Lennym1984 Posted July 3, 2018 Report Share Posted July 3, 2018 Hi I'm thinking of fitting an underdrive pulley but am a little bit concerned about grinding down the boss and thus making the mod irreversible. Has anybody experienced any downsides/problems from grinding down the boss? Link to comment Share on other sites More sharing options...
edc Posted July 3, 2018 Report Share Posted July 3, 2018 Just don't grind down too much and remember what size belt you need if you do a belt change in the future. Link to comment Share on other sites More sharing options...
Boxob Posted July 3, 2018 Report Share Posted July 3, 2018 3 hours ago, Lennym1984 said: Hi I'm thinking of fitting an underdrive pulley but am a little bit concerned about grinding down the boss and thus making the mod irreversible. Obviously impossible to put the boss back but surely the mod is otherwise reversible i.e. revert to standard pulley? Link to comment Share on other sites More sharing options...
toplad Posted July 4, 2018 Report Share Posted July 4, 2018 Downsides? 1. It costs about 100 pounds 2. Doesn't seem to do much 3. You have to grind a bit off the engine 4. Gets your hands dirty 5. You've wasted a couple of hours of your life Link to comment Share on other sites More sharing options...
Lennym1984 Posted July 4, 2018 Author Report Share Posted July 4, 2018 10 hours ago, Boxob said: Obviously impossible to put the boss back but surely the mod is otherwise reversible i.e. revert to standard pulley? I had heard that grinding the boss left insufficient material to realign/hold the original pulley. I had also heard that it made it difficult to do work that might require locking the camshaft. Link to comment Share on other sites More sharing options...
edc Posted July 4, 2018 Report Share Posted July 4, 2018 27 minutes ago, Lennym1984 said: I had heard that grinding the boss left insufficient material to realign/hold the original pulley. I had also heard that it made it difficult to do work that might require locking the camshaft. That's if you grind too much off. Link to comment Share on other sites More sharing options...
Lennym1984 Posted July 4, 2018 Author Report Share Posted July 4, 2018 Okay makes sense. I assume one just goes little by little in order to find the minimum amount required to take it off. It seems that the general opinion is that it is worth doing for the 2.5 Link to comment Share on other sites More sharing options...
Nobbie Posted July 4, 2018 Report Share Posted July 4, 2018 1 hour ago, Lennym1984 said: Okay makes sense. I assume one just goes little by little in order to find the minimum amount required to take it off. It seems that the general opinion is that it is worth doing for the 2.5 I did it on my 2.5 and I can't say I really noticed any difference to performance as that is not the main reason I did it, my main reason for the mod was to reduce strain on the other components as I tend to use mine for spirited weekend driving and have already had the water pump let go and didn't fancy having to do the alternator as well. I don't think anyone could discern a handful of bhp increase in available power at 6700rpm, but if you expect it to feel more powerful, then you will probably think you can #placebo. Link to comment Share on other sites More sharing options...
Boxob Posted July 4, 2018 Report Share Posted July 4, 2018 I thought the point of the mod is that it makes the engine more free revving. Link to comment Share on other sites More sharing options...
edc Posted July 4, 2018 Report Share Posted July 4, 2018 This mod was originally conceived for more track biased driving where the revs are higher for longer. In those conditions the PAS pump can overheat and fail. The side benefits are really the main benefits of using is on a daily or road car. Link to comment Share on other sites More sharing options...
Newhart Posted July 4, 2018 Report Share Posted July 4, 2018 EDC has the winning ticket! The UDP relieves stress on the peripherals when you are cranking it out at the track, rarely dropping below 4k ! Otherwise you can see just how long a power steering pump lasts when you are bumping against the limiter for 20 minute (or longer) sessions! Added horsepower is horse whatever. If you’re not tracking, you can pass on this mod. Only my somewhat experienced opinion. ? Link to comment Share on other sites More sharing options...
Terryg Posted July 17, 2018 Report Share Posted July 17, 2018 On 7/4/2018 at 11:08 PM, Newhart said: EDC has the winning ticket! The UDP relieves stress on the peripherals when you are cranking it out at the track, rarely dropping below 4k ! Otherwise you can see just how long a power steering pump lasts when you are bumping against the limiter for 20 minute (or longer) sessions! Added horsepower is horse whatever. If you’re not tracking, you can pass on this mod. Only my somewhat experienced opinion. ? I have one, as yet unfitted as I have the same dilemma as the OP, I don't track the car but I do follow @loz quite a bit at 4000rpm plus, often for more than 20 minutes (in low gears, before anyone gets smart) so now my dilemma is even greater. Link to comment Share on other sites More sharing options...
Lennym1984 Posted July 17, 2018 Author Report Share Posted July 17, 2018 I see in the US that there are companies who produce a larger pulley for the PS pump, this under driving the ps pump but not the other ancillaries Link to comment Share on other sites More sharing options...
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