Garrett Gt2860r-7 Oil Drain Tube

[TXSquirrel]

Hi folks, R32 noob here from Texas.

I am looking to replace the old stock turbos in my 1990 GTR. My ideal turbo is to have the least lag at low end for good street driving, and I do not care for high output. After comparing compressor maps, my eyes are on Garrett GT2860R-7's at the moment. If you folks know another turbo that is less laggy and has better low end power please share!

So from my search I find the oil drain outlet on -7's is smaller than stock, so what is a good solution? I find a matching oil drain tube from GCG, and I am curious if anyone has experience with that?

My plan is to source the turbos stateside with installation gasket kit from Kudos.

Thanks in advance.

[Sinista32]

Locals prefer -9's if your staying with twins

If your prepared to entertain a single then something like a Precision 6262 twin scroll

Go single - technology has moved on since the -7's, -9's

Oh and use adjustable cam gears. Keep the stock cam shafts or get the Type R

Edited April 4, 2016 by Sinista32

[sneakey pete]

The costs of swapping out to -9's is way way less than the costs of going a single if you're only after low 300kw's, so suggesting a single swap is probably a bit out of place in this case.

but yes, -9's.

Not 100% sure on the oil drain but i'm sure someone will be able to help you out there.
Note you'll need a oil feed restrictor also. I'd suggest getting braided oil feed and water feed and return lines while you're changing out the turbos, makes everything so much easier.

[TXSquirrel]

Thanks for the responses.

My plan is to keep my entire car as stock looking as possible, so twin setup is my choice. I have thought about rebuilding stock turbos, but I decide to indulge myself with a little modernization of ball bearing.

I will get Kudos' install kit with HKS oil restrictor. But I am still on the fence between new OEM drain hose and braided lines. Braided lines are too eye catching (I am probably the first person to see that as a negative.) If I use them I may pay a little extra to get black braided lines.

I am on the fence as well between -7's and -9's. As far as I know the turbine side is absolutely identical - wheel and housing - and so is the compressor housing, with the only difference being the compressor wheel.

But that is where I get confused. Compared to -9's, -7's has slightly larger compressor wheel but interestingly smaller trim. By looking at both compressor maps they seem to tell a totally different story. The -7's shows a much lower surge limit, starting at 56,000 rpm as compared to 75,000 of the -9's. The -7's efficiency suffers as a result, with only a small 71% island shifted to the left, while the -9's has a large 75% center island that covers majority of -7's would be 68% island.

-7's

-9's

So my conclusion is that -7's has better low range while -9's has better mid and upper range. But the efficiency of -7's is so inferior compared to -9's that its peak 71% island is still within the 72% island of -9's. And that efficiency is what keeps me on the fence...

Edited April 5, 2016 by TXSquirrel

[TXSquirrel]

Wow totally off topic here

So here is a picture of factory drain tube modified to fit the smaller oil outlet pattern of -7's. Provided by another member on Nico forum.

And here is a picture of factory gasket over -7's oil outlet, also modified.

Is there a better solution than hacking off the factory drain tube to fit the -7's? (or -9's since they both have same smaller oil outlet)

[Piggaz]

Thanks for the responses.

My plan is to keep my entire car as stock looking as possible, so twin setup is my choice. I have thought about rebuilding stock turbos, but I decide to indulge myself with a little modernization of ball bearing.

I will get Kudos' install kit with HKS oil restrictor. But I am still on the fence between new OEM drain hose and braided lines. Braided lines are too eye catching (I am probably the first person to see that as a negative.) If I use them I may pay a little extra to get black braided lines.

I am on the fence as well between -7's and -9's. As far as I know the turbine side is absolutely identical - wheel and housing - and so is the compressor housing, with the only difference being the compressor wheel.

But that is where I get confused. Compared to -9's, -7's has slightly larger compressor wheel but interestingly smaller trim. By looking at both compressor maps they seem to tell a totally different story. The -7's shows a much lower surge limit, starting at 56,000 rpm as compared to 75,000 of the -9's. The -7's efficiency suffers as a result, with only a small 71% island shifted to the left, while the -9's has a large 75% center island that covers majority of -7's would be 68% island.

-7's

-9's

So my conclusion is that -7's has better low range while -9's has better mid and upper range. But the efficiency of -7's is so inferior compared to -9's that its peak 71% island is still within the 72% island of -9's. And that efficiency is what keeps me on the fence...

Flip a coin. Generally, guys make a few kw of each other given the same mods.

Go through the RB26 results thread.

[TXSquirrel]

Not sure what happened to those pictures previously, but they have been updated here.

So my original question remains, is there a better solution than hacking away the factory drain tube to fit these Garrett's?

Wow totally off topic here

So here is a picture of factory drain tube modified to fit the smaller oil outlet pattern of -7's. Provided by another member on Nico forum.

And here is a picture of factory gasket over -7's oil outlet, also modified.

Is there a better solution than hacking off the factory drain tube to fit the -7's? (or -9's since they both have same smaller oil outlet)

[Shoota_77]

You can buy alloy billet AN10 fittings that replace the factory drain tubes. That way you can go a fancy braided hose if you wanted to. There's not much room to play with under the turbos between the turbo outlet and the block fitting to be stuffing around with AN fittings though.

[Piggaz]

http://gcg.com.au/turbo-parts/oil-drain-fittings/garrett-gt-38mm-hole-centres/oil-drain-kit-garrett-gt-gtx-series-rb26dett-detail

Buy these.