It was suggested that a worthwhile upgrade would be to install 4" intake tubing and I have a couple things I don't quite understand about that.

I can easily see that adaptors can be used to reduce the size so that it would fit onto the 90mm throttle body and to the existing maf sensor.

My question is; if the diameter of the intake tube has to be reduced to 3.5" on the tb end and ?" on the maf end, then will there really be measureable gain to be had if the middle section(s) is increased to 4"? (I don't know the diameter on the stock maf end)

It seems like the entry point diameter would need to be as big as possible to get real gain in air volume to the supercharger... but that's just what it seems like to me and I don't know squat.

It was also suggested that I might want to consider getting rid of the maf and going to a 2 bar tune. Is that a good idea because then I can get rid of the maf, go to 4" intake all the way to the tb?

I assume that there are air filters available that will fit on a 4" intake tube. (I'm gunna search Summit for that item next)

Pardon my ignorance... I am clueless when it comes to this stuff.

 

Your intake is only as wide as its narrowest point. In order to maximize a 4" intake you'll need at least a 90mm throttle body, a 100mm MAF and a large intake filter such as the Airaid unit.
A speed-density tune can eliminate the MAF for smoother flow along the pipe and has other benefits. A 2-bar tune for a boosted engine allows finer tuning at higher boost levels and can be done at the same time as a SD tune. This is known as open-loop-speed-density or OLSD and requires a 2-bar MAP.

 

A 4" silicone coupler will attach the intake tube to the throttle body, there's no need to reduce to 3.5". I made one myself with 4" aluminum.

 

Ok. I thought that since 90 mm = 3.54" I'd need an adaptor to squeeze down the 4" intake tube to seal onto the tb.

 

You've confirmed what I was thinking.

I have a 90mm tb so I'm good to go on that end. I'll be getting the truck tuned in a couple weeks, as soon as I get the 2.6" pulley installed, so I'll do the 4" tube and 2 bar speed density tune then.

 

The 90mm blade is an ID of the flange dont forget. The outside is a great match for a 4" silicone coupler. I just made mine out of 4" aluminum tubing and an elbow. Plus you are getting close to maxing out the MAF.

 

Do the silicon couplers provide enough vibration resistance to protect the MAF and/or prevent rattling ?

 

Yes. Also, if you are looking for a 100mm MAF, I have one for sale. It's in great shape.

 

What's the downside to doing a 2 bar and speed density getting rid of the maf?

 

On another note: I just called Texas Speed to order a crankshaft pulley to speed up the sc and was told they don't have one for the truck engine. Any comments/ideas/suggestions?

It looks like IW is $550.