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Cam interchangeably - is it possible??
by
ein bora
on 05 Feb, 2010 06:20
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Is there any cam shaft that will give better performance than the stock one for a 1.9 IDI. I know in performance cars changing a cam is a popular upgrade.
Thanks.
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#1
by
Turbinepowered
on 05 Feb, 2010 06:53
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Usually cam swaps are to improve breathing to get more fuel+air into the engine. Diesel cams are fairly free- breathing, and the fuel is injected directly, so the result of a cam swap is usually minimal.
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#2
by
Rabbit on Roids
on 05 Feb, 2010 08:57
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the effort required to change the cam is much larger than the gains you actually get from the cam.
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#3
by
idgtd
on 05 Feb, 2010 13:08
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The piston/valve geometry of our engines precludes the use of wild cams with lots of overlap to improve high end engine breathing. Instead, our cams are much more like 80's gasoline "emissions" cams that actually have a big dead spot at TDC (end of exhaust stroke) when both valves are closed. We also cannot take advantage of late intake closing to improve high speed power since it has a detrimental effect on compression pressure and thus cold starting. Basically, you have to find your hp gains elsewhere.
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#4
by
8v-of-fury
on 05 Feb, 2010 15:06
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I think all the idi cams are the same. If I recall correctly Smokey Eddy is running his entire 1.6td valve train in his 1.9 AAZ prothe head.. Or may be just the cam and lifters..
Either way there is no gain to be had by cam work on an idi diesel. having the valve open later to allow that extra air in or out will allow the pistons to smack the valves. The tolerences are very very tight between pistons and valves in these motors.
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#5
by
theman53
on 05 Feb, 2010 18:33
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Nah...
I think that if you have an engine that has a cam it can always be upgraded. Eventhough we wouldn't want to loose compression or keep it open too long from BTDC through ADTC if you could change the duration to keep it open longer in between BDC and TDC. Make sure there is never a time when ex and in are open at the same time so we don't loose boost out the tailpipe, then we could squeeze more air into the cylinder in theory. The problem lies that we would have to have something custom made to do this since I don't know of any VW diesel aftermarket cams.
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#6
by
truckinwagen
on 05 Feb, 2010 18:38
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I am currently looking into the european K grind gasser camshaft used in UK spec caddies.
it has a fair bit of negative overlap(enough to clear the piston at TDC) and similar duration numbers, but has more lift.
it could be made fit with a modified cam gear and retails for $50 from TT
exact specs are hard to find though, so I am still trying to verify whether or not it will actually work before I buy one and try it.
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#7
by
stewardc
on 06 Feb, 2010 04:42
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When I hotted up my AAZ, we used a pre-1990 1.6 cam as it was supposed to be the best, but really, there is very little difference. There was a guy making aftermarket shafts, but no longer. The improvement was imperceptible.
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#8
by
macka
on 06 Feb, 2010 06:48
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The quick and cheaper way to improve performance on a diesel is to improve the intake and exhaust systems. The more air it gets, and the more exhaust gets out per stroke (to point) the better. So by deep sixxing the restrictive air box and replacing it with a better breathing one the better (don't get a cone get a bigger air box and mod it)the intake airflow is. Increasing the exhaust diameter is next, the less back pressure the better for the turbo. The head work comes next. A better intake and exhaust manifold (add a pyrometre to the exhaust mani.)to the will up power. Then you can port the intakes and exhaust ports, and if possible upgrade the valves to a bigger size. With that all done, get the bigger fuel pump from Giles and injectors. Make sure the bottom end is good to go, otherwise you'll be doing a bottom end refresh or rebuild. This is the plan I have for my jetta.