dewmanshu

iTrader: (4)

Cool, thanx Flyer...class is dismissed!

Hoover87

I'm in WA at about 100 feet above sea level and with the stock 3.4 pulley I've shown 8-8.5 lbs of boost from day 1. Now that it is fall, today with a temp of about 45 degrees I was seeing 9+ lbs of boost with the stock pulley and the truck was pinging....pulled my foot out a bit to stop the pinging and held her right around 8.5 - 9 lbs. We took her out a few weeks ago in 30 degree weather and darn near hit 10 lbs of boost with the 3.4 pulley!...and of course it was pinging to beat hell. I think I might put a bigger pulley on it just to keep it from pulling timing and to get the boost closer to where the tune is. I'm curious which would make better power....the high bost, or a better running truck with less boost that I can lay my foot into.

Flyer

iTrader: (1)

I think you should conside looking at your exhaust. It sounds like it might be restrictive if you're seeing that much boost. Maybe some true duals would help you out.

Hoover87

I had just about the same boost when I tried running it with open headers.

For kicks and to keep the pinging down with the cold weather, I put a 3.7 pulley on it tonight and it peaks at about 7 lbs now. I don't hear any pings now, but I can certainly notice less truck there when I jump on it from a slow roll. I'll drive it like this for a bit and see if the computer decides to adjust.

James B.

iTrader: (1)

This is all true and therefore excellent advice. (as usual Flyer) I haven't yet read the rest of the thread but I have some contributions.

"Boost" as we measure it is rarely an acurate measure of how much air is getting into the engine. There are many factors. The important thing is how much pressure you can get into the combustion chamber without detonating. Swapping a cam out, for example, to one with more lift will result in more air getting in with the same amount of boost. Comparing the before and after on a cam swap boost is typically observed to drop, meaning more air is getting through now than before due to less resistance.
Out-of-the-box cat-back systems are just about worthless on a boosted motor. These are sized for naturally aspirated engines. NA motors need some backpressure to keep combustion chamber pressures high enough to make good power at low RPM where velocities are low. That entire concept is totally different with forced induction. Where we have control over manifold pressure it is better to get to that critical threshold of combustion chamber pressure with boost rather than by restricting exhaust. Exhaust should be as open and free-flowing as space and noise tollerance allows for maximum power.
Besides a dyno or G-force run, the next best way to see what effect mods have made on engine performance is to look at mass air flow. Asuming that air is being kept at the right mixture with fuel, the more there is going in the more power is probably being made. Manifold pressure alone has too many other variables to be considered a measure of performance.

James B.

iTrader: (1)

Paul is one of the best people in this industry I have ever had the pleasure of working with.
Paul's HydroBoost on my truck improved the crappy OBS brake system so well that I almost crash into stuff when I drive a stock OBS truck! I still remember the first time I drove on the hydroboost, I was nose-diving for a few days!

There's a reason HD truck have always come with hydroboost and a reason why new 1500's do too - it's BETTER. There is a reason too why older 1500's did not come with it - COST.