for questions and answers about alternative power transplants on the T25, GTi, Porsche,Subaru etc, this is the place. You must register to post but anyone can read.
The prospect of the technical challenge has the strongest appeal for me
but even VW designed the wbx for the rear engined golf as 16V ohc - pushrod might be ok in a rev limited V8 diesel but makes no sense for a petrol flat 4 that I can see - pushrod is the limiting factor and camshaft the weakest point in the wbx design, do F1 engines have cambelts or cog driven cams - I always liked the Zeus timing gear mod for the LR il4
I thought there was a VW prototype 16v in existance but I have never managed to find any pics of it. Are there any out there?
Pushrods will run up to 6k rpm easily but the hyd lifters might be a problem as they can start to pump up.
As for the cams, the oem material is the root of the problem. Hardenable iron is cheese compared to chill-cast.
Aftermarket firms like Arao and Dominion Performance also had similar offerings.
I think Simon may be right about the inlet manifold, the flange positioning would put a real squeeze on the useable volume available for ports and valvegear. But I would prefer to leave the exhaust and coolant connections well alone.
First instincts are that this might be a bridge too far Ian...
One development problem or in service issue could spiral costs...
How about lightly blowing a 2.1 ?
Fair comment. As Simon said earlier, maybe an improved 2 valve head to sort out the inter-port cracking problem would be the way to go, but what does it really achieve over AMC's ?
Without seeing if it is even physically and mechanically possible within the packaging constraints, any potential market is moot. I do feel that the USA is the real market for this sort of thing, so back to my opener: I am just suprised that it hasn't been done before (bar the odd example of grafting Alfa 4v heads onto a type 1 or 4)
Pushrods work fine.. if everything is proper......
Better cam and lifters (lighter lifters - I have an idea on this) and there is less need for silly spring pressures.. easily rev high enough..
Better head design.. even crossflow as per type 4... better induction ports.. (turning the intake gasses 180 degrees is silly)
Modern intake and ignition
And why not improve the mad cooling system... (something I have been working on for a while.. LOL)
... but being 2014 going '15 that's a technology 30 yrs old and it wasn't exactly ahead of its its time then...
So...
It'd thus have to be spot on from day one... and gain a good reputation very quickly.
... and if you've ever tried to sell to the Americans, you'll find its hard work in more ways than one. They are used to a one way street... West to East... anything else throws up many issues, real or imagined. Ask RJES
I do like a bit of retro-tech. What goes on at 750MC beggars belief as I am sure you are aware!
Its a nice chewy project to exercise the grey matter though.
As before, considering what goes in in Aircooled circles ...
And yes I know first hand about getting ripped off by "the good ol' boys"
Purely by way of a comparison, the Subaru as we know has similar cylinder bore to the wbx and only 1mm difference in the bore spacing:
Similar heights suprised me, but the increased bulk is marked:
I had forgotten that the EJ22 is only 75mm stroke, so where does all the torque come from? Better controlled injection, ingnition, more complete burn? Higher port velocities? http://en.m.wikipedia.org/wiki/Subaru_EJ_engine" onclick="window.open(this.href);return false;
A bit of a read reveals the trend back toward non-hydraulic valve lifters, coated piston skirts and increased pin offset to reduce running frictional losses...
Yes! Higher port velocities and thus better cylinder filling... cam/inlet/port and accurate timing up to the higher detonation threshold due to combustion chamber design..
I also read that the latest generation of Subaru engines now have a narrower included valve angle and 86mm bore and stroke, to improve fuel consumption through use of a more compact combustion chamber and bring the torque band down the rev range.
I dug out a grim head for a bit of a CNC carve about this morning, ironically the one from the syncro's original DG that started this whole wbx journey so I take that as a good omen!
Removed the valve seats without ceremony (cutting disc across the usual crack) and then milled out the combustion chamber to 94mm dia x 20 deep, the idea being to see what kind of working envelope a 4v arrangement requires.
More later