Improvements to CIS when increasing boost?

drew1 · 09-29-2002, 08:06 PM

I'm in the process of rebuilding the motor on wife's 924t. I've thought about getting an aftermarket 930 .8 bar waste gate spring to up the boost from the stock .45 to .5 bar.

I wonder if any of you 930 boys could give me hints or info on CIS injection mods needed with higher boost.

Warm up regulator? Do you do any adjusting here?

Stock injectors? Are they enough?

This car has a frequency valve that sends gas back to the tank decreasing control pressure according to O2 sensor. Does 930 have this & if so what about resizing?

Thanks,
drew1

O Yeah, I'll gladly accept the "Where's the motor?", "glorified VW", "What's an Audi?", "You've only got 4 spark plugs", "That things a radiator, whats it do?" jokes if they are accompanied with helpful info.

beepbeep · 09-29-2002, 11:25 PM

You don't need stronger wastegate spring, just bleed-orifice on a wastegate pressure line. (Electronic boost-controller is also a good but costly option)

Connect lamda-monitor to your lambda snesor and see if you are running lean before tweaking your CIS.

Cheers.

drew1 · 09-30-2002, 02:43 PM

Goran,

Thanks for the reply. I've thought about the bleed orfice, or a regulator type bleed to fool the waste gate. I've tuned the mixture flap thing rich to even get the car to run. It has a bad valve and I had to fool the lambda control. Everything is sooted up in the exhaust, so I thought I would clean the waste gate & put a stiffer spring. I figure this would not give me another component to worry about.

I do need some kind of lambda monitor to get things right. Thanks for the advice. I wonder if I could splice into the connection and run a monitor/gauge in parallel with the lambda control in the car. What do you do?

A big problem I'm having is waiting on rebuild parts. I've waited over a month on rod bolts. There is none in the USA.

drew1

TimT · 09-30-2002, 03:49 PM

an easy trick to get more fuel is to fire the cold start valve when the engine is on boost. All it takes is a relay and another pressure sensor

drew1 · 09-30-2002, 04:08 PM

Tim,

Thanks. The cold start injector isn't in a good location to feed all of the cylinders, but I could use that idea with another centrally mounted injector.

I see GT5s. Are you going to run at the Nov PCA Race at CMP in Kershaw, SC?

drew1

Doug Zielke · 09-30-2002, 04:19 PM

Slightly on the same topic.....(not for a turbo, though).

Can anyone comment on how a CIS fuel distributor is "shimmed" to richen the overall mixture? (I'm thinking 3.0/3.2 conversion here, which some experts say, needs more fuel to optimize performance).

TimT · 09-30-2002, 04:25 PM

I dont know to much about the 944 intakes... but you could drill and tap a 6th injector (discounting the cold start valve) in a more suitable location. Get a pressure switch that triggers at 0.8 bar or what ever is just below your target boost level and have a go at it that way.

The monitor you are looking for you would be a quality EGT gauge and migtht be found ...here Pelican may have them as well.

My car is on jackstands now I missed this whole season, so next season I'll try and make kershaw. I have had my car on a diet all summer...... target weight is less than 1800#

drew1 · 10-01-2002, 02:06 AM

Doug.

I imagine that where the fuel line comes in. There is some kind of pressure regulator there with shims & an O ring.

Tim,

I'll check around for a good gage. Hope your winter isn'r too cold or your pocket too empty to get the car off of jack stands next year.

drew1

drew1 · 10-01-2002, 06:07 PM

bump

Doug, check new post to you, I gave you wrong info.

drew1