Ported blower?

[Blind]

Could my truck have a ported blower on it?

I installed a boost gauge last weekend, an autometer electric gauge with a engine bay mounted MAP sensor, it calibrates every time I start the truck (I tapped into the fuse block to a 30amp fuse that stays hot during the key start cycle, but is off when the key is off). I understand this is the most accurate style gauge you can get.

http://i40.photobucket.com/albums/e237/blindbatts/harley/stereo/IMG_1574.jpg

It has an 8.5" lower pulley, which is a lightning 4lb, should be +2lb on a HD.

HD should make 6lbs stock, but when I was jumping on the freeway after installing, I saw 10lbs.

Truck has totally stock exhaust, stock airbox, paper filter, with a ram air tube going into the bottom of the stock airbox from the bottom of the bumper area. MAF and T/B look stock.

I can't think of anything else that would account for the extra 2lbs?

[BISKIT]

I hate to say it, but it could very well be just the cold.

I remember Jay when he had his lightning had readings all over the place and even Mike with his HD sometimes read more than what it was supposed to in the cold.

I might be dead wrong and it could be a ported blower but you would be amazed at what a lil none-used-to socal cold will do sometimes.

[Blind]

the outside temp thing read 62*, I would understand if it was in the 40's, but 60's?

[BISKIT]

the outside temp thing read 62*, I would understand if it was in the 40's, but 60's?

Hmmm..

Yeah, the "wierd' readings that I remember Jay and Mike talking about were usually at night when it really got colder than a witches tit.

[Greg@RET]

HD's make 2# lower then a lightning does. So if you put on a 4# lower you would see 12# on L, or 10# on a HD. Its right...

[Mizry]

HD's make 2# lower then a lightning does. So if you put on a 4# lower you would see 12# on L, or 10# on a HD. Its right...

thats what I added up too... 4 psi lower is a 4 psi lower, add that to the 6 psi and you get 10...

[Blind]

thats what I added up too... 4 psi lower is a 4 psi lower, add that to the 6 psi and you get 10...
but the lowers do -2psi compared to what's advertised, as they're setup for the lightning upper pulley. so a 4lb on a HD makes 2lbs more than stock, or 8psi.

fwiw, I saw 12.5psi in 3rd gear last night and it was 61* on the outside temp display. 1st and 2nd gear it stays lower, around 10-11psi.

[Mizry]

so what pulley is the same as the lightning, the upper or lower..?? I thought the upper was different.. if the upper is the differance then it would be correct at 10psi... if the lower is the smaller than the lightning then it would be 12 psi with the 4 psi pulley...once the pulleis are the same, upper and lower, then its no differnet than a lightning engine...

[Blind]

the upper's are different, the HD has a larger pulley so the effect of the lower pulley's is 2psi different for a HD vs a lightning.

a 4lb pulley would make 4lbs on a lightning, but only 2lbs on a HD (from 8lbs to 12lbs vs from 6lbs to 8lbs).

[Mizry]

how is that...? you just said your self the upper is the 2 psi loss...the total boost will be 2 psi less than a lightning with what ever lower.. that is untill you get the lightning upper....

[Blind]

hmm, I don't believe it works that way.

the 6lb on a lightning would make 14lbs, vs that same 6lb on a HD would make 10lbs.

It's not a 2lb difference in the total, it's a 2lb difference on the effect of the pulley (4=2, 6=4, etc) starting from the base of 6lbs.

[RedRyder]

holy chet, this thread hurts my head.

[Greg@RET]

Your boost is correct, your over thinking it.

[Nicksbluestang]

Blind, you do not have a factory freak.
Your questions have been answered by 2 knoledgeable wrenchers.

[Blind]

Your boost is correct, your over thinking it.
well if the #'s are in line, then I will look forward to porting the blower myself :)

[Mizry]

blowers are pretty easy to pull from a lightning.. just the brackets that use the blower bolts can be a pain to work around them...make sure you clean off the area around the blower, once the blower comes off, the cooler will say semi tight on the manifold, so you dont want any dirt getting between the gakets...and becarefull not to scratch the gasket or metal gasket surface by draging the blower, there are two locating dowls that usually stick to the blower bottom and can grab at the metal gasket..