[greatfox]

So, I've got a 2.0 16v and I'd like to get my cylinder head ported. When it gets ported, should I opt to get larger valves?
I want to keep the car very streetable, this is why I have chosen techtonics ABF based "sport" camshaft set.
Will the valves increase torque as well as HP, or will it rob me of my precious low end?
On a related note, would it be complementary to all this to buy (and use) a 50mm mani?
Thanks for the help

 

[VWralley]

Re: Supertech valves... (greatfox)

a good way to increase flow through the head is to use a smaller dia valve stem. that alone is a supposid 12% gain in flow.
i dont know the specifics on how to do this, but if you can get in contact with shawn vaneer up at kinetic, he might be able to help u out http://****************.com/smile/emthup.gif

 

[X K R O M X]

Re: Supertech valves... (VWralley)

Hey fox,The supertech Valves you speak of run what is called an "undercut"stem like rally is talking about, the standard on a 16v is 7mm the supertech intakes are undercut by one millimeter below where the valve protrudes into the port under the guide.Less surface area inside the port is better being it yields less frictional losses for the air entering the combustion chamber.they are also over-sized by .5mm to allow for more air into the combustion chamber.
I currently run these valves on my solid head they are also nitrate coated for better wear and heat transfer.

Your horse power to tq loss is dependent on how much overlap,duration, and the base center in which the the cams have been measured off of,not the actual amount of port work or the size of the valve with larger cams you have more overlap.Because of the duration in which the valves are open in the rotation cycle, it leaves time for incoming air to escape out either the exhaust or intakes on the compression cycle of the bottom end.depending on how the cams were built and the ones you choose could effect either TQ or HP .
The best way to look @ port and head specifics is kind like this, Imagine trying to breath through a straw...pretty hard.now breath through a 2" tube much easier your head act's as the mouth and lips of the motor and the air passing through it should have the least amount of resistance making it easier "to breath".
Farrea also makes good valve but they are more money if you want to go completely nuts they now also offer hollow stemmed race valves with a hardend tip where the lifter contact's them.they are lighter which is less weight off of the reciprocating mass of the valve train which could account for more power.

If you want to get either of these 3 types of valves hit me up I get a smoking deal on them.

Modified by X K R O M X at 4:30 PM 10-31-2006


Modified by X K R O M X at 4:32 PM 10-31-2006

 

[greatfox]

Re: Supertech valves... (X K R O M X)

Thanks a bunch Jarod!

Here are the specs of my TT sport cam set. Supposedly they are based off the ABF cams:
16V Street
Advertised duration : 254°
Duration @ .02" : 229°
Duration @ 1 mm : 219°
Duration @ .05" : 214°
Lift : .423"
Lobe Center: 110.5°
In. Open @ .05" : -3.5° BTDC

So as you can see, it is a very mild cam. It basically lets me rev to redline without the power dropping off while maintaining almost all the low end torque of the stock engine.
If I'm understanding you correctly, you say that its the cams (and overlap) that determine the amount of hp/torque tradeoff you have.
Does this mean that larger valves fall into the "free hp" category like head porting?
I already know there is a slight low end torque loss with the 50mm manifold, but I think it would nicely complement a head porting and larger valve setup

Can somebody elaborate on the benefits/downsides to running larger valves on a relatively tame, hydro cam engine?
Thanks http://****************.com/smile/emthup.gif

 

[antichristonwheels]

Re: Supertech valves... (greatfox)

they are kinda esoteric. if you need new valves, I would get them. If you want a bit more power, get them. I would not touch them unless I had a good ported head as well.

 

[G60RRADO]

Re: Supertech valves... (X K R O M X)

you have im

 

[Fast929]

Re: Supertech valves... (G60RRADO)

I currently run the same setup using TT's 288 race cam set (hydro head) and running ITB's. All Supertech valves train including Ti retainers.
Great stuff. Highly recommended provided the rest of your motor build is up to spec. Really, there are many other places money is better spent for HP gains. The stock valves are very good.

 

[greatfox]

what places can my money be used better if my goal is higher horsepower with minimal (if any) torque loss?
I'm trying to find out a way to make my NA 2.0 16v have more power, but retain its low end torque.
So far I have stock Motronic management (standalone is too expensive for me, plus it will take away the stock appearance of my engine bay), but I have a TT eprom chip.
I have a full 2.25 TT exhaust with 2 resonators and a venturi ending in a dynomax muffler.
I have a TT high flow catalytic converter and a brospeed ceramic coated street header.
I have a eurosport intake box w/ an ITG filter.
I also have a TT sport camshaft set.
I'm looking to get the cylinder head ported because from what I've read, this will give me both torque and hp increases.
I'm debating getting a 50mm intake manifold and a velocity ported and oversized throttle body. (I fear I may gain some hp at the expense of torque)
but the real question is about the valves. Do they cause a torque loss so that you gain some hp in the top end?
Will somebody clear this up for me? Thanks.

 

[chrislane31]

Re: (greatfox)

I am curious also I have essitially the same set up as greatfox, except I already have the TT street cams and head work, what would be the next good mod without losing a lot of low end

 

[greatfox]

Re: (chrislane31)

nice! well, one correction, I do have the street cams installed, but no headwork is right.
How much did the headwork help out??

 

[chrislane31]

Re: (greatfox)

I did the cams and headwork together. I still don't have any good 1/4 miles times to back it up. But I can stay with or reat mk4 24v's and some 1.8t's. Everyone is always very surprised with the car.

 

[FlyGTI84]

Re: (chrislane31)

Big valves alone won't change your HP/TQ band, it's the porting and cams that will change where your TQ band is. I am doing a head right now that has 276 TT cams and we are using the Supertech valves. If you are to use oversize valves, some porting is required, mainly in the pockets, to accomodate for the larger seats. The .5mm valves are perfect for a good street setup, with the cams you are running they would help a bit, but it's hard to say whether they are worth the money, because not only do you have to buy valves, but you need to have larger seats installed in the head to get them to fit, this usually costs about $200 or so. I have not flowed those valves vs. the stock valves yet, but have heard the the undercut alone is worth 5% more airflow on a stock head, and I am sure that the .5mm is worth at least another 5%. You can call me if you have any quick questions......
HTH



Modified by FlyGTI84 at 3:12 PM 11-1-2006

 

[X K R O M X]

Re: (FlyGTI84)

The supertech valves do not require the use of new seat's.if you go over .5mm larger in diameter yes, but not in this case.

 

[greatfox]

Re: (X K R O M X)

if they use the same seats, what is the point of the valve being larger? I don't get how flow would be improved with a standard seat...

 

[X K R O M X]

Re: (greatfox)

Quote, originally posted by greatfox »

if they use the same seats, what is the point of the valve being larger? I don't get how flow would be improved with a standard seat...

Because when the machine shop cuts them they take away the needed material.If you look @ a seat you will see there is plenty of room to cut them further out on the radius of the seat.


Modified by X K R O M X at 9:20 AM 11-2-2006

 

[greatfox]

gotcha http://****************.com/smile/emthup.gif

 

[FlyGTI84]

Re: (X K R O M X)

The exhaust valves are ok with the stock seats, but the intake valve O.D. (1.280" -- 32.5mm) is larger than the the factory intake seat O.D. (1.276" -- 32.41mm) I would not recommend running them like this. For one, you can't run the 45 seating surface to the outside of the valve, which reduces low lift flow on a flowbench, and for two, if you take material out of the I.D. of the seat to make the oversized valve worth it, then you run the risk of the seat caving inward and falling out, which I have seen on cylinder heads I have fixed.
Good luck

 

[greatfox]

Jarod, what did you do about the above issue on your head?

 

[X K R O M X]

Re: (greatfox)

I ran it,that way it is and have yet to have any issues.The point may be relative but I have never had a need to chage the seats on my head's with these valves yet.

 

[Fast929]

Re: (X K R O M X)

My stock seats were also cut to accept the larger valves. No issues to date.