Compounds finally done... Now the real battle

[TRUBBS]

Hey in that third pic, you did put a nut on that head stud? LOL

Looks like it does have a nut?

 

[Marty]

Hey in that third pic, you did put a nut on that head stud? LOL

LOL its there but looks like its missing.

 

[PowerstrokeJunkie]

F you both! looks like a flush-top H-11 without a nut!

 

[silverpsd_06]

yes it has a nut i personally stuck that bitchh on there :slap:

 

[PowerstrokeJunkie]

Would you agree in the *picture* it looks as if it's missing? That much of the thread even on arp's don't stick up past the nut. Unless you had it halfway in the block

 

[silverpsd_06]

When i put them in the motor I took them as far down as I could some went further than others and no I did not torque them down any with the Allen head

 

[young7.3]

VIDEO!!!!!

 

[silverpsd_06]

See senior working late I'm trying to get one for you guys..

 

[Dieselboy.]

Video x2......

Silver, do you think there is anyway to accommodate 5" exhaust out from the the factory location ?

Im not fond of the exhaust in the wheel well.

And its been a bit since I went through the thread, are you wastegating both chargers or just the high pressure ?

 

[TRUBBS]

Would you agree in the *picture* it looks as if it's missing? That much of the thread even on arp's don't stick up past the nut. Unless you had it halfway in the block

i agree, took a bit of looking to make sure it was in fact their, but then again im looking on my iphone.

 

[silverpsd_06]

The only way you may be able to do it is reduce down to four inch and squeeze it in between the oil fill and the heater box but that particular charger would have to sit up 3-4" higher than what it is set at in the pictures, which would mean changing the way it went into the intercooler and making it almost a straight drop right out with two tight 90's.
Personally if i was going to do that i would reccomend cooling both stages make it easier to fit the atmo in the wheel well. Always easier to run a smaller charger than what i did the damn thing is massive and took a near act of congress to get jammed in there.

 

[Charles]

I ran a 4" downpipe in the factory location with a 3" to 3.5" intermediate leaving the charger in the factory location and heading through that same basic area, headed up to the first stage charger.

There was -.125" of extra space between the pipes. They are both ground down a little where the V-band of one passes the other pipe.

Downpipe on the left and intermediate on the right. The wastegate port later hooked around and dumped into the intermediate just past the 3 to 3.5" transition.



My next set of compounds will have both chargers hung off the right side of the engine with nothing but open valley to work with.

 

[silverpsd_06]

Ya Charles' first stage is hung much higher than mine because of no a/c compressor to compensate for. Just out of curiosity Charles when does your primary charger start to light??? And can you run through the math to calculate total boost through the compound system? I read your post on psn but didn't quite follow the math you were using

 

[Dieselboy.]

I think I could live without AC lol.

Looking good Charles, I would like to do mine like you have. Your basically wastegating the high pressure at the collector before it enters the turbine housing correct ?

By dumping into the intermediate pipe that would aid in getting that big charger going I presume ?

 

[Vader's Fury]

I believe charles wastegate is welded to the exhaust housing on his 38r. And yes you dump that into the intermediate pipe to assist in lighting off the big charger. If you were to vent it to atmo you would basically just be wasting all that energy.

 

[Charles]

Ya Charles' first stage is hung much higher than mine because of no a/c compressor to compensate for. Just out of curiosity Charles when does your primary charger start to light??? And can you run through the math to calculate total boost through the compound system? I read your post on psn but didn't quite follow the math you were using

With the GT47 the first stage would run 2 to 5 lbs pretty much any time the truck was moving along. No perceivable difference in one charger vs the other.

Even with the 94mm GT55 it still ran a few lbs of boost just cruising along at 50mph or so. It is a much bigger charger on both the hot and cold sides though, and did have a noticable delay between when the 38R would hit the stop set in the PCS and when the 55 would jump on up to 30 or so. Even still, I have little doubt that the majority of this was due to my having the wastegate control table holding the 38R gate closed for too long, not allowing sufficient drive to power the 55 until the 38R was all the way at max allowable boost before the gate would dump anything to the 55.


As for calculations, what do you want to know? I can probably help.

 

[silverpsd_06]

The second stage at 14.7psig would be running a PR of 2:1, but the first stage at 25psig would also be running a PR of 2.7:1 (25psig + 14.7psia / 14.7psia).

And when you compound, the first stage would take in air at 14.7psia and compress it 2.7 times, yielding 36.69psia (25psig). The second stage then takes in this pressure of 36.69psia and compresses it 2.0 times, yielding 79.38psia (64.68psig).

So in reality, a pressure ratio of 2 from the second combined with 25psig from the first stage results in just a hair under 65psi on the manifold.
This is your post from psn chuck.. Now if my math is correct the first stage is making 25psig or your 2.7 pressure ratio =39.69 psia, now the secondary takes in 39.69 and compresses it twice so that would equal 79.38psia which would yield 64.68psi at the manifold? Is that correct? Your example was different I didn't know if it was just a typo way back when or there was some reason I was not seeing why it came up different for me on the first stage math?

 

[Charles]

The second stage at 14.7psig would be running a PR of 2:1, but the first stage at 25psig would also be running a PR of 2.7:1 (25psig + 14.7psia / 14.7psia).

And when you compound, the first stage would take in air at 14.7psia and compress it 2.7 times, yielding 36.69psia (25psig). The second stage then takes in this pressure of 36.69psia and compresses it 2.0 times, yielding 79.38psia (64.68psig).

So in reality, a pressure ratio of 2 from the second combined with 25psig from the first stage results in just a hair under 65psi on the manifold.
This is your post from psn chuck.. Now if my math is correct the first stage is making 25psig or your 2.7 pressure ratio =39.69 psia, now the secondary takes in 39.69 and compresses it twice so that would equal 79.38psia which would yield 64.68psi at the manifold? Is that correct? Your example was different I didn't know if it was just a typo way back when or there was some reason I was not seeing why it came up different for me on the first stage math?

I don't see the disparity.


If the above is a quotation of one of my posts then from it we have the following:


First stage: PR = 2.7:1, outlet pressure = 36psia

Second stage: PR = 2.0:1, outlet pressure = 79.38psia



And in your above example you had exactly the same values. I am not seeing the disparity.

 

[silverpsd_06]

It's just a typo then I saw where I came up with 39 and some change for the first figure and you came up with 36 didn't know if I missed something along the lines...

 

[Charles]

It's just a typo then I saw where I came up with 39 and some change for the first figure and you came up with 36 didn't know if I missed something along the lines...

I didn't even see that you had 39 instead of 36. Yes, it must have been an equally focus lacking moment on my part before. The correct value is what you posted above. I must have used the correct value in the calculations but for some reason typed 36 instead.

You are correct in your work.