picking the right turbo: compressor maps

[fiznat]

okay, Nathan and I decided we to graph out the flow charts for a couple turbos. Seeing as it's mostly hearsay which turbo is "better" for a particular boost level, etc, these charts should help.

Both charts are drawn figuring the KA engine of course.

T04E - 60 trim

[fiznat]

T04E- 50 trim

[fiznat]

*note for both graphs, each line has 2 hash marks on it. The first marks out 3500rpm, the second 5500rpm. I figure this is a good way to scale it because that is where most daily driving/accelerating happens.

Nathan and I were both kinda dissapointed on how these turbos are somewhat less than ideal for the given flow rates. Ideally, we'd like to see the main "island" of efficiency right up in between those hash marks, but in both cases the turbos seem to be more suited for higher RPMs (or, more specifically, higher flow rates).

Anyone have any input on this?

[fiznat]

we also have a excel spreadsheet of the flow rates at various RPMs and boosts. Below is a pic, click HERE to download the .xls file.

[Nathan]

In light of these maps, I have found that the 60 trim isn't really the "upgrade" to the 50 trim I thought it might be. If the 60 trim managed to make 18psi by 4000rpms, it'd be surging. Also, even at higher boost, the 50 trim manages to keep up, even so far as being able to stay above 72% efficiency right through 24psi at 6500rpms. If you look and imagine where the points would be for 18psi (I graphed them on paper, unlike Fiznat who's cool and used the computer) the efficiency island is almost perfectly centered between 4000-6500 rpms. I'm keeping my 50

Edit: Oh, and dont even think about the 57 trim, at 15psi: 6500 rpms, it's at less than 70% efficiency. At 10psi: 4000rpms, its finally efficient, but thats about the only place

[TrunkMonkey]

*note for both graphs, each line has 2 hash marks on it. The first marks out 3500rpm, the second 5500rpm. I figure this is a good way to scale it because that is where most daily driving/accelerating happens.

Nathan and I were both kinda dissapointed on how these turbos are somewhat less than ideal for the given flow rates. Ideally, we'd like to see the main "island" of efficiency right up in between those hash marks, but in both cases the turbos seem to be more suited for higher RPMs (or, more specifically, higher flow rates).

Anyone have any input on this?

always plot a point for redline. you'll easily rev past 5500 when you're accelerating, so it's best to know what your compressor will do in the higher rpms. doing this will put both islands between 3500 and 6900, so then it comes down to which compressor stays more efficient through a larger rpm range. this is where the 50 trim shines.

the 60 trim is not a bad compressor if you don't try mating it to a t3 turbine. it's surge limit is it's downfall, so you'll need a t4 turbine to make sure it doesn't spool too fast. the 50 trim on the other hand is almost impossible to surge. it's nice to be able to spool 15psi at 3000rpms and still be at 70% efficiency .

-demetrius

[Nathan]

the 60 trim is not a bad compressor if you don't try mating it to a t3 turbine. it's surge limit is it's downfall, so you'll need a t4 turbine to make sure it doesn't spool too fast. the 50 trim on the other hand is almost impossible to surge. it's nice to be able to spool 15psi at 3000rpms and still be at 70% efficiency .

-demetrius

And that is why I think it's pretty much the perfect street turbo for KAT's Now I just want a compressor map for a T04R darnit.

[boost infested]

they have a "super" series from turbonetics. i have the t04e super 57. its slightly better than the regular t04e 57.

they have:

super 46, 50, 57 etc.

[Nathan]

So is it only turbonetics that has the "super" series? I had seem maps for them but never seen one sold (not that I really looked). Where did you get yours?

[MarkEmark]

Fiznat/Nathan-

Very useful charts/graphs. That'll help some people in choosing turbos.

Where did you guys get the figure 85% for VE? Is that an average VE for modern 4 cylinder overhead valve engines?

I'm wondering if you guys would be able to make one of the graphs for a T3 Super 60 @ 10 psi. I'm curious to see how my turbo looks--Probably not as good as the other ones you guys posted.

Here's a link to the T3 Super 60 compressor map.

http://www.turboneticsinc.com/...per60

Again, good info!

[Nathan]

Hmmm, do Art Appreciation homework, or make a graph for a Super-60...coming right up! Oh, and 85% is pretty accepted, I've heard of using 80-90 so we just picked the middle

[Nathan]

As you can see I graphed for 10, 15, and 20psi just for everyones benefit. The hash marks are also as follows:1st from left: 3000rpms2nd from left: 5000rpms3rd from left: 6500rpms

It should also be noted that this map is missing the efficiency percentages at each island, I would assume the center island is >70%, probably 74 or something. The super-60 isn't really ideal for a KA, but it seems to do okish at 10psi. Thats not to say you have a BAD turbo though, if your happy and the car does what you want and does it reliably then it's all good in my mind

[boost infested]

i think the T3 super 60 is a little small. best for the street is t04e 50trim, .63 turbine housing and stage 3 exhaust wheel.

here is a link to the "super" t04e series.

http://www.turbocalculator.com/garrett.html

[MarkEmark]

As you can see I graphed for 10, 15, and 20psi just for everyones benefit. The hash marks are also as follows:1st from left: 3000rpms2nd from left: 5000rpms3rd from left: 6500rpms

It should also be noted that this map is missing the efficiency percentages at each island, I would assume the center island is >70%, probably 74 or something. The super-60 isn't really ideal for a KA, but it seems to do okish at 10psi. Thats not to say you have a BAD turbo though, if your happy and the car does what you want and does it reliably then it's all good in my mind

Exactly--looks to me like it's not that bad a turbo at 10 psi (which i wont exceed unless I rebuid my engine in which case the turbo will be upgraded and I'll run 20 psi of boost). So STOP KNOCKING on my small turbo, you jerks! :icesangel

[Nathan]

here is a link to the "super" t04e series.

http://www.turbocalculator.com/garrett.html

Hmmm, they dont look too "super" to me, the normal 50 trim is a good bit more efficient at 20psi and 6500rpms than the Super 50 is and even marginally more efficient at 15psi, 5000rpms.

[TrunkMonkey]

Hmmm, they dont look too "super" to me, the normal 50 trim is a good bit more efficient at 20psi and 6500rpms than the Super 50 is and even marginally more efficient at 15psi, 5000rpms.

those super series compressor maps are completely jacked up. i've seen some better ones somewhere. i'll post them if i find them.

-demetrius

[Nathan]

those super series compressor maps are completely jacked up. -demetrius

Agreed, they are just plain hard to read even. They look OLD too me. It'd be awesome if you find better ones!

[TrunkMonkey]

So STOP KNOCKING on my small turbo, you jerks! :icesangel

the numbers for the t3 super 60 are exactly the same as the t3 60 trim. lemme hear you talk smack now .



-demetrius

[MarkEmark]

the numbers for the t3 super 60 are exactly the same as the t3 60 trim. lemme hear you talk smack now .



-demetrius

Looks like Nathan has another homework assignment

You're right though Demetrius--the graphs look exactly the same. So why would they distinguish between the T3 60 trim and the T3 super 60? If anything, I like how my turbo has the name super in it. It's not just a T3 turbo. It's a SUPER t3 turbo :ylsuper

I'm confused who the "you" is in your response--is the fact that the T3 super 60 and the T3 60 trim are exactly the same supposed to be bad?!? Sorry, I'm really burned out---I had a 2 hour calculus exam at 730 this morning

[Nathan]

Looks like Nathan has another homework assignment

Maybe after I finish the REAL homework assignment I have

[TrunkMonkey]

You're right though Demetrius--the graphs look exactly the same. So why would they distinguish between the T3 60 trim and the T3 super 60? If anything, I like how my turbo has the name super in it. It's not just a T3 turbo. It's a SUPER t3 turbo :ylsuper

look very closely at both compressor maps. the super 60 has a slightly broader efficiency range than the 60 trim. the difference is easy to spot if you follow the line for the surge limit for both maps. someone on a saturn forum told me that the super 60 is slightly more efficient (by like 1-2%, but he couldn't prove it), but it's still too small for the KA.

I'm confused who the "you" is in your response--is the fact that the T3 super 60 and the T3 60 trim are exactly the same supposed to be bad?!? Sorry, I'm really burned out---I had a 2 hour calculus exam at 730 this morning

i'm picking on you. go to sleep.

-demetrius

[C-Kwik]

Demetrius is right. You want to plot through redline. The KA still has some juice at 6000 RPM and at least with a large enough turbo, up to redline.

Secondly, plotting 3500 RPM for each boost level may be inaccurate. Assuming the turbine is the same at each boost level, the boost threshold will not be reached at 3500 RPM in each gear. I am assuming this is why you chose 3500 RPM. But way if at 10 psi, you reach max boost at 3500 RPM, then you may reach max boost of 15 at maybe 4000 RPM and perhaps 20 psi at 4500 RPM. The higher you boost, the later on the rev band it will reach peak boost. The peak boost RPM range will be shortened since redline stays the same as well. In the case of high boost turbos, you want to draw a line up from the point (0 CFM,0 PR) which should give you roughly the shape of the boost curve. You also want the upper portion of this to be in a good efficiency area as much as possible as well. Particularly the section you drive in the most under boost.

That being the case, each of your lines would start to the right more. The T04E 60 probably won't be surging in this case on the KA. If someone can host it, I can email a modified version of the T04E-50 Map that fiznat originally posted and what I'm saying may make more sense.

[fiznat]

Both of the charts I posted are graphed through redline. The far right of each line (where it ends) is just at about 7000rpm, so yeah, got that bit covered.

...Just to emphesize: The charted lines on each graph START (far left) at 1000 RPM and END (far right) at 7000 RPM. The hash marks are just for in-between reference.

C-Kwik, yeah I know about the fact that the turbo might not make full boost by that specific RPM, but I had no way of telling where exactly the boost threshold would be crossed, so I just graphed the entire RPM range (1000 to 7000). I figured 3500 would be nice cause its right smack dab in the middle and 5500 is a decent number cause that's right around acceleratiing RPM range. Yeah I know we rev higher than that, but I thought it was a good foothold. Pretty much arbitrary numbers otherwise though.

I can also host any images you might need, just email me.

Also guys, its not hard to chart these things yourself. Look at the spreadsheet I posted-- all you need to know is the pressure ratio (dependent on boost- look at the top of the spreadsheet) and what the begining (low rpm) and end (redline) points are, then draw a straight line between them.

[huguetpj]

from http://katcostarica.240sxonlin...n.htm

The diagonal line is what C-kwik is talking about... but using 2-3 rpm vrs CFM points.

[fiznat]

meh, I like mine better

We can try to make this as idiot proof as possible, or people can just suck it up and read a book themselves...

[C-Kwik]

Pedro's pic is along the lines of what I'm talking about but imagine the andgled line extending further up and about the same angle and intersecting the other two horizontal lines as well. That would be more realistic of what it would like like.

Fiznat, i need your email address. I don't think the email function on this board will let me send an attachement. If you prefer not to reveal your email address to the rest of the list, send me an email, [email protected]

[fiznat]

[email protected]

hook me up, or AIM: foosternit

[C-Kwik]

you got mail

[huguetpj]

Pedro's pic is along the lines of what I'm talking about but imagine the andgled line extending further up and about the same angle and intersecting the other two horizontal lines as well. That would be more realistic of what it would like like.

I thought about using the same angle but it doesn't add up. Using a simple 3 rule (x:y::z:?) since the slope remains constant I get that if I spool to 10PSI by 3.5k I would be spooling to 20PSI by 7k and I don't think that's right, I hope

So I think that using the #s you gave before is a better way to do it ...

Quote »But way if at 10 psi, you reach max boost at 3500 RPM, then you may reach max boost of 15 at maybe 4000 RPM and perhaps 20 psi at 4500 RPM.[/quote]

... since the turbo system is a cycle so spool up between 0-10 PSI should be way slower than spool up between 10-20PSI.

[C-Kwik]

Actually, I'd say with a reasonable T4 turbine, the KA should see 20 psi somewhere around 4500 RPM at about 28 CFM. You're line would be fairly close.

Sppol up characteristics are dependent on many things including the engine's volumetric efficiency, the compressor's efficiency, EGT's, and turbine flow characteristics. Hell, even gear and load has a lot to do with it.