Author Topic: Very rich on boost, any ideas?  (Read 7958 times)

1938vw

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Very rich on boost, any ideas?
« on: 13:14, Sun 29 April 2012 »
Hey guys odd one here, I'm running a 32 dis on a 1600 aircooled beetle.
Everything's going well apart from one thing, on full boost (11psi) it's way too rich I have a wide and and I'm currently running 11-10.5:1! I've read up about it and as far as I can make out this is controlled by the second stage turbo enrichment. Unfortunately it seems that you can't replace this or make it smaller by soldering!


What can I do!?

James5

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Re: Very rich on boost, any ideas?
« Reply #1 on: 15:28, Sun 29 April 2012 »
Quote from: "1938vw"
Hey guys odd one here, I'm running a 32 dis on a 1600 aircooled beetle.
Everything's going well apart from one thing, on full boost (11psi) it's way too rich I have a wide and and I'm currently running 11-10.5:1! I've read up about it and as far as I can make out this is controlled by the second stage turbo enrichment. Unfortunately it seems that you can't replace this or make it smaller by soldering!


What can I do!?


What size jet's are in the rest of the carb, air corrector? main jet? ? have you checked what size the 2nd stage jet is?

Worst case if the 2nd stage has been drilled out it's either get anither carb body or drill out the 2nd stage jet and tap it so you can put in an air corrector jet in there so you can have an adjustable 2nd stage (this has been known to work as I have done it myself on some of my own carb's in the past, and it has aslo been known to fail Not my own but have seen others whom have tried and not succeded).

1938vw

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Re: Very rich on boost, any ideas?
« Reply #2 on: 18:42, Sun 29 April 2012 »
I have....
0.9 air corrector jet
130 main
55 idle jet.

It behaves as it should ie starts around 14.7 then gets richer under boost. I haven't checked the 2nd stage size yet but I will do.

What thread size is the air corrector?

I've done a fair bit or drilling and tapping so it might not be too bad.

James5

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Re: Very rich on boost, any ideas?
« Reply #3 on: 19:14, Sun 29 April 2012 »
Before you mess with the 2nd stage jet have you tried using a standard main jet which is a 120 and putting a bigger a/c in place aswell say a standard 125and seeing what it does it that should lean it out quite a bit?

1938vw

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Re: Very rich on boost, any ideas?
« Reply #4 on: 19:38, Sun 29 April 2012 »
No, I thought that as its running well off boost that it's best not to.

It wouldn't hurt to try and it would make sense to try it. I have a wideband afr so I should be able to keep an eye on it.

I wonder if it will work.

James5

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Re: Very rich on boost, any ideas?
« Reply #5 on: 19:52, Sun 29 April 2012 »
Quote from: "1938vw"
No, I thought that as its running well off boost that it's best not to.

It wouldn't hurt to try and it would make sense to try it. I have a wideband afr so I should be able to keep an eye on it.

I wonder if it will work.

 :D

1938vw

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Re: Very rich on boost, any ideas?
« Reply #6 on: 21:29, Sun 29 April 2012 »
I'll take that as a yes!

Ash-Lee

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Re: Very rich on boost, any ideas?
« Reply #7 on: 21:44, Sun 29 April 2012 »
This is an odd question, a lot of people here are going to provide answers based on there experiance using the carb on a Renault 5 engine.

Would a VW forum not have more answers? There must be a reason as to why you have fitted this carb to a VW engine, is it a common modification?

1938vw

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Re: Very rich on boost, any ideas?
« Reply #8 on: 23:09, Sun 29 April 2012 »
Common no but not unheard of.
There are only a handful that I have ever heard of and they don't really let out any secrets!

In the aircooled vw world there aren't any factory turbo carbs so the knowledge is very limited.

The 32DIS is such a versitile tuneable carb. That's why I have come to you guys ;)

I can imagine that some of the guys on here wouldn't even want to discuss this if it's on a vw and that's fair enough. That's why I really really appreciate any help I get!
CHEERS GUYS

James5

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Re: Very rich on boost, any ideas?
« Reply #9 on: 23:27, Sun 29 April 2012 »
Sorry :D  = Yes it should work.

adjusting the 32dis should have the same effects on the vw lump as on the C1J.

Keep me posted on how things go:)

Brigsy

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Re: Very rich on boost, any ideas?
« Reply #10 on: 14:31, Wed 02 May 2012 »
Make the air corrector bigger or make the main jet smaller. In my experiences they can both make a big difference to on boost fuelling.

1938vw

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Re: Very rich on boost, any ideas?
« Reply #11 on: 21:08, Thu 03 May 2012 »
So, I took the triangular part off and measured the 1st stage and the second stage bush and they are standard sizes!

I took the advice of changing the main from 130 to a smaller 125, unfortunately this meant it didn't really run well at all went up the road and turned round sharpish!

Afr normal running was higher than 18:1, the max of my gauge will go. Didn't put it under boost as it was so lean and totally undrivable!

Sorry guys.

As I can't remove the 2nd stage bush what can I do now!?

I'm running around 11 psi at the moment. Would more boost help?

James5

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Re: Very rich on boost, any ideas?
« Reply #12 on: 08:12, Fri 04 May 2012 »
And that was just a main jet decreasement in size hmmm was expecting it to go that lean for you. Did you try increasing the air corrector jet and putting the 130main back in??

Increasing the boost will help to lean out more but your prob going to need to run another 6 or so psi more to get into the high 11's

1938vw

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Re: Very rich on boost, any ideas?
« Reply #13 on: 08:23, Fri 04 May 2012 »
Oh dear that's a bit to much boost for my poor engine!  I have an 0.9 AC in there at the min as recommended by mike @ gt turbo spares. I have the original one I think that's a 1.2 I thought the larger AC jet made it rich for some reason. Will the larger AC lean out the whole mixture throughout the rev range or just on boost?

James5

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Re: Very rich on boost, any ideas?
« Reply #14 on: 09:27, Fri 04 May 2012 »
Quote from: "1938vw"
Oh dear that's a bit to much boost for my poor engine!  I have an 0.9 AC in there at the min as recommended by mike @ gt turbo spares. I have the original one I think that's a 1.2 I thought the larger AC jet made it rich for some reason. Will the larger AC lean out the whole mixture throughout the rev range or just on boost?

Yes the larger AC will lean it out a bit on boost matey,  the smaller AC has the same effect if you put your finger over a hose in that it makes more fuel come out