holyford86
Some guy with a problem
Supporting Member
Article Contributor
RBV's on Boost
GMRS Radio License
- Joined
- Aug 6, 2007
- Messages
- 2,390
- Age
- 39
- City
- Plattsburgh
- State - Country
- NY - USA
- Vehicle Year
- many
- Transmission
- Manual
- Total Lift
- 7
- Tire Size
- 33x12.50R15
I just finished up my GenV M90 from GTP onto my '98 4.0 OHV, Here. The problem I am facing sounds similar to yours. I am running the 3.8 stock pulley, but I cannot get any boost.
After looking into it, the stock 3800 has a 7" harmonic balancer. The 4.0 OHVs have 5.79 - 6". I am thinking this is the main issue. The 3800 comes with a ratio of 1.85. When swapped to a 4.0, it sits at ~1.58.
When you were running the stock pulley on yours (getting 1lbs), how did your truck perform? Could you even tell the SC was on there?
I was at atmospheric pressure with the stock pulley, the math told me that's roughly where I would be though. I'm running a 2.2 inch pulley now which maxes the blower rpm rating at redline and I'm getting between 5 and 6.5 depending on air temps and density now. I'm looking to get it rebuilt and may need to up the pulley size at that time but I'll see.