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Discussion Starter #1
Ok..this is going to be a bit long but stay with me. So I went Garrett's website to calculate what compressor I need to run for my d15b after I build it with the vitaras and I came up with some really odd numbers. The formulas I used are on the following page.

http://www.turbobygarrett.com/turbobygarrett/tech_center/turbo_tech103.html

Ok, so first you have to calculate your airflow for a certain HP. I am shooting for 350 whp so i put that in, used a 12 AFR, and used .55 for the brake specific fuel consumption. So using those values I come up with 38.5 lb/min.

Plugging that value into the next equation for the required Manifold Absolute Pressure (using 7100 rpm, 130 degree intake air temp, 90% VE, 91.53 cubic inches, and airflow from the previous equation) I come up with 48.6 psia (or 33.9 psig).

So, then using that value I went ahead and calculated the Pressure Ratio and I came up with 3.55 as my pressure ratio (using the formula they have on their site). I know these values are way off so what's wrong here guys? I know I'll probably want to run a t3/t04e 57trim .60/.63 but this is seriously confusing, haha.
 

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Discussion Starter #4
I know the equations aren't that complicated but I am just getting some fucked up numbers. So has anyone else plotted their points on a compressor map? If so what equations did you use?
 

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http://michigan-nissans.20megsfree.com/turboguide.html

Try this, I put it together useing the formulas from Garretts site useing a .55 BSFC, 125 degree intake temp, and 95% VE. I woulden't call it perfect, or use it to estimate dyno charts, but it will put you in the ball park.
 

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Discussion Starter #8 (Edited)
yea from what i am calculating, none of these points that I am plotting on compressor maps are working out...I think I'll go with instinct and example on this one and get the t3/t04e 57 trim .60/.63. That's what I think will work best with the setup I am going to be running. Maybe a 54 trim.
 

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How did you determine your brake specific fuel consumption..

Honestly, that looks to be a little bit high, I would have guessed somewhere between .40 or .45...

The brake specific fuel consumption is a very critical part of what you are looking for, so you need to be pretty accurate or you will get bogus results..
 

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How did you determine your brake specific fuel consumption..

Honestly, that looks to be a little bit high, I would have guessed somewhere between .40 or .45...

The brake specific fuel consumption is a very critical part of what you are looking for, so you need to be pretty accurate or you will get bogus results..
I took the number from Garrett, if anyone knows of a way to figure a more realistic number I'll do it.
 

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I know nothing about compressor maps or how to figure them but one of the major problems I am having is figuring the amount of power I can get from a t3/t4 .57 trim. ATPTurbo's website said it may only be good for around 450 at the crank plus you have to figure in drivetrain loss....plus that is on a 1.8-2.0L engine, what about my 1.6? My question is what happens when I get the top end built on my vitara system and wanna start to push the numbers up more, am I gonna destroy my turbo by pushing it to hard? I wanna break 400hp but I also want to be able to do more if I want to down the road... I don't mind spending 700-800 for a name brand because I figure they will be more reliable (and you can easily find garrett t3/t4 .57 for that) but I don't really wanna go much over due to this being a budget build and wanting to show the versatility of these d series motor to those in my area. I know I am asking a lot for little money so please don't flame me for it. Ideas?:?:
 

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Discussion Starter #13
Guys have gone over 400 whp on the 57 trim with just a built bottom end so I wouldn't sweat it too much. Plus, if your just trying to show versatility then you don't need to go too far over 400 to prove that.
 
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