dewmanshu

iTrader: (4)

I know I know, some one always asking how much boost from what size. I am not really, but I always find it interesting that the difference between everybody's responses are not always that close... one guy will say 3.1 at 8psi and another says 3.1 at 10psi. Now I know 2psi doesn't sound like alot but it is almost a third of an increase from the stock radix setup(assuming 7psi stock I believe) and that different setups offer different results, but inquiring minds what to know. The 5.3 radix with a decent head job, headers, and a cam...what should you reasonable expect from a 3.0" pulley.

Flyer you have the 3.1....what are you running now and what would be your "edu-mucated" guess on the 2.9" that you are looking to go with.

My concern is...I have the mods in my sig and in the beginning I was producing 8.5psi. Then somewhere later in trying to fix some repairs all of a sudden I had 9.5psi. THEN...I got rid of my brake booster and installed a hydra boost system (runs on steering pump) for my brakes and I now show on the digital gauge at WOT 10.6psi. If I am towing the trailer and 4wheeler and lay into her she will show 10.9psi. In researching around for standard psi jumps it seems you should expect an extra 3psi from the 3"...so 7psi plus 3psi equals 10psi...? But I was producing 8.5 in the begining? Am I worrying about nothing here? Hmmmm. Sounds okay? Safe?

Last Call

iTrader: (4)

3.4 pulley shows 7 psi at WOT. Otherwise, about 5.5 psi and part throttle. 8.5 seems a bit high. Restrictive intake and exhaust can attribute to higher boost levels, however that does not seem like a problem for you.

dewmanshu

iTrader: (4)

Most certainly not on the restrictive incoming and outgoing...some bad plug wires and lots of raw fuel in my exhaust completely fried my cats that came with the Dynatech system (and made for some dirty oil), so I haven't put my power cats on yet so that to make sure I have fixed the problem first, but...it's three inch exhaust into a custom y-pipe which stays 3" inch dual all the way back with no cats. So plenty of room for exhaust to leave. The TB is still stock but shouldn't be a problem I'd imagine. Always checking filter to make sure of clean air entry.

Yep, seems high. No pinging or hints of mechanical damage....yet.

Flyer

iTrader: (1)

Freer flowing intake will give you better boost, but a constrictive intake will lower boost. A freeier flowing intake will drop boost, but a constrictive exhaust will raise boost.

I have a small cam, a notch under yours, headers, really free flowing exhaust, and a Volant intake. with the 3.1 on there now I will see 8.5, until it shifts, then it will bump up to 9 and hold 9. With that 2.9 pulley I would anticipate 11psi if I got no belt slippage.

Let's hear some more detail about that brake thingy your talking about. How much, where from, why, etc. etc.

dewmanshu

iTrader: (4)

[QUOTE=Flyer]Freer flowing intake will give you better boost, but a constrictive intake will lower boost. A freeier flowing intake will drop boost, but a constrictive exhaust will raise boost.[/QUOTE]

Hmmm...well I would definitely consider my exhaust free flowing...so...I could get more boost by knocking that dual down to a single 3". But mathematically speaking...I imagine there is a fine line of balance when getting more boost from a more restrictive exhaust would hurt more than do good...power wise speaking.

[QUOTE=Flyer]I have a small cam, a notch under yours, headers, really free flowing exhaust, and a Volant intake. with the 3.1 on there now I will see 8.5, until it shifts, then it will bump up to 9 and hold 9. With that 2.9 pulley I would anticipate 11psi if I got no belt slippage.[/QUOTE]

I still don't think it will....that 1105 belt might as well be welded on.

[Quote=Flyer]Let's hear some more detail about that brake thingy your talking about. How much, where from, why, etc. etc.[/QUOTE]

Long story...I live here in the short, hilly, blind turns, roads of western Maryland. When I am at a stop with a blind corner to my left and just as I let off the brake and hit that gas somebody is flying (the nerve!) around that turn and with a fast truck or not....in all reality I need to stop. Well from that split second of brake then 10% throttle then brake....the brake pedal is ROCK hard and has no interest in keeping my 5300LB *** from going out past that stop sign and taking one for the team in the driver side door. The sorry problem of loosing boost under accelaration to the brake boost. (Who usually needs to push the brakes and throttle at the same time right? Well, at least that is the car manufacturer's theory...they must know about us!)

So days of research later I find out that some HD guys and all diesels come with what is know as a HydroBoost Brake system. Commonly referred to as "hydrobooster or hydravac" over the years, a high performance hydraulic brake assist booster is a powerful alternative to a vacuum assist type booster. This type of assist unit uses the hydraulic pressure from the power steering system to provide a potent brake pedal assist.

I freaking love it. Expensive? Yeh figure spending around 600 for the product alone. It has it's own little whine too...LOL...minature SC under the hood. It's a custom unit... goto http://hydroboost.com/index.html and check it out, it answers most if not all questions on FAQ page. Give Paul a call to make sure your year is good (I think the NBS' trucks master cylinder foot is alot bigger)to go and wholla...5 days later you'll be set and that's if he doesn't have any stock...he makes them on order usually.

They're so good they will change the way you do burn outs. They really hold them rotors still. I haven't taken my truck to the track yet do to alot of problems I have been working on, but just goofing off and practicing launching...I can hold her pretty close to my stall. Obviously not on the stall, but nice and solid take off. IMO a definte advantage to draggin somebody who doesn't have them.

Long enough answer? LOL

Will Baty

Remember altitude makes a difference on boost. I have the 3.4" pulley on my '99 with the 5.3 I make 7 1/2lbs of boost at 5,300 feet. When I drive to California the truck makes 9lbs of boost at sea level.

Flyer

iTrader: (1)

[QUOTE=dewmanshu][QUOTE=Flyer]Freer flowing intake will give you better boost, but a constrictive intake will lower boost. A freeier flowing intake will drop boost, but a constrictive exhaust will raise boost.[/QUOTE]

Hmmm...well I would definitely consider my exhaust free flowing...so...I could get more boost by knocking that dual down to a single 3". But mathematically speaking...I imagine there is a fine line of balance when getting more boost from a more restrictive exhaust would hurt more than do good...power wise speaking.

A freer flowing exhaust will reduce boost, but that doesn't necesarily mean there's a loss of power. ALl it means is it's taking less pressure to move that much air through the motor.

With that blower sitting on top of the motor, your motor is no longer an air pump. Your motor drives the air pump and is a restriction now. The exhaust is a big place to free up some of the restriction.

The intake side is along the sameprinciple, but the blower is having to suck air in. The harder it has to work at getting that air in, the less boost it will create.

dewmanshu

iTrader: (4)

In my past research I tryed my best to take that into consideration, most guys are from Texas or the midwest on here and altitude seemed to be not too much of a factor with most responses.

dewmanshu

iTrader: (4)

Ahh...I always forget to look at it that way...the NA Engine is just an air pump.

So, if you had you straight header exhaust (keeping in mind we are discussing the 5.3 in our conditions of a vehicle) that would obviously create a lot less boost but the power factor from that ease of removal would keep the power great because this heavy *** intercooled radix is needing to do less work to remove the combustion wastes? Bear with me here, how does that really effect the boost though. I am imagining that the intake valve is closed and as the exhaust valve opens the piston pushes out the waste.....ahhhhh.... I answered my own question. The force of the air and combustion of the other chambers is what makes it possible for this piston to "push" the waste out and if the waste leaving is less restrictive then its easier for the other combustioned pistons to push. See...just talk it out is what I always say. LOL

But back to may original statement then, I am just saying too free of an exhaust couldn't be all that great...you need some sort of back force right?

Need to change this thread to "Engine 101"

Flyer

iTrader: (1)

Some backpressure is good, but with the blower, you need a lot less than if you were still n/a.