Very true!! I would have thought a x-flow head would be ideal on such a large capacity motor. It will inevitably want to rev harder though As you say, for one with such a large "heart" I suspect even the fitted Pack C counterflow head did not have the "lungs" for optimum breathing. Maybe a deliberate ploy to concentrate power and torque lower down and why such a large capacity wasn't suited to the 16v? Piston speeds getting marginal? With such extensive internal work and increase of stroke over stock, I expect the loads inside the block were greatly increased. Extra rpm can only be bad in that respect.
Very true!! I would have thought a x-flow head would be ideal on such a large capacity motor. It will inevitably want to rev harder though As you say, for one with such large "lungs", I suspect even the fitted Pack C counterflow head did not allow optimum breathing. Maybe a deliberate ploy to concentrate power and torque lower down and why such a large capacity wasn't suited to the 16v? With such extensive internal work and increase of stroke over stock, I expect the loads inside the block were greatly increased. Extra rpm can only be bad in that respect.
A 99mm crank would give a mean piston speed of 4500 fpm (feet per minute), fine for a race engine. Bring the regular rpm back to 6300-6500 (all you would ever need on a grunty road 8v, and even a "sporty" 16v tuned for strong road performance) and you could expect decent road milage.
Possibly, a big capacity 8v would make good use of 42mm inlet valves rather than 40mm items, a 16v would fair better. From the testing I've done so far, it does'nt look like a crossflow head will make a great deal more flow than the original type head when both a modded to the same spec. The key to the crossflow is a reduction in the intake air heat path, and the "potential" of allowing bigger valves to breath due to bigger port potential (more on that as development progresses), so maybe a help toward feeding bigger capacity engines. The "99mm" stroke engine I mentioned above is actually a 100mm stroke! When I asked the engine builder today what they rev like, expecting around a 7500-7800 peak zone, I was told "they are rev limited to 8600rpm, and hav'nt even hit peak at that point (!), they are limited because the engine makes lots of torque, so why not use it rather than try and break it"! If we're talking long stroke for us VW types, a grunty road/rally type spec, tall block based 2.1 16v with a factory 95.5mm crank would work well to around 7k in the interest of decent milage. An 8v would never need to run that high in road form... 6500 would be enough.
cc listed as 2164cc (Source: Volkswagen Audi Car, April 1994) Maths: 83 x 99 = 2143cc 83 x 100 = 2164cc
Head flow aside, I could only imagine that the angles the piston force will be transmitted, on a 99-100mm stroked engine would be even worse than lesser stroked 144mm rod engine. Possiblely not good for piston wear/rock. Many more crankshaft torques from a similar piston force yes but less hours before strip down. Perhaps less overall torque, via less stroke, revved higher and geared suitably my be a more feasible way.
It certainly would. It would be a bit of a no no on the 144 rod, wit ha rod/crank ratio of 1.45.... maybe why there were oil control issues in the past if they were built as such. A tall block would be ok with 159 rods, giving a 1.6 ratio. Would need a trick piston, doable, but then the issue comes down to feeding the bigger lungs.
thats nuts! is there a formula for working out the rev limit or rev reduction based on the bore:stroke ratio? what/where are these 100mm cranks sourced from?
^ i have done! the reason i ask as aftermarket companys such as eurospec and neuspeed for example often to take an oem part and put it in a different box! they do that with the 95.5mm diesel crank, which is of course simply a 1.9tdi item i was wondering if the 'custom' 100mm crank was the same? and as such what it comes out of?
^ i have done! the reason i ask as aftermarket companys such as eurospec and neuspeed for example often take an oem part and give it a different name/put it in a different box! they do that with the 95.5mm diesel crank, which is of course simply a 1.9tdi item i was wondering if the 'custom' 100mm crank was the same? and as such what it comes out of?
wonder if there are any rods that fit but take a smaller diameter big end? then you can offset grind the crank pins for more stroke, common on minis in the olden days
Was just about to post the very same thing! You could do a small offset using same rods, but thicker shells, not much though...
well you could the early 1600 rods but they are 136mm long but they have a 46mm journal which could make save 1.8mm 3.6+95.5= 99.1mm you have it a long stroke but really but R/L tho you ll need super short skirt piston to clear the crank on bdc
It's the piston speed that needs an eye keepin on... but depends on the application. The engine I'm referring to is'nt a VW engine I'm affraid, and has plenty of breathing potential through the head to feed it's large (2.5ltr) capacity. From memory, the 2.2 16v that did the rounds a few years ago did'nt make anything special in terms of power, some due to development, but a lot due to feeding the big capacity.... plus you have to look at cost. From our point... the 95.5mm crank can do a good job, subject to what it's going to be used for.
Steve creswell at candr enterprises did say about his 2.2 16v he used to use a lot of oil about a 1 litre a month Nas
