yorgog Posted February 13, 2005 Report Share Posted February 13, 2005 I am putting a Radix on my SS. What is the best pulley you guys recommend. I see a lot of people using the 3.0. Do you think I should go to 2.9 or do you think that would be too much boost and it would hurt my Motor. Remember this is my everyday vehicle but I am not afraid of it being to obnoxious. I dont ride my family around in it. I also have a Yank 3000tt with billet servos and oversized pressure boost valve to give you an Idea how I don't mind it jerking around too much. Let me know what you guys think. I want to do this once and I want to do it right. Link to comment Share on other sites More sharing options...
BenKey Posted February 13, 2005 Report Share Posted February 13, 2005 Depends on your comfort level with how much you want to spin your blower. I had a 2.75" and ended up going back to a 2.9" pulley. IMO, it's the best overall pulley to go with. It worked better with the increase in timing vs more boost with the 2.75". First you have to figure out where you want to shift. So, let's just say that your highest rpm shift was the 1-2 shift and you wanted to do that @6200 rpms. Based on that: Stock crank pulley = 7.75" Radix pulley = 2.9" RPMs = 6200 NUMBERS USED FOR EXAMPLE ONLY 7.75"/2.9" X 6200 = 16,569 blower RPMs 3.0" comparison 7.75"/3.0" X 6200 = 16,017 blower RPMs Magna says they can handle 18,000, but that's not advertised. Link to comment Share on other sites More sharing options...
6.0ss Posted February 14, 2005 Report Share Posted February 14, 2005 I am getting ready this month to install my Radix that has a 2.9 inch pully. Do I need to get a custom tune to run that pully? This is my Daily driver as well and want to be safe as well... Link to comment Share on other sites More sharing options...
BenKey Posted February 14, 2005 Report Share Posted February 14, 2005 Yes, a custom tune will be needed with a 2.9". Link to comment Share on other sites More sharing options...
slimsoftball Posted February 14, 2005 Report Share Posted February 14, 2005 Depends on your comfort level with how much you want to spin your blower. I had a 2.75" and ended up going back to a 2.9" pulley. IMO, it's the best overall pulley to go with. It worked better with the increase in timing vs more boost with the 2.75". <{POST_SNAPBACK}> I plan on going back to a 2.9 now that I finally have bought my own tuning software. Of course I have new heads and long tubes to add too. Link to comment Share on other sites More sharing options...
moregrip Posted February 14, 2005 Report Share Posted February 14, 2005 I thought the stock crank pulley was 7.5" Link to comment Share on other sites More sharing options...
BenKey Posted February 14, 2005 Report Share Posted February 14, 2005 I thought the stock crank pulley was 7.5" <{POST_SNAPBACK}> That's possible. I go by what came off of my '99 5.3L. Didn't think it had changed. The math is still the same though. Just need to plug in new numbers. Link to comment Share on other sites More sharing options...
infinus Posted February 14, 2005 Report Share Posted February 14, 2005 What is the smallest pulley that can be run on a Radix with stock exhaust and intake? I'm running a 3.3 right now. Link to comment Share on other sites More sharing options...
BenKey Posted February 14, 2005 Report Share Posted February 14, 2005 I think the smallest made is 2.75", but have heard mention of a 2.7". A 2.75" looks like there is not much left to go smaller. Link to comment Share on other sites More sharing options...
BigTex Posted February 14, 2005 Report Share Posted February 14, 2005 I measured a stock crank pulley last month, and I think its really a 7.625" diameter. Of course its probably a metric measurement, but its more than 7.5 but less than 7.75, that I do know. As far as I know, the cranks from the 4.8. 5.3, and 6.0 are all the same diameter for all year models. Link to comment Share on other sites More sharing options...
dcairns Posted February 14, 2005 Report Share Posted February 14, 2005 My Radix was mistakenly shipped with a 3.1 pulley, and I have been runing that for 30,000 miles with the standard tune and our wonderful Southern California premium gas, which is only 91 octane . So you could run the 3.1 quite safely. Link to comment Share on other sites More sharing options...
SSLink Posted February 14, 2005 Report Share Posted February 14, 2005 I think the smallest pulley actually manufactured by Magnuson is the 2.9", which they officially recommend for high altitude applications. Other shops such as Pulley Boys and South Florida Pulley make aluminum pulleys down to 2.75" which can be safely used on a Radix with the proper tuning. It seems most guys on this board are happiest with the 2.9" and 3.0" pulleys. These may be optimal on the LQ9. Mine is just a tad smaller at 2.85" ;) Link to comment Share on other sites More sharing options...
6.0ss Posted February 15, 2005 Report Share Posted February 15, 2005 I am starting to get excited now!!! HEHE,, Nelso or pcmforless is getting a call here soon!!!!! Hope to have it in by Feb 25th my birthday!!! Link to comment Share on other sites More sharing options...
hank Posted February 15, 2005 Report Share Posted February 15, 2005 i have had my radix in for about 23k miles now. its my daily driver and i love it. before i installed the 2.9 pulley, i was using a 3.0 with magnas tune. it ran fine. 14.2 at the track. then i went to a 2.9, 160* t-stat, and a custom tune and ran a 13.5 et. much better. Link to comment Share on other sites More sharing options...
MN C5 Posted February 15, 2005 Report Share Posted February 15, 2005 1st with a stock cam don't shift at 6200. Your better off shifting at 58 or 59 hundred and spining the crap out of the blower. Magnason shipped my Radix with a 2.8 pulley and a sticker that said the blower was for off road use only LOL... Larger lower pulleys can be had and I'd recommend a larger lower with a 3.0 to reduce slip. You can be more boost from the 112 but don't bother with High RPM shift points if you want the most out of your 112...it's done by 58 or 59 hundred and probably sooner if you have a larger cam with overlap. Just my .02 cents Link to comment Share on other sites More sharing options...
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