slap929

Robstah, you are always so helpful.

refresh951

Stock 951 intake port cross section.

eman930

Looks like that valve guide and the material around it need to go.. Huge restriction

URG8RB8

Nice work Shawn, a lot of so called professionals are cringing right now! Ha Ha Ha! All this cloak and dagger crap on a nearly 30 year old platform is so ridiculous!

TonyG

I don't know about that. Cutting a stock head apart only shows you the obvious things. It doesn't make up for the lack of years of port development work.

Case in point... my JME head using stock 951 valves, stock lifters, on a 2.5L engine using stock pistons, with a ported intake, a SFR header/3" exhaust and a 60-1HiFi turbo made 400 RWHP at 17psi, 415RWHP at 18psi.

I have yet to see any 2.5L make those numbers at those boost levels... which is clearly shows a top end that flows very well.

No big valves. No big boost. No big displacement.

That's why he got the big money for his work. It's all in the data. And the data doesn't come cheap. It's from years of engineering work, testing, and development.

TonyG

gruhsy

Ported intake? Sorry do you mean the head intake runners or something done to the actual intake?

TonyG

The head was a ported head.

The stock intake manifold was also ported.

TonyG

David Floyd

JME and MM do not fit in the "so called" category IMHO

refresh951

Agreed. My goal here is learn and hopefully develop some basics for self porting the 951 head that show reasonably good results. No doubt in my mind that experienced experts could do a better job and deserve whatever fees they charge. I have an incredible amount of respect for JME, MM and others. But, if I can get 50-75% of the benefit doing it myself I would be extremely happy. My goal has always been to strive to keep cost down as the ROI is low. Sometimes this approach has worked other times not. Until I try and measure the results I really do not know if it will be fruitful...but it sure is fun learning

gruhsy

Ah I see. Thanks

V2Rocket

this CAD drawing from the V2 school of tribology is my estimation of "where to start" here.

red lines would be smoothed/radiused out (is this the "short side radius work" that people talk about often, that sharp corner just above the valve seat on the inside bend?) - valve guide maybe trimmed on that side along with some aluminum around it to make a thinner protrusion

red spray would be smoothed down casting line

green spray slightly ovaling out the port to promote flow around the valve guide protrusion

green lines, perhaps minor shallow cnc cuts on the "floor" on the short radius as a sort of flow-director for flow attachment around the bend?

TonyG

Start with a N/A head.

And stock valve sizes are clearly large enough to make big power at "lowish" boost levels. Therefore it's all in the port shape and cam spec.

But if you don't have the rest of the top end flowing well, then you're not going to get there. The top end all works together. All it takes is one piece not work as a sys and the numbers won't be there.

TonyG

refresh951

I am still working on different "approaches" but it is highly complex and I am reading and learning as much as possible. One of my ports will be "hogged" out big and then lined with clay so I can flow different port changes/shapes pretty quickly. Once I further develop the approaches to be tested I will post them for review and comments. Should be interesting.

Van

Great pictures! Neat to see it cut like that.

refresh951

I have an NA test head also and will be flow testing it also.