Nissan 370Z Forum - GTM Garrett kit vs MHI TT kit

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GTM Garrett kit vs MHI TT kit

Forgive me if this has been asked but I couldn't seem to find it anywhere.... I'm pretty convinced that I'd like the Garrett turbo kit because of the quicker spooling capability, but I don't like that you have to tap the oil pan..... Anyone know if you can use the new larger oil pan that comes with the MHI kit on the Garrett kit?
Thanks
Ross

Or maybe even easier, get the Garrett turbos with the MHI kit?

Yes that has been answered on the MHI Kit thread....Sam Said that you can go with the MHI kit and if you wanted to switch to Garret turbos later in the future you can still use the same setup of the MHI kit but all you gotta do is just switch out turbos. Hope this helped out :)

if you like the garret kit, there are a couple guys selling them in the classifieds and you can order the oil pan separately.

It's not a given that the Garrett kit will outspool the mhi kit. The 16gs will probably be as responsive as the small GT28, if not more so.

The 16gs will fall flat out on the top end tho while the gt28s will keep on "sucking"

Oh, I agree completely. I was just addressing his concern about responsiveness.

From Sam

Quote:

Originally Posted by SAM@GTM (Post 2331527)

Yes, it is possible and will be available for sale separately. You can mount the pan with the Garrett kit to get more volume. However, we don't recommend using the returns on the oil pan with the Garrett kit since the Garrett turbos are a lot more sensitive to oil return line. We have extensive experience with Garrett turbos and even per Garrett's recommendation, the oil return needs to be above the oil level.

Bear in mind that we didn't wait until now to do an oil pan out of laziness or to make installing the original turbo kit harder. There is a technical reason for requiring drilling of the upper pan for the oil returns on the Garrett kits. Putting the oil return in the lower pan drastically increases the chances of developing a smoking issue. Basically, the oil will go out the turbine shaft seal into the exhaust instead of into the pan. Keep in mind that ball bearing turbos require just a fine mist of oil to lubricate the bearings and when it comes out of the bearing section that is spinning at 50,000 - 130,000 rpm, it is very frothy and does not flow very well compared to liquid oil. This is why the return needs to be above the oil level: to give the return oil enough room to flow out of the line and calm down.

This is not an issue with the Mitsubishi journal bearing turbos since they require much higher oil volume and pressure to support the journal bearing riding on a film of oil. That is why we can use the oil pan on this kit.

Sam

I don't see why you would have any issues spooling 18g or even 20g TT's quickly. Ball bearing does not equate to faster spool directly. There are many factors involved. I don't have any issues with lag in my situation.

If you can find someone with a Greddy TT kit in your area, get them to take you for a ride. That will give you a general idea of how 18/18/20g twins will work out with GTM's application.

EDIT: for spelling errors

Getting the Garrett kit for "quicker spooling" is, to be honest, about the last reason you should get that kit. It costs a lot more, is a lot harder to install and truthfully only worth doing if you're going to build the engine and go for big power.

Go with 16g's or 18gs, you'll spool just fine and have plenty of power for the stock bottom end.

Please don't take this the wrong way but tapping the oil pan is one of the lesser invasive things you're doing to your car going TT. FWIW I don't think it should be the deciding factor between which kit you get.

Don't they offer the Greddy oil pan? No tapping involved unless you want to.............

^Read my post above.

Yeah SPOHN is right, still need to drill the top

Quote:

Originally Posted by SPOHN (Post 2393189)

^Read my post above.

We must be talking about different products. The one I have has ports for oil return.

Quote:

Originally Posted by roplusbee (Post 2393546)

We must be talking about different products. The one I have has ports for oil return.

...

What the thing he quoted saaaaaays, is that you need to have the return be in the UPPER oil pan so that it pours out into the sump above the oil level.

Presumably because the backpressure of pumping into the oil lower in the sump (below the oil level) slows the flow and causes pressure buildup in the turbo cartridge, causing oil to seep into the turbine/compressor housing and cause smoking.

Put the dump above the oil line it just splashes out into the sump, or sprays onto the crank or whatever, and doesn't seep past the turbo's seals.

To test this phenomenon, next time you're at a restaurant, blow into your straw. Notice how much pressure it takes to blow bubbles with the straw at the bottom of the glass? Then pull the straw out and blow into it without being inside the drink. Big difference, huh?

Deeper the straw is, harder it is to blow the bubbles out. (Until you get a good stream of bubbles going, but that's because you're blowing a gas into a liquid and the bubbles will create a cavity thus reducing the pressure on the outlet of the straw... Just pretend that resistance doesn't go away, as it wouldn't if you were blowing liquid into liquid...)

I'd consider tapping the head to be more of an issue than tapping the oil pan.

Garret for ballers
MHI for everybody

Quote:

Originally Posted by G37sHKS (Post 2393705)

Garret for ballers
MHI for everybody

FI for ballers
everything else is for non-ballers