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Replacing check valves to correct low boost ('the bolt fix')

4K views 14 replies 10 participants last post by  everetthope 
#1 ·
Hi

Sorry to repost this query, but I think it's got a bit lost in the lengthy thread about correcting poor boost.

I've done the (in)famous 'bolt fix' and blocked off one of the lines going into the boost control valve. It's done the trick, but I'm keen to install some new check valves and restore things to stock. I know you can buy the whole tube from Saab but this will cost a fair bit and is overkill really.

I've read that some people have done this with home-made valves, but I'm not really up to this so was looking for some alternatives. The valve from what I've read could go in near the throttle body.

I've found this:

http://www.thornycroftparts.co.uk/product207754_422910.aspx

Would this do? Any potential pitfalls with using a valve like this in a vacuum system?

Also, if I needed some extra hose what sort of thing would I need? is there anything special about it or would any old rubber hose suffice?

I'd be grateful for pointers.

James
 
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#2 ·



That would be a BIG NO NO! That valve is only designed to stop fuel from dripping out. It's not designed to hold the amount of pressure that the check valves handle. It might work for a little while, but I would not suggest it.

Quote from the details:

"Stop fuel siphoning back down the pipe. Holds the fuel in the pipe.
Suitable for Carbs and low pressure fuel systems"
 
#4 ·
That one seems closer. I don't want to tell you it would work and then have it fail. Still i am not 100% sure. The BOLT MOD is really the only GOOD way to over come this issue in the first place. I would suggest calling a saab mechanic directly or SAAB directly and tell them what the 2 valves are you need and get real replacements. However... they WILL just fail again. I know people who did this to saabs with under 20,000 miles on them and left it there to this day. My personal mechanic was not a fan of the bolt mod, but that was because he didn't understand what it was for, or what blocking that hose actually accomplished. This mod was first made public by one of the most reputable saab tuners out there. I would just leave it alone with the bolt in, and forget about it
 
#5 ·
My three 9-5's have managed over 10 years running (between them) with the bolt mod in place.......
 
#8 ·

The boost control valve is the little black plastic item with 3 rubber pipes connected to it - just above the e of elksport in the picture. Remove the top rubber hose/tube and plug it with a screw/bolt, leave the outlet on the valve open to air. Job done.
 
#10 ·
So I just noticed something and am curious, in the link provided a few post up regarding the bolt mod, the second picture shows the bolt in the top hose and the valve blocked off. Yet in the picture directly posted in this link the poster and picture state "leave the outlet on the valve open to air. "

Can we/I get some clarification on this?
 
#11 ·
You block the pipe NOT the valve ;)

The second pic doesnt show the valve blocked so I'm confused as to what you refer to?

Unless its the text I put in the pic about "remove and block off" - I refer to the pipe not the valve - sorry if its unclear!
 
#13 ·
Hi

Sorry to repost this query, but I think it's got a bit lost in the lengthy thread about correcting poor boost.

I've done the (in)famous 'bolt fix' and blocked off one of the lines going into the boost control valve. It's done the trick, but I'm keen to install some new check valves and restore things to stock. I know you can buy the whole tube from Saab but this will cost a fair bit and is overkill really.

I've read that some people have done this with home-made valves, but I'm not really up to this so was looking for some alternatives. The valve from what I've read could go in near the throttle body.

I've found this:

http://www.thornycroftparts.co.uk/product207754_422910.aspx

Would this do? Any potential pitfalls with using a valve like this in a vacuum system?

Also, if I needed some extra hose what sort of thing would I need? is there anything special about it or would any old rubber hose suffice?

I'd be grateful for pointers.

James

if your one way valves are toast you have nothing to loose try air compressor check valves as they are tuff or any air pump valves

this is what i found on ebay:
http://cgi.ebay.com.au/1PCS-ISTA-St...296988?pt=AU_Pet_Supplies&hash=item19bf65b85c

http://cgi.ebay.com.au/NEW-ONE-WAY-...10587804856?pt=AU_Barware&hash=item19bf8bfcb8

check the fitting size first it should be around 4-6mm if im not wrong
 
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