Where to get 3.5 SS downpipe? - Page 4 - Diesel Forum - TheDieselStop.com
'99 & up Upgrades and Aftermarket - 7.3L Engine Upgrading or adding OEM or aftermarket equipment to your 1999-Up Super Duty or Excursion with 7.3L Power Stroke diesel engine. Please confine discussion of topics in this forum to those items that are specific to the 7.3L Power Stroke engine.

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post #46 of 48 (permalink) Old 06-30-2015, 11:55 PM
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Originally Posted by blue99stroker View Post
a stock truck boosts to 16 psi. im not sure who said the 7.3 only wants 12 psi on stock inejctors.
He was very active on a number of diesel sites (just not here) up until about mid-2010.
If you are interested in the "why" behind how stuff works, Google his name on a 7.3 topic that interests you.
As a former engineer, he had a very analytical (and mathematical) approach. I don't always agree with his conclusions, but his math is impeccable.

Originally Posted by blue99stroker View Post
38r is another story, it can handle up to small hybrids (238/100) with no issues with backpressure.
I'm not sure what you mean here... If you are saying that the 38R doesn't suffer bearing wear/failure due to side loading at high pressures, then I am inclined to agree.

If you are saying the exhaust side of the 38R breathes freely enough to not develop backpressure, then I strongly disagree. Even with moderately-hard driving, I regularly see my back-pressures peg the guage. I thought the 1.0 A/R Exhaust housing was going to solve that problem, but it didn't. What is actually needed is a larger turbine, and the correspondingly larger hole for it.

The van turbo has a 69.85mm exducer, as opposed SD 38 & 38R which both share the same 67.69mm turbine. 2.16mm doesn't sound like much, but after accounting for the center-shaft volume, it is almost a 20% enlargement in the hole exhaust gasses have to escape through.

I've considered many times obtaining a spare 1.0 A/R Exhaust housing and boring it out to 70mm and see if the truck would still run...
And to clarify, by "run" I mean RUN (like a scalded ape).

01 Excursion Limited, GTP38R, 4" Down & Exhaust, Programmed, Custom Dayco 1100 RPM TC, Harpoon, ZooDad, 3-way Headlights, fog-light only / fog-light with high-beam mod, F250 rear springs w/ Bags, 30mm Rear Sway Bar, AIH Delete, IH Water Pump, 205 Thermostat, E99 (all metal) IC, 6.0 (31 Row) Trans Cooler, Nippondenso Starter, Odyssey 65-PC1750T Batteries, Motorcraft GL-360 215A Alternator

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post #47 of 48 (permalink) Old 07-01-2015, 01:35 AM
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i guess i should have said it can handle more abuse/higher backpressure than the journal bearing stock SD turbo.

The stock turbo hates any backpressure over 1:3. (30+ psi of boost 60-90 psi backpressure)

The van turbos are pretty tough. if i ever upgrade injectors i will get a van turbo over a 38r. My friend has a van turbo and is around 425 rwhp and sees perfect 1:1 backpressure ratio, no issues with egts either. But like you said that larger turbine wheel really helps exhaust flow.

i saw a 1.0 exhuast housing on ebay the other day. it was used and looked to be in good shape.
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post #48 of 48 (permalink) Old 09-22-2016, 06:15 AM
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Magnaflow Part# 15459 SS 3.5 downpipe and extension. I am getting this and am going to wrap it for sure around trans lines.
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  Diesel Forum - TheDieselStop.com > 1999-2007 Ford Super Duties > '99 & up Upgrades and Aftermarket - 7.3L Engine

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