SC kit for 308/328/Mondial

He didn't answer the question of whether he's doing his own special mod or if it's the Lee Rice mod that is apparently popular among Porsche guys... but maybe you know and can answer that meanwhile?

http://members.rennlist.com/dtdvo67/riceaccelboost.html

 

Sorry I did not respond faster, I have been out of town.

I am the one that designed and built the "Imagine Auto modified fuel head" Steve Kaspar of Imagine Auto did the testing and setup on the cars, I do all his fuel distributor work and he sells them under his name. I have also talked to Steve Kaspar about Lou's and Mike's SC units.

Lou,
Your fuel delivery is not enough. 1100cc is the min spec. Your fuel distributor will flow 1240ccpm to 1320ccpm at WOT. So when over half the volume is sent to the injectors you are unable to keep enough pressure.

Larry

 

Well, after learning the LM-1 outputs are not back compatable, using the new reader, I constructed this labled graph of Lou's run.

The black line is rpm
The purple line is A/F ratio
The blue line is manifold air pressure (boost)

Several key points are labeled on the graph

I'm trying to make a better graph with a scale but hold on.
I think the graph well shows the initial mixture enrichening but the fuel delivery cannot keep up.

More later
Image Unavailable, Please Login

 

Re-size, this time with axis labels
Looks to me at 1:22:41 you have gone wide open on your fuel flow and as the rpms and pressure build the fuel pump or distributor simply can't keep up and the mixture progressively becomes more air without more fuel until 1:28:39 when it simply cannot run anymore at an A/F of 15.6
Interestingly, in my NA carb'd car, just as in this graph, right at about 15.5 is where the engine starts to miss.
I like how your boost builds linearly with rpms - I guess that is to be expected.
It's interesting to see at 1:19:33 how something (WUR? or the barn door air flow plate banging open) tells the control pressure "Whoa nelly! - give 'er all you got!"

EDIT >>> You are MAX flowing fuel by 5064 rpm.
Image Unavailable, Please Login

 

I don't believe Carl is using the Rice unit. The one Carl is sending is a modded stock Porsche 928S unit (086) with boost sensitive control pressure decrease, has an added pressure adjustment screw. No mention of any additional fuel line or control pressure damper as explained in the Rice installation text @ the above link. We will have to look to Carl to elaborate and explain further.

Still looking for comment on fuel delivery etc. from my previous post, boys.

-L

 

Hey Larry,

So.. just to be crystal clear, you understand that my current fuel delivery is 1800ccpm @ the tank return line, post CIS, engine Not running. I have been doing 30second tests (per your instructions), 900cc per half minute. In short you are saying I should have a minimum of 2200ccpm post CIS engine not running ? If I am following the concept properley here.. the lack of volume causes a change in control pressure differential and therefore the CIS leans out the A/F ? Whats my solution, Obiwan , pump? (mine is new, maybe not good, but new)?

-Lou

 

Well, This is interesting. I can tell you from your graph that the air flow plate is pegged wide open at 5064 rpm delivering max flow.

So in addition to needing more flow, you also need to meter it where the air flow plate does not hit the stop untill max hp delivery point. So, you need more delivery pressure and well as more fuel pressure holding the air plate in its range longer.
Just more pressure all around. - is there a main fuel pressure regulator you can just turn up?

 

As the fog begins to lift.....

I am getting a handle on how the CIS really works now. The fact that it uses the fuel delivery as hydraulic fluid to operate makes maintaining ample volume and consistent pressure in the lower chamber key . (insert picture of lightbulb here).

There is a system pressure regulator on the inlet side of the CIS that I believe is adjustable, but I don't think that is the issue, my system pressure is in spec. I think its a volume problem CAUSING a pressure drop in the lower chamber @ WOT, hence the flow plate max out, and the lean out.

I am tinking vee must PUMP-ME-UP mit ein uberflow new Porsche or Mercedes Bosch pump from Deutschland, jawohl?

Lets see what the Guru has to say.

-Lou

 

That fuel enrichment (whoa nelly give her all) is a direct result of the 094 boost enrichment WUR I have on it now. 8psi boost drops the control pressure to below stock cold spec (24 psi), it begins to drop the control from 52psi @ about 2.5 psi boost. works pretty good, hope the modded one Carl is doing works better.

 

OK. Here is my solution:

http://www.fiveomotorsport.com/FuelPumps.asp

and 5 miles from my home, go figure ! But which pump is the best choice ?
I mean, I want "the bomb" but I dont want to BE THE BOMB if you know what I mean. I am thinking the 400 lph/180 psi is way overkill. Maybe the 255 lph/170 psi ? Comments, anyone, Larry?, Carl?

-Lou
Image Unavailable, Please Login

 

see reply on fuel pump thread for one way to approach

http://www.ferrarichat.com/forum/showpost.php?p=136910612&postcount=10

 

I am doing the Bosch 255/170 unit. I called them up, got the man on the phone and he is letting me come over in a half hour (on a Sunday, what a cool guy) and pick it up ! Literally six blocks from my house, unbelievable. Old one is coming out now for inspection and comparison to the new unit. Sweet.

-L

 

Sorry - just caught the last few posts and thought I'd ask: Is the fuel pump really the restriction in getting enough fuel? A bigger fuel pump can definitely increase the amount of fuel, but it can also heat-up the fuel also (though on a mid-engined car, I'm not sure that wouldn't have happened anyway.)

When trying to figure out the fuel issues on my MB C230 Coupe (when I increased the boost pressures), I tried a Kenne Bell Boost-A-Pump. This basically steps up the voltage to the fuel pump to help "over-drive" it and increase fuel line pressure. It is a less invasive solution as you're just taking the 12V positive that normally goes to the fuel pump and plugging that into the BAP and hooking up a vacuum sensing unit to the motor. A rheostat is provided to adjust the amount of voltage increase that is sent to the pump.

 

Funny you should mention that. I considered the Kennebell thing, and as a matter of fact my new pump puts out (post CIS) 1000cc per 30sec @ 12 volts, 1250cc @ 14 volts confirmed, more on this later.

 

Ok... so I deceided to purchase and install the Brand new in the box Bosch 190 litre per hour / 140 psi (a notch above the stock spec 140LPH/120psi) because it was a direct replacment as far as connection size and type, electrical posts etc. The higher volume pump had a smaller inlet and would have required an adapter on the pressure side, plus with the bolt on kit aspect, I didn't want to go too big, just get above minimum spec. When I removed the almost new pump the PO's mechanic had installed in 2004, it was found to be a wimpy ass little non bosch, non ferrari aftermarket thing in a big fat rubber isolation collar (go figure). pics below:
Image Unavailable, Please Login
Image Unavailable, Please Login
Image Unavailable, Please Login

 

So then, because I'm getting a little frustrated, as you can imagine, upon install I rechecked and cleaned everything. Cleaned and checked all the inlets and outlets of the entire fuel system including the fuel distributor (did not dis-assemble it, because I know better), accumulator, lines, everything. Blew everything out with compressed air @ 70psi, used a little carb cleaner, confirmed smooth operation of the fuel distributor etc. New crush washers as needed, rechecked voltages and current draw, you get the picture, no stone left unturned.

Now here is what I have:

New higher pressure higher volume pump (190 LPH @ 140 psi).

11+ volts battery / solid 12 volts w/alternator spinning ,tested @ pump connection posts.

A current draw from new pump of 7.2 amps, operating.

Performance of the system now? :

Test below performed tapping fuel @ post CIS fuel return port

@ 11 volts battery 950cc per 30sec
@ 12 volts (alternate source) 1000cc per 30 sec
@ 14 volts (alternate source) 1250cc per 30 sec

Test below performed tapping fuel @ pre CIS fuel supply inlet (full pump volume)

@ 11 volts battery 1650cc per 30 sec (198 LPH if you do the math)

Test below performed with engine running for 30sec, fuel tapped @ return post CIS

1000cc per 30 sec (does not include amount sent to injectors of course)

Control pressures cold and warm remains unchanged and in spec as before.
cold 1.8bar (26psi) warm 3.6bar (52psi)

System pressure remains unchanged and in spec as before
5.2bar (74psi)

Road test A/F results are almost exactly as before, maybe another 300 rpm before danger zone A/F. But @ 6750 rpm I am pushing 10.26 psi boost !?!

I don't know what to think at this point, maybe fuel distributor issue ?

Carl, what's up with the 086. any thoughts on the current fuel volume issue?

Larry, comments on this ?

-Lou

 

Hi Guys,
Carl text'd me on Saturday that he took 3rd in the Pike's Peak race with his Porsche 928. Very cool! Since he might not be home yet, he may not answer back very quickly. I just thought you might like to know.
Thor

 

I'd suggest NOT making any other changes until you get Carl's custom WUR... then see what change that makes.

 

i would also suggest waiting for Carl. I've been looking at my CIS chart and this is what your results say to me as a rank amateur at this supercharging stuff:
1. Your previous fuel pump by the numbers did not meet flow specs, and may not have met new hp (flow) requirements. With the new pump, you absolutely know you have excess to requirement. I think this was the right thing to do.

2. Your fuel distributor is doing exactly what it is designed to do -- the pressure regulator at the entry to the fuel distributor is working well. It does not allow the base working pressure from which the control pressures are derived above a certain level. I think you will need an over all higher pressure because:
the feed back pressure to the air sensor plate is to low causing it to bottom out faster and provide the max pressure to the injectors (and in this case flow) allowed as regulated by the pressure regulator. I.e., it's my understanding that the air mass plate varies the pressure seen by the injectors mechanically over the range of its travel - and when it bottoms out, the fuel distributor is allowing the maximum pressure mechanically available to the fixed resistance injectors, thereby maximum flow. So, as I understand it, to get more flow across the range of the air mass plate travel, each degree of travel will have to allow a greater amout of pressure to the injectors -- so you will need a greater internal system pressure.
The new wur will allow a greater control pressure seen by the air plate, but somehow the fixed resistance CIS injectors are going to have to see more pressure to allow more flow.

I'd love to hear if any of these conclusions are incorrect and why - I am trying to understand what is going on

 

Man!! Iv'e been so into my own car I forgot about the Pikes peak !!!

Congrats Carl !!! (pic below of Carl and the 928motorsports supercharged pikes peak car in action)

WOO HOO !!
Image Unavailable, Please Login

 

Thanks for all the input and opinions. I agree I need to wait for Carl and the modded WUR before making any changes. I don't fully understand what is going on here either, but at least I know all of my stock components are clear, clean and working in spec. Personally I think the boost enrichment of my current Audi Turbo wur is dropping the control pressure too far and too fast, that could account for the air plate early bottom out. I'll bet the modded 086 allows for a more controlled enrichment and minimum control pressure adjustment. At least the control pressures on the audi wur are stock spec, unlike my smog modded original.

I think I may remove the boost line (go back to "stock" vacuum attachment and stock spec control pressure) and see what run data I get with the new proper volume pump and everything working "as stock". That will 1) give us a true "stock baseline" to compare to, and 2) let me know if my original lean out problem was related to the wimpy pump.

Meanwhile, I wait patiently for Carl to come down from the Pike's Peak buzz and wash the champagne out of his hair.
Image Unavailable, Please Login

 

The modded 086 WUR is on its way to me from 928Motorsports!! Expect some comment from Carl on the recent issues with the fuel pump etc. soon as he catches up from being gone at the Pike's Peak competition.

 

Hi guys, this is Stephen from ImagineAuto. I have been asked to step in here and see if I can help. I hope you don't mind.

I am sorry to ask you to be redundant but can you go over the specifics again. I know that is a selfish request because I don't want to go back through and read 20 some pages

I am sure I can help but I need to know a few things. Please go over all the pressures with me. System and control as well as control under boost (enrichment) what Bosch numbers are you using for the WUR and Head as well as injectors. Lastly what projected HP (wheel) are you looking at?