slate blue

Hint, you may soon find out, but not in exactly the way you might think, can't say anymore.

Brendon, bloody well done with that link!

Cheers Greg

BC

The 2V heads have alot of potential with harder springs, WAY bigger valves, and porting. We just have to get over the hump of putting non-porsche stuff in there.

John Veninger

The valves in a Euro head are very large. How much bigger of an intake valve do you think you can fit in that space?

m21sniper

"Yes, we have a cold-air intake for our systems in R&D right now. It was always planned."

Is that for SC only apps, or will the cold air kit work on any 16v setup?

I'd love to get a cold air kit for mine.

FBIII

The valve size of the euro s is limited by the bore size. Their is plenty of room between the valves but if you go larger the valves get real close the vertical walls of the combustion chamber. When the bore gets increased you get to widen the combustion chamber, which unshrouds the valves giving you room for effectively using bigger valves. Running a larger bore is a win win situation. Using a small block chevy as a standard for valve sizes they have been using 2.02 intakes and a 1.60 exhaust for decades. This translates into a 51mm intake and a 40.32mm exhaust. The euro s uses a 45mm
intake and a 40mm exhaust.

slate blue

That might just be what I have done.

FBIII

Come on Greg kiss and tell. What are you building? I have an 81 Euro S 5 sp that I am sorting out and at the same time collecting stuff for a future build. I have a pair of 84 heads with the cast in tubes in the exhaust ports and a set of the 84-86 cams that on paper look a little hotter than the 80 -83 cams.

slate blue

I'm waiting on the valves, but they are the Ferea Nascar valves made from their top material. They have 7 mm stems, the size is 2.02 and 1.65. The exhaust valve has a 24 degree tulip while the intake only has 12 degrees. I had no option on this point. The crossover point with the flow is 0.250 lift, after this the smaller degree head flows better. It should be noted that the valve area has not be unshrouded in any big way, waiting for the headgaskets or the new bore to do that.

With the smaller valves in the head at the moment, the intake flows 250 cfm or about 515 hp and the exhaust with a 1.60 flows 190 cfm. Without the intake valve in the head, the port flows 275 cfm. Were are hoping with more development these will flow at least 275 cfm with the 2.02'' valves. That will support 580 hp. Standard flow on the intake is 211 cfm at 0.500'' lift. That's all for now folks.

FBIII

Kind of interesting that your heads "theoretical hp" numbers are incredibly close to the numbers Bob Devore got with his 6.2 liter! I guess we can kind of infer what size valves he was running. Back in 1990 Bob Devore and a few others "perfected" the technique of completely boring out the cylinders in the 928 block and pressing in and epoxying oversized steel sleeves. I'm puzzled why this practice has seemed to be abandoned. Especially for the 2 valvers, where there isn't an appropriate oversized piston. I can't get too excited about running an 85 or 86 5 liter shortblock with a piston that has 6 valve reliefs cut into a piston crown that is far from flat to begin with. With the pressed in sleeves you wouldn't be limited to the 104mm constraint of the five liter block or have to run a coated piston. I think that Bob Devore was running an engine before he died that was at least 6.5 liters and I think he was doing it with a welded crank not a stroker. So he must have been running a huge bore.

John Veninger

Why not? Want more than 360hp from a N/A 5.0L? Can always supercharge instead of a big bore "experiment".

FBIII- you seem to be someone who doesn't want to let people know who you are or your location.

P928Drvr

"FBIII- you seem to be someone who doesn't want to let people know who you are or your location."

That is the truth ! FBIII, I have my 4.5L comming out this weekend, come on over!

Carl Fausett

The most I have ever seen documented from a 16v motor is 430 CHP - and I wrote about it here:
https://rennlist.com/forums/928-forum/200891-customer-story-430-chp-cis-sc-k-jet.html

In case the link does not work, it is a thread called
"Customer Story - 430 CHP CIS SC K-Jet "

I had long said that I felt the ceiling on the 16v motor would be about 400 HP. Wrong again! Or too conservative. Anyway... so Adrian on his side of the Big Puddle and I (in the Colonies) are into kind of a shooting match on this one...
and I am doing a build of a 16v CIS motor now that I hope to do 450+ HP on the dyno.

We'll see. The damn engine rebuild is taking too long cuz I keep interrupting myself to finish other, smaller products that we are introducing. I'm loosing the summer! I finished our rear sway bar yesterday with aluminum drop links - you will read about it soon.

FBIII

I didn't intend to be mysterious but I'm more of a lurker than poster as seen by my number of posts in the last 2 years. I really enjoy the technical posts and the troubleshooting. I'm more interested in the 2 valvers but follow the 4 valve stuff as well. I tend to follow the "traditional" hp means being more of a stroker than turbo or supercharger type. I really enjoy engine building and modifying as well as troubleshooting. My first Porsche was a 1970 911S I bought in 1973. First 928 an 81S in 1986 and I'm presently on my fourth a needy 81 Euro S 5 sp. I'm also into Astons and Land Rovers. There I'm out of the closet.
Fred

m21sniper

Hey FBIII, you're right in my neck of the woods. We should get together sometime for a show and tell.

Fastest928

Unfortunately, Bob and others at DEVEK never quite perfected the replacement large displacement steel sleeving for street use. I have the last revision of Bobs block. For a long time I also had the 709 hp heads in house ... they were a work of art and well characterized. The amount of work in those heads could have purchased a nice 85/86 928!