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General Information => FAQ/Tech Tips/Please Read First => Topic started by: theman53 on March 23, 2012, 10:52:25 am

Title: 1.6 and aaz valve diameters
Post by: theman53 on March 23, 2012, 10:52:25 am
1.6 is 34mm in 31mm ex
1.9 is 36mm in 31mm ex
Tdi is same as aaz but slightly different lengths

I robbed this from a post. Don't know if it is 100% accurate, but I wanted to be able to find this next time around. I think this is the main reason the aaz head is the upgrade to the 1.6...time will tell.
Title: Re: 1.6 and aaz valve diameters
Post by: R.O.R-2.0 on March 23, 2012, 12:38:29 pm
port shape is also much better on the AAZ.
Title: Re: 1.6 and aaz valve diameters
Post by: rallydiesel on March 23, 2012, 01:58:47 pm
And later AAZ and all tdi have 7mm stems as opposed to 8mm.
Title: Re: 1.6 and aaz valve diameters
Post by: theman53 on March 23, 2012, 04:27:00 pm
port shape is also much better on the AAZ.

So I hear people say, but I really think the oval will flow better than the D. The D might have less turbulance or less tumble, but until my next project I won't know for sure.
Title: Re: 1.6 and aaz valve diameters
Post by: R.O.R-2.0 on March 23, 2012, 04:28:12 pm
port shape is also much better on the AAZ.

So I hear people say, but I really think the oval will flow better than the D. The D might have less turbulance or less tumble, but until my next project I won't know for sure.

i would think the D port would flow better, because its bigger..

bigger ports usually flow better..
Title: Re: 1.6 and aaz valve diameters
Post by: theman53 on March 23, 2012, 07:07:14 pm
port shape is also much better on the AAZ.

So I hear people say, but I really think the oval will flow better than the D. The D might have less turbulance or less tumble, but until my next project I won't know for sure.

i would think the D port would flow better, because its bigger..

bigger ports usually flow better..
Agreed somewhat. The my 1.6 head intake port measures 1-3/8 tall x 1-1/8 wide oval. My AAZ head intake port measures 1-7/16 tall x 1-1/16 wide. I really think the valve is the big difference in flow. The shape is probably to reduce tumble/turbulation, which should help performance. I want to do both a 1.6 and 1.9 head and see what actually does better at a HG change....horribly off the topic here, sorry. If I go further I will split the thread.
Title: Re: 1.6 and aaz valve diameters
Post by: erice1984 on September 10, 2012, 08:12:57 pm
1.6 is 34mm in 31mm ex
1.9 is 36mm in 31mm ex
Tdi is same as aaz but slightly different lengths

I robbed this from a post. Don't know if it is 100% accurate, but I wanted to be able to find this next time around. I think this is the main reason the aaz head is the upgrade to the 1.6...time will tell.

I can vouch for the 1.9 and 1.6 Exhaust valves being the same diameter, I ordered them that way for my AAZ head.
The Intake valves are different, AAZ larger, 1.6 smaller.