Turbo and Horsepower
 

I guess this would be the right section. Anyway, I have been thinking and don't really understand this. After installing my boost elbow I gained about 3 psi and then after clamping the hose off i gained about 5 more psi. Now what I don't understand is how that doesn't give you more hp? I mean a bigger turbo gives you more air, more psi and more hp. So why wouldnt an increse in psi on your stock turbo give you more hp? Maybe I am hearing two different stories but that was the first part I heard. I then also heard that for each psi of boost you gain 10 hp. Can someone help to set me straight? Also explain one more time how clamping that hose off gives me more psi and what it it does to the turbo? Sorry to be a pain but Im trying to learn!

You need add more fuel along with more air to increase HP.;)

So if I added more fuel then I would gain hp from that additional psi from the elbow and clamping? And is it true its 10 hp for every 1 psi?

The rule you were speaking of is1 lb boost for every 10 HP to keep the EGTs cool http://www.dodgeram.org/tech/dsl/mor.../power_isb.htm (answer to 4th question). That is just a general rule. The boost doesn’t make the power it keeps the EGTs cool, however you do need some air to support combustion. If you have a lot of black smoke and high EGTs you could use more air or better fuel atomizing injectors like the EDMs.
The boost elbow has a small hole in it to bleed off air before it gets to the waste gate actuator so it will take more pressure to open the waste gate. With stock injectors you might be ok pinching off the line but if you ever add bigger injectors like EDM 1.5s or DD2s you could get into trouble with over spinning the turbo.
Here is some good info on turbos:
http://www.dodgeram.org/tech/dsl/FAQ/turbo_faq.htm
Just my $0.02 worth.

In addition to what Bill said:

If you block the wastegate, and see your boost go up, that _generally_ means you were starving for air, and as such, you've likely increased your HP a bit, as you had some unburnt fuel looking for oxygen.

How much? Probably not much, and if you increase boost past the efficiency range of the turbocharger, you've _generally_ lost HP, as the compressor will be superheating the air.

Rod

Remember what was said. Fuel makes power. Air and fuel makes cleaner power. I installed 300 HP injectors alone and gain about 30 HP. Boost went up cause of more rpm and fuel. I installed a #10 plate. More power. I removed the 300's and installed 370's. More power on a stock hx35. Then a 14cm2 housing and the temps came down and boost increased. 3K governor springs and more boost cause of more rpm. A hp increase cause of efficient detination in the cylinder. A 4 inch exhaust and AFE filter from Jack and the temps came down more. More HP? I don't think

Point, fuel makes power. Boost puts the air in the cylinder to burn it clean. A 450 hp truck on a hx40 runs down the track smoking like a coal train. Installed the twin turbo from Garmon's Diesel and a puff at launch, clean on down the track.

That's sort of how it works. Nothing techical here.:D

..Preston..

Just curious, how much boost in psi can a stock turbo push? This includes any modes other than a different turbo. Thanks

I used to push 35 out of my HY35 all the time.

From what I’ve read, good cool air about 35 maybe up to 38 psi after that you are heating the air. You can still make boost but it will be hot air and any higher than that you will approach over spinning the turbo. I'm no expert so someone who is more knowledgeable than I can correct this. If someone has a map for the HX35 they can verify this.
Just my $0.02 worth.

Bottom line to all the above discussion is that you need BOTH air and fuel increase to increase hp... From the factory the wastegate setting and max throttle fuel input are matched... If you defeat the wastegate, all you do is slug more air, and without increasing the max fuel input you'll get no power increase... The ECM controls fuel metering, so to get more fuel you need to alter the "brain"...

So how do you find that sweet spot with the boost so it does not produce too much hot air but provides enough for the fuel level you have? I was seeing 1200+ temps with just a #6 plate and 3k GSK with about 32 psi but very little smoke. If I ease up on the boost level a bit (back off of the elbow) will I see lower temps (at the sacrifice of go power)? Is there a formula (math or seat-of-pants) to balancing boost level with existing HP? I see many posts where some are running very high boosts but I'm not sure if my HP is enough to support it.

Get a bigger exhaust...straight pipes. The bigger the pipe the easier it is for the exhaust to get out. Which means the exhaust will move faster, turning your turbo faster. Your EGT's go up to 1200 degrees because it's being cooped up between the manifold and turbo. Actually, 1200 seems a bit high. Some people on here like to run their EGT's around 900 degrees when towing, but I don't know what kind of set-up they have. Lots of people on here also have 4" single exhaust or 4" dual stack exhaust, or even 5" dual stack exhaust for the serious drag racers/truck pullers. And it's agreed that the catalytic converter and muffler only hinder performance. They restrict airflow, making your boost pressure lower and your EGT's higher.

If you have the 12 V engine you can also turn up the pressure on your fuel pump. I've read about that here, so just do a search on it and you might find it. Type in "star-wheel" or some variation on that.