Pelican Parts
Parts Catalog Accessories Catalog How To Articles Tech Forums
Call Pelican Parts at 888-280-7799
Shopping Cart Cart | Project List | Order Status | Help



Go Back   Pelican Parts Forums > 1- Porsche Technical Forums > 911 / 930 Turbo & Super Charging Forum


Reply
 
LinkBack Thread Tools Rate Thread
Author
Thread Post New Thread    Reply
Registered User
 
Join Date: Jan 2004
Location: Sacramento
Posts: 7,269
Chris,

That is disappointing.

Years ago I retained as a consultant an expert on CIS to help me better understand how it worked.

He told me that adding a wedge to the top of the metering plate would make it advance faster. That he used this for turbocharging NA CIS motors as a path to enrichment.

Latter Lee Rice told me that even with his WUR running very low control pressure, he could run a motor on the dyno at full tilt and if he used a long screw driver he could push the metering plate down further and flood the motor.

Between these two data points I was hoping Fishers Velocity plate would help extend the fuel deliver capacity.

He never billed it as doing that only that it would accelerate how fast the metering plate would move with changes in air flow.
Old 03-29-2010, 03:11 PM
  Pelican Parts Catalog | Tech Articles | Promos & Specials    Reply With Quote #21 (permalink)
Registered User
 
TurboKraft's Avatar
 
Join Date: Mar 2005
Location: Phoenix, AZ
Posts: 2,493
I'd like to repeat this back-to-back on an engine dyno in a dyno cell (environmentally controlled) to get more scientific results.

Anyone else tested this? Jeff Gamroth of Rothsport? Steve Weiner of Rennsport Systems? Someone? Bueler?

I don't doubt that Lee Rice was telling the truth. I've dealt with him for years and always found him to be very knowledgeable, experienced, friendly, and helpful. If he says he could flood the engine out by pressing down on the metering plate, I believe him.

On this 930, we took off the fuel metering contraption and installed Cole's. A few days later we re-dynoed the car when scheduling permitted. I expected that I would see some measurable changes -- different AFR plots from better metering, more torque & power, more top end from the airflow mods to the CIS housing... something -- but really, the HP, TQ, and AFR plots looked pretty much the same as the earlier week's runs.

Did those mods help in this case? Not that I could see.
Is there room for improvement in the metering plate and housing? I'm sure of it.
__________________
Chris Carroll
TurboKraft, Inc.
Tel. 480.969.0911
email: info@turbokraft.com
http://www.facebook.com/TurboKraft - http://www.instagram.com/TurboKraft
Old 03-29-2010, 03:40 PM
  Pelican Parts Catalog | Tech Articles | Promos & Specials    Reply With Quote #22 (permalink)
Registered User
 
Join Date: Jan 2004
Location: Sacramento
Posts: 7,269
Chris,

Thanks for the great info!

Volvo's Group B program had different metering cone's with different profiles on top of bigger injectors, 8 bar system pressure, and big fuel pumps.

If Lee Rice is right about the metering arm stalling, a new cone profile might get us more fuel up top. It could also cure the to fat on first boost issue if done right.

The key's to the 'Rice Fueler' was a lower control pressure on boost and conversion of the WUR to be [I]vacuum sensing[/U]. He told me the 75-77 3.0 turbos worked this way but the 3.3's where changed to trigger enrichment later and on boost and this was at the expense of throttle response in his opinion.

This seems to reduce the restriction on the intake side and let the turbo spin up faster.

When I built my own programmable WUR some 7-8 years ago (Andial Frequency valve w custom controller) I used this strategy and it did seem to get me faster throttle response and boost onset.

My next turbo will probably use a BL adjustable WUR converted to be vacuum-sensing, Larry's modified Lambda Fuel Distributor with the Lambda function removed as it has more fuel delivery potential (up to a plus 30% more fuel), and some re-profiling of the metering assembly.

That and a lot of attention to the ignition side (advance curve, modified stop on the boost retard pot, and possibly dumping the Vac-retard function).

I just love the idea of staying with mostly period components though a programmable MSD and a boost controller that can be programed by RPM is tempting.

Sorry, I got carried away again.

The best.
Old 03-29-2010, 05:07 PM
  Pelican Parts Catalog | Tech Articles | Promos & Specials    Reply With Quote #23 (permalink)
Registered User
 
Join Date: Jan 2004
Location: Sacramento
Posts: 7,269
Chris,

Thanks for the great info!

Volvo's Group B program had different metering cone's with different profiles on top of bigger injectors, 8 bar system pressure, and big fuel pumps.

If Lee Rice is right about the metering arm stalling, a new cone profile might get us more fuel up top. It could also cure the to fat on first boost issue if done right.

The key's to the 'Rice Fueler' was a lower control pressure on boost and conversion of the WUR to be [I]vacuum sensing[/U]. He told me the 75-77 3.0 turbos worked this way but the 3.3's where changed to trigger enrichment later and on boost and this was at the expense of throttle response in his opinion.

This seems to reduce the restriction on the intake side and let the turbo spin up faster.

When I built my own programmable WUR some 7-8 years ago (Andial Frequency valve w custom controller) I used this strategy and it did seem to get me faster throttle response and boost onset.

My next turbo will probably use a BL adjustable WUR converted to be vacuum-sensing, Larry's modified Lambda Fuel Distributor with the Lambda function removed as it has more fuel delivery potential (up to a plus 30% more fuel), and some re-profiling of the metering assembly.

That and a lot of attention to the ignition side (advance curve, modified stop on the boost retard pot, and possibly dumping the Vac-retard function).

I just love the idea of staying with mostly period components though a programmable MSD and a boost controller that can be programed by RPM is tempting.

Sorry, I got carried away again.

The best.
Old 03-29-2010, 05:08 PM
  Pelican Parts Catalog | Tech Articles | Promos & Specials    Reply With Quote #24 (permalink)
Registered Driver
 
Helmsy's Avatar
 
Join Date: May 2008
Location: South Australia
Posts: 281
Garage
I have been trying to balance the AFRs on my car using a wideband gauge and after hours and days of testing in the 14s on idle and cruise I have found that my car does not like being in the 14s and idles much more smoothly in the very low 13s.

I would rather run in the 14s however it just doesnt idle smooth at all. I have had to remove the wideband meter and just tune maually to get it smooth.

Is idling in the low 13s and running high 13s/14 just the nature of CIS or does it sound like a hose leak or other issue? Also I have a msd 6al installed. Could plug gap help or hinder as I have tried standard gap vs larger gap and see no difference in the richness it needs to be smooth.
__________________
Ben
'85 930 - Black on Black
'95 993 Turbo - Silver

Last edited by Helmsy; 03-31-2010 at 03:17 PM..
Old 03-31-2010, 03:13 PM
  Pelican Parts Catalog | Tech Articles | Promos & Specials    Reply With Quote #25 (permalink)
Registered User
 
xbmwguy's Avatar
 
Join Date: Apr 2008
Location: west palm beach fla
Posts: 1,612
Garage
ben my car too likes the low 13s to idle well, and ihave adjusted it that way for a while now especially with 964 cams., but when i go on my long cruises too see my knucklehead friends in nc i plug my o2 sensor back in and see 21-23 mpg on the hway
Old 03-31-2010, 03:26 PM
  Pelican Parts Catalog | Tech Articles | Promos & Specials    Reply With Quote #26 (permalink)
 
Registered User
 
Join Date: Jul 2006
Location: S. Florida
Posts: 7,224
Frank beat me to it.

964 cams have more lift, duration(which also means the intake valve closes a little later during the beginning of the compression stroke so you loose some compression and air fuel mixture at idle >"pumping loss"), and overlap than stock or SC cams and because of that the motor needs a little richer mixture to idle smoothly.
Anywhere in the 13's is OK if the motor doesn't drop below idle speed and come back up after you blip the throttle and you like how it runs.

It can also mean you have uneven injector spray from some injectors and running richer masks that at idle if it's really bad.

I have 964 cams and I have idle AFR around 13.5-14:1, cruise hovers around 14.7:1 and boost is around 12:1 depending on rpms and air temperature.

Don't worry about the intake valve closing late and causing loss of some compression and torque at idle and low speeds.
At high rpms this cam and valve timing fills more air into the chambers because of the inertia of the high velocity airflow coming in the ports continues to fill the chambers even though the piston has started coming back up the cylinder and the intake valve is closing.
Then with boost that situation is accentuated even more.
Old 03-31-2010, 03:44 PM
  Pelican Parts Catalog | Tech Articles | Promos & Specials    Reply With Quote #27 (permalink)
Registered Driver
 
Helmsy's Avatar
 
Join Date: May 2008
Location: South Australia
Posts: 281
Garage
Thanks guys. Nice to know it's ok.

I am planning to get in an check my pressures and clean up a few areas over the weekend so I'll reset my afrs and see what I get. I would like around 13.5 idle and 14s cruise.

I guess richer is better than leaner so I can't complain too much.
__________________
Ben
'85 930 - Black on Black
'95 993 Turbo - Silver
Old 03-31-2010, 04:44 PM
  Pelican Parts Catalog | Tech Articles | Promos & Specials    Reply With Quote #28 (permalink)
Crotchety Old Bastard
 
RarlyL8's Avatar
 
Join Date: Jan 2000
Location: Huntsville, AL
Posts: 13,427
Garage
I use SC cams; Idle 13.5:1 Cruise 14.7:1 Boost 12:1
As Jim stated this is about optimal. The idle AFR fluctuates seasonally ~0.5:1 and a little bit depending on where you set the cam timing.
__________________
RarlyL8 Motorsports / M&K Exhaust - 911/930 Exhaust Systems, Turbos, TiAL, CIS Mods/Rebuilds
'78 911SC Widebody, 930 engine, 915 Tranny, K27, SC Cams, RL8 Headers & GT3 Muffler. 350whp @ 0.75bar
Brian B. (256)536-9977 Service@MKExhaust Brian@RarlyL8
Old 03-31-2010, 06:51 PM
  Pelican Parts Catalog | Tech Articles | Promos & Specials    Reply With Quote #29 (permalink)
Registered User
 
Join Date: Jan 2004
Location: Sacramento
Posts: 7,269
Ya, the 3.3's do not have any provision for enrichment fuel and they do not seem to atomize well at idle. They are going to run better off idle if in the 13's.

Pre-boost max TQ is at about 13.2/1.

They seem to be able to run a little leaner at cruse if you have an adjustable WUR and want to.

You might also try pulling the Vac-Retard connection to the distributor (not the boost retard side). It should pick up some, run a little better, and run cooler at idle . You will have to readjust idle if you try this.

Just a thought.
Old 03-31-2010, 07:21 PM
  Pelican Parts Catalog | Tech Articles | Promos & Specials    Reply With Quote #30 (permalink)
Registered User
 
totle's Avatar
 
Join Date: Oct 2008
Location: Norway / Miami
Posts: 1,297
Garage
Like you guys mentioned here, running 1 bar boost you need to improve over stock intercooler or play with wur mechanicaly or digital.

In the thread
Control Pressure Dampener from 930SE
I understand from that italian guy that this is exactly what this "dampener" does.

Last edited by totle; 04-02-2010 at 04:55 AM..
Old 04-01-2010, 02:09 AM
  Pelican Parts Catalog | Tech Articles | Promos & Specials    Reply With Quote #31 (permalink)
Registered User
 
Join Date: Jan 2004
Location: Sacramento
Posts: 7,269
totle,

Sorry I do not understand, what dose the dampener do?

I am very interested.

Thanks.
Old 04-01-2010, 06:50 AM
  Pelican Parts Catalog | Tech Articles | Promos & Specials    Reply With Quote #32 (permalink)
Reply

Thread Tools
Rate This Thread
Rate This Thread:

 


All times are GMT -8. The time now is 11:21 PM.


 
Powered by vBulletin® Version 3.8.7
Copyright ©2000 - 2018, vBulletin Solutions, Inc.
Search Engine Optimization by vBSEO 3.6.0
Copyright 2018 Pelican Parts, LLC - Posts may be archived for display on the Pelican Parts Website -    DMCA Registered Agent Contact Page
 

DTO Garage Plus vBulletin Plugins by Drive Thru Online, Inc.