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Discussion Starter #1
I get that larger nozzles will give you more fuel, but how is the quality, what I mean is the misting of the fuel? How does it compare to taking an auto tranny 11mm pump and putting it on a manual car?

If you did this, wouldn't it pressurize the fuel much higher and have about the same effect as larger nozzles but with finer misting of the fuel?
 

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I am not 100% sure because I haven't tried it but from what I've heard, it's even better. The pressure goes up and as a result, there is better quality and misting of the fuel. When there's better atomization, there's better fuel burning.

I think the reason it isn't done regularly instead of nozzles is that it requires timing belt removal and is more expensive. But I know that tdiclubbers have done it with good results. It's also best to not swap just heads, since most "heads only" are chinese built ones. The best solution is to use the whole pump.
 

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Here is a dyno from someone who swapped a 10mm pump w/11mm head to a full true 11mm pump. I highly doubt the conditions were the same because one was done in dec and one run was done in may so this can change the results. At least it looks like the same dyno was used. Comparing 2 different dynos is pretty much useless if they are on different brand machines.

But the idea is sound. A true 11mm pump should give better results than a 10mm pump with a 11mm head.

And 11mm pumps should give higher pressure and finer fuel atomization and more fuel injected during the same injection window than a 10mm head, assuming the same setup/nozzles are used.





from http://forums.tdiclub.com/showthread.php?p=1461140#post1461140
 

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Yeah, something to remember is that quality and quantity both are important. From least pressure to highest pressure, I think it goes b4 passat, later a3 jetta, all mk4 10mm, all mk4 11mm automatic trans. Higher pressure injects more fuel and is like larger nozzles but better due to finer atomization. Hopefully, nozzles with more than 5 holes will become the norm for larger sized nozzles.
 
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