datnut Posted March 5, 2008 Share Posted March 5, 2008 I've exhausted my search options on this question, so I hope it has not already been posted elsewhere. I am trying to determine if I can use the larger 1000HP ATI damper on an RB25det. I realize that either of the dampers offered from ATI will fit the crank, but the 1000HP one includes a new water pump pulley and I have not been able to verify that the water pump pulley, designed for an RB26dett will work on the RB25det. As a fall back I will order the 600 HP damper, but I would prefer to order the larger one if the water pump pulleys are interchangeable. On a side not, if they are interchangeable, can you then use the Greddy light weight pulleys on an RB25det? Thanks in advance, Paul Quote Link to comment Share on other sites More sharing options...
mattyice Posted March 6, 2008 Share Posted March 6, 2008 its my understanding the water pumps are the same, people do put the N1 water pumps from nismo on both the RB26 and the 25 so I would say it should be okay...but then again I'm no expert on the RB's but I know that they are the same pump Quote Link to comment Share on other sites More sharing options...
Careless Posted March 6, 2008 Share Posted March 6, 2008 They will bolt up. It's 4 holes and 4 studs threaded into the water pump and then fastened with the pulley between the hub and the nut. All are the same bolt pattern. They might not have the same clearance, yet... I think they would. Dimensions are pretty much identical as far as I've seen for the blocks. I myself got a larger water pump pulley from Nissan I can get the part number this weekend. price was roughly 25 dollars as far as I remember. Quote Link to comment Share on other sites More sharing options...
datnut Posted March 6, 2008 Author Share Posted March 6, 2008 Thanks for the help. I believe the two OE water pump pulleys have different part numbers, but I am now starting to think that the differences lie in the diameter of the pulleys and they may be different to compensate for a difference in the OE Crankshaft pulley diameters. If my assumptions are correct then I guess I would be fine using the ATI 1000HP pulley since its water pump pulley has the correct diameter to work with it. Again, thanks. Paul Quote Link to comment Share on other sites More sharing options...
Careless Posted March 7, 2008 Share Posted March 7, 2008 Thanks for the help. I believe the two OE water pump pulleys have different part numbers, but I am now starting to think that the differences lie in the diameter of the pulleys Yes, they are different diameter. Below is the picture of the larger water pump pulley.... Racinjitter was impressed by the size of my pulley, indicating mine is larger than average. (has anyone noticed how much the water pump itself looks like a set of gonads?) and they may be different to compensate for a difference in the OE Crankshaft pulley diameters. If my assumptions are correct then I guess I would be fine using the ATI 1000HP pulley since its water pump pulley has the correct diameter to work with it.As far as I know, there is no difference in any crank dampener pulley inside diameter or crank snout outside diameter. RB25, 26, and 30 crank pulleys are said to have been used on either of the engines, and usually people with RB30's put the RB26 dampeners on. People with RB25's do too, as they RB26 is supposedly a touch lighter. And there are two different part numbers for the water pump pulley, yes. the first part of the number is the category, the second part of the number is the application. if you know the part number (i don't right now) of the water pump pulley, the application for RB25 should be XXXXX-42L00, and RB26 XXXXX-58U00 or something like that. XXXXX being the "water pump" category number. I have them at my other house, I'll get them for you if you need them. Let me know. Quote Link to comment Share on other sites More sharing options...
datnut Posted March 9, 2008 Author Share Posted March 9, 2008 I went ahead and ordered the big ATI, so I can compare sizes to see whether it overdrives, underdrives, or doesn't change the water pump. Quote Link to comment Share on other sites More sharing options...
240Z_Master Posted March 12, 2008 Share Posted March 12, 2008 I have the normal ATI Damper which comes with a somewhat normal sized water pulley. The large ATI Damper for 1000HP has it's own larger pulley as noted above. Sorry, it's been like 1000 years since I've posted on the site. Quote Link to comment Share on other sites More sharing options...
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