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No, in my opinion the 964 heads have superior port characteristics than the 993 head in spite of the larger valves of the 993 heads. In otherwise identical engines the one with the 964 heads will make more torque. To date we have not managed to measure a meaningful performance increase from the 993 exhaust either....
Good interesting info Colin
So does this mean that 964 heads with 993 valves is a good bet?
Please can you expand on the no meaningful performance increase from the 993 exhaust? Do you mean it gives no more performance than the 964 or you can't improve on the 993 exhaust?
thanks a lot Colin,
if an ECU supports several maps,
for a road track car, you could have one map with short parallel trumpets for track and one with long trumpet for road that last one mostly used all the time.
when arriving at track pushing down the 6 trumpets and switching map should not be a big deal, maybe that's is to consider rather than a VRM engine
thanks a lot Colin,
if an ECU supports several maps,
for a road track car, you could have one map with short parallel trumpets for track and one with long trumpet for road that last one mostly used all the time.
when arriving at track pushing down the 6 trumpets and switching map should not be a big deal, maybe that's is to consider rather than a VRM engine
It would be only a little more bother to adjust the trumpets on the fly assuming aftermarket ECU, double dog dare you
waking up an old thread, i got myself a varioram intake.
And with that came some questions for you who made the conversion.
Do you use the old vacuum canister or the 993 version, is it much bigger?
The drawings don't show clearly were some vacuum hoses go, the green arrow, is that hose thicker than the normal plastic vaccum hoses? and where does it go?
So, now I can answer my own questions, the top green ring is for tank venting, the blue ring is for C2 brake booster vacuum so I capped that having a C4, the green bottom ring is for the vacuum tank for the varioram solenoids, I just built my own tank a bit bigger than the 964.
I used the 964 ISV, stock fuelrail but with bigger injectors, the MAP signal i took out from the capped outlet on the manifold marked F on the drawings.
You figured it all out, GREAT. And YES, "F" is the same point I use for MAP. One other item I added in the vacuum line system is a vacuum gauge. The Varioram will not work without vacuum pressure, this allows me a quick check if there is a leak. If you get the 993 varioram ECU - this would not be necessary as it has/does a vacuum test on start up.
thanks a lot Colin,
if an ECU supports several maps,
for a road track car, you could have one map with short parallel trumpets for track and one with long trumpet for road that last one mostly used all the time.
when arriving at track pushing down the 6 trumpets and switching map should not be a big deal, maybe that's is to consider rather than a VRM engine
Konstantin we're still awaiting your success on this please
With my M84 its simply a case of plugging in and upload to ECU with the map you want (likely also diff fuel)
03-03-2014, 01:59 PM
