Neverendz

Hey all,

I have a stock '87 944 turbo. For some reason it is running 20+ psi boost at full throttle. I didn't hold it long enough for fuel cut-out. I was also wondering what stock boost should be in psi?

Any help would be greatly appreciated.

, Bill

BKiller

Stock KLR should never allow 20psi???

hosrom_951

doesn't allow 12psi, some people got 13-14psi max with stock chips.

Check the line to the wastegate.

2bridges

stock boost should be in the 11psi range.

20 is very dangerous overboost if you are stock.

xsboost90

mine has spiked up to 25 psi when my MBC was routed wrong. After installing a ZT2 wideband i found that over 14-15psi it gets dangerously lean, so even if it takes a few seconds before boost cut comes on-if you hold it long it will come on - you could be melting pistons or valves beforehand.

special tool

It probably won't melt these pistons - they are very tough.
It will blow the gasket or break the cylinders, unfortunately.

toddk911

A. Are sure it is 100% stock??

B. If so, how would you know you are hitting 20psi on stock boost guage?

C. Are you sure you not looking at stock gauge reading of 1.5 or so BAR and assuming that is 20 psi?

Ian Carr

yeah, how are you reading boost? On the dash 1 bar = atmospheric presure = 0 psi

Neverendz

I installed an aftermarket boost gauge this morning to diagnose. I've had this car for 4 years. It's been in storage. This is the first time I've driven it on open road. The car has had a lifetime of abuse from what I can tell. I've had many other projects over the past few years and I'm finally getting to this car. I drove it last week and it boosted to 2 bar+. The bypass valve blew up. I got a new bypass valve yesterday. I pulled the DME this morning and it has the stock chip. I didn't open the KLR.

This is what's strange. I thought it would shut down at 20 psi. At 3/4 throttle it boosts at 15 psi.

Thanks for all of the quick responses.

, Bill

toddk911

Blown out wastgage diaphragm???

Keithr726

Maybe you need a new KLR. Check to see if there is holes under the battery which would cause water to reach the DME and KLR. Happen to me but I got almost no boost.

Keithr726

Was it fun?

Neverendz

Was it fun? Yes! But fear of a fuel cut out kinda offsets the joy. I hate when that happens. . .

gt37vgt

when all is fuelled and tuned well 20 psi is about what what is the standard hot set up is as most turbo maps hit max efficentcy and max flow at this 2.4:1 pressure ratio

adrial

Check the banjo bolt that connects to the rear (if standing in front of the car looking at the engine) of IC pipe the air goes through as it exits the turbo on its way to the IC. Be careful not to lose the 2 crush washers. Check if there is a restrictor installed (common oldschool method of upping boost).

If nothing is there, check the condition of the line that runs from the cycling valve down to the wastegate. If this line has a leak, you will see high/uncontrolled boost.

Your issue is probably one of those two.

The 26/6 in a stock 944 turbo is not efficient at 20psi.