Oettinger, Graf, KR and ABF heads - How much do they flow?

Here you go Gary....

www.clubgti.co.uk/forum/showthread.php?p=1467799#post1467799

 

I hear a rumour that you've made a decision, and bought the bits!

 

Ok, as a brief update, a standard "051" ABF head bare inlet port flow (well my standard one at least) is 121 cfm at 10''

The only thing I have to compare this to at the moment from VW is my fully modified 12v VR6 head which, coincidently had practically the same BPF, 120 cfm at 10''

More to come as-and-when it becomes available. I may also send off an old "027" casting for comparison purposes.

 

if its still of interest and i havent got the wrong end of the stick i have just had my slightly tweeked 2.0l 16v oettinger head flow benched and then re-ported so although i dont have any completely stock figures for the head it shows a comparison between a oettinger and a stock 16v and also a ported 16v?
from memory it shows the oettinger head is worse on the intake than a stock 16v and with more porting brought the flow figures just higher than a stock 16v head, but the exhaust as standard flows more than a fully ported 20v head !!! got some print outs and stuff i could post if its of interest ?

 

So, very brief update to this ancient thread. Out of the box so to speak, a Graf head flows 121 cfm at 10'', exactly the same as a standard ABF head. The testing of the exhaust ports made some comedy reading, 135 cfm. That is 112% E/I ratio when 80% is plenty. I'm not exactly sure what the designer was thinking that day, perhaps they had an early turbo application in mind. Who knows?!?

 

The port sizes are fine to be honest, it is the profile of the inlet ports that is a little odd. This is "as-cast" though. I guess these heads were designed for use on 1600 size units which don't require as much airflow, and most were probably modified before being raced. We will see where it ends up after some gentle modification.

 

The old valve guides are now out, the valve stems are 8mm diameter and the guides were not shaped at all, as a result, bare port flow (BPF) went up nearly 12 cfm on the inlet side. So, as cast, without guides we are up to 133 cfm without any work on the ports. I'll try to get a picture or two up so people can see what I am talking about.

 

the oettinger too run as standard 8 mm stem
huge stems for a valver
but like that they could use the same valves keys and retainer as a standard 8V
cheap and easily available
what are you planning to do with the graff head???
differente valves ??
I m building a high revs Oettinger with bigger valves smaller stem and 90.5 mm stroke

 

With regard to the graf head, just a gentle tidy-up and resoration. I think it is too rare to consider a complete re-engineering job so the standard valves will remain. On test, bare port flow was the same with the valve in at 10mm ish lift as it is with no valves in the head so the shape of the existing valves is pretty much perfectly suited to the head.

The Oettinger sounds like an interesting project, how big are you going with the valves?

 

Just one mm bigger on inlet and exhaust
And going much smaller stem tho 5.5 mm unstead of 8 mm
This will avoide the need of really stiff valves springs
And save serious weight on the valve trains
Please post some pics of your head

 

Here you go. All early days at the moment...

1. As I received the head (about two years ago!)



2. After a clean (about two weeks ago)



3. As above



4. Guides out...



As I say, we will see where this ends up, but this will not be a complete re-engineering job, just a light restoration and race prep job.

 

Superb to see one of these Graf heads.
Proper valve angles giving decent combustion chamber shape.
Why oh why did VW not do this. Realistically, how much extra would it have put on to the production costs to have gone with a better design?
VW epic fail in my book.

 

The packaging width of the head is clearly the payoff - massive!

Plus of course the Audi V8 beancounters were loving it []

Cue daved!

 

Is that the reason you only love the 8 V danster lol

 

Various other manufacturers, eg. Lancia managed to fit proper twin cam heads in FWD transverse engine platforms.

VAG are German, not Scottish!

Has daved taken up snooker?

 

I got to admit it s a nice head
How did you clean it the result is pretty immaculate?

 

Very true Romain.

Why did VW try to create a high revving engine with crud OEM 16v head on an under square engine in the first place?
The fact so many after market companies had a go at producing an alternative head says it all IMO.

 

FAIL!!!

They produced 16v heads because all they had as an alternative at the time was a crummy 8v

Once the production 16v came on stream, the aftermarket lot packed up and went home edit: even though it may not have been as good!

 

But were the likes of Oettinger not linked to VW in some way? So all their development work along with others was not taken on board by VW. Even without the likes of Graf, Drake and Oettinger, the best design of cylinder head based on engineering principles was known back in the 1930s for goodness sake.

FAIL right back at you!

Also, were these heads not all fitted to smaller capacity engines in the early days? Shorter stroke, oversquare engines which are better suited to high rev applications.

 

That is my understanding, yes. I guess that is why the VW 16 valve engines make pretty good road engines, but making them more suitable for 2L race applications takes a lot of thought, time and money, hence the issues highlighted in the BTCC thread.

FWIW, the OEM 16v heads are not that bad, flow-wise, inlet or exhaust. I think the performance issues come from the combustion chamber shape and the fairly undersquare bottom end.

As to why VW did not use the R&D from the aftermarket tuning companies, well, I would hazard a guess at packaging, intelectual property rights, and manufacturing costs. Perhaps VW also looked at their own design and though it was good enough for road applications, and at the time of design, had no desire to go on a serious racing development program. Who knows