Me, too. IMO, high drive pressure can only take its toll when it's significantly higher than boost, which is a bad situation to begin with.

If you get DP much higher than MAP, then you'll have flow reversion, and really high EGTs from the lack of fresh air.

IMO, the engine doesn't care if you are forcing high pressure air in from the exhaust or the intake-- both are somewhat capable of increasing cylinder pressures.

That said, the relatively inert exhaust wouldn't really support combustion like fresh air would, hence it can't contribute as much to peak cylinder pressures.

I personally think that boost pressure is a bigger factor than DP, but neither is as big as timing...

JMO

 

I had noticed with the boost elbow that the boost would take longer to drop off between shifts. This is why I was wondering if a boost elbow would benifit or not?

 

Well clutch1,since this thread started out about the 62/14, one would think thats the turbo were talking about
If we were talking about the 71 series, your information would be usefull here.

 

Don't drink the hateraide! Good info clutch1 =P

 

Hey Tony, the 62/14 can be in the 65 or 71 series, so their both applicable here.

 

Yes I know. But this thread is about the HTB2 62/14.
The HTB2 and the HT71 turbos are two completly different tubos.
All that was said in my 1st post was to turn the boost up a little, because the 40psi from HTT, just doesnt seem to clear the smoke to well IMHO.
Then, of course the thread went haywire from there. It turned into a who seems to know more about turbos.

 

i didnt catch where he mentioned it was an HTB2 must have missed it, sorry I think.

 

Nobody mentioned HTB2 till clutch1 did. Not arguing just clarifying.
Turbine size was never specified.

The reason why you didn't catch it was because it wasn't there to catch.
So you didn't miss it and no need to be sorry.

 

Don't have your knack for analysis...but I think that point could be argued either way!
For example.. What about the temp of the reverted exhaust gas at say WOT? Wouldn't that increase cylinder air temp and therefore cylinder pressure?

Probably a subject for a different thread!

RJ

 

Since we're off-track already...

Let's think of it inthe context of combustion energy. What are the components of energy? Well, there's potential energy, kinetic energy, and chemical energy. Chemical energy is really a form of potential energy (which is the diesel fuel).

Anyway, let me head that long post off at the pass and just head down this route: does EGR increase power or decrease it? It decreases. Does cooler intake air increase power or decrease it? To the point where efficient combustion still occurs, it increases it.

Power output is a direct function of cylinder pressure, so hotter air means less peak pressure (which is all we care about with HG life).

JMO-- I'd have to try pretty hard to actually "prove" it, and I'm not sure I could.

 

Glad to hear you like it i was considering almost that exact same setup. but what about your tranny is it stock?

 

Neglecting the fact that high drive pressures can push open the wastegate flapper, a boost elbow is poor way to go. As stated it strictly restricts the flow to the wastegate line through a tiny orfice, BUT if the boost pressure was there long enough the pressures on both sides(of the elbow) would balance and the wastegate would open. But most of the time the boost is not there long enough, hence why they work.

The best way to adj. wastegate IMO, is what I did. Use a adj. pressure switch wired with a 3 way manifold valve in your wastegate line so when your below your set point the wastegate side is open = 0 pressure, then with an instant of breaking your set point full pressure hits the wastegate opening it instantly. Put the switch in your cab and adjust on the fly!!

Just my $.02
tim.

 

The adjustable (and non adjustable) elbows I've seen have a bleed off hole so the pressures won't balance out.