Rocker ratio changes are very popular way to increase performance in many makes of cars when guys hot rod them.. even with VW, but from what I've seen, only air cooled. I can't say that I've ever seen anyone change the rocker ratio on a water cooled car yet. Not that I've looked very hard..

For several months now I have been talking with a couple engineers at Schaeffler about our rocker arms. The reason is that I want more than the 11mm lift that all the aftermarket cams have for the 24v VR6.

Today I was happy to receive the following email-

"found one that MIGHT be beneficial to you and it has a slightly higher ratio. There is
no guarantee that it will fit or operate successfully without running a
full analysis on it. These calculations take weeks, unfortunately my
boss wont let me do side jobs like that. Buy a set (or one) and try it
out on the bench to see how things line up.

Good luck! Let me know how it works"

Sounds like typical engineer disclaimers to me. They have the full specifications of both right in front of them, I'd imagine they would bother telling me about them if they didn't think they were going to work. I'm stoked!

The 'slightly higher' ratio he is talking about is roughly a 14% increase over stock.

They should jump the lift on the Schrick cams from 11mm to a hair over 12.5mm.

I can't find my old email file from Willy @ Supertech with the specs on the stock valve springs, but if I remember correctly somewhere around 12.5 was the coil bind limit on them. I should have that info again tomorrow when he responds again. Looks like I might need to change them out if this rocker is indeed functional in this application.

I also sent an email to the Schrick engineer I converse with to see what his thoughts are just for fun.

While these rockers would be a cheap way to gain power on any of the 24v regardless of cams or head, I am especially looking forward to them as my ported head is capable of decent peak CFM over stock.

aprox .430 VS .490 with the stock rockers and these new ones..about a 15cfm gain intake side at peak lift.

For those of you wanting to know more about changing rocker arm ratios, here is a quick page with a nice graph showing area under the curve. By opening and closing the valves at a faster rate, the engine flows more air for the same number of degrees of valve duration. It is for old American iron, but the concept is the same.

http://www.pontiacstreetperfor....html

Interesting idea thats overseen by many in the import car game.

Do they actually have a rocker arm that could be mounted in our heads ? What kind of price ??

im also curious on what this would cost also.

very interested in this, i knew my P&P would come in handy later on.

Quote, originally posted by PowerDubs »

I can't find my old email file from Willy @ Supertech with the specs on the stock valve springs, but if I remember correctly somewhere around 12.5 was the coil bind limit on them. I should have that info again tomorrow when he responds again. Looks like I might need to change them out if this rocker is indeed functional in this application.

so even if springs are not required (which they may be) would they be recommended?

also what about retainers?

i would assume these rockers combined with this set would benefit significantly with a P&P head. correct?

Specs:

* 13.90mm max lift
* Coil bind at 17mm
* Rate 12.6lbs/mm

Modified by r32dub88 at 11:33 PM 2-3-2010

Quote, originally posted by Daemon42 »

Make sure your friend changes out his blinker fluid and muffler bearings too.

3.2 N/A people COSWORTH will make us a manifold with enough interest check it here
http://forums.vwvortex.com/zer...53413
300BHP CAMMED R

Douglas Volkswagen
491 Morris Ave.
Summit, NJ 07901
parts 908-277-1100, service 908-277-3300

How cheap? Last I priced out doing similar it was getting pretty expensive.

Quote, originally posted by PowerDubs »

I also sent an email to the Schrick engineer...

Schricks N/A cams for the 16v are 12mm/11mm and use stock valvetrain.

The R32 and the 16v utilize the same rocker set up, springs, etc.
I imagine you would at least be good up to 12mm lift.

I was all about this after having my engine fora few months a seeing that cams might be a struggle. There is a gain to be had from this is there, but in stock form it is not as impressive as what you are going to see with you worked head. I plan on keeping the head stock for quite a while so I kept barking up the camshaft tree, found a solution and I am content to see what they do first. Here are HPR's AXW 16v numbers that I put into a chart, you can see that jumping from 11mm stock to 12mm aftermarket is minimal at this point. Headwork will most likely open the spread much more....

Looking forward to what comes from all of this.

Now i am not sure on this particular cylinder head if we can upgrade valve train without removing the head.I know some motors you can pull the cams and then fill the cylinder with air and do the springs and reatiners.It would be nice to beable to do it that way and not have to pull the head.Hopefully someone can chime in here if they done so.

Hopefully we can got that route if need be without pulling the head

3.2 N/A people COSWORTH will make us a manifold with enough interest check it here
http://forums.vwvortex.com/zer...53413
300BHP CAMMED R

^ those are some "feel good" numbers, with assurance like that in your valvetrain you're not going to have to worry about a damn thing! If Powerdubs is right (considering he always is) that's a great improvement over stock.

Quote, originally posted by -Bude- »

In Germany is no calendar yet arrived. I hope he comes this year. Am very machined. Greetings

I had Jeff's spare rockers in my hand and my R32 rockers side by side and the rockers were clearly different in size with the 16v being shorter then the R32 rockers. I even went further as to find 3.6 rockers and those were the same as R32 rocker arms.

West Indian Crew

"a Fool can make the most simple things complex, It takes a genius to make the most complex things simple."

Some thoughts...

The only way to change the rocker ratio is to change the location of the roller section that hits the cam. My concerns would be with the change in cam phasing if all else is left the same. I had to draw it out below. The numbers are just for reference, they mean nothing compared to actual parts. I just started drawing it out and some of the dimensions might be on the large side so the effect would be exaggerated.

Stock type cam, stock rocker:

Increase rocker ratio by moving center pivot toward lifter. This is a ~25% change in designed pivot and ratio. You can see that the lifter would have to pump up slightly to compensate:

Now we take this bad boy to the old full lift cam angle, notice the offset from the new full lift cam angle.

Also, notice that the true rocker ratio at full lift is higher. This is due to the rocker tip needing to 'slide' out to keep valve contact. Some of that can be mitigated with a radius on the end of the rocker arm where it hits the valve, but it was hard to draw

I might redraw it with real numbers if someone could measure a rocker (length, pivot location, lifter ball dia, etc), and get me the approx base circle, tip circle, lift, of the cam, etc. That along with the difference in the new rocker pivot, I can calculate approx differences in how the new rockers will act. *Hint*

Modified by need_a_VR6 at 10:23 AM 2-4-2010

For example, the cam gear could adjust up to 20 degrees and each gear tooth is 20 degrees apart (not real numbers)

Modified by Euro-tuner at 8:17 AM 2-4-2010

Quote, originally posted by -Bude- »

In Germany is no calendar yet arrived. I hope he comes this year. Am very machined. Greetings

There might be ways to get the cams to be in the right spot. The thing I would worry about at first with having the centerline retarded is exhaust valve lift @ tdc would be higher. This could possibly be compensated with the vvt somewhat, or with different centerline cams.

#1. Stop asking me what engine the rockers are from. There is no way I am releasing that info yet as these could potentially destroy an engine if they do not fit correctly or smack pistons.

I'll tell you 2 things about them though-

They are NOT from a VAG product.

They are NOT from any engine available in this country (unfortunately).

#2. I have no idea what cost is yet. If there are similar to the stockers in cost then that would put them around $300ish for a set. I'm going to guess and say more since they have to be imported and don't appear to be as common as our stockers.

True the ported head will gain more.. but remember this isn't about peak flow #'s.

For those that didn't click the link above to read the article and see the chart..increasing the ratio "the opening and closing rates are much faster, and the area under the overall "curve" is much greater."

For the rough guess $300ish these cost.. if they work I would call them a no brainer.

CHART-

Sent you what I have so far. I think it is enough to be of some use.

Happily awaiting pretty pictures.

1st ALL MOTOR STREET CAR to go 11's
http://www.youtube.com/watch?v...annel

Seeing as these are the ones he recommends (and INA is the company that makes our stock ones) I don't think you need to look elsewhere at this point.

At this point the only source I have found for them is a used parts place in the UK.

I would like to find a source for them new, although I might buy 1 used to test.

Heard back from Willy @ Supertech.. yes we will need to change the springs to run this much lift so that drives the cost up a lot, as well as much more involved install. This just went from cheap and somewhat easy to fairly pricey and more involved.

Oh well.. no guts no glory!!

New drawing of stock with some actual numbers. Started with 11mm peak lift from the Schricks and worked from there..

New 2.3:1 rocker

Two things - the ratio of the old vs new lift doesn't rise as fast as the change in rocker ratio. For this configuration max lift goes from 11mm to 11.65mm.

The cam timing error of 2deg with the rocker change seems reasonable.

One thing I didn't get right is the dia of the rocker rollers which does influence how much the lifter needs to move when the pivot is moved. Once I find my spare rockers or someone else measures one for me this is about as much as I can do.

Even if I'm off on the low side .65mm extra lift and small cam timing error doesn't sound bad as long as it's not crazy money.

Correct. I'm not sure what the stock cams lift is off the top of my head, but Willy said the stock springs bind around 12mm in an email today.

Boo.. not enough! I was happy with the 12.5 figure off the top of my head.. even if it meant new springs + retainers the flow increase made the hardware changes worth it. Of course if the true lift really is only 11.65 then the stock springs will still work.

I'm going to send those drawings..(and maybe a link to this thread) to the INA engineer. Maybe it will catch his interest enough he can help us with some further input.

( numbers @10``multiplied x 1.67 )
flow @ 28``H20 should be:
inlet /exhaust
2mm 60.12 / 56.11
3mm 90.34 / 85.67
4mm 118.73 /111.39
5mm 143.62 / 130.59
6mm 167.33 / 142.78
7mm 189.21 / 149.63
8mm 209.08 / 153.47
9mm 223.94 / 156.14
10mm 231.13 / 158.15
11mm 234.97 / 159.65
12mm 239.31 / 161.15
13mm 241.65 / 162.32
no valve 239.8 / 174.0

On Catcams Full race profiles ( no pump lobe) who are used now by some engine builders
Up to 13.10mm valve lift / 7.80 Cam lift / 314 degr@0.1mm/266degr @1mm /105degr
Rocker ratio is 1.68 / 1.69 std rocker ( axw- axx - bhz ) source: Catcams

The TFSI cams ( with pump lobe) are ready , but not tested in a car so far
All cams are mechanical lifter /non hydro

Modified by HPR at 12:57 AM 2-5-2010

Quote, originally posted by robocopywriter »

Some say he has a third nipple shaped like the Nurburgring.

props.

Question for you guys. I know the 2.8 24v and 3.2 24v have many differences and some similarities in the head. Are the rockers different in the two engines?

Modified by VR6VDub172 at 9:48 AM 2-6-2010

Quote, originally posted by s74n70n »

waiting for vtec is like waiting for really bad sex....all the anticipation...no boost...then disappointment.

I had a reman 2.8L 24v BDF head that used cast aluminum rockers. The other BDF head and BJS heads I had at the time both uses a stamped steel rocker. I'll try and take pics of the 'reman' ones as they seem to not be the norm. Dimensions between both sets seemed similar enough that I didn't measure anything.