# HEAD/Compression ratio question.



## MGaz (Aug 9, 2006)

hi, What is it that makes the difference between the lower compression ratio HEAD on the UR Q's turbo engine VS the high compression 'non' turbo 5 pot.

can someone please tell me if its the cylinder head that determines the Compression ratio, or if its the pistons that are different. ?

The reason I ask is to know if a high flow head such as the big valve TSR C pack head, can be fitted to the turbo 10v. ???
I know people put them on the naturally aspirated engines,.. but what about putting them on the turbo lumps to give some more power! Can it be done?
If not, are there high flow, big valve heads that DO work on the 10v turbo?


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## Sepp (Dec 10, 2002)

*Re: HEAD/Compression ratio question. (MGaz)*

Awesome question.
Although I can't answer it all, My urq had it's cracked block (original lower compression WX) replaced with a higher compression block from an MC.
The block, with pistons raised the compression ratio up torwards the specs of the original higer compression MC engine.
The result was a quicker launch off the line, and a slightly higer boost response from the turbo. (less lag)
I've seen many higer flowing bigvalve heads for normally aspirated 10v's, but never anything for the 10vt.
In your "textbook" list of urq horse power mods, a higer flowing head isn't usually on the list.
Maybe the power gains aren't worth the money vs. bigger turbo, inercooler, etc.


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## MGaz (Aug 9, 2006)

*Re: HEAD/Compression ratio question. (Sepp)*

well someone on another site picked up a second hand TSR pack C head and a high lift cam for only 300 English pounds. i think.
So at that price, to me thats quite cheap for a head AND cam!

I'd of thought ' _someone_ ' must of tried this?


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## Sepp (Dec 10, 2002)

*Re: HEAD/Compression ratio question. (MGaz)*


_Quote, originally posted by *MGaz* »_
I'd of thought ' _someone_ ' must of tried this?









Yup, apparently a fellow urq owner here in the states swapped heads from a bigger valved unit from a 5KT..
no word on power gains as it is an on-going project.


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## Quattro Krant (Sep 15, 2004)

*Re: HEAD/Compression ratio question. (Sepp)*


_Quote, originally posted by *Sepp* »_
In your "textbook" list of urq horse power mods, a higer flowing head isn't usually on the list.
Maybe the power gains aren't worth the money vs. bigger turbo, inercooler, etc.
Sure, they have high flowing heads, it's called a 20VT







In all seriousness, I also think that is why you do not see a head upgrade for the 10VT engines. People realize that after they spend $xxxx on the head and cam, they will still be way behind a 20VT. So most people wanting a decent hp increase just go that route. Look at the 'performance" mods for the 4kq, the head and a cam that some places sell for what $1500? Put that towards a 5kt donor car and perform an MC1 swap. Your situation isn't one that many people experience, finding a cheap head and cam for the 10vt.


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## WAUOla (Apr 15, 2005)

maybe....
But, for easy hp-gains, a stock 20V head is better than a worked 10V head... so it's cost efficient.
But for more serious builds, I think it's a matter of taste. I'd rather have 10V 400hp (not regarding the cost), than a stock 20V 400hp car...


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## Longitudinal (Nov 13, 2004)

*Re: HEAD/Compression ratio question. (Sepp)*


_Quote, originally posted by *Sepp* »_Yup, apparently a fellow urq owner here in the states swapped heads from a bigger valved unit from a 5KT.

5KT had 38mm intake valves. UrQ intake valves are even smaller?


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## Sepp (Dec 10, 2002)

*Re: HEAD/Compression ratio question. (Longitudinal)*

I started this discussion, and bigger valves came up...
http://forums.vwvortex.com/zerothread?id=3229090


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