Quest for Turbo knowlege
Jan 6, 2005, 05:23 PM
#16
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Originally Posted by jj_008
Ok, I will go out on a limb and ask a turbo question.
What is better in regards to power and spool up. A bigger turbine wheel or a bigger A/R housing. Case in point would be a GT30R with a 76mm wheel w/ .84 A/R compared to the GT35R with a .63 A/R? According to the Garrett catalog they move the same amount of mass.
What about the compressor size? I noticed that a 3071 is available with a .60 A/R which is the same as a GT30R. Would the bigger wheel make that much of a difference? If you used the bigger compressor housing on the 3071 and a bigger .83 turbine A/R, wouldn't that produce roughly the same power as a GT30R but spool faster?
What is better in regards to power and spool up. A bigger turbine wheel or a bigger A/R housing. Case in point would be a GT30R with a 76mm wheel w/ .84 A/R compared to the GT35R with a .63 A/R? According to the Garrett catalog they move the same amount of mass.
What about the compressor size? I noticed that a 3071 is available with a .60 A/R which is the same as a GT30R. Would the bigger wheel make that much of a difference? If you used the bigger compressor housing on the 3071 and a bigger .83 turbine A/R, wouldn't that produce roughly the same power as a GT30R but spool faster?
With turbine wheels and turbine housings it all depends. Some turbine housing are generic in that the same turbine housings are machined for different wheels. In this case the internal geometry (volute) design may not be optimal for different wheels. Garrett supplies turbo's that are both matched well and some that aren't. What I mean by that is that some turbo's are configured for diesel applications where greater exhaust flow is neeed. For example the GT35R works very well with the .63 or .84 A/R. But the GT35 in Garrett's catalog is more suited for diesel applications (larger A/R turbine housing and smaller compressor wheel). You really have to experiment with different A/R's and measure exhaust backpressures to find a point where the pressure ratio between the intake and exh. pressure gets close to each other while still not causing too much lag. As far as the two examples go I would go with the GT35R with the .63 rather than the GT30R with the .84 Also the compressor wheel plays a major role in spool up. Not only the size but the configuration of the wheel affects spool up. The 61mm inducer GT35R wheel is simply awesome, for the HP level and spool up it beats the 30R 76mm exducer (56mm inducer) in performance. The 71mm exducer GT30R wheel gives up some horsepower to the 76mm GT30R wheel but it spools up much quicker (given the same exh. wheel). Again, many times the actual real life performance will vary and will depend on the engine size, the VE of the engine, RPM range, ect.. so data from the garrett catalog will get you in the ballpark but testing is still needed to get the details down. Oh..another example is I ran the GT35R with a .84 A/R housing and the .63 A/R turbine housing. The horsepower difference was about 5whp but the spool up was about 500-600rpm slower with the larger housing. This test is detailed and show with dyno graphs in that turbo article that I wrote for modified mag. BTW we'll have all those articles up on our website available for viewing in the next week or so.
Your second question..
the A/R of the compressor cover has much less affect on the power and spool compared to the turbine housing. I've ran a TO4B (small A/R), TO4E (larger A/R), and then the TO4S cover (.70 A/R) and the difference isn't that great. Yes the potential of the GT35 with a TO4S and a TO4B might be 20-30whp, and the spool up difference is negligable. The TO4S is a much larger compressor cover than the TO4b though... it all depends on the packaging of the turbo and if you have room for the larger housing. The difference between the TO4E and the TO4S was less thatn 10whp, and difference is taken up by using a ported shroud TO4S (slightly lower efficiency).
As you can see there are many factors to take into consideration and many variables to play with and measure. The important thing to remember is to not run weird combo's, meaning very larger compressor wheels and small turbine wheels, these combo's don't work well at all. Part of the reason it took me so long to release the turbo combo's for our turbo kit is because I tested about a dozen different turbo's with different housings, ect. to pick the best.
If you want me to elaborate on anything I mentioned above or you have different questions, let 'em rip!
Regards,
Jan 6, 2005, 05:24 PM
#17
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Originally Posted by DynoFlash
Great news
I'll be calling you next week about that new fuel system you have, I need to get rid of my fuel cell to be NHRA SRWD legal for next year
Happy new year
I'll be calling you next week about that new fuel system you have, I need to get rid of my fuel cell to be NHRA SRWD legal for next year
Happy new year
Jan 6, 2005, 06:05 PM
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Originally Posted by AMS
As you can see there are many factors to take into consideration and many variables to play with and measure. The important thing to remember is to not run weird combo's, meaning very larger compressor wheels and small turbine wheels, these combo's don't work well at all.
BTW, thanks for taking the time to answer questions. I will think of some more questions later. Hopefully, some one will come up w/ some better questions then me.
Thanks for the responses!
Jan 6, 2005, 06:54 PM
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it depends how the T67 is configured. If it's the same 67mm inducer wheel that I've used I've had some success with it. The way I had it setup it spooled about 300-400rpm later than the GT35R but it made about 40-50whp more. The 67 wheel is not a high pressure wheel though, it would work better on a larger engine at lower boost. Which specific T67 are you talking about?
Jan 6, 2005, 10:14 PM
#21
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Originally Posted by AMS
it depends how the T67 is configured. If it's the same 67mm inducer wheel that I've used I've had some success with it. The way I had it setup it spooled about 300-400rpm later than the GT35R but it made about 40-50whp more. The 67 wheel is not a high pressure wheel though, it would work better on a larger engine at lower boost. Which specific T67 are you talking about?
Here is an easier question. How does Garrett come up with the part #'s of the turbos. Like GT3071, 3037, 3076, 3052, 3040, etc. Some seem to be turbine wheel sizes, but others are different.
Another question. Is there any advantage using a bigger wastegate then a 38mm?
Jan 6, 2005, 11:34 PM
#22
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Ah, then we are talking about two different turbo's, the Greddy T67 and the Garrett 67mm turbo are completely different. Nomencalture is tough one, each company has it's own method of naming turbo's.
In general, this is garrett's method for naming the GT series turbo. The first number is the series of of turbine wheel, the next is the exducer (the outside diameter) of the compressor wheel. For example the GT3071 and GT3076. Both use the GT30 turbine wheel (which has various trims BTW) but one has a 71mm exducer sized wheel and the other has a 76mm exducer sized wheel. To find the size of the inducer (the inlet size) you have to know the trim of the wheel. The trim refers to the relation between the inducer and exducer of the wheel. TRIM= ((inducer diam)^2/(exducer diam)^2 ) X 100 so you can solve the equations if you have two of the three variables. The 3040 or 3037 is HKS nomenclature and again I'm not too sure how they do it but it sounds like they use the second set of number to define the series of the compressor wheel.
WG size is really a function of boost control. More importantly WG placement and how the exhaust gas feeds the wastegate has more to do with boost control than the wastegate size itself. A properly executed 38mm gate setup will work for 99% of the turbo users.
In general, this is garrett's method for naming the GT series turbo. The first number is the series of of turbine wheel, the next is the exducer (the outside diameter) of the compressor wheel. For example the GT3071 and GT3076. Both use the GT30 turbine wheel (which has various trims BTW) but one has a 71mm exducer sized wheel and the other has a 76mm exducer sized wheel. To find the size of the inducer (the inlet size) you have to know the trim of the wheel. The trim refers to the relation between the inducer and exducer of the wheel. TRIM= ((inducer diam)^2/(exducer diam)^2 ) X 100 so you can solve the equations if you have two of the three variables. The 3040 or 3037 is HKS nomenclature and again I'm not too sure how they do it but it sounds like they use the second set of number to define the series of the compressor wheel.
WG size is really a function of boost control. More importantly WG placement and how the exhaust gas feeds the wastegate has more to do with boost control than the wastegate size itself. A properly executed 38mm gate setup will work for 99% of the turbo users.
Nov 26, 2006, 06:31 PM
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IMO HKS's is the better system , I'd want to know which family the compressor wheels are from because you can have the same (very similar) wheel diametre and trim with different wheel types ie GT37 76mm and TO4S 76mm .
We have had no end of problems in Australia because every other person orders a "GT30R" but very few end up with the real GT3076R (700382-0012) . ANY BB turbo with a GT30 turbine can honestly be called a "GT30R" . Many many people have been burnt here with GT30/TO4S compressored dinosaurs or even GT3040R's (GT3082R) and they are pigs . What you all call a "GT30R" in the US is the real one generally .
One thing that does happen over there is this habit of calling a compressor wheel by its inducer diametre , pointless really because Garrett ALWAYS use either the wheels family or major (exducer diametre) . Armed with only the inducer diametre size very little can be determined about the compressor wheel lurking behind the compressor housing . It could be a small wheel with a large trim size or it could be a large wheel with a small trim size . If the wheel family is known then yes measuring the inducer diametre gives the approximate trim size away but without knowing the major diametre your flying blind .
I find it difficult to understand how turbos like GT3540R's (GT3582R) can work with small AR turbine housings like the factory GT35 .63 type because if you look at Garrets turbine maps the maximum mass flow is reduced with the small housing . I'm not about to deny AMS's findings but its difficult to see how reduced exhaust flow works with high compressor capacity . Logging turbine inlet pressure vs compressor housing outlet pressure will tell the story .
Cheers A .
We have had no end of problems in Australia because every other person orders a "GT30R" but very few end up with the real GT3076R (700382-0012) . ANY BB turbo with a GT30 turbine can honestly be called a "GT30R" . Many many people have been burnt here with GT30/TO4S compressored dinosaurs or even GT3040R's (GT3082R) and they are pigs . What you all call a "GT30R" in the US is the real one generally .
One thing that does happen over there is this habit of calling a compressor wheel by its inducer diametre , pointless really because Garrett ALWAYS use either the wheels family or major (exducer diametre) . Armed with only the inducer diametre size very little can be determined about the compressor wheel lurking behind the compressor housing . It could be a small wheel with a large trim size or it could be a large wheel with a small trim size . If the wheel family is known then yes measuring the inducer diametre gives the approximate trim size away but without knowing the major diametre your flying blind .
I find it difficult to understand how turbos like GT3540R's (GT3582R) can work with small AR turbine housings like the factory GT35 .63 type because if you look at Garrets turbine maps the maximum mass flow is reduced with the small housing . I'm not about to deny AMS's findings but its difficult to see how reduced exhaust flow works with high compressor capacity . Logging turbine inlet pressure vs compressor housing outlet pressure will tell the story .
Cheers A .
Nov 26, 2006, 07:43 PM
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Originally Posted by discopotato03
IMO HKS's is the better system , I'd want to know which family the compressor wheels are from because you can have the same (very similar) wheel diametre and trim with different wheel types ie GT37 76mm and TO4S 76mm .
We have had no end of problems in Australia because every other person orders a "GT30R" but very few end up with the real GT3076R (700382-0012) . ANY BB turbo with a GT30 turbine can honestly be called a "GT30R" . Many many people have been burnt here with GT30/TO4S compressored dinosaurs or even GT3040R's (GT3082R) and they are pigs . What you all call a "GT30R" in the US is the real one generally .
One thing that does happen over there is this habit of calling a compressor wheel by its inducer diametre , pointless really because Garrett ALWAYS use either the wheels family or major (exducer diametre) . Armed with only the inducer diametre size very little can be determined about the compressor wheel lurking behind the compressor housing . It could be a small wheel with a large trim size or it could be a large wheel with a small trim size . If the wheel family is known then yes measuring the inducer diametre gives the approximate trim size away but without knowing the major diametre your flying blind .
I find it difficult to understand how turbos like GT3540R's (GT3582R) can work with small AR turbine housings like the factory GT35 .63 type because if you look at Garrets turbine maps the maximum mass flow is reduced with the small housing . I'm not about to deny AMS's findings but its difficult to see how reduced exhaust flow works with high compressor capacity . Logging turbine inlet pressure vs compressor housing outlet pressure will tell the story .
Cheers A .
We have had no end of problems in Australia because every other person orders a "GT30R" but very few end up with the real GT3076R (700382-0012) . ANY BB turbo with a GT30 turbine can honestly be called a "GT30R" . Many many people have been burnt here with GT30/TO4S compressored dinosaurs or even GT3040R's (GT3082R) and they are pigs . What you all call a "GT30R" in the US is the real one generally .
One thing that does happen over there is this habit of calling a compressor wheel by its inducer diametre , pointless really because Garrett ALWAYS use either the wheels family or major (exducer diametre) . Armed with only the inducer diametre size very little can be determined about the compressor wheel lurking behind the compressor housing . It could be a small wheel with a large trim size or it could be a large wheel with a small trim size . If the wheel family is known then yes measuring the inducer diametre gives the approximate trim size away but without knowing the major diametre your flying blind .
I find it difficult to understand how turbos like GT3540R's (GT3582R) can work with small AR turbine housings like the factory GT35 .63 type because if you look at Garrets turbine maps the maximum mass flow is reduced with the small housing . I'm not about to deny AMS's findings but its difficult to see how reduced exhaust flow works with high compressor capacity . Logging turbine inlet pressure vs compressor housing outlet pressure will tell the story .
Cheers A .
Last edited by kiddevo; Nov 26, 2006 at 07:53 PM.
Nov 26, 2006, 08:18 PM
#27
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Here is an excel file that can be used to do turbo matching. It takes some interpolation, but you can get a good idea of the math used for turbo matching. I also wrote my senior project in college on turbo system optimization, I will see if I can find and post it.
Generic turbo match
For compressor and turbine maps you can use www.turbobygarrett.com
Generic turbo match
For compressor and turbine maps you can use www.turbobygarrett.com
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