Does it seem to make more psi/power vs the 2.6" Even with water injection, had the temps gone up more then normal? any 1/4 mile comparisons vs a diff size pulley? I'm on the fence on going to the 2.5. Any input would be good.
Thanks
Nate
Evolution of Cavyboy-->C22t--> C24na--->c24s/c
1995 Cavalier W/2k1 Engine
GM S/C 13.940@99.78pmh w/2.068 60ft
the 2.5 wont really help much unless you have the s/c ported to help it otherwise you are just going to be moving hot air. the 2.5 is also spinning the s/c past its rated specs.
the only person i can think of having the 2.5 on is jimmyc99z24 but there are others probably
http://www.cardomain.com/ride/857357
i want to know this information as well, the 2.6 with my race head just isnt enough, josh f said that it does move alot more hot air which makes you either stay the same as with the 2.6 or lose alittle bit, i could care less if im spinning the charger on the edge because i think the serious gm s/c guys are trying to get the most power outta this little thing instead of worrying about realiability, as long as its on the edge and not going to spin a bearing im game.
Monkey wrote:the 2.5 wont really help much unless you have the s/c ported to help it otherwise you are just going to be moving hot air. the 2.5 is also spinning the s/c past its rated specs.
the only person i can think of having the 2.5 on is jimmyc99z24 but there are others probably
Ya james told me that he ran a lot hotter, and prolly only benefitted b/c he has the ported s/c.
But was curious to see if anbody else has a 2.5 with a stock s/c.
Nate
Evolution of Cavyboy-->C22t--> C24na--->c24s/c
1995 Cavalier W/2k1 Engine
GM S/C 13.940@99.78pmh w/2.068 60ft
Bringing back the dead lol. I have the 2.5 pulley on and I see 9.5 to 10 psi on a cold day without the alky installed. I bought the setup off Andy Murrell aka Mr. Pute so he would know about the difference between the 2.5 and 2.6 seeing as I have never switched out the pullies. Unfortunatley I never had the motovation to install the alky kit to feel if that made a difference. I know everyone will say that it just makes the charger run hotter but I have no temp readings, dyno runs or quarter mile times to know if the car has any benefit because of the smaller pulley.
For those of you who can monitor your IAT temps with the 2.5" pulley and my alky i see around 145 degree IAT temps. WIthout the alky on the car see's over 170 degrees and if it is run hard i actually saw 200 IAT's one day
The amount of airflow the charger can flow is pretty much maxed out with the 2.6" on the stock gm s/c. As far as spinning past its rating i'm not sure, i've heard so many different numbers on this. The porting of the charger really shouldn't be making my IAT's much lower than an unported s/c, the amount of compressed air in the charger would be about the same mine just flows a bit more efficiently.
John when I tuned your car i was seeing IAT's in the 140 range.
"Horsepower is the Ultimate Accessory"
its probably been said already but i HIGHLY!! suggest against the 2.5" pulley... the 2.6" pulley is spinning the M45 to fast as it is, and you will probably notice a big jump in PSI right before you shift with even the 2.6" pulley... roots superchargers have their RPM range that they best work at... the further out side of that you go the more unstable it will be and the worse the heat soak gets...
for most people 8-9psi consantly (not a boost spike) will be all you will ever see on the M45... some say they see 10psi and i can kind of see that i guess but you definatly wont see that untill your high rpm range... do your s/c'er a favor and dont go any smaller then a 2.6" pulley and even at that i recomend Alky injection as a MUST
just as a side note... i saw the same psi levels with the 2.7" +alky as i did with the 2.6" and alky...
The First Twin Charged jbody
blue car (R.I.P) - 240whp @7psi..
silver car - 305whp 315lbs.tq @15psi (91 Octane) or 420whp & 425lbs.TQ @20psi (94 octane+Alcohol Injection)
All dynos run on a Mustang dyno
Heat soak is the largest issue with going with a smaller pulley. I personally wouldn't run even a 2.6" pulley without alky, however with alky I don't see a problem with a 2.6". To go any lower than that you will need to port out the s/c so that you will be able to actually get all of that air out of the s/c, also i wouldn't run the 2.5" or port the s/c unless you plan to have the head ported with larger valves as well.
"Horsepower is the Ultimate Accessory"
