Compressor Maps

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Mar 18, 2007 | 10:13 PM

schmity

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Compressor Maps

I have been working on an EXCEL Spreadsheet ( Look Here ) that will calculate air-flow rates and pressure ratios for the 7.3L (or any engine). I also have Compressor maps for the H2E, GTP38R, and the GT4082 plotted for comparison with the calculations.

Input variables are (my assumptions in parentheses):

Ambient Air pressure (14.7 psi)
Pressure Drop across Air Filter (1psi)
Pressure Drop across Intercooler (1psi)
Intercooler outlet Temperature (100-130F)
Engine Volumetric Efficiency (0.9)
Brake Specific Fuel Consumpion (BSFC) (0.5-0.4)
Air Fuel Ratio (14.5)

I thought I would throw the file out here for everyone to look at...and find the errors. I am hoping to get a stock compressor map and I think that the Ball Buster-HTT-TN-Phatshaft compressor is the T66(yes/no?).

Mar 18, 2007 | 10:44 PM

ernesteugene

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From: Fulltime RVer

Quote:

Originally Posted by schmity

Schmity, I downloaded your file and took a quick look. I'm getting ready to hit the road in a few days, and I'll play with it when I get a chance. I'm interested in understanding turbo surge issues, so I want to see how your maps are read to see where the surge limits are, and how to measure the surge margin. I've got the early 99 OEM turbo which comes with the so called wicked wheel, and I'm not sure if it's one of the ones included on your sheet?

Please provide directions for how you made it available for download. Someday, I want to provide some analysis on hp required to overcome drag with and w/o my wing, towing up grades, etc...

Mar 19, 2007 | 08:28 AM

schmity

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Quote:

Originally Posted by ernesteugene

The stock compressor map is not there yet. I am planning to get it and I will let you know when I do. You can find an explanation of compressor maps at http://www.turbobygarrett.com/turbobygarrett/tech_center/turbo_tech103.html.

I basically uploaded the file to a public website.

Mar 19, 2007 | 11:30 AM

ernesteugene

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From: Fulltime RVer

Quote:

Originally Posted by schmity

I basically uploaded the file to a public website.

Well, could you tell me how to do that in 10 words or less, maybe just the link for the one you used? I've never done anything like that before, I'm kind of new to the internet.

Mar 19, 2007 | 09:50 PM

schmity

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I am paying register.com to give me space for a website. You may contact your internet provider....thay may have space for you. They can tell you how to make your files public.

Mar 19, 2007 | 10:39 PM

444dieselrod

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From: Braham MN

dude those are pretty sweet, there a lil dificult to read on a spreadsheet VS. the 3-D diagrams, but there better then what I had before and that was nothing.

keep me informed when you find one on the stock turbo.

Diesel Rod

Mar 20, 2007 | 01:00 AM

schmity

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I have updated the Excel File to include the Stock GTP38, GT4294R, GT4088, and T66 compressor maps. I had a vendor for the HTT, Ball-Buster, TN send a compressor map for these turbo's and it was a t66 (I am assuming they are all the same).

Just playing with the #'s I have discovered that Ambient Pressure, IC Delta P, and VE do not impact the calcualtions as much as Air Filter Delta P, Air Fuel Ratio, IC outlet Temp, VE and BSCF.

I am assuming that the Delta P across the air filter is below 1 psi and is somewhate negligable.

IC outlet temp should be between ambient and 130.

VE should be between 0.88 and 0.95 and is therefore negligable.

The only two things I would like to get a better feel for are the Air Fuel Ratio and BSFC.