Tennesseejed Posted January 8, 2012 Share Posted January 8, 2012 (edited) Does anyone have actual volumetric efficiency data on a turbo/L6 that they are willing to share? I have finally seen the light and am coming over to the dark side . . . Er, I've decided to convert my NA N42/N42 into a high compression, low boost, turbo engine. I am very interested in the new Borg Warner EFR series turbos. HybridZ Thread Retail Product Information Borg Warner also offers a really neat turbo calculator found here: Match Bot Video tutorials for the Match Bot program are found on the bottom of the page. And you can "save" your work if you copy, paste, and save the link on the top of the page to Word or Notepage. For example, here is my current Match Bot work up (still in progress): My Match Bot In addition to having Corky Bell's bible on my bookshelf, and spending a lot of time researching turbo theory here and elsewhere on the interwebs, I found this guy's workup to be particularly helpful: Linked in Turbo FAQ Section What I have determined, hence the question above, is that volumetic efficiency is a very significant variable in turbo application calculations. For example, the guy's workup for the L28ET (last link) assumes a constant VE of 80% for all rpms. Match Bot, on the other hand, uses pre-filled (but adjustable) VEs ranging between 85% at low rpm to 105% at high rpms. If you assume a VE of 80%, at 6500rpm, your air requirements for 16psi are approximately 36.5 lbs/min (See, L28ET workup). If you assume a VE of 105%, your air requirements are approximately 49.5 lbs/min (Match Bot calculation). When plotting data on turbo flow characteristic graphs, the difference between 36.5 and 49.5 (lbs/min) is the differnce between selecting a small turbo or the next bigger one. For the Borg Warner line, this is the difference between the 6255 and 6258. I know that no two engines are going to perform identically in the real world. And that modifications to the intake manifold, head work, valve size, and exhaust type (among other variables) are all going to effect the ability of the engine to breathe under operation (VE). I don't think assuming a constant VE of 80% (L28ET writeup) is correct. I think the common wisdom that a VE of 80%-85% is reasonably accurate applies only to a naturally aspirated L6 engine. While my knowlege of turbo theory is still relatively weak, I think putting 15 or 16psi into your intake system may well put your actual VE at, or over, 100%. As noted, whether this is correct, plays a large part in turbo selection. My understanding is that VE can be calculated during dyno runs using a MAF sensor. Among the many and very knowledgeable residents here on HybridZ, would anyone be willing to share actual VE data for low (10-15psi) turbo engines so that I can more accurately understand what VE values to use in calculating my turbo airflow requirements? Edited January 8, 2012 by tennesseejed Quote Link to comment Share on other sites More sharing options...
letitsnow Posted January 8, 2012 Share Posted January 8, 2012 (edited) That program is likely looking for the approximate VE in N/A form, most do. I think 80-90% peak VE is a fair range for a stockish L28. The torque curve and VE curve should fall very close to one another(the shape, not the numbers), peak torque is where peak VE happens. The Borg Warner EFR turbo's are bad ass, lookingforward to seeing how it works for you. Edited January 8, 2012 by letitsnow Quote Link to comment Share on other sites More sharing options...
Tennesseejed Posted January 8, 2012 Author Share Posted January 8, 2012 Well, my brain is getting all tangled up with this. Now knowing that peak torque and peak VE occur in the same area of the curve, I just spent about an hour trying to calculate actual VE by looking at various dyno graphs where the poster also list their boost levels. I don't think it can be done without having actual air flow measurements because the two variables - VE and air flow - are dependent on one another. And my head hurts too. Quote Link to comment Share on other sites More sharing options...
letitsnow Posted January 9, 2012 Share Posted January 9, 2012 I would set up the program to approximate a setup that has been on the dyno and adjust the VE numbers until the power and torque are about right, that should be close. Both the 6258 and 6758 look pretty good, I think the 55mm turbine is probably too small for an L. Quote Link to comment Share on other sites More sharing options...
Tennesseejed Posted January 9, 2012 Author Share Posted January 9, 2012 (edited) I'm virtually positive that I'll go with the 6258. Unfortunately, the 6258 .64 a/r has a T25 inlet and the 6258 .92 a/r uses the T4. The smallest T3 housing in the BG EFR line is the 7064 which is WAY beyond what my needs are. I suppose an adapter can easily be had, but I'd really prefer to have a T3 housing. And because I live in Alaska, this project will have to wait until April/May. Until then, lots of time to buy parts, plan, and engage in mental masturbation. The EFR quick reference guide puts most of the useful information in one handy location (Linky) Edited January 9, 2012 by tennesseejed Quote Link to comment Share on other sites More sharing options...
letitsnow Posted January 9, 2012 Share Posted January 9, 2012 (edited) Even the 7064 looks pretty good. THIS is what I came up with on the match bot. Edited January 9, 2012 by letitsnow Quote Link to comment Share on other sites More sharing options...
Tennesseejed Posted January 10, 2012 Author Share Posted January 10, 2012 Very cool. Too busy to play with Match Bot more tonight unfortunately. Quote Link to comment Share on other sites More sharing options...
260DET Posted January 10, 2012 Share Posted January 10, 2012 I would set up the program to approximate a setup that has been on the dyno and adjust the VE numbers until the power and torque are about right, that should be close. .................... That's what I would do too, better still if a couple of dyno charts from similar engines were used, averaged out, then work backwards from there. Should not be that hard to do, just a matter of finding suitable charts from known engines. Quote Link to comment Share on other sites More sharing options...
Tennesseejed Posted January 17, 2012 Author Share Posted January 17, 2012 (edited) So if I am following you guys . . . This guy's chart (Dyno Chart) shows 11.5psi (I averaged 11 & 12), peak torque of 264 at 4600, HP @ 4600 of 230ish, and AFRs of 11.6. I put this into Match Bot - only the fourth rpm value - and came up with a VE of ~76. Match Bot Workup Am I on the right track? P.s. Work has been a boitch. Sorry about letting this thread languish. I really am interested in getting some concrete VE numbers. Edited January 18, 2012 by Tennesseejed Quote Link to comment Share on other sites More sharing options...
letitsnow Posted January 18, 2012 Share Posted January 18, 2012 (edited) Multiply his power numbers by 1.2, that graph is rwhp, this calculator is crank hp. The matchbot I posted above turns out to be relatively close taking that into consideration. Edited January 18, 2012 by letitsnow Quote Link to comment Share on other sites More sharing options...
Tennesseejed Posted January 18, 2012 Author Share Posted January 18, 2012 Good point about crank HP v. at the wheels. Looks like an appoximate VE of ~91 (Match Bot Workup) I also edited my previous post to reflect 264 as the max torque value that I used. Quote Link to comment Share on other sites More sharing options...
letitsnow Posted January 18, 2012 Share Posted January 18, 2012 Pretty close to what I got. http://www.turbodriven.com///performanceturbos/matchbot/index.html#version=1.2&displacement=2.8&CID=170.856&altitude=50&baro=14.681&aat=75&turboconfig=1&compressor=70s75&pt1_rpm=1500&pt1_ve=75&pt1_boost=4&pt1_ie=99&pt1_filres=0.08&pt1_ipd=0.2&pt1_mbp=0.5&pt1_ce=60&pt1_te=75&pt1_egt=1550&pt1_ter=1.16&pt1_pw=3.49&pt1_bsfc=0.43&pt1_afr=11.5&pt1_wts=300&pt1_wd=83&pt1_wd2=74&pt1_wrsin=69033&pt2_rpm=2500&pt2_ve=80&pt2_boost=10&pt2_ie=95&pt2_filres=0.1&pt2_ipd=0.2&pt2_mbp=1&pt2_ce=68&pt2_te=73&pt2_egt=1600&pt2_ter=1.38&pt2_pw=12.22&pt2_bsfc=0.45&pt2_afr=11.5&pt2_wts=320&pt2_wd=83&pt2_wd2=74&pt2_wrsin=73635&pt3_rpm=3500&pt3_ve=87&pt3_boost=11.5&pt3_ie=95&pt3_filres=0.12&pt3_ipd=0.3&pt3_mbp=1.3&pt3_ce=73&pt3_te=72&pt3_egt=1650&pt3_ter=1.67&pt3_pw=41.2&pt3_bsfc=0.48&pt3_afr=11.5&pt3_wts=340&pt3_wd=83&pt3_wd2=74&pt3_wrsin=78238&pt4_rpm=4500&pt4_ve=92&pt4_boost=11.5&pt4_ie=92&pt4_filres=0.15&pt4_ipd=0.4&pt4_mbp=1.5&pt4_ce=76&pt4_te=71&pt4_egt=1650&pt4_ter=1.82&pt4_pw=50&pt4_bsfc=0.5&pt4_afr=11.5&pt4_wts=368&pt4_wd=83&pt4_wd2=74&pt4_wrsin=84681&pt5_rpm=5500&pt5_ve=87&pt5_boost=11.5&pt5_ie=90&pt5_filres=0.18&pt5_ipd=0.5&pt5_mbp=1.8&pt5_ce=73&pt5_te=70&pt5_egt=1650&pt5_ter=1.94&pt5_pw=51.5&pt5_bsfc=0.52&pt5_afr=11.5&pt5_wts=400&pt5_wd=83&pt5_wd2=74&pt5_wrsin=92044&pt6_rpm=6500&pt6_ve=75&pt6_boost=11.5&pt6_ie=85&pt6_filres=0.2&pt6_ipd=0.6&pt6_mbp=2&pt6_ce=65&pt6_te=70&pt6_egt=1650&pt6_ter=2.03&pt6_pw=36.67&pt6_bsfc=0.55&pt6_afr=11.5&pt6_wts=400&pt6_wd=83&pt6_wd2=74&pt6_wrsin=92044& Quote Link to comment Share on other sites More sharing options...
Tennesseejed Posted January 20, 2012 Author Share Posted January 20, 2012 Letitsnow, I think you're going to have to help me understand what your are doing in your MatchBot posts. Your two MatchBot links are in posts #6 and #12. Is post #6 your own car? Is post #12 your calcs on the dyno graph I linked? It's probably obvious to others, so forgive my ignorance, but what do your links show? Quote Link to comment Share on other sites More sharing options...
letitsnow Posted January 20, 2012 Share Posted January 20, 2012 The first one was based off what I thought my car should be like, the second was the same as the first, just tweaked a little. It seemed to line up nicely with the dyno graph you posted when you account for the difference between rwhp and crank hp(I like 20%). Quote Link to comment Share on other sites More sharing options...
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