Hey guys, I just installed the Paul's High Performance extrude honed upper plenum and Accufab throttle body on my '02 HD. WOW! I couldn't believe the boost gauge when it showed a gain of 2 lbs of boost! Problem is, I think it may not be usable HP, because my pyrometer is reading 1300-1400 degrees at WOT. Is this too hot, meaning I'm running lean? The sensor is installed before the cats, next to stock 02 sensors on driver's side.

Starting from bone stock engine, only Bassani cat-back, I was making 5-6 lbs of boost.

Then I installed the stock upper Lighting pulley along with NGK TR6's. This brought me up to 9 lbs of boost on my Autometer Lunar series boost gauge.

Today I added the upper blower plenum and throttle body for another gain to 11 psi at WOT. Looks like time for a chip to get into tune.

Still haven't installed the AFM power pipe and PSP air filter kit, but I'll be at the track tomorrow, testing the current mod's.

 

Dude...you are running 5lb without a chip - You are asking for trouble!

I would definately go to your nearest tuner and get that baby put on a dyno for a chip-tune....before you blow something.

There is a boost efficiency curve...after 10lbs it pretty much levels off.

 

That's just it.... How is it making this much boost with only Lightning upper pulley, which is only supposed to be 2 #'s more, and extrude honed plenum and TB? Is the Autometer inaccurate or misreading boost level? I'm at a loss here

Aside from the L pulley, I've only added mod's to improve the airflow efficiency, NOT boost levels! Any help is appreciated.

 

I wonder if that could be the volume side of the equation. The SC begins to become less efficient at packing air into any volume of space. I think maybe the increased volume for air flow allows the increase in pressure - i.e. boost. The pressure/volume/temp relationship should be the same on both sides of the SC, an increase in volume could yield pressure increases if temperature can be regulated.

Or I may have forgotten some of my high school physics class, but I think I'm on to something.

BTW how is the truck running with the 5 lb pully and no chip. I have been speculating in my post (mod confusion) that the HD could run up to a 6lb L lower pully with no new chip.

 

boost=heat therefore if you dont have enough fuel to cool down the heat/lean motor you will have bog trouble

 

Read this ????

http://www.nloc.net/forum/showthread.php?threadid=31269

 

Time for a chip Dude... and a good one. Ask drop-top what a too-lean condition can do to your motor. No need to chance it...

 

After some research, I've found that the additional boost is a product of increased air density, due to the increased airflow efficiency.

Interestingly, on Saturday morning I installed the 12" air filter in place of stock airbox and I lost 1 lb of boost. WTF, I thought that the conical filter was more efficient than stock panel filter? Anyways, here's the track results:

1st pass:
60'- 2.22
1/8- 9.27
mph-78.44
1/4- 14.32
mph- 96.95

2nd pass (1 hr cooldown)
60'- 2.26
1/8- 9.33
mph- 77.97
1/4- 14.40
mph- 96.35

On 2nd pass, I raced a Dodge R/T, supercharged- 6 psi, and he had me by 1- 1 1/2 lengths until 3/4 track, where I caught him and passed. I won by 1 length and it was a good run. Caught up with him in the pits and talked a bit. Very cool guy, hangin with the Dodge club. He siad his truck weighs about 4,100 lbs. I was shocked, but happy for the moment. My truck has never been able to break the tires loose until this day. Can ya tell by my 60' times? lol

Anyways, off to find a chip. Heck, might as well change lower pulley if I'm gettin a chip!