My brothers Saff 4x4 has a little issue with his turbo boost. The car is original except for a 044 pump, exhaust and stage 1 chip. When giving full throttle it boosts to aprox 1.1 bar but then after 4000 rpm the boost starts to whobble a bit. To 1.2 bar and back to 1.1 and up to 1.2 and down again. It's not steady.

Any idea's?

 

Good morning,

had a simelar issue on my stage 2 had a leakage on the dumpvalve .

When I pressurized the system I found it leaking ever so slightly ... this I assume caused it to build up pressure / loose some / ...

Worth a try ...

Steven

 

Good point, will put check the dumpvalve asap

 

I've fitted the original dumpvalve to the car but that doesn't cure things.

This time I did a little video with my phone of the boost gauge, it's in bars. The maximum is 1.5 bar and the yellow line before is the 1 bar mark. This was filmed while in 3dr gear and revving till 5000 rpm max.

http://s945.photobucket.com/albums/a...t=MOV00826.mp4

 

Roy isn't 1.5 bar to much for stage 1 mate?

 

Marco, the gauge has a maximum reading of 1.5 bar. The car isn't boosting to 1.5

It's just a tad above the 1.0 mark.

 

Hi ,

looks like something is trying to regulate it .

Try to connect the wastegate actuator straight to the inlet of the turbo without the amal valve then see if it stays stable. Only moving one hose over worth a try.

Make sure you are not running to much boost by taking the amal out .

Other thing I think can happne is that if you got a 2 bar map sensor and you are going over slightly the boost it can take I am not sure what that does.

But I put a stage 1 in a friend of mine overboosting 1,2bar and holding 1 bar with all the standard equipment may be worht a try to regulate the boost 0.1 bar down and see if it is still present then you know you are at the border of a reading from a sensor.

gr,steven

 

Looking at the video I think you need to reduce the boost by 0,1 bar holding 1.0 not 1,1 hopefully this will help.

Steven

 

who's chip have you used

 

Sorry Roy it was a bit early this morning

Like Steven says, set boost a little lower and see what happens

 

Thanks for the replies.

We've tried to get the boost lower but we haven't achieved that. It's a Garrett -31 actuator and we have lenghtend the rod as long as possible to get the boost down without the being too lose so the wastgate has no preload.

The chip is made by Dutch Cosworth specialist Gerry Knubben. Some people in the UK also know this guy. He did some work for Ford Motorsport in the 90s

 

Try another Amal valve

 

it looks to me as though you have boost mapping issues ie the boost map is std
the primitive valve cannot accurately control boost and the l8 only has a simple boost strategy
to eliminate this possibility ground pin 16 of the ecu or ground it at the amal valve temporarily
and report your findings please

 

You have a spare one Marco?

Will ground pin 16 and post the results here

 

Hi Roy,

Gerry revised some turbos for me on my stage 2 . I know he is also doing some live mapping ...

I am from Belgium so you should not be to far away from me .

Let us know how you get on .

Steven

 

I will swap the amal valve tonight with the one from Marco's car. If that doesn't help I'll try what Tony suggested.

My brother didn't bought the chip from Gerry, it was allready in the car when he bought it a couple years ago. But the car was rarely used so he never noticed this issue really. We are from Limburg so that should be to far of you I guess

I'll post an update as soon as I know more.

 

See you guys tonight Roy, I'll bring a standard ecu along so we have some options mate

 

We've put the Amal valve from Marco's car on my brothers and now the boost stays steady. Looks like the Amal valve is the cause of the problems so trying to get a new one asap

 

Glad it was a easy fix for Nick mate

 

Hoi Roy,

also from Limburg but the otherside of the border ( gruitrode )

Steven

 

Cool, there are quite a lot of Cosworth in this area then, we are from Roermond