When I was trying to figure out which pulley to go with it was hard for me to find info on using the 2.65" upper pulley. Many people told me not use the 2.65" because of belt slip but I've come to find out that the GT500 guys are using pulleys smaller then the 2.65" so I decided to give the 2.65" a try.
Here's what I found... I have very little, if any belt slip. I'm used a 100mm auxiliary idler, which you have to remove to put on/off the belt due to the high side wall of the RR 2.65" pulley. I used a Napa belt (part # 080740), I believe it's a 74 5/8”. The car made 14.41#s of boost. I have LT headers so I may have lost a little boost but I wouldn't think it'd be much. I'd guess that if I had the factory headers that I may have hit 15#s.
Here is a list of my mods so you guys know what I had and the results I got.
MODS
Posi Performance race port (on factory Eaton blower)
2.65" upper pulley (factory lower)
Accufab single blade throttle body and plenum
JLT 12" high boost cold air intake (new version)
SCT BA-3000 MAF with 105mm housing
60 LB injectors (from Sieman Deka)
BAP
MAC long tube headers
MAC off-road H-pipe
MAC 3" catback
ECG delete
BilletFlow 100mm idler pulley
Napa belt (part # 080740)
Cobra made
518rwhp
497rwtq
14#s of boost
Here are a few pics to show fitment
DYNO
Tuned by HBH
Here's what I found... I have very little, if any belt slip. I'm used a 100mm auxiliary idler, which you have to remove to put on/off the belt due to the high side wall of the RR 2.65" pulley. I used a Napa belt (part # 080740), I believe it's a 74 5/8”. The car made 14.41#s of boost. I have LT headers so I may have lost a little boost but I wouldn't think it'd be much. I'd guess that if I had the factory headers that I may have hit 15#s.
Here is a list of my mods so you guys know what I had and the results I got.
MODS
Posi Performance race port (on factory Eaton blower)
2.65" upper pulley (factory lower)
Accufab single blade throttle body and plenum
JLT 12" high boost cold air intake (new version)
SCT BA-3000 MAF with 105mm housing
60 LB injectors (from Sieman Deka)
BAP
MAC long tube headers
MAC off-road H-pipe
MAC 3" catback
ECG delete
BilletFlow 100mm idler pulley
Napa belt (part # 080740)
Cobra made
518rwhp
497rwtq
14#s of boost
Here are a few pics to show fitment
DYNO
Tuned by HBH
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