Lightning Rodder banner
1 - 20 of 67 Posts

·
JDM Built/KB 3.2
Joined
·
2,175 Posts
Damn! those things make boost huh?! I am getting one shortly... Currently JLP is modifying my intake for the 3.2. Anything else I should know switching from a 2.6 - 3.2? Everything else bolt up alright?
 

·
Registered
Joined
·
3,682 Posts
Don't have a 3.2 but just for comparison, Chris and I have similar heads which has a big impact in the variation of boost. I have a baby 2.6 with 10# lower and 4" upper as well and see 18 to 19#'s on the street. Looks like the 3.2 is making a few more #'s than the 2.6 and 2.8. Hard to compare since all combos are different. size of heads, Cam profile and exhaust can really change the boost
 

·
Panty Dropper
Joined
·
5,911 Posts
Seems very weird. JL picked up 6psi with no pulley change just going to the 3.2 from the 2.6.
 

·
Worlds Fastest Street HD Truck
Joined
·
14,677 Posts
I'll add mine in next year, probably won't get #'s this year, but I'm aiming to start with an 8 lb lower and I'll have a 4.0, 3.75, 3.5, 3.25, and 3.0 upper in the tool bag to dial it in where I need it. Aiming for 18 street and 24 track





Dug up your other thread where I posted all the pulley ratios, just for quick comparison sake for guys running different size lower/uppers, it's easier to compare ratio's since then it doesn't matter what size pullies......



========================================================

Was 10lb lower and 4.0 upper for 20-21 lbs

Going to 8lb lower and 3.0 upper looking for 25-26lbs
3.250 upper and 8lb lower just saw 26/27 lbs.
Just put a 3.250 upper on with 10lb lower and saw 29-30 psi and had to let out immediately



Just "talking" out loud here...from your data so far...

2.50:1 Ratio (4.00 Upper / 10 lower): 20-21 lbs
2.92:1 Ratio (3.25 Upper / 8 lower): 26-27 lbs
3.08:1 Ratio (3.25 Upper / 10 lower): 29-30 lbs


Guessing inbetween points....doing a little math on pulley combos and some interpolation on boost curve. May not be exact obviously based on blower efficiency curves, and will obviously vary dependent upon the combo, but it's a starting point...

Blue = guesstimate points, Black = blowerslut data points...

2.38:1 Ratio (4.00 Upper / 8 lower): ~18 lbs
2.50:1 Ratio (4.00 Upper / 10 lower): 20-21 lbs
2.53:1 Ratio (3.75 Upper / 8 lower): ~20.5-21.5
2.67:1 Ratio (3.75 Upper / 10 lower): ~23-24 lbs
2.71:1 Ratio (3.50 Upper / 8 lower): ~24-25 lbs
2.86:1 Ratio (3.50 Upper / 10 lower): ~26-27 lbs
2.92:1 Ratio (3.25 Upper / 8 lower): 26-27 lbs
3.08:1 Ratio (3.25 Upper / 10 lower): 29-30 lbs
3.17:1 Ratio (3.00 Upper / 8 lower): Kaboom!

So sounds like a 3.5 upper / 8 lower may be what you want for around 25 lbs.


Although my combo has always seemed to run about 2 lbs less on equal pulley combos as you and dude L have ran, assuming something TF head related, so still on the fence if I should keep my 10. I guess I'll definitely plan on acquiring a 3.75 and 4.00 upper, my 3.00 may have to get turned into a trophy since I probably won't ever use it again even with an 8 lower lol


Keep this updated on any other pulley combos, I'll try to put together a chart for others for future use averaging out boost levels between what you see and what I end up seeing once mine's together.
===========================================================
 

·
JDM Built/KB 3.2
Joined
·
2,175 Posts
Once I have mine running with the 3.2 I will chime in.
 

·
A1 TRANSMISSION
Joined
·
4,815 Posts
Discussion Starter · #12 ·
On some of my early figures it was just a very quick smack in the throttle because the tune changed so much what i know for sure at this point.

10 lower and 4.0 upper i saw 20-21

6lb lower and 3.250 upper 25-26


I have raced both of these combos.


Sent from AutoGuide.com Free App
 

·
Registered
Joined
·
546 Posts
10lb lower and 3.5in upper = 24-25 lbs
10lb lower and 3.25in upper = 27 lbs

I don't have testing in a bunch of different air temps yet.
 

·
Worlds Fastest Street HD Truck
Joined
·
14,677 Posts
So why am I seeing 22 pounds with a 3" upper and 8lb lower
Not sure, that part of my post was from several months ago and guesstimating boost levels off what little info was out there based on the 2 or 3 data points blower slut had. The pulley size to ratio is all correct info though.

I'm surprised you're not higher with TF heads, they seem to have higher boost #'s than PI heads from comparing my 2.6 PI combo to other similar 2.6 TF combos.

10lb lower and 3.5in upper = 24-25 lbs
10lb lower and 3.25in upper = 27 lbs

I don't have testing in a bunch of different air temps yet.
That's probably the closest comparison for me since we've got almost identical JLP powertrain combos. Pretty sure I'm going to do an 8 lower instead of my 10 lower, and see where that lands me.
 

·
105's Coming Soon!!!
Joined
·
2,359 Posts

·
Registered
Joined
·
3,682 Posts
Cams can make a huge difference. Curious to see what the overlap is between the two? :smt102
 
1 - 20 of 67 Posts
Top