Jump to content

2.9" pulley vs. 3.3".....


FuelSlut

Recommended Posts

im giving this a shot... and a thought. In theory the 3.3" pulley was designed to spin the radix at optimum efficiency for the 6.0L lq9 that exact rpms (of the blower) and that exact boost level... creating the temperature designed to run that efficiency... correct? Now unless i have a good aftermarket/ported/altered comp ratio heads and camshaft combination... how am i benifiting from more boost/spinning the blower more/faster/hotter (out of efficiency) when all i can effectively boost is what was designed for my package? Does this not seem like a "five pounds of crap in a one pound bag?" deal? I figure, if i run the designed amt. of boost from the designed rpm of the blower my intake air temps will decrease, efficieny will be optimum, will be taking in as much as i can get out... all allowing more timming etc., another thing..... i know for sure i could use/get a hell of a lot more timming right now as this motor stands... the program/tune is a tad bit off.... so.... here is what i did and why tonite, i put the 3.3" pulley back on... now since i lacked timming for the 2.9" i should be at an "ok" timming number with the 3.3" but could still use more... and maybe just hold the 2.9" pulley till i get diff. heads and a camshaft... camshaft not completely solving the problem (not even fooling it, but just would help nicely) but not as much as a good head/comp ratio combo for more boost efficiently...

 

i dunno... maybe im onto something, maybe im completely retarded/desperate? I will know for sure wednesday if i can make it to the track....

 

so far tonite... it did "feel" a bit as if it were pulling harder.... i dunno, possib. a mind state?

Link to comment
Share on other sites

  • Replies 30
  • Created
  • Last Reply

it's certainly possible. you won't be nearly as lean with that pulley as you were with the 2.9. if you're looking for the in between to run at max injector with a stock cam, you'd want a 3.0-3.1 pulley. with a stock exhaust, stock airbox, stock manifolds, etc. on mikes truck we got a 13.5 with the 3.3 pulley. it would be interesting to see how fast you can make one with the 3.3 pulley with the intake and exhaust opened up using the right tuning... :dunno:

 

what do you say we find out... :D

Link to comment
Share on other sites

i dont mind at all... its just money is low... and im itching to get this truck where it rightfully SHOULD be... and i truely believe i have all the elements/requirements to make this truck move into the numbers i desire... its just simply lacking tune....greatly.... we need / i need to put down the wallet and pick up the books/information/knowledge at this point.... jus need some help fellas!

Link to comment
Share on other sites

I don't think that using a 2.9" is necessarily taking the blower out of its efficiency range. The 3.3" pulley was not put on there for the blower, it was put on there for the motor and the fact it is at 10:1CR. I do believe that the 2.9" is as low as you should go though. I felt I was making more power with the 2.9" pulley vs the 2.75", but I was also shifting at 6300 at one point. That put my blower rpms well into the 16k rpm range. If you look at the efficiency map of the MP112, 16k is starting to hurt you more than help you. Again, all dictated by your shift rpms.

 

You can't rely on the stock Magna tune though. Not for making max power. The Magna tune is an ultra-safe mixture to make it easy for them to maintain the powertrain warranty that they offer. An after-market adjustment can get you at least 40-50 more hp, or so I have been told.

Link to comment
Share on other sites

Changinging pullys on mine from the 3.3 to the 2.9 made huge diff. With the 3.3 I would only run 13.7 at the track and the 2.9 I ran a 13.3. Both with the Stock Radix tune. With the 2.9 pully I only got 1.5 deg knock. I think with better track conditions I could be close to 12's. I don't think there any way I could get the 3.3 the run that good.

Link to comment
Share on other sites

:withstupid:

 

well see on wednesday.... given rain holds off....

definatly feels like my 60 foot / 0-60 isnt as dramatic as it used to be, but top end feels like an entirely diff. truck....

 

this should be interresting...eh?

Link to comment
Share on other sites

i got the pulley on last nite pretty late in the evening, and all day today ive been slammed at work and havnt had a chance to run it with the tech 2 hooked up. Ill let you know how much timming i have as soon as i get a chance... though i have no way of adding or taking out...

 

tune that is currently in my truck at the moment if from pcm for less... meant for the 2.9" but lacking timming for the 2.9" so i should be alright...

Link to comment
Share on other sites

I did run a 14.1 with a 3.3 pulley on stock 20's but hardly tread. I pulled off a 14.3 on 22's with hardly any tread, so there might be a gain with that pulley.

 

a gain with what pulley? what pulley did you have on when you ran w/out the 22s, and what pulley with the 22s... i dont exactly understand

Link to comment
Share on other sites

:withstupid:

 

well see on wednesday.... given rain holds off....

definatly feels like my 60 foot / 0-60 isnt as dramatic as it used to be, but top end feels like an entirely diff. truck....

 

this should be interresting...eh?

 

What Track Are You Going To?

Link to comment
Share on other sites

good ole Milan Dragway 94 West to 23 South, exit 25 - Plank Rd.... my stompin grounds! lol i'm not even 21 years old... what stomping grounds? Anywho.. yeah Milan is usually PACKED so ill prob. get 2 maybe 3 runs in...

Link to comment
Share on other sites

Archived

This topic is now archived and is closed to further replies.


×
×
  • Create New...