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1998 Nissan Patrol Wagon RD28ETi
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95 Posts
Discussion Starter #1
I have a 1998 GU RD28ETi wagon. I was running a factory turbo (Gt1752s) with manual boost controller set at 18psi. I also run a Donator Speedbox. Needless to say the journal bearing factory turbo couldn't handle that much boost and it died a horrible death. Lots of oil and about 5mm of play in the shaft.

Now for the Good news (maybe). I swapped out the GU manifold for a GQ manifold (T25) and mounted a brand spanking new Garrett GT2554r on it. GT2554r specs are stock: 41mm compressor with .82A/R housing and 54mm turbine with .64A/R housing.

Now here is where my expectations were shattered. I now get maximum boost of approx 12psi. The boost doesn't move from zero until approx 2000rpm and max's at about 3200rpm. I did some research and found Mambatek do a smaller turbine housing - .42A/R (6cm) in a kit which I purchased.

Is there anyone here who has much tech knowledge about any changes in the boost rev range and max boost with this smaller turbine housing?
 

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Premium Member
1999 GU Wagon ST RD28
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439 Posts
I have a 1998 GU RD28ETi wagon. I was running a factory turbo (Gt1752s) with manual boost controller set at 18psi. I also run a Donator Speedbox. Needless to say the journal bearing factory turbo couldn't handle that much boost and it died a horrible death. Lots of oil and about 5mm of play in the shaft.

Now for the Good news (maybe). I swapped out the GU manifold for a GQ manifold (T25) and mounted a brand spanking new Garrett GT2554r on it. GT2554r specs are stock: 41mm compressor with .82A/R housing and 54mm turbine with .64A/R housing.

Now here is where my expectations were shattered. I now get maximum boost of approx 12psi. The boost doesn't move from zero until approx 2000rpm and max's at about 3200rpm. I did some research and found Mambatek do a smaller turbine housing - .42A/R (6cm) in a kit which I purchased.

Is there anyone here who has much tech knowledge about any changes in the boost rev range and max boost with this smaller turbine housing?
can't comment on the GT2554, but the GT2052V which is in the ZD30 works great with the RD28. I get 12psi boost at 1500rpm and 18psi at 1800rpm. These turbos are designed to run 18-22psi boost all day. They can be purchased with billet compressor and ceramic housing for $649 from ebay
Control the VNT with a Digibooster from tuning-diesels.com to give you full control of how the turbo performs.
Just make a 'J' pipe out of steam pipe from manifold to a suitable position as per pic..
See pic of easy setup...

514459
 

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Registered
1998 Nissan Patrol Wagon RD28ETi
Joined
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95 Posts
Discussion Starter #3
can't comment on the GT2554, but the GT2052V which is in the ZD30 works great with the RD28. I get 12psi boost at 1500rpm and 18psi at 1800rpm. These turbos are designed to run 18-22psi boost all day. They can be purchased with billet compressor and ceramic housing for $649 from ebay
Control the VNT with a Digibooster from tuning-diesels.com to give you full control of how the turbo performs.
Just make a 'J' pipe out of steam pipe from manifold to a suitable position as per pic..
See pic of easy setup...

View attachment 514459

Any more pics of the back end
 

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Premium Member
1999 GU Wagon ST RD28
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439 Posts
Here's the J pipe


514479
 

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Premium Member
1999 GU Wagon ST RD28
Joined
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439 Posts
Slight mod to the guard, but if you get the angle right, no need to do this...
 

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Premium Member
1999 GU Wagon ST RD28
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439 Posts
Old turbo vs new - bit of size difference...

514480
514481
514482
 

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Premium Member
1999 GU Wagon ST RD28
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439 Posts
Ive tidied up all the silicone joiners and pipes. These photos were taken April 2017. The original concept was experimental. But it has proved an excellent conversion
 

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Premium Member
1999 GU Wagon ST RD28
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439 Posts
All the plates were laser cut. I have the drawings available if anyone wants them
 

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Registered
1998 Nissan Patrol Wagon RD28ETi
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95 Posts
Discussion Starter #9
Looks pretty good. Looks like your still using factory intercooler and factory airbox. I've changed all my setup. I have a homemade vac tank on the firewall, then 2 alloy water tanks/reservoirs, Then stainless airbox with 8 inch x 5 inch pod filter. So I don't have the room to high mount a turbo like yours.

So I changed out the turbine housing from a .64A/R to a .42A/R. Looks like it did nothing to increase max PSI or lower the rev range of boosting.

I think its time to just bite the bullet and go for a supercharger mod. That way I can get Boost at 1000rpm. Modify an intake manifold to mount a supercharger. make an idler pulley bracket to run longer double drive belts. Then I can ditch the turbo manifold and put on a set of extractors into 3 inch exhaust. Probably won't need the top mount intercooler either.
 

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Registered
1998 Nissan Patrol Wagon RD28ETi
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95 Posts
Discussion Starter #10
Took my car for a dyno and testing to see if there was any reason for the lack of boost. Looks like the GT2554r turbine is too big for the RD28.

The dyno shows peak power and torque with donator speedbox disconnected and connected. However there was no other tuning posible to lower the boost range and increase max boost.
20200108_164949.jpg
 

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Premium Member
1999 GU Wagon ST RD28
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439 Posts
Be interesting to plot the boost on there too, but yeah, doesn't look real driveable...
 
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