Anyone Ever Use Variable Vane Turbos?
Generally EGT's as high as gasoline will be borderline on destruction in a diesel, and any with enough fuel to get that high would be belching smoke like ****. No OEM setup should ever be anywhere near that, hence their VNT turbos would never need to sustain such temperatures.
According to Banks anything over 1300 is "edgy" on a diesel for turbine inlet temps. 1500-1700 is the norm for turbo gas performance engines what what I've read. Seen some guys push 1800-1900 on land speed cars.
1300 is old school numbers. Reality is 1600 is where you should keep it under for short bursts. My 7.3 would see 1800 for short spirited runs. If 1500-1700 is normal for a high HP gas motor than there is little difference between gas and diesel. If my S366 can take those temperatures on a regular basis than a factory garret turbo should have Zero issues.
Last edited by oscs; Jan 17, 2015 at 01:20 PM.
1300 is old school numbers. Reality is 1600 is where you should keep it under for short bursts. My 7.3 would see 1800 for short spirited runs. If 1500-1700 is normal for a high HP gas motor than there is little difference between gas and diesel. If my S366 can take those temperatures on a regular basis than a factory garret turbo should have Zero issues.
Yeah no worries. Just wanted to make clear that there is no difference in turbo quality/heat resistance characteristics between a diesel/gas turbo. Sized appropriately they work/last the same.
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From: Norn Iron
If VNT's were able to cope with EGT's of a gasoline engine then they would be commonplace just as they are with diesels.
But for cheap generic stuff like S366's etc which are so cheap because they're a very common diesel fitment, they will work either way
That is simply not the case when it comes to VNT though. If VNT's were able to cope with EGT's of a gasoline engine then they would be commonplace just as they are with diesels. But for cheap generic stuff like S366's etc which are so cheap because they're a very common diesel fitment, they will work either way
Last edited by oscs; Jan 18, 2015 at 01:50 PM.
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From: Norn Iron
Please provide information where a VNT turbine designed for a diesel motor can not cope with "high" gasoline EGT temps. As stated before the two are relatively close to each other. There are literally thousands of people running tuners on the 6.0/6.4 F series truck seeing 1400+ degrees daily.
http://en.wikipedia.org/wiki/Variabl...y_turbocharger
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From: Norn Iron
Taken from two sources about diesel EGT's
Banks Power
Dieselhub
http://www.dieselhub.com/performance...peratures.html
And you can bet money no OEM will be pushing those sorts of EGT's with their diesels simple because there is no need for them to push so hard.
Gasoline on the other hand would see those temps and more routinely with no issues even 1600degF would be quite normal pre turbine.
So a normal OEM gasoline would probably run some 3-400degF hotter than a diesel in most cases.
Banks Power
So the big question is, what constitutes excessive EGT? If everything is working properly, 1250º to 1300º F. is a safe turbine inlet temperature, even for sustained running, mile after mile. Above 1300º F. things can start to get edgy. Remember, excessive EGT damage is cumulative. Over 1400º F., you're usually gambling against a stacked deck and it's only a matter of time until you lose.
The absolute maximum safe EGT is debatable. The universal rule of thumb (whether you have a Cummins, Power Stroke, Duramax, or even an older IDI) is to not exceed 1250 degrees F for extended periods of time, and not to operate in the 1250 - 1300 degree F range for more than a 5-10 second burst. Here at Diesel Hub, we live by more conservative standards. We recommend you do not hold more than 1200 degrees for an extended period of time and back off the throttle anytime you see over 1250 degrees. You may have heard of competition vehicles logging up to 1800 degrees during a drag race of sled pull. These engines have been extensively modified in order to survive at these temperatures, do not try to replicate this in your truck.
And you can bet money no OEM will be pushing those sorts of EGT's with their diesels simple because there is no need for them to push so hard.
Gasoline on the other hand would see those temps and more routinely with no issues even 1600degF would be quite normal pre turbine.
So a normal OEM gasoline would probably run some 3-400degF hotter than a diesel in most cases.
Good reads there. However in real life 1200 is an optimistic number. In reality it is much higher. As far as cruising goes. My unloaded 7.3 sees 700-800 on the freeway. Even if a gas motor sees 1200 at cruise that is still well within the "recommended limits" the trick is not pegging your gauge at 1400-1800 degrees for long periods of time. I'm sure that holds true for any turbine. I'll stand by my statement that any turbo that came off of a diesel truck would be more than fine on a gas engine so long as the turbine was sized properly. I've seen a lot of high HP diesels on stock turbos. Excessive EGT's an all. It's not something I've ever worried about.
I guess what I'm trying to say is that I doubt a company like garret would use inferior materials on a production turbo. Than say borg on an "aftermarket" piece.
I guess what I'm trying to say is that I doubt a company like garret would use inferior materials on a production turbo. Than say borg on an "aftermarket" piece.
Last edited by oscs; Jan 18, 2015 at 02:18 PM.
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From: Norn Iron
Good reads there. However in real life 1200 is an optimistic number. In reality it is much higher. As far as cruising goes. My unloaded 7.3 sees 700-800 on the freeway. Even if a gas motor sees 1200 at cruise that is still well within the "recommended limits" the trick is not pegging your gauge at 1400-1800 degrees for long periods of time. I'm sure that holds true for any turbine. I'll stand by my statement that any turbo that came off of a diesel truck would be more than fine on a gas engine so long as the turbine was sized properly. I've seen a lot of high HP diesels on stock turbos. Excessive EGT's an all. It's not something I've ever worried about.
I guess what I'm trying to say is that I doubt a company like garret would use inferior materials on a production turbo. Than say borg on an "aftermarket" piece.
I guess what I'm trying to say is that I doubt a company like garret would use inferior materials on a production turbo. Than say borg on an "aftermarket" piece.
And how many Garrett or BW, or any other VNT turbos do you routinely see on gasoline engines ? They use materials appropriate for the specific use they are designed for.
An aftermarket piece doesnt have a single specific application, whereas OEM do.
There are no aftermarket VNT's with full universal application that I'm aware of ?
And again, just because people who tune the diesels are prepared to run higher EGT's, the OEM arent, they dont. They dont need to. Hence they can build reliable ( well..semi reliable ) VNT setups and offer them to the public to buy in diesel cars.
But yes any conventional turbo off a truck will be quite fine on a gasoline application. But that's a different comparison.
And yes people are using diesel VNT's on their gasoline engines too as a DIY retrofit...but they dont have warranty claims to consider and they probably wont be doing hundreds of thousands of miles either and are happy to take the risks.
In time VNT may become commonplace on gasoline too, but as they seem to be able to get great spool and performance from other technologies, maybe they just dont need to in all but the higher performers like Porsche etc.
And how many Garrett or BW, or any other VNT turbos do you routinely see on gasoline engines ? They use materials appropriate for the specific use they are designed for. An aftermarket piece doesnt have a single specific application, whereas OEM do. There are no aftermarket VNT's with full universal application that I'm aware of ? And again, just because people who tune the diesels are prepared to run higher EGT's, the OEM arent, they dont. They dont need to. Hence they can build reliable ( well..semi reliable ) VNT setups and offer them to the public to buy in diesel cars. But yes any conventional turbo off a truck will be quite fine on a gasoline application. But that's a different comparison. And yes people are using diesel VNT's on their gasoline engines too as a DIY retrofit...but they dont have warranty claims to consider and they probably wont be doing hundreds of thousands of miles either and are happy to take the risks. In time VNT may become commonplace on gasoline too, but as they seem to be able to get great spool and performance from other technologies, maybe they just dont need to in all but the higher performers like Porsche etc.
All the technical Mumbai jumbo is basically irrelevant at this point. I've seen factory VNT turbines take excess amounts of EGT's have you? Fact is a VNT off a diesel will be fine on a gas motor. So OP give a try.
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From: Norn Iron
Different comparison? This entire subject was created to see if a diesel truck VNT turbo will work on a gas engine. You clearly stated earlier that you wouldn't run one becuase of the concern in increased EGT vs diesel. Yet you just stated it would be fine.
All the technical Mumbai jumbo is basically irrelevant at this point. I've seen factory VNT turbines take excess amounts of EGT's have you? Fact is a VNT off a diesel will be fine on a gas motor. So OP give a try.
All the technical Mumbai jumbo is basically irrelevant at this point. I've seen factory VNT turbines take excess amounts of EGT's have you? Fact is a VNT off a diesel will be fine on a gas motor. So OP give a try.
I'd also say give it a try, but I wouldnt expect to get say 50k from it. It may last 100k, or it may last 5k though
Longevity is defiantly the better argument. To date my buddy's 6.4 with the Spartan tune. (500ish HP) stock turbos have lasted 2yrs so far. He drives a lot so I'm going to say that's at least 40k. However there are failures. I've seen factory turbo blades that look like a serrated knife. IMO I would say more turbos live than die. This is a combination of first hand experience and a lot of reading on boards like powerstrokearmy/compD and Powerstrokenation
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From: Norn Iron
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From actual data of various diesel engines, turbo out temp is closer to 400C/750F for a similar-sized diesel engine at 100% load. Not sure what exhaust manifold temp is, though. I'm guessing closer to 700C/1300F.
Double the size of our engine and we get closer to 1000C/1830F temp coming out of the exhaust manifold and 625C/1150F turbo out.
The idea is great for aftermarket use, like us. Every OEM is trying to get rid of them, though.
Double the size of our engine and we get closer to 1000C/1830F temp coming out of the exhaust manifold and 625C/1150F turbo out.
The idea is great for aftermarket use, like us. Every OEM is trying to get rid of them, though.