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The 38r wastegate comes set way to loose.

If your running 175/80 injector or smaller tighten it all the way down.

I'm running stock injectors. AD I believe. I didn't think the Garret BB 38r was adjustable.
 

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GTP-38R

What was the issue with the 38r wastegate? I will say that my stock turbo with the bighead wastegate boosted up to 26 lbs. The 38r barely reaches 22 lbs.
I'm running stock injectors. AD I believe. I didn't think the Garret BB 38r was adjustable.
The 38R uses the same wastegate controller setup as the stock turbo.
The only notable differences in the 38R, aside from the obvious BB cartridge, are Ported Compressor Housing with larger Exducer, and a 1.00 A/R Exhaust Housing.
As a side note, my only gripe with the 38R is that they did not use the larger turbine from the van turbo.

When I first installed my 38R, I cranked the Controller (a Banks Bighead) all the way down. I was able to hit 42PSI regularly.

That said, I now have set my wastegate to 14PSI, and my truck runs MUCH better for it. When I was running 40+PSI boost, it was like my truck was running into a wall @90. When I backed my boost down, she pulled hard all the way to the rev-limiter.

Long story short, don't run stupid-high boost if you don't have the sticks to back it up. If you can't burn all that extra air, you're actually losing HP and performance compressing it.

ErnestEugene proved conclusively that a 7.3 with stock injectors can't burn more air than is in 12PSI of boost. I smoked a little too much @ 12, and upped it to 14PSI.


After i fitted my 38R i found the stock w/g actuator wasn't sufficient so i fitted this http://www.dieselsite.com/19995-2003ford73lpsdwastegatecontroller.aspx which is a mechanical w/g arm , i have more control over boost now.:thumbsup:
Googs,
I find the mechanical wastegate controller intriguing. However, I don't seem to be suffering any of the symptoms that it is supposed to solve. Probably due to my using the Banks BigHead instead of what came with it.
Even so, I may just have to pick one of those up and play with it...
 

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I found the W/G actuator on the 38R was a little weak, even though i was adjustable (not easy though) i went with the TM W/G just for the ease of adjustment.

I agree with you 14 - 20 psi is plenty for stock injectors with an 38R if you have a good flowing intake and are tuned.
 

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a stock truck boosts to 16 psi. im not sure who said the 7.3 only wants 12 psi on stock inejctors.

and the stock wastegate starts to open at 5-7 psi unless tightened anyways.

the reason for setting the wastgate lower on the stock turbo is to save the thrust bearings from too much side load.

38r is another story, it can handle up to small hybrids (238/100) with no issues with backpressure.
 

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a stock truck boosts to 16 psi. im not sure who said the 7.3 only wants 12 psi on stock inejctors.

and the stock wastegate starts to open at 5-7 psi unless tightened anyways.

the reason for setting the wastgate lower on the stock turbo is to save the thrust bearings from too much side load.

38r is another story, it can handle up to small hybrids (238/100) with no issues with backpressure.
Agreed. My stock turbo boosted 15-18 lbs unchipped and stock.

After the Big Head install, it went up to 21 lbs. Then I chipped it. 26 lbs+.

I think it is good to install gauges at first so you can see how your performance mods affect the readings.

I will say that I have less coal rolling out the tailpipe with the new turbo.
 

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ErnestEugene

a stock truck boosts to 16 psi. im not sure who said the 7.3 only wants 12 psi on stock inejctors.
ErnestEugene.
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.

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).
 

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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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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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