GT12 Questions

[aa2000]

Hey guys

I'm doing a project on turbocharging the KTM engine in our FS car. Now I've done the calculations to match the engine to the Garrett GT12, but I have a couple of questions.

The turbo requires oil cooling for the bearings, and water cooling for the shaft between the compressor and turbine. Our engine is a dry sump, so we need to fit a separate pump and oil resevoir for the turbo. Has anybody done this? Or have any idea how much oil would be needed?

Second question: My project supervisor mentioned that the restrictor causes low pressure which might suck oil in from the bearings into the compressor housing. Is this likely to happen? Any suggestions on how to solve it?

Apologies if these are noob questions!

Anirudh

[aa2000]

Hey guys

I'm doing a project on turbocharging the KTM engine in our FS car. Now I've done the calculations to match the engine to the Garrett GT12, but I have a couple of questions.

The turbo requires oil cooling for the bearings, and water cooling for the shaft between the compressor and turbine. Our engine is a dry sump, so we need to fit a separate pump and oil resevoir for the turbo. Has anybody done this? Or have any idea how much oil would be needed?

Second question: My project supervisor mentioned that the restrictor causes low pressure which might suck oil in from the bearings into the compressor housing. Is this likely to happen? Any suggestions on how to solve it?

Apologies if these are noob questions!

Anirudh

[Kirk Feldkamp]

You're in luck! There are a bunch of threads talking about what causes oil to leak past the seals, so check those out to understand the "why" for this one. Long story short, dedicate one scavenge stage to the turbo oil drain, and you should be in business. This will generally keep the pressure differential going the right way, and keep oil from escaping into the housings. You don't need to have a separate oil volume for the turbo... it can use the same sump that the engine does. Just make sure you're supplying the turbo with the oil pressure and flow spec on the drawing.

The water cooling isn't entirely necessary, but recommended. The turbo bearings are mostly cooled by the oil during operation, and the water cooling is actually for cooling things after the engine stops running. For *much* more info, check out this document: http://turbobygarrett.com/turb...01_Water_Cooling.pdf (http://turbobygarrett.com/turbobygarrett/sites/default/files/Garrett_White_Paper_01_Water_Cooling.pdf)

-Kirk

[Jon Burford]

Good advice from Kirk
We are running water cooling for now, but I do understand that people don't.

We are running a dry sump setup, but it's the standard unit, which isnt really suitable for scavanging the turbo.
We are just using gravity and "the" cunning trick to stop oil breaching the seals.

Yes, take time to consider your engine oil though. You should pick an appropriate one!

[Kirk Feldkamp]

A dedicated scavenge is nice, but as long as the pressure differential discourages flow out of the center housing under all conditions, that's all that matters. If you're using the gravity feed to go back to the sump, then the drain probably still sees *some* suction from the pump (which is good).

[Jon Burford]

Agreed.
Any experience with feeding the drain direct into the top of of the dry sump tank, as this maybe more direct for us depending upon where I can get the tank in?

[aa2000]

Thanks for the help, Kirk and Jon

I've searched the forums for the threads you mentioned and I reckon I have a good idea on how to deal with the problem and what sort of set up needs to be run depending on where the turbo is placed in our car. I think we're able to run a gravity feed back from the outlet since the turbo will be mounted higher up than the inlet back into the sump.

This might be a stupid question, but since I have yet to receive the turbo from Honeywell, I'm slightly confused by their drawings. Is there just the one inlet and outlet for oil in to the turbo, or one of each for the compressor and turbine bearing?

Anirudh

[Jon Burford]

yeah it's not so easy with the GT 12
on the oil flange drawing the large hole is the return and the small hole is the feed. it's all done through one flange.

[aa2000]

Thanks Jon! This certainly makes the piping easier.

Out of curiosity, how long have you guys been running a turbo? and what engine are you using it with?


Anirudh

[Jon Burford]

This is our first season and we are running a Yamaha genesis 80fi, it's an in-line twin.

[Kirk Feldkamp]

<BLOCKQUOTE class="ip-ubbcode-quote"><div class="ip-ubbcode-quote-title">quote:</div><div class="ip-ubbcode-quote-content">Originally posted by Jon Burford:
Any experience with feeding the drain direct into the top of of the dry sump tank, as this maybe more direct for us depending upon where I can get the tank in? </div></BLOCKQUOTE>
Not specifically, but I don't see an issue with it. You will still probably get blowby into the compressor housing after throttle transients this way unless you take other measures to eliminate the pressure differential under those conditions.

<BLOCKQUOTE class="ip-ubbcode-quote"><div class="ip-ubbcode-quote-title">quote:</div><div class="ip-ubbcode-quote-content"> Originally posted by aa2000:
This certainly makes the piping easier. </div></BLOCKQUOTE>
Haha. Wait until you package the parts to make that conclusion! In my opinion, it would actually be a LOT easier to have them separated. Most turbos do.


We ran a GSXR600 with the GT12 back in 2006 and 2007. The resources required to keep the engine running well proved too great, and the team abandoned that path after the 2007 season. Many on-track factors also led to the decision, most of which centered around having more power than the drivers could ever really use and a less responsive engine than the drivers wanted. There are myriad threads on this forum (Reasoning your way through the FSAE design process (http://fsae.com/eve/forums/a/tpc/f/125607348/m/217101453) and Any way to objectively choose engine? (http://fsae.com/eve/forums/a/tpc/f/125607348/m/824105905) are two good ones) that talk about why you would or wouldn't want to go after big power.

[Jon Burford]

Yes the Pipe work is bitch to get done well. We have our drain coming off the flange at an angle which makes it even easier!

Thanks for your help Kirk, We have to run a CVT with our engine which will hopefully work well with the turbo. In theory.

[aa2000]

<BLOCKQUOTE class="ip-ubbcode-quote"><div class="ip-ubbcode-quote-title">quote:</div><div class="ip-ubbcode-quote-content"> Haha. Wait until you package the parts to make that conclusion! </div></BLOCKQUOTE>

Good point, I guess I should wait till I actually start designing/building the system before making that judgement.

The engine we're using (KTM 525 XC) is a dry sump one, and I'm not sure as to how to incorporate the turbo oil cooling into the engine oil cooling. I believe there is a port to the oil sensor which I can take the oil from to the turbo inlet, but I am not sure where to send the drained oil back into the engine considering there is no oil pan. Is it possible to drill a sufficiently large hole back into the engine for the drain?

Or would it be more beneficial in this case to have a separate system for oil cooling the turbo. For example getting a small mechanical or electric oil pump for the turbo?

Finally, am I right in thinking the oil in the turbo will be a lot hotter than the engine oil, so we would need a different grade oil?

Thanks for your help so far guys, its been invaluable!

Anirudh

[Jon Burford]

Hi There.
I agree with your comment on oil, I run only Mobile 1 10W-50 no problems so far.

You can drill a hole in your crank case to return your oil. That is the way it's normally done. I can cheat with our engine. It has a plastic cap which you can remove to get at the crank shaft end. I made a fitting to replace this cap and then threaded a big banjo bolt into it. But as discussed above it might be possible, depending on your system, to route your return back into the dry sump tank.
Your oil return is gravity fed so it should never run up hill and preferably no flat either, ideally directly down to the sump. People who mount their turbo's low down do use electric oil scavange pumps, they are available online, although they are fairly heavy and expensive.

I supply my turbo oil through a oil sensor port.


Good luck

[aa2000]

Cheers Jon

We'll look into the oil situation and choose the best option.

Also, how is the turbo held in place? I know there are two boltholes near the oil inlet/outlets, but should these be used to fix the turbo to something?

I presume the piping is not enough to hold the turbo in place, correct?

Thanks

Anirudh

[Jon Burford]

You are correct, If you inquire with Garrett, they will send you an information pack.
This conatins a detailed drawing which indicates the mount points.
Mounting can take many forms and the best solution for you is heavily dependant on your proposed setup. Googling "Turbo support" should help. If your manifold is short, you can suspend the turbo from above or you can rigidly bolt it to a frame with a longer manifold by using a flexible joint or bellows to isolate the vibration.

[claas900]

You can run your drain right back into the top of the oil tank. If you Google Yamaha 700r turbo you'll see some pics.
I dont own a 700r but they tap oil right from the oil filter cover, its my understanding that the 700r has something like 9lbs of oil pressure and they plug right into the turbo. I know its a bigger motor but they also run a gt22. They say there is no perfect turbo for a single, but some of them run a gt22 turbine and gt20 compressor.
I guess the problem isnt getting it enough air the problem is getting rid of the exhaust, thats why they run the bigger gt22 turbine

[Kirk Feldkamp]

The stuff in the "Garrett information pack" can also be found here: http://www.wwufsae.com/Shared_...ibrary/Engine/Turbo/ (http://www.wwufsae.com/Shared_FSAE_CAD_Library/Engine/Turbo/)

They may have added/subtracted something, but the drawings and notes are still the same.