Porsche owner considering TT RS - Newbie Questions

[granteg]

Hi - I have a few questions about the RS, please:

1. Are the US-spec seats the same as those on the S4 3.0TFSI (they look a little different on the Audi site)

2. Is the 2.5TFSI using a dry-sump oiling system like the R8 or regular wet-sump?

3. Are there any aftermarket products to improve steering feel?

4. Is there a stiffer rear swaybar available to give a more oversteer cornering attitude (does aftermarket Haldex controller achieve that)?

5. Does the car survive long sessions at the track without overheating the engine or brakes?

6. Any expected changes for MY 2013?

Thank you!

[JohnLZ7W]

1. I'm not sure if the S and RS seats are the same. I think the RS seats get larger/tighter bolsters.

2. It's a regular wet sump

3. Yes, there are bushing kits available that increase caster that are supposed to also increase steering feel. Superpro makes one and Whiteline does also.

4. There are a couple of options for rear swaybars and increasing spring rates should also achieve the same goal. Uprated haldex controller probably isn't going to do too much since the RS already has a sport controller.

5. The 2.5T does run hot but I've never seen any issues with overheating the motor on the track, and that includes lots of feedback from folks that go to the Ring. The brakes do suffer from overheating and there are a number of ways to address that (pads, fluid, RS4 calipers and rotors all the way up to C7 RS6 390mm rotors).

6. No changes announced or expected.

[granteg]

Thanks!

[DrDomm]

There is a Haldex "race" controller that is supposedly even quicker to transmit torque to the rear.

I don't think this car understeers as much as you would think, considering the 60/40 weight distribution. The added power seems to make it more neutral.

I haven't been to the track with this car. I wouldn't be aggressive on its brakes, personally.

[granteg]

I wouldn't be aggressive on its brakes, personally.

The rotors are enormous (in diameter) - are they not very thick?

[Stevelev]

Yes a larger rear sway bar is available. For lots of info from a more "mature" UK forum, check out: http://www.ttforum.co.uk/forum/viewf...e63e847b141ddb

[tdi-bart]

the seats are the same as in any other TT including the base TT and any R8

[Koa1]

It's a dry sump engine not wet as another member incorrectly advised. I wouldn't have purchased the ttrs if it wasn't dry sump. Here's the link: http://www.audi.co.uk/new-cars/rs/tt...si-engine.html

[JohnLZ7W]

It's a dry sump engine not wet as another member incorrectly advised. I wouldn't have purchased the ttrs if it wasn't dry sump. Here's the link: http://www.audi.co.uk/new-cars/rs/tt...si-engine.html

That's the first I've seen that. The factory repair manual shows what appears to be a fairly conventional oil pan and oil pump arrangement.

[LongviewTx]

which means, it really is a wet sump, no?

[DrDomm]

The rotors are enormous (in diameter) - are they not very thick?

They are not floating rotors. Most reviewers complained of overheating.

Some people here are confident the system is adequate with the right pads, though.

[32vSC]

which means, it really is a wet sump, no?

See:
TT-RS Self-Study

for a bare-bones non-technical description.

The 2.5 RS lump has an integrated crank scraper, a typical oil pump, and a vacuum pump - although the vacuum pump's purpose seems to be to control crank case pressure. But, keeping the crank case (and head(s)) from getting pressurized is part of the job a dry-sump system does. Keeping oil from getting foamed-up or otherwise entrained in bizarre places is another typical job of a dry-sump system. In this case I would assume the integrated scraper will do a lot to keep the crank from whipping the oil into a froth that bearings don't like.

It's a hybrid dry-ish sump? Kinda, sorta?

[granteg]

It's a dry sump engine not wet as another member incorrectly advised. I wouldn't have purchased the ttrs if it wasn't dry sump. Here's the link: http://www.audi.co.uk/new-cars/rs/tt...si-engine.html

Yes, I think I saw that awhile ago and was the reason for the question. Is there a separate oil tank? I wonder if it's really a wet sump, but they are playing fast and loose with the truth the way Porsche has been doing with its water-cooled motors. They call them "integrated dry-sump", but they've really been wet sumps from 1999 (except in some turbos and all GT models).

[granteg]

See:
TT-RS Self-Study

for a bare-bones non-technical description.

The 2.5 RS lump has an integrated crank scraper, a typical oil pump, and a vacuum pump - although the vacuum pump's purpose seems to be to control crank case pressure. But, keeping the crank case (and head(s)) from getting pressurized is part of the job a dry-sump system does. Keeping oil from getting foamed-up or otherwise entrained in bizarre places is another typical job of a dry-sump system. In this case I would assume the integrated scraper will do a lot to keep the crank from whipping the oil into a froth that bearings don't like.

It's a hybrid dry-ish sump? Kinda, sorta?

Yep, seems similar to Porsche's lower motors with "Integrated Dry Sump". If it doesn't have a separate oil tank, then it's a wet sump in my book. It does look like they took some steps to prevent oil starvation under g-loads though.

[32vSC]

...but they are playing fast and loose with the truth the way Porsche has been doing with its water-cooled motors. They call them "integrated dry-sump", ...

Heh. I almost mentioned Porsche's "integrated dry-sump" in my post above and how a number of early 996 owners popped their motors the first time they put track tires on them and ran them at DEs.

Photos or technical drawings that illustrate the arrangement would be interesting.

See the link I posted above.

The RS lump does not have anything that appears to be an air/oil separator which would be needed (I would think) to deal with the foamy mess that comes out of the vacuum pump of a true dry-sump system that's sucking everything out of the crank case.

[JohnLZ7W]

There's no separate oil tank, or oil accumulator anywhere in the system. As far as I can tell there's a pump to deliver oil throughout the engine and it drains back down to the oil pan. I think even the old 1.8t had an oil scraper setup. It seems like a pretty conventional wet sump to me.

From the diagrams it looks like the lower oil-pan in the 2.5T is at least baffled to prevent starvation issues.

The vacuum pump is possibly associated with the cyclonic oil separator elements in the valve cover that is aimed at reducing blow-by and carbon build-up on the valves.

Checking through the maintenance procedures for oil changes it all seems pretty conventional too, nothing like changing oil on the R8 which has a true dry sump system.

[32vSC]

Yep, seems similar to Porsche's lower motors with "Integrated Dry Sump". If it doesn't have a separate oil tank, then it's a wet sump in my book.

I agree mostly. What, though, if the oil tank is underneath the crank case?

In any case, with no (obvious, apparent) way to separate air from oil before it goes back into the main supply, I'd rate it a wet sump.

It does look like they took some steps to prevent oil starvation under g-loads though.

Yup. It is my understanding though, that the 996 motors popped because the oil sloshed to one side or the other under high-g. That's only one of the ways to feed air to the bearings.

Oil starvation can result from a number of sources: clearing the oil pick-up, churning most of the oil in the (wet) sump into foam that - with no way to separate the oil - gets fed back to the bearings, suspending oil at high rpm in a big slug above the crank, slowing drain back from the head(s) due to crank case pressure, pushing oil out of the breather system (again, due to crank case pressure), etc.

Audi seems to have integrated a couple of the tricks used by engine builders to deal with the problem though: scraping the crank to keep the oil liquid and in the sump and controlling crank case pressure.

[32vSC]

The vacuum pump is possibly associated with the cyclonic oil separator elements in the valve cover that is aimed at reducing blow-by and carbon build-up on the valves.

Yeah, that's what it looks like to me too. Hopefully it does a good job of sucking the aerated oil out of the head and crank case through the separator set-up in the cam cover. Pedantically, you can't really reduce blow-by that way though. But, you can relieve the pressure in the crank case created by blow-by.

One other thing I see:

Note
All components required for cleaning and ventilation are integrated in the cam cover. If one of these components fails, the complete cam cover must be replaced.

I'll bet that cam cover is cheap out of warranty. Not.

[- Jeremy -]

I recall reading a document that stated that the 2.5T had a baffled oil pan and they also increased the fill to 6.5L to prevent oil starvation. That's quite a lot of oil for such a small engine.

- Jeremy -

[tdi-bart]

when i did my oil change i poured in at least 7 litres

[JohnLZ7W]

Spec is 6.5liters, 6.9qts

[granteg]

I recall reading a document that stated that the 2.5T had a baffled oil pan and they also increased the fill to 6.5L to prevent oil starvation. That's quite a lot of oil for such a small engine.

- Jeremy -

For comparison, the early 911 was only 2.0 Liters and had an oil capacity of 11 quarts (true dry sump).

[32vSC]

The Audi doc in the link above specifies 7 liters for the initial fill. So, 6.5-ish for an oil change is probably about right.

[mageus]

5. Car takes a beating at the track without overheating. Remove the hood weather gasket to improve airflow.
Rotors are awesome. Pads are fine for the street, but can't take heavy track use. Upgrading the pads/fluid is sufficient for the track. Uses typical Brembo F40-style pads (2010 STI pads are a perfect match). I use Carbotech XP10 and they work great.

[granteg]

5. Car takes a beating at the track without overheating. Remove the hood weather gasket to improve airflow.
Rotors are awesome. Pads are fine for the street, but can't take heavy track use. Upgrading the pads/fluid is sufficient for the track. Uses typical Brembo F40-style pads (2010 STI pads are a perfect match). I use Carbotech XP10 and they work great.

Good to know