Alright, so I got rained in my house today with nothing to do... so I spent all day working out air flow charts for the KA. and KA-T. It should be useful to you guys trying to select turbo for your KA. I did pretty much all the work all you gotta do is get the compressor map and plot your points. I really hope at least someone can use this because it took me all day.
I'm not sure if anyone has made a post like this yet or not, if so I couldn't find it, and if so I sure would like to compare numbers
I'm fairly sure my calculations are accurate, so I'll just tell you what I came up with: turns out you can draw the air flow graph of a 2389cc engine using the equations: f(x)=0.358728372x this will give a graph in cubic feet per minute (CFM) f(x)=0.0024752252x which will give a graph in lbs/min Or, you could look at this long could look at the chart I typed up:
RPM | lbs/min-------------------- 1000 | 2.4752 1100 | 2.7227 1200 | 2.9703 1300 | 3.2178 1400 | 3.4653 1500 | 3.7128 1600 | 3.9604 1700 | 4.2079 1800 | 4.4554 1900 | 4.7029 2000 | 4.9505 2100 | 5.198 2200 | 5.4455 2300 | 5.693 2400 | 5.9405 2500 | 6.1881 2600 | 6.4356 2700 | 6.6831 2800 | 6.9306 2900 | 7.1782 3000 | 7.4257 3100 | 7.6732 3200 | 7.9207 3300 | 8.1682 3400 | 8.4158 3500 | 8.6633 3600 | 8.9108 3700 | 9.1583 3800 | 9.4059 3900 | 9.6534 4000 | 9.9009 4100 | 10.148 4200 | 10.3959 4300 | 10.6434 4400 | 10.8909 4500 | 11.1385 4600 | 11.386 4700 | 11.6335 4800 | 11.881 4900 | 12.1286 5000 | 12.3761 5100 | 12.6236 5200 | 12.8711 5300 | 13.1186 5400 | 13.3662 5500 | 13.6137 5600 | 13.8612 5700 | 14.1087 5800 | 14.3563 5900 | 14.6038 6000 | 14.8513 6100 | 15.0988 6200 | 15.3463 6300 | 15.5939 6400 | 15.8414 6500 | 16.0889 6600 | 16.3364 6700 | 16.584 6800 | 16.8315 6900 | 17.079 7000 | 17.3265
It's pretty straight forward, but if you are having trouble with it, it's shows the air flow in lbs/min at a given RPM (not sure how someone wouldn't be able to figure that out though)
Next is the chart that really matters though, it shows the air flow at a given boost and rpm, hope you guys like this one:
RPM | N/A | 5psi | 7psi | 10psi| 12psi| 15psi| 18psi| 22psi-------------------------------------------------------------------------------------- 2000| 4.951 | 6.634 | 7.308 | 8.318 | 8.991| 10.002 | 11.012 | 12.359 2500| 6.188 | 8.293 | 9.135 | 10.398 | 11.240| 12.502 | 13.765 | 15.449 3000| 7.426 | 9.951 |10.962 | 12.477 | 13.487| 15.003 | 16.771 | 18.539 3500| 8.663 |11.610 |12.789 | 14.557 | 15.735| 17.503 | 19.271 | 21.629 4000| 9.901 |13.269 |14.616 | 16.636 | 17.983| 20.004 | 22.024 | 24.719 4500| 11.139 |14.928 |16.443 | 18.717 | 20.232| 22.505 | 24.779 | 27.810 5000| 12.376 |16.586 |18.269 | 20.795 | 22.479| 25.005 | 27.530 | 30.898 5500| 13.614 |18.245 |20.097 | 22.875 | 24.727| 27.506 | 30.284 | 33.989 6000| 14.851 |19.902 |21.923 | 24.954 | 26.974| 30.005 | 33.036 | 37.077 6500| 16.089 |21.561 |23.750 | 27.034 | 29.223| 32.506 | 35.789 | 40.168 7000| 17.327 |23.221 |25.578 | 29.114 | 31.471| 35.008 | 38.544 | 43.259
Note: Air flow is writen in lbs/min *Edit: To convert air flow from lbs/min to CFM (cubic feet per minute) divide by the number 0.069 -Example: 3000 rpms at 10psi= 12.477 lbs/min 12.477/0.069= 180.826 CFM
I graphed from 2000-6500 rpms at 5,7,10,12,15,18, and 22 psi on a t3 50 trim compressor map, and a t3 super 60 trim compressor map, Im not too go at linking things and i dont know how to put a pic in my post so i just made a yahoo breifcase and put the two compressor maps on there, the url is :
http://f2.pg.briefcase.yahoo.c...o.com/
just copy and paste it in.
hope this helps you guys and girls out.
-James
This should help you turbo guys out
I have a crap load of compressor maps, I think im going to map them out for the ka24, if anyone has any request on which ones I should please tell me and ill try and do them for you, although im going to try to map out all the popular ones I have maps for. I am also thinking about doing a little research on the sr20 but if i do ill post that in the sr20 section. But first I'm going to do the the gt28rs (disco potato), vs. the gt28r, gt32, ect
-
Redline240
- Posts: 892
- Joined: Sun Dec 08, 2002 1:34 pm
- Car: 95 240sx
-
C-Kwik
- Moderator
- Posts: 8070
- Joined: Thu Aug 01, 2002 9:28 pm
- Car: 2013 Chevy Volt, 1991 Honda CRX DX
Re: This should help you turbo guys out (CCXLsx)
What VE are you basing this off of? This will have a small effect on how it plots out on the compressor maps. And while for the most part looking at compressor maps with a constant VE will usually suffice, a motor actually has different VE at different RPM's. VE will typically peak right at peak torque as well.
Re: This should help you turbo guys out (C-Kwik)
Most of what I've learned about turbo chargers and forced induction is from reading articles online and I have a copy of the book I picked up last year "Turbochargers" by Hugh MacInnes (im sure you've seen it), it is a pretty infromative book, everything I have up there is based on information I got through that book. all my numbers are based off of a 85% volumetric efficiency if thats that wanted to know. I know that the VE isnt always going to be at 85%, I used that number as the an average, because olds are at max VE our engine doesnt go much passed that (at max its most likely isnt more than 91or92%, maybe not even that much), and at its lowest it isnt much less than that (im guessing 78 or 79)Does anyone else agree with me on this?C-Kwik wrote:What VE are you basing this off of? This will have a small effect on how it plots out on the compressor maps. And while for the most part looking at compressor maps with a constant VE will usually suffice, a motor actually has different VE at different RPM's. VE will typically peak right at peak torque as well.
Re: (WDRacing)
WOW! really I'd be glad to; Ill finsh up with the maps and load them to that yahoo breifcase that I linked, unless someone can host them somewhere, for now ill just load them there
Re: (CCXLsx)
Why are most of those starting out in the surge zone? I realize that the giant t4e-54 is hypothetically spooling at 2500rpm, but at 10psi, is doesn't hit the map until a bit after 4500 rpm. And most other turbos are surging at points they'd make boost at. A ballbearing option on any of those turbos seem like they'd be past the surge line for most low-throttle driving. -Jeff
Re: (Jeff240sx)
I gave that some thought to and what I came up with was: all my graphs are starting at 2000 rpms, and the line goes straight up to the disired boost. This is just a reference, I know no one is going to be at 22psi by 2000 rpms. Being a little over the surge line at 2000 rpms isnt really a big deal cause odds are by the time you get up to boost you will not be at 2000 rpms, but if around half way through the power band if you still arent passed the surge line than one might worry.... does that make sense to you guysJeff240sx wrote:Why are most of those starting out in the surge zone? I realize that the giant t4e-54 is hypothetically spooling at 2500rpm, but at 10psi, is doesn't hit the map until a bit after 4500 rpm. And most other turbos are surging at points they'd make boost at. A ballbearing option on any of those turbos seem like they'd be past the surge line for most low-throttle driving. -Jeff
I know my graphs arent the only ones that do this look at this:http://www.stealth316.com/imag...c.gifthis map is for the 91-99 3000GT, or Stealth. since that engine has two exhaust sides he had to base the CFM or lbs/min on half of his engines displacment. this compressor map, that is why even though his engine is larger than ours we can still use a single larger turbo, (that pretty obivous though). he was lucky enough to know the different VE at the given RPMs of his engine so this map is more accurate than mine. If anyone has charts with the VE of the ka24 I would be more than happy to rework all my number -James
I printed some of the maps out and I've started graphing them by hand, I should have them scanned and posted in my yahoo breifcase within the hour. please check them out and leave me feed back as to which way you guys like more, the first way I was doing it, or by hand?
the link is:http://f2.pg.briefcase.yahoo.c...o.com/
the link is:http://f2.pg.briefcase.yahoo.c...o.com/
Re: (WDRacing)
ok thats fine, cause i dont know how to post pics on NICO yet. lol. I just posted a T04E-50 and a T3-50 map, on my yahoo account, they are called T04E-50 Drawn and T3-50 Drawn...tell me what you guys thinkWDRacing wrote:Just a heads up, members have unlimited bandwidth for posting pics on NICO.
Re: (WDRacing)
Hey WD, hows that sticky looking?