ZX3tuning

I took the car out for a long drive this past couple of days, total of about 1000km round trip and I noticed a few things that concerned me....

first,
under boost the engine goes extremely rich, from 10flat to low 11s is common place with even light throttle input with a load on the engine. idle is at 14-15, part throttle cruise around 13.5, .4bar boost just off cruise is mid 12s.

second,
under full boost and 1/2-to-full throttle the engine cuts out, for a moment before being there again, off boost(granted i have probabaly let off the gas more than a fair bit). aside from being very rich, AFR's do not spike lean that i can tell. this can be very un-nerving when pushing speeds above 150kph...

the dirt:
Car has the Imagine Auto stg2 upgrade and all that intails, Imagine Ported fuel head, we also opted for the K27hyflowS turbo and i also have an Innovate LC-1 Wideband gauge so i can keep an eye on things.
we had the kit installed at Weissach Porsche up here in Vancouver, a very reputable place in the eyes of basically all local Porsche owners. when we picked up the car they told us they had set it to run on the rich side under boost and had scaled back the fuel pumps to cutout as a safety measure.

Not knowing these cars i just sort of dismissed this as "the way it is".

In first gear once on boost, it builds so fast and hard you pretty much have to keep your hand on the shifter to swing it into 2nd. only down side to this is again, it seems to cutout before 6000rpm. well, to be honest it could be as low as 4500rpms, i'm to busy keeping an eye on the road and what is now screaming towards me as i mash to go-pedal!
at first this was the only time id did this but now it is happening more and more in different gears and in different situations; load, boost, throttle application, etc.

i will admit the car does need to be propperly tuned and have the EBC dialed in propperly, just wondering if there is another issue i may be having or if there is something i missed.

please ignore my spelling and grammer mistakes, it's late and i'm tired after driving for the past 5hours.
Thanks in advance!

Mitch

ZX3tuning

anyone?

JBL930

"i will admit the car does need to be propperly tuned and have the EBC dialed in propperly"

Mitch[/QUOTE]


I think you may have answered your own question?
Good luck

ZX3tuning

lol
you forgot the second part to that sentence... "just wondering if there is another issue i may be having or if there is something i missed."

Anyone else got an idea?

My87Targa

if the car needs a tune then that should be your problem

ZX3tuning

ok so then it is possible to scale back the fuel pumps as a safety measure so they cut out at full boost?

PorschePhD

It simply needs to be leaned out a bit. Low 11s is too rich. You chould target 12.0 WOT under full boost. This is not the way it is.

ZX3tuning

ok so then what should i look for at idle?
if i lean it out at the 3mm detent screw it makes it idle kinda rough and up in the 15+ range...

or is there another location to lean the off-idle mixture at?

DonE

Does your shop know how to tune a CIS car? What does "scale back" fuel pumps mean and how did they do it?

ZX3tuning

the shop that did the original install work was Weissach.
to be honest, i have doubts that they did much in the way of tuning...

I personally do not know how to tune a CIS car which is why i question what i have been told.
I have said it before, i'm new to this brand and platform, but am interested in learning as much as i can. I'm not new to cars or turning a wrench and have tuned a bunch of high powered FWD cars, but nothing like a CIS Porsche... basics are there, just do not know where to start
any help would be appreciated

diabolos88

When you make your adjustments do so with little turns or you'll be creating a nightmare for yourself. FYI, CO adjustments should first of all be done with a proper meter like a CO meter (gas analyzer e.g Gunson) while your adjusting, and your target CO% should be 3.4%.
Sounds like you leaned it out too much hence the rough idle and LC-1 15% readout. I don't believe there's a baseline or factory setting for the adjustment screw, like some kind of definition to give a reasonable starting point from where to start turning from like a carb does. But bare in mind since you're new to this CIS platform, if you turn the screw too much counter clockwise the idle will go low and eventually stall the engine. If too much clockwise the idle will start to "hunt" on you. A very small turn of the screw will cause a signifcant change in the CO%.

ZX3tuning

I am aware of that. i recently had to get the car thru emissions by building an exhaust with a cat and then leaning it out and turning up the idle. i returned everything back to where it was before i made my adjustments, i made notes and marks on where everything was and how much i turned the Detent screw and idle screw.
good to know about the 3.4% on the CO but is that all i'm tuning for?
oh and my LC-1 readings were 14-15+ on the AFR, not CO...
i have a 5gas analyzer at my shop i use for getting cars through emissions, should i be watching any other readings?
O2?
HC?
NOx?
CO2?

thanks for your help!

slownrusty

ZX3Tuning - Off topic are you bidding on some H&R springs on eBay right now?

Yasin

ZX3tuning

nope.
i'm a H&R Dealer... however i have no intentions of selling parts to the Porsche market.

nathanUK '81 930 G50

So, you have the idle too lean and when on boost it is too rich ?

If that is so then it sounds like you may have an air leak on the intake side.
Maybe your WUR has gone bad. Maybe you should get it made adjustable and rebuilt.
You could connect some CIS test gauges and check the pressures according to the workshop manual.
Are you overboosting and the cut out switch is cutting in ?