GT15v

[waz]

Has any team had any success with the GT15V Garrett turbo?

[waz]

Has any team had any success with the GT15V Garrett turbo?

[Maxwell]

bump- I am interested as well

[Kirk Feldkamp]

Better yet, does anyone know the kinds of EGTs the GT15V will live with? I've heard that a lot of non-diesel cars have trashed variable vane turbines because of the higher EGT's. Has anyone honestly had any problems spooling the GT12?! Ours jumps into boost like a bat out of hell!

-Kirk

[waz]

Interesting! I asked this question over 6 months ago and got no replies but I do now know the answer your question. The VNT garrett says can operate at EGT's of up to 900 degrees C without damage. We ran ours this year with mild anti lag setup at temps in excess of 1100 and without failure. Our car has now completed many days of running.

VNT turbos in street petrol applications are famous for failing but mainly due to the very rich mixtures used to control EGT's fowling the vanes and causing them to jam.

We were able to control EGT's by other means. With a very free flowing exhaust, low exhaust back pressure due to large turbine housing and lambda values around 0.9 we had no problem typically 850-900 EGT. We have not tested the GT12 but were happy with the performance of the GT15V.

Should you choose to use it have fun working out how to control the boost!

WAZ
UOW Racing Engine Group Leader 2004

P.S kirk where are you from?

[Kirk Feldkamp]

Thanks for the temperature info. I figured it would have to be somewhere around there. How long were you at 1100? I'm betting it was only for some short bursts, ie the antilag enrichment. Do you have any quantitative analysis of spool times you care to share? On those same lines, were you able to get different housings for the unit? From what I remember, the actuator on the GT15V only actuates on vacuum to change the guide vane position. For the boost control on the GT15V, did you end up adding a wastegate too, or do you just have it controlling the boost off of the housing sizes?

Lambda at 0.9 seems a little lean, but I guess whatever works, works! The motor is about to go back on the dyno soon to add the boost controller and an EGT, so let the fun begin!

I'm from U.C. Berkeley. I know you've never heard of us at the comp, but we're going to comp for the first time this year.

-Kirk

[waz]

I have not quanitative measurments of spool time.

All our development was done in the car as the dyno has limitations on ramp rate. We never could see any sign of lag on the dyno but in the car it was a major thing.

Also the leaner the better in terms of spool up

[RickyRacer]

From what I have found out, the turbo will not fail past 900 degrees. The adjustable vanes begin to slow down past those temperatures. We ran one two years ago with success, if you can call it that. We got the engine started three days before the competition and siezed a connecting rod bearing the day before the competition. So the turbo did work, too bad the engine did not want to.
Ricky
Long Beach, CA

[Matt N]

From what I understand, the GT12 has problems with the CHRA seal on the intake side when under vacuum. Does the GT15V have a better sealing system here? Does anyone know?

Matt
UW Engine '05

[RKemmet]

The GT15v is just as bad at sealing on the intake side as the GT12. We lost a motor last year due to the seal throwing all the oil into the intake. There will hopefully be a carbon seal made for the GT12 in the near future, but there is not one for the GT15v...

Ryan

[James Waltman]

<BLOCKQUOTE class="ip-ubbcode-quote"><font size="-1">quote:</font><HR>Originally posted by RKemmet:
carbon seal made for the GT12 in the near future... <HR></BLOCKQUOTE>
Where did you hear that? From what we were able to gather: those seals are available for the GT12 from Garrett in Australia but in the U.S. they couldn't help us.

[Kirk Feldkamp]

Hey James,

Did you guys throw together that IHI yet?

-Kirk

[James Waltman]

Not yet. We had a pretty lame group of guys working on it last quarter. Our mandrel bender and water-jet cutter were both broken too so no headers or flanges yet (pretty poor excuses). We just got the parts in to fix the bender this week so I plan on making tubes for headers by this weekend. It will still take a few weeks to get it together. I'll let you know how it goes. I am still trying to get some of the turbo info for you.

I thought the GT15V would be way too big so we never messed with it. Maybe we should dig that one back out and give it a try...

[Kirk Feldkamp]

I just took another look at the maps for the GT15V, and it looks like it's almost identical to the GT12. The turbine side of the GT12 (72 trim, 0.43 A/R) looks like about 4/5 open on the GT15V (58 trim, 0.42 A/R). As for the compressor side, if you look at the housings, it's pretty easy to see they use the exact same housing on both units. I think the only difference is the GT12 has a 50 trim compressor wheel, whereas the GT15V uses a 45 trim compressor wheel. Both have 0.33 A/R housings.

If you compare the two compressor maps, they are virtually identical, both in shape and in numbers. The GT15V has a slightly more vertical surge line (on the top) pretty much everywhere. The efficincies are also essentially identical as well.

All this stuff suggests to me that Garrett did their homework before giving these things to us. The two units are essentially identical, except for the strategies you have to use to control them. The way the GT12 spools for us, I don't think that it's a problem to stick with this unit. It sounds like the UOW guys have gotten the GT15V working just fine now too.

Has anyone found different housings for either of these units?

Waz: For boost control on the GT15V did you end up adding a wastegate too?

James: Mandrel bender?! Water jet? Life must be rough for you guys up there at WWU! Last time I made an exhaust I had to shape it using tools made from rocks! http://fsae.com/groupee_common/emoticons/icon_razz.gif Thanks for trying to hunt down that info too. http://fsae.com/groupee_common/emoticons/icon_cool.gif

-Kirk

[drivetrainUW-Platt]

so the gt15 is the variable intake area turbo correct, the one with the vanes that change angle under rpm, i have read that the rate at which they move is not always ideal, Cornell did electronic wastegate, how about electronic vane angle???
oh ya im lookin for a gt 12/15V if anyone is lookin to sell one, see want adds.

[Sparky]

We didnt use a wastegate last year, however we are looking into implementation one this year. The speed of the angle change on the vanes depends on what you use to control them. We used a servo motor controlled by the MoTec which gave us pretty good rate of movement.

*drools* at the thought of having a mandrel bender and waterjet cutter in house.

[A Reinke]

Have any of you guys measured intake restriction caused by the restrictor?

This is the main reason oil is being sucked past the seals because you lose pressure behind the compressor wheel with a high restriction.

Of course now that I work daily with turbos, I see how blind I was last year with our FSAE engine. http://fsae.com/groupee_common/emoticons/icon_smile.gif

Let me know if you guys have any numbers on that.

~Adam

[waz]

We placed a map sensor in the pipe between the restrictor and the monitored the restricted condition.Once the retrcuted condition is reached the pressure plumits to around 80Pa. 84 we calculated based on sonic velocity at the throat. Pressure changes like a switch too.

[waz]

I thought i would add something too. Check out our turbo on the dyno.

www.uow.edu.au/eng/racing/ (http://www.uow.edu.au/eng/racing/)

It the photo in the top corner.

[VFR750R]

The main reason turbos leak oil is throttle location within the intake. With the Throttle closed means the turbo is under manifold vacuum, the restrictor is nearly insignificant unless you turn your turbo motor past 12,000.

[James Waltman]

Yeah, we are pretty spoiled. The madrel bender is ours entirely. The water jet is in the lab next door and we don't get unrestricted access. So I spent the last few days making these:
http://dot.etec.wwu.edu/fsae/HostedPics/James/Tubing_for_Headers_Small.JPG

[Grover]

Is that stainless you've so artfully wasted!!!???

You have way too much money and you should give some to us.

[Denny Trimble]

Nope, if that's what I think it is, mild steel, and they got a good deal on it http://fsae.com/groupee_common/emoticons/icon_smile.gif

WWU has great facilities, but not much money for the SAE team. That's part of why they make a higher percentage of parts on their car than any other team (except maybe Delft - it would be close). Awesome equipment + boeing surplus aluminum = make everything for cheap. It might take a while though http://fsae.com/groupee_common/emoticons/icon_smile.gif

At least, that's what I've gathered.

[James Waltman]

No it's not stainless. It also didn't cost us anything (just took me a few days). Denny is absolutely right, we got the tube for free from "our"� sponsor. There is a real emphasis here on making our own stuff. We have the equipment to make pretty much anything and little enthusiasm for fundraising. Making as much as we can gets us in trouble sometimes but none of our graduates are worse off because of it.

We will use all of those bends. We need to make a set of headers for our dyno engine, the car, our new IHI turbo, and a set for another project with F3 heads.

[Adam Coombes]

Billet blocks of ally big enough to machine a V8 bottom end and trans axle dont come cheap tho do they. http://fsae.com/groupee_common/emoticons/icon_wink.gif
Bloody impressive stuff on your site, i wish we had use of those kind of facilities and backing.

[jack]

..hey its way easier when you get other people to do this stuff for you! http://fsae.com/groupee_common/emoticons/icon_biggrin.gif

[A Reinke]

Waz,

Do you have that information you could email me? I'm curious to see it.

If any of you guys can measure what your restrictor causes for intake restriction in inches of H2O or Hg, it'd be helpful. Oil sealing capability goes down with more restriction, and I never measured ours on the FSAE engine before I left.

~Adam

[drivetrainUW-Platt]

Does any team have the dimensions or a soild model of the GT12?

[Vassili Wang]

Since anti-lag may damage GT15V, how about "Gear Change Ingition Cut"? Will the misfire lead to an over high EGT?

[Kirk Feldkamp]

I don't see anywhere in this very old thread that said "anti-lag" would damage either turbo. If anything, the UOW experience said you can push the limits a bit and still be ok. The whole point of the GT15V is that you can do a lot of normal "anti-lag" type things without having to dial out a bunch of timing. Just use the variable-vane mechanism the way it's designed and you'll be 90% of the way there. The UOW guys have used this turbo with *excellent* results for a number of years!

Gear change ignition cut won't damage a turbo. The gear change event is very short, and any 'extra' heat loading would be so small that there really isn't any danger.

-Kirk

[Vassili Wang]

Thanks?Kirk~