[Genespleen]

Hi all,

I've installed an Dawes-type MBC on my 95 900SEt (manual trans.), and even after backing out the adjustment all the way, I'm still getting fuel-cuts as the boost reaches deep into red. Is this the dreaded boost spiking, or am I right that perhaps I need a softer spring inside the MBC? Can anyone think of appropriate places to find such a spring? My local Home Despot doesn't have anything like what would fit inside.

Other ideas welcome, of course.

many thanks,
David

 

[Tweek's Turbos]

it doesnt sound like it is connected properly. Where do you have the lines hooked up?

 

[Genespleen]

Hi,

I think it's corrected correctly, as per http://www.lehigh.edu/~cak7/Upgrades/Stage1/MBC.html

> 90-degree output nipple to wastegate

> straight input nipple to turbo compression housing

 

[SPATL]

Open up the MBC and make sure the ball and spring are in the correct orientation. Ball should be against the strainght barb end, and spring to the elbow.

If it is a dawes or MP MBC, that spring has problems with being too soft never too stiff.

 

[Genespleen]

Thank you both; the malfunction is all down to me. I *did* install the MBC bass-ackwards. All seems fine now, although I'll want to find a stiffer spring, (or maybe a shim through using a washer?).
embarrassedly,
David

 

[SPATL]

A washer inside works well. I use one. I think it iseither a #6 or #8 size washer inside placed on the outlet side above the spring. Works well once set.

You can use a stiffer spring, but try the washer first. It may be enough to do the job.

 

[julianBC]

A washer inside works well. I use one. I think it iseither a #6 or #8 size washer inside placed on the outlet side above the spring. Works well once set.

You can use a stiffer spring, but try the washer first. It may be enough to do the job.

Where would one find a stiffer spring? Haha, I am still having my boost problems but have been too busy/lazy to crawl under and check the hoses. Soon, soon.

 

[SPATL]

I have found springs at a hardware store that were the same ID and modified it. It takes some time to get it right but once you cut is, then you must grind the end flat to make it work. You can do it but it takes a little time. I did one for someone who was running 20psi and it worked well.