More specific questions for once :)

[MrMazda92]

Hey everyone, I finally managed to get my hands on a DE(thanks 2fazed), and am planning my build finally.
My goal is 18 PSI, but I'll settle for 15 if I must.

The turbo I've been looking at the hardest is a holset hy35, and I'm curious if many people have boosted a kl with it. It appears to fully spool at around 3k RPMs, but will it hold boost through th power band? How long can these go before a rebuild? Will it have a pleasant sound, or remind me of a vacuum cleaner winding down?

My other question is simpler, will Millenia S red tops be sufficient for 15-18 lbs of boost?

[RS_OBD'oh_2]

PSI is a useless scale. I can't believe people are still stuck on this. A small snail VS a large one, PSI can be the same but the CFM will be waaaay different. Post the stats on the turbo.

[MrMazda92]

I'm still a FI noob, so if you need more lemme know.
Compressor inducer: 54mm
Compressor exducer: 78mm
Turbine wheel: 58/65mm

[Daninski]

PSI is a useless scale. I can't believe people are still stuck on this. A small snail VS a large one, PSI can be the same but the CFM will be waaaay different. Post the stats on the turbo.

Most people would relate CFM (GPM/LPM) to orifice size wouldn't they. But ya your correct in that PSI is only one part of an ever bigger consideration.

[MrMazda92]

Okay guys, let's get over the fact that you don't like my wording, you understood the gist of my question, so please try to answer it at least partially :/ What would the increase in hp at the crank be w/ 15-18 psi? Approximately please:/ then I'll be able to answer the injector question myself.

[RS_OBD'oh_2]

Hard to tell.. Pressure of air is not the same as quantity of air. What is the turbo rated for? Did you google the stats on the turbo? If you give us some numbers (aside from AR) we can help. It's a little much for you to ask without doing the searching yourself.

[johnmx3ze]

mellinia s injectors will not be enough for 15 psi, last year i was at 7 psi and mili s injector duty cycles were at 90% with stock fpr

[MrMazda92]

@ RS, Sorry about my lack of info. I did some research, but have only an iPhone for Internet... I'm very limited in ability to store information accurately and concisely. The hy35 is a diesel truck turbo, and can safely handle 15-18 psi easily, and seems fairly compact as well as affordable without sacrificing quality.

@ John, crap I'll look into larger ones

[RS_OBD'oh_2]

http://dodgeram.org/tech/dsl/FAQ/turbo_faq.htm" onclick="window.open(this.href);return false;

There are your specs. Expect a rebuild kit if used. I am also confused that the WG is set to 20+ psi. Expect to get a new WG or blow the hell out of your engine. With the rebuild kit and a new wg.. you'll be better off getting a more decent turbo. Also expect to get custom pipes as it looks like this is a different flange than the T3 that the kits come with. I am guessing:
Rebuild ~200-500
WG ~200
Welding to make 1 off turbo mani ~300
+ $$ whatever for the turbo

So, given this thing is good for an engine making 235 and 29+ psi, you can probably guess that an engine with 160hp will struggle to turn it. You may have major lag. Seems like a bad idea to me.

Get a T3 kit like everyone else.

[MrMazda92]

I'll keep that in mind, thank you for your input and research.

[wytbishop]

In general it works like this...

*1atm (1 atmosphere of pressure) at sea level is 14.7psi. As eleveation increase the relative pressure of 1atm decreases as the air gets thinner.
*In an unpressurized (i.e. naturally aspirated) engine the pressure of the air ENTERING the intake is approximately atmospheric.
*Combustion is a chemical reaction. The energy released in the reaction is directly proportionate to the mass of fuel burned.
*To burn more fuel you have to stuff more air into the engine.
*Now think about a/f ratio. Ideally you would like the mass of air to be 14.7 times the mass of fuel.
*Neglecting all other variables (and this is a massive generalization) if you increase the intake pressure by 10% this will increase the mass of air entering the engine by 10% and the amount of fuel you can add by 10% and the energy released during combustion by 10% .

Sooo...if you see 7-8psi boost (measured at the intake manifold) you are increasing the air pressure entering the intake and the mass of air and the mass of fuel and the energy released by 50%. Of course there are losses and you have to select a turbo whcih is capable of making that amount of boost...etc. but you can guestimate that if your engine is making 130hp n/a and you add 15psi boost you will make something like 220hp after considering losses to heat and other issues.

Now the boost snobs will pick my explanation apart...but that's the science in a nutshell.

[Ryan]

I don't understand how some of you say PSI is irrelevant.

As long as the CFM of the turbo at your desired PSI isn't less than the engine demand, CFM is irrelevant. If your turbo could do 120 PSI at 20 CFM (maybe 12A air compressor) then yeah, PSI is irrelevant because your engine draws more than that at idle.

A turbo, or different turbos can't do different CFM's at different PSI's at the same RPMS's, unless of course its incapable of that CFM or PSI.

The way I see it, the only REAL difference would be in the inertia of the turbo, as in the bigger one takes longer to spool. The correct turbo would spool fast enough to get you into boost around 3-4k, and hold/increase it till 7.5.

[MrMazda92]

@Wytbishop, thanks a TON!! That was concise and cleared up several of my questions!!!
@Ryan, do you know of any turbos that are small enough to fully spool by 3-3.5k, and will hold all the way to recline?

[RS_OBD'oh_2]

A T3 - or T3 hybrid would be the most common turbo for your set up. It's one of those tried and true turbos on the KLs. This is largely due to fack that the turbo piping kit will allow the T3 frame to bolt directly up. There is nothing wrong with going outside the box, but expect to pay big bucks to do so. There are too many other options to mention.

Look for your HP goal, after you have your power goal, find a turbo that will support that goal. This selection is not done with PSI, every turbo has a specific hp range. If you go too far above that range you will have massive lag and poor lower end. If you go below that range, your turbo will spool early and you will loose out on top end power.

-All this information you should already know. If not, you should be doing lots of independant reading to catch up.

I am sorry to anyone who read my last post... I did more typing than thinking.

[MrMazda92]

Thanks RS, I'll look into that again. Quick question though, the benefit of the t3/t4 hybrid is a smaller housing isn't it? I knew about the Bolton piping, I'll start reading up on the t3s and t4s. Thanks for the help everyone!