TT Conversion Revived

[911TT33]

Hey guys,

I’m reviving my ‘89 Carrera (3.3L) TT conversion after a very long hiatus (due to other family and home renovations projects priorities taking over the 911 works).

Anyway, I have a few questions for you guys who have BTDT 😁

I’m using modified 993TT heat exchangers because I want to retain my heater. I’m using rebuilt hybrid K16/16Gs with high pressure 1.2bar wastegates. Yes, there are better BB options out there, but for now I’ll be using these hybrids.

Now, I want to pump the turbos oil returns back into the oil tank, via a TurboWerx Exa scavenge pump. Where’s the best spot to tap a -8AN port on the oil tank?

Yes, I’ve considered pumping it into the engine breather plate at the top rear of the motor but I just cannot get access to it, and I don’t really want to drop the engine by myself in my garage.

Unless I remove my intake manifolds to get acces to it? Seems like a big job! 🙄

OR, another option is I just pump the turbos oil back into a -8AN port that’s tapped onto a lower valve cover? I have some really nice Hargett billet lower valve covers (which are tapped for the upcoming twin-plug conversion), so before I install those I can get a -8AN port installed on the lower left valve cover easily enough.

Advice greatly appreciated from all you turboholics 👍🏼

[quattrorunner]

The breather cover is simpler in the long run if you ask me. you can remove it and do the work on it/clean it easily plus from memory it's actually a better place for that hot unfiltered oil to re-nter the system.
You can do a "partial engine drop" easily.

[911TT33]

Originally Posted by quattrorunner

You can do a "partial engine drop" easily.

Cool. Is there a HOWTO I can refer to? 😁

[quattrorunner]

Simply put a jack under the engine/transmission and loosen the engine and trans mounting bolts till it's weight is on the jack (take care that you have it all well balanced and safe) lower it till you have room to get back there. This will give you at least 4" more than without the drop.
You'll want the drop to be primarily the engine rather than the trans. This means the engine will tilt down rather than drop straight down.

[quattrorunner]

It would be nice if you have a helper. The transmission wont drop at the front of it as it's still attached to the shifter.

[911TT33]

Originally Posted by quattrorunner

It would be nice if you have a helper. The transmission wont drop at the front of it as it's still attached to the shifter.

Thanks for the tip.. I’ll definitely look into this option.

I’ve seen other conversions where the oil from the turbo is dumped into a port welded onto the lower valve covers. This is an easier option for me since I’ve got the new valve covers boxed up and can send them out to get a male -8AN weld-on fitting welded on.

Then it’s just a short -8AN oil line from the TurboWerx pump to this port. Planning to mount the scavenge pump to the torsion tube cover using U-bolts. Plenty of airflow to keep it cool too.

[quattrorunner]

Ya if the turbo is higher it's a good option cheaper too

[911TT33]

Originally Posted by quattrorunner

Ya if the turbo is higher it's a good option cheaper too

Turbos are low due to 993TT headers placing them too low for gravity drain, thus the electric pump to scavenge the oil and pump it back into the motor, somewhere.

Actually, might look into a M20 x 10AN banjo bolt at the engine oil drain port, and have the TurboWerx pump push the oil back into that port?

[Rodsrsr]

Originally Posted by quattrorunner

The breather cover is simpler in the long run if you ask me. you can remove it and do the work on it/clean it easily plus from memory it's actually a better place for that hot unfiltered oil to re-nter the system.
You can do a "partial engine drop" easily.

This is what I did.

[911TT33]

So I’m looking at exhaust configurations for my TT build and am leaning towards something like this:



I’m just not sure whether I go with 2.5” tubing or 3.0”.

I don’t want it to drone on the FWY and I don’t want it obnoxiously loud, so I’m leaning more towards a 2.5” system. I believe it’ll flow enough for the power levels I’m expecting, which is around ~550HP @ ~1.2 bar.

What do you guys think?