pump gas king?

[14.5 drift]

here's another one I like..........

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[espinelli]

here's another one I like..........

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what compressor map is that?

 

[14.5 drift]

Gt30 chra 60lbs min


http://www.agpturbo.com/customer/home.php?cat=67

 

[pneumo]

If you're trying to keep spoolup around 3.5k on a stroker motor, don't get too big of a turbo. I don't think you need to worry about spoolup so much, tho. With a high compression stroker motor you will have plenty of power and responsiveness without hitting boost. That's a common misconception that you have to hit full boost in order to have any power. While it may be true of a small turbo setup with few supporting mods, it doesn't apply to what you say you will be doing with your car.

Here's a quick shortcut for plotting engine load points on a compressor map. It takes roughly 10 pounds per minute of airflow to make 100 HP, so if you plan on making 400 HP you will be flowing about 40 lbs/min. (That's a rough estimate that depends on many other factors, such as supporting mods and tuning.) Since you will be using about 19-20 psi boost, go to the 2.4 pressure ratio line and follow it across to where it meets 40 lbs/min. That is where you are on the map. Try it. On your first map it puts you at 74% efficiency, on the second map (which is the one I recomended) you are right at 78%, on the third map I think it says 72%? (it's blurry). If you think you'll make 500 HP, follow the 2.4 PR line out to where it meets the 50 lb/min line and compare again.

You can use this info to see how ANY compressor map works with your intended goals, so you won't have to start a new thread everytime you come across another turbo. In other words, stop bugging us! J/K

 

[14.5 drift]

I just read over the article swiftkid posted, and that was not treally the one I read before, that one was much simpler.


I have more questions now though......


First one is basic, what is surge and how do I tell weather i am within or outside of the surge limit


Second, how is any of this really apply? It says that if the turbo is pushing 20 psi, and flowing 50 lbs it will be at around 70% efficiency level. How do I know that my car will be able to pump 50 lbsmin @ 20 psi? What if it is able to pump more than 50 lbs min, than i will be pulling my turbo out of it's range.


And third question, if you can even call the last one a question, how can I relate rpm to lbs min as well as to the displacement by looking at a turbo map?

 

[14.5 drift]

If you want to answer one one day and another on another day that is fine with me.


That way I don't get all cluster####ed

Wich ever ones you guys feel are most pertinant.

 

[midnght]

.... in the next few months it will be another turbo as the "50 trim" craze will fade as the 20g faze did a few years ago.
Andrew

That is already happening with the newer GT30 turbos and other BB's out there. The 5otrim is still a great option, but many are going the newer BB way.

For example, if I wanted to run the most power at 16-17 psi, am I right in thinking that the 20g will flow more and make more power at this psi versus a 50 trim?

But yet, with the greater efficiency of the 50 trim at higher boost, can I run more boost safely with the 50 trim.

Right thinking, but switch 20G for 5otrim and 5otrim for 20G.

 

[pneumo]

First one is basic, what is surge and how do I tell wether i am within or outside of the surge limit?

If a turbo is going to surge it usually happens during spoolup. If a turbo is surging the engine will buck and jerk. For MOST of the turbos out there, and there are exceptions, surge won't happen because the compressor is matched with a large enough turbine wheel and housing, which keeps the turbo from spooling up too early.

Second, how is any of this really apply? It says that if the turbo is pushing 20 psi, and flowing 50 lbs it will be at around 70% efficiency level. How do I know that my car will be able to pump 50 lbsmin @ 20 psi?

If it is pushing 50 lb/min, it means you're making about 500hp, that's how you'll know. The turbo will only supply what your engine can handle. If you don't have the supporting mods for 500 HP, then you won't flow 50 lb/min. simple as that. When plotting points on the compressor map, try to estimate how much power you think your supporting mods will make, then find a turbo to match that power output.

What if it is able to pump more than 50 lbs min, then will I be pulling my turbo out of it's range?

IF your engine pumps more air than the turbo can supply, then the boost will drop off. Sound familiar? It's what happens when someone tries to use a T25 at high boost. It rarely happens with anything bigger than a 16G, tho.

And third question, if you can even call the last one a question, how can I relate rpm to lbs min as well as to the displacement by looking at a turbo map?

That's a complex question, are you good at math? I'd rather not attempt answering it just yet. The shortcut I gave you up in reply #27 works very well.

 

[14.5 drift]

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from the brief lesson i learned in this thread on reading maps, it seems this turbo has a broader island in the power range I'm looking for. At 20 psi it turns out 30 - 55 lbs/min within the 70 percent efficiency range. Not as overall efficient as the gt30r, but it seems the 30r will be just a few ponies shy of my goals.

If any one has any suggestions of a more efficient turbo that will dish out 52-55 lbs/min, I am open for suggestions.

Looking at the 60-1, looks like it might do better up top, but not as well down low.

As well the gt35r, will do better up top for sure, but way too much for my needs I think.

Any ideas when this turbo should spool on a 2.3?


Later,

Chris