in the garage.
Having them tested next week. Billet injector blocks and DWUR coming.

Cole

[JBL930]

When i had these two new hybrid K16/24's installed on my 993 lump





I set off for Le Mans 2008, i got nearly 2 miles down the road and the new BOV'S i'd had fitted



Failed! What happened next was strange. The BOV's were second hand, they didn't open on vacuum. The right hand turbo stalled, the nut then came off the end of the shaft on the compressor side and the left hand turbo sucked it all the way around the back of the intake and into the compressor of the LH turbo, Basically destroying both turbos. Not a good day!
Stock Porsche BOV's in now and all is well, RS Tuning use the stock 993tt BOV's in even their most extreame road turbo builds.
Lesson being, use proper BOV's

[cole930]

Jonathan that gave me chills !!!!!!

Sorry man.

Cole

[stup]

Jonathon dont think many people had the luck you have had,nightmare!!

[911nut]

Originally Posted by 911st

Look back at the forces in the factory digram above. The metering plate in the cone is basically a big valve. The more air flow or pressure through it the more it opens the vavle. At some point the valve goes past its intened range and spills over. That is when we stall.

That's why I think the gurney flap would be more efficient (not to mention easier to make). The air will have to travel over the flap at all angles of opening. In your proposal the plate is only effective through a small range.

[stup]

HERE it is guys!!!....This is like a step back in time with this picture!

Finally got my mate who has got my catalogue to send me pic until he returns it however its been sent to me via mobile phone so aint so good quality!

It does mention quicker fuel enrichment due to the design so they also have went for that pitch

Cole was the "venturi plate just flat on the underside??,,if so cnc lathe is the way to go!!...I have a manual lathe in my garage and could machine them however with a CNC, you would just write a program and could turn them out a lot quicker,At my old work place my mate could knock them up on the side at very reasonable cost!

When you get results we will look into manufacture!


For us with not so good eye sight it says!

THE FASTER THE AIR ENTERS YOUR ENGINE THE SOONER THE TURBO SPINS UP AND THE SOONER YOU GET UP TO SPEED,ITS THAT SIMPLE.AND HERE IS A WAY TO GET QUICKER ACCELERATION.OUR DOME SHAPED ALLUMINIUM VENTURI PLATE INREASES THE AIRFLOW PLATE SURFACE TO GIVE YOU BETTER AIR FUNNELING AND QUICKER FUEL ENRICHMENT.SIMPLE BOLT ON REQUIRES NO MODIFICATIONS.YOU WILL NEED A FEELER GAUGE FOR SETTING THE PLATE HEIGHT.

[WERK I]

The MP "stalls" because the pressure differential between the top of the plate and plenum is zero. Steve at Rennsport solution's is the beauty of its simplicity. By modifying the fulcrum so that when the stall pressure differential is zero, the fuel distributor is at max fuel delivery.

You can also modify the air delivery to the metering plate. By redirecting the air to the outer or inner diameter of the metering plate, you're affecting the amount of "leveraging" force the air traveling across the plate. Everyone remember the mysterious cone in the air cleaner housing that sits above the metering plate?

[911nut]

Sounds like we're all talking about the same issue: how to get more force on the metering plate at large angles of attack.
Here's a question: how does the weight of the metering plate affect overall performance?
The best solution will have to be easy to implement and cheap. Otherwise, the benefits will dimish to the point that it won't make sense to modify CIS if the level of effort and expense gets close to the implementation of EFI.

[WERK I]

Originally Posted by 911nut

Sounds like we're all talking about the same issue: how to get more force on the metering plate at large angles of attack.
Here's a question: how does the weight of the metering plate affect overall performance?
The best solution will have to be easy to implement and cheap. Otherwise, the benefits will dimish to the point that it won't make sense to modify CIS if the level of effort and expense gets close to the implementation of EFI.

I agree.
I suspect the mass of the metering plate would be based on the same principle of a lightweight flywheel.... inertia. The mass of the plate tends to dampen subtle variations of air flow over the plate for smoother fuel metering.

[cole930]

stup & 911nut

That's great that you found the ad. I would really like to have a copy of it when
you get it back.
I got mine from Chris Fisher in a box of 934 parts I bought from him. Chris was
on of the Principles of the original Power Haus. The only way I even knew what
it was is by reading an article in the April 96 issue of European Car that
featured the White Car. In the article it mentioned a high-flow fuel distributor
with a "special dished air-flow plate. When I found it in the box the disc, a copper
metering plate, and the mounting bolt were taped together. I remembered it
being mentioned in the article so I recognized what it was..
I called one of the old Power Hause guys yesterday and ask him about the
plate. He told me that Chris had seen one on a Mercedes CSI he had in his car.
They were screwing around with fuel distributors at the time and decided to try
it on the Porsche CIS. Chris's logic behind trying it was Mercedes would not have
added anything without throughly testing it extensively and it might be exactly
what they needed to get the metering plate moving. Power Hause did dyno the
engines with the plate and it did improve throttle response and plate movement.
He could not remember any of the dyno differences specifically. Apparently it
worked well enough because they had a local metal spinner make one with the
correct diameter for Porsche CIS and after testing had them made in larger
quantities and marketed them; hence you ad in Automation. Interesting price in
the ad, I was told they only cost a couple bucks each to make.

Cole

[911nut]

Originally Posted by cole930

stup & 911nut

Apparently it worked well enough because they had a local metal spinner make one with the correct diameter for Porsche CIS and after testing had them made in larger quantities and marketed them; hence you ad in Automation. Interesting price in the ad, I was told they only cost a couple bucks each to make.

Well, there's a clue.
A metering plate made by metal spinning would be very light.
It wouldn't be expensive to make except for the tooling charge ($$$).