Question for Wyd (or others) re gt35

[hobieboy]

Thanks for the very informative & interesting discussion - subscribing

One question about cooling of the GT turbos - a few mentioned that you run oil thru it without the restrictor (that's the little ball in under the oil pressure switch, right?)?
If I'd keep the stock scavenge pump, will it have the capacity to drain fast enough? And, is there downside to running oil thru the water passage?

[kellcats521]

I am also very interested in this topic - not that it really matters, but simply bringing up non-KKK turbos on other web discussion sites will quickly bring out a virtual 'tarring ang feathering'.....

One such topic on another site resulting the following challenge - send us one of your 'better' turbos so we can dyno it in our shop (where we control the conditions and therefore will INSURE that our unit is better in some way, shape or form ). Unfortunately I don't see this vendor (who throws this challenge out to all other turbo options) sending any of their units out (free of charge, I might add) to the other guys so they can test.....

It is basically rediculous to expect anyone to send free turbos out for a comparison, and I doubt that any one here is interested in buying 6 or so from different vendors to do an unbiased comparo for all of us interested parties, so we are left with evaluating dyno data (and seat of the pants data) from many sources along with these discussions.

I won't dis any turbo manufacturer, but there is huge merit IMO to openly debate the pros and cons of KKK and the alternatives.

[Porschefile]

Hobieboy, I'm by no means an expert on the topic however much of this stuff is common sense and not rocket science as some might have you believe. Here are a couple examples of oil restrictors:

Link 1
Link 2

The oil "restrictor" is usually placed somewhere between the oil supply, oil supply line, and the inlet oil port on the turbo. Hobieboy, I think you are talking about the oil pressure relief valve, but that's a completely different thing. Some turbos actually come with a built in restrictor in the port itself, such as this Garrett Gt28 . Basically, it's as simple as adding a restriction to the internal oil flow of the line by necking down the internal diameter with a simple fitting like the 2 listed above. The flared AN fitting listed above is almost identical to the restrictor I'm using on the Gt35r for my 944. The exact internal diameter of the restrictor itself can differ between cars, different brand/model turbos, different motors, etc as different motors can have different oil systems that have different flow rates, etc etc. According to Garrett, it's recommended to restrict oil flow to GT series turbos to not much more than 40psi. Most cars tend to run much more than that, so most cars are going to require a restrictor. Judging by the pressures I've seen with 911's, I don't see any reason why any 911 would NOT be running an oil restrictor with a GT series. I normally see ~2bar at idle and ~5 bar under heavy load or WOT so that's quite a bit more than 40psi (~2.75bar). Hopefully some more people with them on these cars will chime in with their personal experiences as things sometimes work out different in real life than they do on paper.

Running oil through the water passages at least provides some sort of cooling to the entire bearing section as opposed to just parts of it. Running the water ports dry isn't recommended by Garrett. While I'm not an engineer and by no means have lots of first hand experience with this stuff. I would suspect part of if not the main reason why this is so is that running the ports dry would result in hot spots in certain areas of the center section which could cause abnormal wear.

Kellcats521, I completely understand and agree with your point of view. Personally, I think the best thing would be if an individual that has no personal investment, bias, etc and does not work for one of the turbo manufacturers, retailers, etc was to do some tests between 2 turbos. That would give an unbiased opinion. The nice thing about Garrett is they give you all the info you could ever want. If you want to know the turbo specs and you want to see compressor/turbine flow charts, they are all provided on Garrett's website. At least you know exactly what you are getting because of this. As far as KKK turbos go, there really isn't much info or flow charts out there so it's hard to say. With the Triple K stuff, I've seen titanium/Inconnel wheels & shafts and other neat things, however nearly every other turbo manufacturer out there has the same type of things so that alone really doesn't mean much. As far as Garrett turbos go, they are the most widely used turbos period. Garrett's, including the GT series, have been proven in every motorsport known to man and on a wide variety of vehicles for years. Unfortunately too many people in our community can't get past the fact that some products may not have already been "proven" on Porsches and so they just dismiss them as inferior. Garrett's and the GT series are proven, period. I've seen lots of people in lots of communities claiming their custom stuff is better than the GT series, and I have yet to see a single person prove it. I mean, does anyone honestly believe that some hybrid concocted in someone's garage with some dremel work (okay, that may be an exaggeration ) can top what huge teams of tens if not hundreds of engineers have accomplished using state of the art technology, equipment, and CFD software? If anything, anyone else's custom turbos, Triple K hybrids, etc are the products that need to be proven.

[YermanCars]

Originally posted by Porschefile
Hobieboy, I'm by no means an expert on the topic however much of this stuff is common sense and not rocket science as some might have you believe. Here are a couple examples of oil restrictors:

Link 1
Link 2

The oil "restrictor" is usually placed somewhere between the oil supply, oil supply line, and the inlet oil port on the turbo. Hobieboy, I think you are talking about the oil pressure relief valve, but that's a completely different thing. Some turbos actually come with a built in restrictor in the port itself, such as this Garrett Gt28 . Basically, it's as simple as adding a restriction to the internal oil flow of the line by necking down the internal diameter with a simple fitting like the 2 listed above. The flared AN fitting listed above is almost identical to the restrictor I'm using on the Gt35r for my 944. The exact internal diameter of the restrictor itself can differ between cars, different brand/model turbos, different motors, etc as different motors can have different oil systems that have different flow rates, etc etc. According to Garrett, it's recommended to restrict oil flow to GT series turbos to not much more than 40psi. Most cars tend to run much more than that, so most cars are going to require a restrictor. Judging by the pressures I've seen with 911's, I don't see any reason why any 911 would NOT be running an oil restrictor with a GT series. I normally see ~2bar at idle and ~5 bar under heavy load or WOT so that's quite a bit more than 40psi (~2.75bar). Hopefully some more people with them on these cars will chime in with their personal experiences as things sometimes work out different in real life than they do on paper.

Running oil through the water passages at least provides some sort of cooling to the entire bearing section as opposed to just parts of it. Running the water ports dry isn't recommended by Garrett. While I'm not an engineer and by no means have lots of first hand experience with this stuff. I would suspect part of if not the main reason why this is so is that running the ports dry would result in hot spots in certain areas of the center section which could cause abnormal wear.

Kellcats521, I completely understand and agree with your point of view. Personally, I think the best thing would be if an individual that has no personal investment, bias, etc and does not work for one of the turbo manufacturers, retailers, etc was to do some tests between 2 turbos. That would give an unbiased opinion. The nice thing about Garrett is they give you all the info you could ever want. If you want to know the turbo specs and you want to see compressor/turbine flow charts, they are all provided on Garrett's website. At least you know exactly what you are getting because of this. As far as KKK turbos go, there really isn't much info or flow charts out there so it's hard to say. With the Triple K stuff, I've seen titanium/Inconnel wheels & shafts and other neat things, however nearly every other turbo manufacturer out there has the same type of things so that alone really doesn't mean much. As far as Garrett turbos go, they are the most widely used turbos period. Garrett's, including the GT series, have been proven in every motorsport known to man and on a wide variety of vehicles for years. Unfortunately too many people in our community can't get past the fact that some products may not have already been "proven" on Porsches and so they just dismiss them as inferior. Garrett's and the GT series are proven, period. I've seen lots of people in lots of communities claiming their custom stuff is better than the GT series, and I have yet to see a single person prove it. I mean, does anyone honestly believe that some hybrid concocted in someone's garage with some dremel work (okay, that may be an exaggeration ) can top what huge teams of tens if not hundreds of engineers have accomplished using state of the art technology, equipment, and CFD software? If anything, anyone else's custom turbos, Triple K hybrids, etc are the products that need to be proven.

My custom Gt37 made 489rwhp @ 16 psi, that is proof, I still have yet to see what others have made. Some of the k series guys have some dyno sheets.

[Porschefile]

Originally posted by YermanCars
My custom Gt37 made 489rwhp @ 16 psi, that is proof, I still have yet to see what others have made. Some of the k series guys have some dyno sheets.

True. Sorry, I hope it didn't sound like I was ignoring your results. I always seem to forget that Garrett does make non-ballbearing GT series turbos like the Gt37, Gt3571, Gt4082 and 4088, etc. Sorry about that. That's definitely some nice power for 16psi! I'm sorry if you've already mentioned this Yermancars, but did you say you weren't running an oil restrictor? I wouldn't think one is necessary since it's a plain bearing center section, though I guess one can never really be too sure until it's been done.

[YermanCars]

No restrictor, but well drained -10. As I stated before, my new turbo is just as powerfull through the rpm range till red line, but not as much peak hp. I will have some serious dyno numbers soon as I am going Efi.

Bye Bye Afm Bye bye

[Lukesportsman]

Hey you forgot my litte GT20's. There also traditional bearing and oil cool only.

I'm in thoughts to run them as twins as Ben (M&K) is doing some custom flange work currently on them. They are rated to 260 a piece so should push mid 400's I'm hoping. I think they'll be more responsive if nothing else.

[Porschefile]

Originally posted by Lukesportsman
Hey you forgot my litte GT20's. There also traditional bearing and oil cool only.

I'm in thoughts to run them as twins as Ben (M&K) is doing some custom flange work currently on them. They are rated to 260 a piece so should push mid 400's I'm hoping. I think they'll be more responsive if nothing else.

Sweet! I have to say, I've never really seen anyone use the smaller sub-Gt25 series turbos on any application before. Those will definitely be responsive!

A pair of these Nissan Silvia Gt28's would make for a relatively cheap twin setup and would have excellent response on a 3.0L+ F6. They are AKA the Garrett Gt2560R. For under $1k they are pretty sweet considering they are a GT series, ball bearing, have an Inconnel turbine, and they're rate up to 330fwhp each so a pair would be good for over 600fwhp! I'd run a pair on my motor if I ever went twin, but singles just sound so much better IMO.

[Lukesportsman]

Yeah, I have the GT20's and when I was looking to boost the 3.0 with the low compression SC pistons and 20/21 cams. I've now changed plans and have decided to build a turbo specific engine from a 3.2 core. Now I'm not certain on the 2054 and have been eyeing the 2560 for big horsepower or possibly the 2554 but for same money - hate to give up the Inconnel. I'm also not sure that the larger compressor makes since with a small exhaust for our air cooled F6. I think you might need the flow of the 60's to keep temps down and to flow with our relatively low boost levels.

I'm getting too deep to change my mind of the TT's. It all started with an idea to run no tail in my 72' and a 915 off some 993TT HE's.

Horsepower is infectous and now it will end up in a different shell and a stronger box. But, I'm staying TT just to be different....because I see lots of early custom turbos spooling up on the streets of Terre Haute, NOT. Hey the 72 still wears a duck and that's cool too.

[WydRyd]

Originally posted by Porschefile
Personally, I'd say technically .78 divided T3 housing is a bit small considering your displacement, and a T4 housing should have some nice improvements in power however it sounds like it works perfect for your needs, and in the end that's all that really matters.

All I know is that even at 1.1bar, when the boost kicks in fast, I'm pointing at a 45 degree angle and the front end gets VERY light

Once I get my twin plugs and CDI ignition sorted out, I'll run it at 1.25bar and get a dyno reading. I'd be happy with anything over 500HP. For a daily street rocket, it pretty much obliterates anything that dares to challenge it anyway It doesn't get much better than top-down driving along the coast and hearing this GT BB monster spooling up right behind your ear. I love it!

[Richard Buckner]

Good evening everyone,

I have a solution for everyone on the topic of bearing life for Garrett turbos for their 930's.
The system works as follows: A time delay relay starts a very small water pump on engine shut down. The pump draws coolant from a remote tank and through the water coolant passage. From their, the coolant passes through a heat sink (small radiator) and back into the coolant tank.
The time delay relay can be set from 5 seconds to 10 minutes. The pump draws only 3.5 amps at 12v dc. and moves enough coolant to stop the heat soak into the bearing cartridge. I will be intalling this system on my 930 soon.

[Lukesportsman]

You can source many of these parts from OEM Ford as they use much of this on their supercharged engines. I don't think you'd need a resevoir in this application but simply a closed loop system with a heat exchanger and small pump. We aren't so much trying to cool an application, but more to prevent cooking the oil and bearings. As long as we're not boiling the water and loosing surface tension, I'd think it would be sufficient enough to get the oil in the bearings below 220F.

[Porschefile]

Originally posted by Richard Buckner
Good evening everyone,

I have a solution for everyone on the topic of bearing life for Garrett turbos for their 930's.
The system works as follows: A time delay relay starts a very small water pump on engine shut down. The pump draws coolant from a remote tank and through the water coolant passage. From their, the coolant passes through a heat sink (small radiator) and back into the coolant tank.
The time delay relay can be set from 5 seconds to 10 minutes. The pump draws only 3.5 amps at 12v dc. and moves enough coolant to stop the heat soak into the bearing cartridge. I will be intalling this system on my 930 soon.

Excellent idea Richard. Actually, the stock 951 turbo auxiliary water pump could be used, and I believe there are a few out there that have done similar setups using this pump. It's relatively compact, so the main issue would be finding/fabricating a small reservoir that would fit in the engine bay. Overall, it really wouldn't be that difficult to implement and you could also use something compact like the typical domestic ~$100-150 oil cooler (B&M, Permacool, etc) as sort of a mini radiator, and mounted around or on top of the IC. I remember seeing a similar setup around here somewhere.

[WydRyd]

Seems like a lot of hasstle for a little extra insurance. I'd just run oil through the water jackets if I was that paranoid, for a track car. For a street car that only sees occassional boost, I don't think all this is required and the turbo will last just being oil cooled and appropriate cool-down measures are taken, religiously. Just my 2c worth.