I am having trouble with my truck; kindof....

I ran it for a while with the KB on a 4# lower and 3" upper. I have seen up to 17#'s of boost with this combo.

I have went to a 6# lower recently, and ran it for a few hundred miles in good air. I have seen a max of 17.5, new belt and all. No belt dust.... I actually saw 18.5 on the dyno with that pulley.

Well; I was at the track, and trying to get a good pass out of it. It was not making the boost I wanted. So, I put a 8# lower on it and could only pull 18#'s The ET improved, but not like I wanted still.

My thinking is that it is sucking the OEM rubber boot closed. Is this possible? I have a REM smooth tube ordered, but am kindof wondering if there could be something else....

 

This was mentioned by JLP in another thread, he was pushing his intake pipes. I asked him (via the thread) how common this was, and he never responded. Led me to believe it may not be as common as they want you to believe? I believe that if you're running a decent sized K&N (style) cone shaped filter, there shouldn't be enough restriction to close off the rubber boot. But, I could be wrong....

 

Unless your flowing more cfm than your filter is rated at or there is a restriction this should not be a problem.

 

Mine is whatever brand 12" long filter that Razors Edge sells. What else could be holding the boost back? With a 3" upper and a 8# lower it should be making over 20#'s with good air.

 

something wrong with the SC perhaps? maybe bearings going bad? belt slip?

 

Mine makes 20 psi in this cooler weather with a 6# lower and 3" upper on the KB. But I am running stock exhaust; if you have LT's then 18.5 psi is about right I'd think.

Jody

 

Casey
I have watched my air filter squeaze down and start to collapse on the chassis dyno. If you get a chance to dyno your truck that would be a good time to check it out.
Dale

 

Is that on a street program? And pump gas???

 

Although I did run it briefly on the street just to do some tuning I normally run 18 psi on the street and pump gas. (6# lower and 3.25" upper)

Jody

 

Thanks Jody,

I'm getting impatient with my engine still not together. I never even thought of using stock injectors to break it in.

I wanted to run the same tune as before until I break it in and dyno tune it, but could I with going from stock(42#) to 60#?

I was running 3.2 top and 4# lower on the KB when I bent the rods.


Casey - what kind of belt and idler assembly are you using?

 

Dave,

You'd need the tune changed for the bigger injectors or run the smaller ones with your previous tune and stay out of the boost, just break in the engine.

Jody

 

Gatorback belt(used one and new one with no change) and a new style Metco idler bracket with a 100mm idler(sits very close to the 3" KB upper)

 

When we first started my new engin with the 16 lb lower on it. I let it warm up and then reved it twice and colapst my K&N filter.
Doug from this board still has the pic.

That was with 1mm over sized valves and port and polished heads.

Suavy

 

That's what I have and you really shouldn't get any belt slippage, but it sounded like your problem.

Also temp&humidity can change boost readings, but you said it was with good air. You could be squeezing the rubber intake like you said. I'm sure you tried cleaning the k&n but I wanted to ask. And you double checked the belt size?

 

I use to run those "outerwear" pre filters until one day on the dyno I noticed that it was being sucked into the grooves of the air filter.

Never had any trouble with the factory boot pulleying up 21-21 1/2 lbs