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GTP38R/ USA (Turbonetics) turbo comparison

12K views 20 replies 10 participants last post by  faster67 
#1 ·
I see alot of things said that may or may not be true about both turbos so I had my turbo shop get a USA turbo and do the comparisons, these are nonbiased specs, no opinions in the specs they are what they are.

GTP38R -- USA (TN)

Shaft DIA @ Joaurnal .400 .470

Shaft @ Shoulder .250 .313

Turbine Exducer 67.69mm 68.58mm

Turbine Inducer 77.47mm 78.74mm

Compressor Wheel
Inducer 65.91mm 60.96mm

Compressor Exducer 88.14mm 91.31mm

There is a larger Turbine wheel availible for the GTP38 with exducer of 69.85 and Inducer of 77.47.

Turbine housings availible for GTP38 include the 1.0 wg, 1.0 nonwg and the 1.15 nonwg, onlt 1.0wg housing for the USA turbo due to the larger turbine wheel.

He also said that this unit looks to be better quality then one we checked out about a year ago.


So there ya go, there is the facts, I will give my opinions later but will leave it at that for now.
 
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#2 ·
I am running the TN right now and like it... I will (WILL!) be Dynoing both when I get the Garret back. The only real issue I had with the Garret was the surge (and thats bad for me!) No issues with the TN unit other then the spool is somewhat slower and my EBPV brake is not working right ( I dont know if thats due to the turbo being larger in some way or if something is messed up on the valve)... I have a Dyno in town and will do both asap.
 
#4 ·
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I don't think that Garrett info is correct. Looks to me like you have mixed some van stuff in with the GTP38R stuff.

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I will double check if you like but that is all directly off a gtpr, the optional larger t wheel would be a van wheel.
 
#5 ·
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the optional larger t wheel would be a van wheel.

[/ QUOTE ]

That's what I thought. I also don't think that stock GTP38R turbine inducer measurement is correct. The van wheels and housings are different and should not be interchanged. You can put the van housings on the smaller wheels but they don't fit right. The GTP38R housings won't fit on a van wheel. Is that 1.0 non-wastegated housing for a van wheel or a GTP38R wheel? And BTW even though I don't know why anyone would want one, you left out the .84 WG housing as a option for the GTP38R.
 
#7 ·
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He also said that this unit looks to be better quality then one we checked out about a year ago.

[/ QUOTE ]

You think they've made some changes to the GTP38R recently? I just dropped mine in my truck last month. The stock turbo was a surge king on my truck, and the GTP38R hasn't come close to surging at all yet. I did have Bob Riley port the compressor housing, so that might have something to do with it as well. Maybe a combination of better initial quality and Bob's porting makes a big difference in whether or not these turbos surge. /ubbthreads/images/graemlins/shrug.gif

There's my rambling, take it with a grain of salt. /ubbthreads/images/graemlins/wink.gif
 
#8 ·
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The van parts are Navistar pieces,not Garrett's. I have the 2 non Garrett built by Garrett versions originally made.

[/ QUOTE ]

Do you have to have a hangover to understand this? I've read it several times and scratched my head from several different angles and still don't get it.
 
#9 ·
[ QUOTE ]
[ QUOTE ]
He also said that this unit looks to be better quality then one we checked out about a year ago.

[/ QUOTE ]

You think they've made some changes to the GTP38R recently?

[/ QUOTE ]

I thought his comment was about the other turbo.
 
#10 ·
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[ QUOTE ]
The van parts are Navistar pieces,not Garrett's. I have the 2 non Garrett built by Garrett versions originally made.

[/ QUOTE ]

Do you have to have a hangover to understand this? I've read it several times and scratched my head from several different angles and still don't get it.

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Ya gotta turn yer hat 'round backerds and stick yer tongue outta the corner of yer mouth when ya read that. /ubbthreads/images/graemlins/biggrin.gif
 
#11 ·
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[ QUOTE ]
The van parts (mentioned above are Navistar parts meaning Navistar owns the tooling and Garret just makes it specifically for Navistar ) are Navistar pieces,not Garrett's. I have the 2 non Garrett( Navistar 1.15 van turbos converted to BB) ) built by Garrett versions originally made for me for testing purposes.

[/ QUOTE ]

Do you have to have a hangover to understand this? I've read it several times and scratched my head from several different angles and still don't get it.

[/ QUOTE ]
 
#13 ·
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Well it sounds like you are saying the 1.15 housing for the GTP38R is the same as the 1.15 housing for the van turbo. Which turbine wheels do those two turbo's have?

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NO,they are not the same hence the above post. Garrett made their own version(smaller)because Navistar owns the mold and the rights to the original larger version.
I have the larger versions.
 
#16 ·
[ QUOTE ]
[ QUOTE ]
He also said that this unit looks to be better quality then one we checked out about a year ago.

[/ QUOTE ]

You think they've made some changes to the GTP38R recently? I just dropped mine in my truck last month. The stock turbo was a surge king on my truck, and the GTP38R hasn't come close to surging at all yet. I did have Bob Riley port the compressor housing, so that might have something to do with it as well. Maybe a combination of better initial quality and Bob's porting makes a big difference in whether or not these turbos surge. /ubbthreads/images/graemlins/shrug.gif

There's my rambling, take it with a grain of salt. /ubbthreads/images/graemlins/wink.gif

[/ QUOTE ]

No I was saying it looked like they made soem changes to the TN unit for the better.

The t/wheel on the GTP38r is the same as a GTP38, interchangable housings on those turbos, you could use the .84 off a stock truck 38 and put it on the bb.
 
#17 ·
[ QUOTE ]
[ QUOTE ]
[ QUOTE ]
He also said that this unit looks to be better quality then one we checked out about a year ago.

[/ QUOTE ]

You think they've made some changes to the GTP38R recently? I just dropped mine in my truck last month. The stock turbo was a surge king on my truck, and the GTP38R hasn't come close to surging at all yet. I did have Bob Riley port the compressor housing, so that might have something to do with it as well. Maybe a combination of better initial quality and Bob's porting makes a big difference in whether or not these turbos surge. /ubbthreads/images/graemlins/shrug.gif

There's my rambling, take it with a grain of salt. /ubbthreads/images/graemlins/wink.gif

[/ QUOTE ]

No I was saying it looked like they made soem changes to the TN unit for the better.

The t/wheel on the GTP38r is the same as a GTP38, interchangable housings on those turbos, you could use the .84 off a stock truck 38 and put it on the bb.

[/ QUOTE ]


BEAN,


So, are you saying the ATS housing will fit the GTP38R also?
 
#18 ·
[ QUOTE ]
[ QUOTE ]
[ QUOTE ]
[ QUOTE ]
He also said that this unit looks to be better quality then one we checked out about a year ago.

[/ QUOTE ]

You think they've made some changes to the GTP38R recently? I just dropped mine in my truck last month. The stock turbo was a surge king on my truck, and the GTP38R hasn't come close to surging at all yet. I did have Bob Riley port the compressor housing, so that might have something to do with it as well. Maybe a combination of better initial quality and Bob's porting makes a big difference in whether or not these turbos surge. /ubbthreads/images/graemlins/shrug.gif

There's my rambling, take it with a grain of salt. /ubbthreads/images/graemlins/wink.gif

[/ QUOTE ]

No I was saying it looked like they made soem changes to the TN unit for the better.
Obvious
The t/wheel on the GTP38r is the same as a GTP38, interchangable housings on those turbos, you could use the .84 off a stock truck 38 and put it on the bb.

[/ QUOTE ]


BEAN,


So, are you saying the ATS housing will fit the GTP38R also?

[/ QUOTE ]

Obviously I'm not Bean, but I know the answer...

No, the ATS housing will not fit on the GTP-38R. For starters, the Inducer opening would be too small. The way the compressor housing bolts to the turbo is different too.

Anyway, Other than that stuff the GTP-38R and ATS housing are of similar design, so even if it did fit, it would be a waste of money.

Hammer
 
#20 ·
So, since you guys are talking about comparing the two I have a quick question. I need a turbo for my truck. Im just wanting to go fast. Id really like to use the dp chip's higher tunes but Im afraid with the stock turbo. I never haul heavy loads, just a couple of dog crates every once in a while. I just want to add horsepower. I also want real good throttle response. So which turbo would I need for this application and who has the best price? Thanks in advance!
 
#21 ·
[ QUOTE ]
So, since you guys are talking about comparing the two I have a quick question. I need a turbo for my truck. Im just wanting to go fast. Id really like to use the dp chip's higher tunes but Im afraid with the stock turbo. I never haul heavy loads, just a couple of dog crates every once in a while. I just want to add horsepower. I also want real good throttle response. So which turbo would I need for this application and who has the best price? Thanks in advance!

[/ QUOTE ]

Someone from Corpus! I know someone locally that can help you out with the parts you want. You need to come hang out with the rest of the Corpus diesel guys sometime. We have videos and pictures from last weekend at the Nationals.

I haven't tried the Turbonetics replacement turbo, but my GTP38R ran 13.357 @ 98.95 and a 1.83 sixty foot with a 5psi launch in my crew cab 4x4 with 222,000 miles. This turbo hits HARD out of the hole.
 
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