In Rob's G35 video, at the end on the street logs the emap was 36psi @ 22 lbs of boost. He capped that off with the explanation that they maxed the G35 turbo out and went through the log graph and estimated that it was 730hp(I believe he said).

So, since they pushed 30+ psi on the dyno but only at 5k rpm , where it read 560 tq. I can only imaging that if they did have a fuel system to handle the 30+ boost that the EMAP would have been so high that the G351050 would have made less horsepower than he made at 22 lbs of boost.

Factor in that Rob's Corvette still has the factory FD upper intake manifold, which is a choke point at that power level , its no wonder there was so much EMAP at 22psi boost.

That said, on a rotary, 100 lbs of air "should" equate to 750hp, and the G351050 compressor map does show 100 lbs of air at 2.6 bar which is 37 psi boost , which on the car is really 27 psi boost and the max RPM on that turbo is 130000 at that point.

Rob's statements in that video were correct and the G351050 compressor map supports it. That Turbo was close to max.

if he had more fuel with that turbo and his set up, he wouldn't have made anymore power.

 

must of been why I stated that it was the wrong turbo for a semiPP 13B then

it didn’t start as semiPP though, that just came out of nowhere after starting out in the other wrong direction because there really is no well conceived goal or objective. It’s just what can we do today to play zoom-zoom and meet the obligations. Because when you have sponsors, subscriptions, etc. you are obliged. That in itself means little to nothing, contrary to the prior claims.

there really is a disconnect from reality on here based on those statements and claims though. It’s such rubbish, and so much of it, that it’s not worth trying to counter or address the specifics.

the majority of the information is all on this forum for those who rightly study and divide it. It doesn’t have to be a drawn out cluster. You can hit fairly close to the goal and then optimize it from there.

then you won’t be selecting a Garrett G40 and pairing it to a stock port T2 engine with a 39 lb/min peak flow turbine housing and the OEM T2 intercooler, only to wonder why boost is reverse flowing out the compressor inlet. Like nobody could possibly project why not to make that combination of selections.

and you’ll understand that A/R is only a comparative physical relationship that serves to establish an order of magnitude and not the actual value that matters. Contrary to the veil of bovine fecal matter that was cast up by people who either just don’t understand or are intentionally being misleading for whatever purpose.

There are plenty of successful examples to work from; here’s one of many:

https://www.rx7club.com/single-turbo.../#post12450545

another one:

https://www.rx7club.com/single-turbo...19whp-1140159/

plenty more …. if you understand enough on how to break them down. How many sponsors, views, subscribers, and so on do they have? Uh-oh …

I made a suggestion and will again suggest that you start there. Or just go on believing it’s all hocus-pocus that you have to guess and bumble your way through.

not at all, but like with any circus; the show must go on for all those who are born every minute.
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Air was flowing out of the ported shroud of the turbo because the compressor was pushing more air than the engine was taking in and the BOV was closed with the engine idling as the BOV was a typical VTA design. If the BOV had been a recirculating design and open with the engine in vacuum, the excess air would vent out the BOV and not gone through the ported shroud of the compressor housing. OEM IC is irrelevant to this scenario with the engine at idle. While actually driving and boosting, the small IC just doesn't drop the IATs as much and is relatively high pressure drop, so the compressor would be operating at a higher pressure ratio than a properly sized IC would do.

As for the SXE369 9180 turbo, it's pretty well matched. 91.44mm compressor exducer, 98 lbs/min, 80mm inducer turbine. Wheel sizing is right between the G40-1150 (88mm comp exducer, 77mm turbine inducer) and G42-1200 (91mm comp exducer, 82mm turbine inducer). Though the G40-1150 does out flow the SXE369 despite being a smaller turbo, but the G40 does cost ~3x more. The SXE369 is quite the performance bargain.

 

100% efficiency won’t overcome trying to stuff 700+ rotary whp through a 300 whp orifice.

I’m starting to conclude that you must be advising them, because it starts to all make sense then.
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??? Do you not understand why the air was coming back through the ported shroud while the engine was idling on the setup that was on the car? We are talking about Rob Dahm's FC with the G40-900 and HKS SSQV on it right? I find it helps me to diagram things out on paper to help figure things out. This is a pretty simple thermodynamics control volume problem, but it does require some basic fundamental understanding of how that particular BOV functions along with basic engine operation. Go ahead and draw it out with the mass flows, pressures, etc and let me know if you get stuck somewhere in the analysis if you can't figure it out.

 

Here are the equations right out of the Garrett catalog,

 

see where the dashed red line (1.06 T4 div) starts at 25 lb/min and 1.3 PR data point on this G40 turbine map:





that’s somewhere near 375-400 whp on a 13B engine

again that 1.06 AR turbine flow peak is more suitable for a 750+ whp 13B engine at full song and you can see that where the 0.85 AR line starts isn’t much better. The reality is that the turbo is too big and so far out of it’s basic operating range. If you go to the compressor map the very bottom line where the map starts is the 50,000 rpm shaft speed. If there’s not an rpm sensor installed then they likely can’t see that it’s spinning well below that at low engine load/rpm due to a lack of suitable output energy relative to the size and flow capacity.

The compressor impeller can’t even overcome it’s own output that low trying to push through the equivalent of a tiny straw orifice. So where else is it going to go except back out the inlet? Because it may be efficient at various points on the compressor map, but only when it reaches those points. Except where it’s operating at in reality is way off the map.

They more or less have it backwards at the current engine level of the Vette and FC projects. The FC with a G35-900 1.06 will still be oversize enough to provide plenty of efficiency for their purpose while being a better fit to the engine operating range. The Vette with semiPP 13B and appropriate fuel system support will be better suited with a G40-1150 1.06 or 0.95 depending on the top end result goal. They could just swap the turbos, but the Vette will be limited to 600 whp or possibly less in order not to overspin the G40-900 compressor housing. The G35-1050 would be a slight improvement on the FC, but still less than ideal.

Trying not to be overcritical about it, because I can understand that there’s a general misunderstanding on how the G-series lines up to equivalent turbo sizing. Yet I also become frustrated beating that drum (my head on the wall) on here for a year or two about it now.

Which I was intentionally trolling some with the previous “it all starts to make sense now” comment, but more with some eye-rolling and sighing than malicious intent.
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You really have no grasp on basic engine operation or turbocharger system operation as you don't understand why the air was going back through the port shroud while the engine was idling. Like I said, do a basic first semester undergrad thermo I control volume analysis on the system. If you need help, I can help guide you.

 

@TeamRX8 it seems you have not been able to figure out why air was going back through the port shroud with the engine at idle speed. I'll get you started with the control volume and components you should be analyzing. The key component you left out of your analysis is the 'throttle'. The purpose of the 'throttle' is to regulate the mass flow of air into the engine. The throttle regulates the flow by being a variable resistance pressure drop essentially. At engine idle speed, the engine speed and load are very low. Hence, the throttle plate is closed all the way. Well, this does depend on if it's older school throttle cable or electronic throttle. But basically, closed all the way creating a massive flow restriction to drastically reduce the mass flow of air into the engine. The other part of the puzzle is the operation of the specific BOV that was on the car which does not open when the engine is in vacuum. Therefore, all the extra air the compressor was trying to push had nowhere to go but out the ported shroud of the compressor housing. If the BOV was of the standard OEM recirculating style which is open when the engine is in vacuum, then the excess air would have exited the system there. Why was the compressor pushing that much air? Because it's connected directly to the turbine and the turbine puts out as much shaft power as dictated by the flow going into it. If you want to calculate the pressure drop of the IC piping, you could calculated it relatively closely knowing that the engine is at idle speed. You know the engine displacement, engine speed, intake manifold pressure, and you can make as assumption on the air temperature; one extra bit of info you have to know is that the rotary puts out one power stroke per crank revolution which differs from a 4-stroke piston engine where each piston puts out a power stroke every two crankshaft revolutions. Something like 80F as a reasonable value for intake mani air temp. So you can calculate the air density and combine that with the volumetric flow calculation. Of course, you have to recalculate the air density for in front of the throttle plate which will be basically ambient. Use that number with the volumetric flow rate and you can figure out the velocity. Knowing the velocity, it's a pretty simple pipe flow pressure drop calculation. And that pressure drop will be very low under engine idle conditions, even if a 1" diameter pipe. Certainly compared to hitting the wall of a closed throttle plate.

 

Except it’s blowing out at wot too for the obvious reasons

honestly you sound just like that guy over in South Africa talking his pitch. He posted a video swearing nobody was ever going to get close to the theoretical 700 hp limit of the Garrett G30-770 because of the compressor to turbine sizing being off, to which I immediately posted up this:



713 whp





but I hadn’t been back in here since the previous post because arguing with you is pointless. If you’re connected with these guys we can put this to bed easily. I have a new Garrett G30-770 1.06 div T4 in my possession that I don’t have any problem at all shipping out there for them to put it on and test to make a direct comparison with.
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Again, you show a significant lack of understanding of turbo operation. I can't help you if you're unwilling to learn and stick to your ignorance. It's your choice to just be wrong and not learn to become better. Should you choose to actually learn something, read this book I attached in .pdf. It's from 1982 and the wheel aero has advanced since then, but the fundamental science is the same.

Edit: I just gave you the tools. Do the engineering analysis to back up your statement, "Except it’s blowing out at wot too for the obvious reasons". Show us the numbers, the engine operating points and the compressor operating points where your statement is true. If you can't do the analysis showing us the math, then you're just guessing. If you're just guessing, then why should anyone believe what you say? Science and engineering doesn't care what you think, it can be proved with numbers. And I don't even know why you bothered posting about the Civic? It has absolutely nothing to do with the topic at hand. I've also never heard of them.

Edit again: @TeamRX8 I'll give you the easy cheater option, use Matchbot. Show us "Except it’s blowing out at wot too for the obvious reasons"

 

I’m not going to play semantics with you. Clearly what we’re talking about is the same thing, but using different words to reference it. Except I’m choosing to use the same words that were used in the video. Pretty much everybody on here understands you can only squeeze so much through a straw with an escalating pressure requirement i.e. porting and other influences. The whole issue though is the turbo chosen is an entirely bad fit given it’s grossly oversized turbine housing with all the choke points between compressor and the exhaust ports.

theory is theory; in addition to the actual poor result already proven, I offered up a $2000 turbo to put it to the real world test. The offer won’t last forever as I’m intending to put it in use myself in due time.

it’s also not necessary to “tag me”. I know when you post up here and again, there’s no point in arguing theory, hence my real world offer. If I’m not responding it’s intentional for this reason.
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To recap, you said air was blowing out the ported shroud of the compressor housing at engine idle speed because the intercooler and piping was too small. You were wrong for two reasons; it was because the BOV originally used was not open when the engine was in vacuum and also because the throttle plate was closed. The closed throttle plate being the massive flow restriction at this engine operating condition. When Rob changed the BOV to one that did vent when the engine was in vacuum, air no longer recirculated through the ported shroud. Why? Because the excess air was dumped out of the BOV that was now open with the engine in vacuum.

Then you said air would go through the ported shroud at WOT too, of which you are only partially correct. The purpose of the ported shroud is to move the compressor surge line to the left of the map by LETTING the air recirculate. When operating near the surge line the flow gets instable at the compressor wheel because it's trying to push more mass flow and pressure than the engine will take in. The ported shroud basically allows that excess flow to recirculate. Because when you're WOT, the BOV is closed.

As you were incapable of doing the MatchBot exercise, like you were unable to do the control volume analysis, I did it for you. Again. If you pay attention to what I'm saying, maybe you'll learn something. Here's a link to the MatchBot analysis:

https://www.borgwarner.com/go/TQQ0JM

I had to make assumptions of course (VE, BSFC, A/F, turbine efficiency, etc), but I put in low values for IC effectiveness and high pressure drop to account for the small stock setup on the FC. I set the boost target to about 15-17psi which resulted in about 300hp which I vaguely recall what Rob said he was running on the track. Maybe I'm making that number up, whatever. I picked BW compressor and turbine sides close to the G40-900. Even with this big turbo, ~15psi at 4k rpms. The first 3 points are relatively close to the surge line, so there may be some flow going through the ported shroud. So you get partial credit there even though you were just guessing. But it's clear that above 4k rpms, the operating points are away from the surge line and therefore no flow would be going through the ported shroud. This setup even has positive engine delta pressure until 7k rpms.

 

acknowledging your post and I’ll come back to comment after reviewing it all in detail, but I can tell you right off the bat that your turbine plot is on the wrong phi line and even your turbine flow numbers are off. The car was only making 350 whp when this discussion started. That’s not going to be 30 lb/min turbine flow indcating on your data sheets; which is going to equate to low 500-ish whp on a 13B, but down in the low-mid 20-ish lb/min off the top of my head.

So while I haven’t looked your data over in detail yet, my rough assessment is that all your numbers are off and the way to see it clearly is to place 25 lb/min on the Garrett G40 1.06 turbine map. That’s only just at the very beginning of the turbine curve on a G40-900 1.06 T4. Again, the turbine is ridiculously oversized for this application. Write an entire novel with numerous graphs and pictures if you want, but it’s all meaningless against the reality indicated below; just barely scratching the turbine curve map at peak rpm. Which is what I’ve been stating over and over again:





so let me give you a tip here. When you’re putting Garrett turbo data into the BW Matchbot program, you have to first plot the data on the Garrett maps and then transfer that over accordingly to the BW maps. Which it isn’t going to align exactly on the BW phi lines with them being different turbos/designs, but it can be plotted on there. Anyone can see the Garrett point for the peak dyno result indicated above is at 1.25 Pr, not 2.00.

All of your numbers are off is my initial just glancing it over assessment. Just because you threw some numbers into Matchbot and it spit out something that matches your expectation doesn’t have any merit. It’s like any program; GIGO (garbage in, garbage out). You have to be able to understand if the computer generated result mirrors the verified output result. So what was plotted out in the copied post above defines that understanding for the person who posted it.
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so this turned out to be an interesting exercise, because I hadn’t ever tried to process such a small output through such an oversize turbine before. And it oversized such that the engine can’t output enough to reach the turbine flow map line until 5500 rpm. Even at the peak 350 whp output it’s hardly putting any flow out the wastegate. Which isn’t going to be easy to control.

I hadn’t considered in the initial assessment of the previous post that with the turbine being so oversized that all the exhaust flow is going through it with essentially little-no wastegate flow until 6000 rpm. However, it doesn’t get there until 5500 rpm and then it just hovers with the data points bunched up on each other.

It took some effort to get the output and flow values to line up in Matchbot. There’s some guestimates involved and not perfect, yet should be close enough that the true combination of values isn’t going to have any significant impact on the numbers.

The bottom line is it’s 750+ rotary whp turbine on a bone stock 13B FC turbo engine including the original factory intercooler, throttle body, intake, ports, etc. thats only making 350 whp @ 21 psi boost with gutless response and lag. With the 1150 compressor it might be a good choice for a big power 13B PP engine:

Screen shot of dyno:

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Compressor (blue) vs Boost (red)


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I used a BW compressor wheel/map similar to the G40-900 along with a BW turbine similar is physical diameters to the G40.

Your values below make no sense.

• First, good luck finding an intercooler that's 95% efficient. Most OEM intercoolers are in the 75% range. Barring that error, you have a random drop in intercooler efficiency from 95% to 79% over a 500rpm span. That makes absolutely no sense.
• Your scaling of pressure drops is not correct. Pressure drop scales to the square of mass flow rate. I did a sample scaling here for you.
• 
• Your turbine efficiency values are too low for a modern turbo.

• You did not adjust the turbine pressure ratios correctly. All the points have to line up on the same flow line. What you have plotted would be like if you had a VGT turbo or you magically swapped turbine housings while the engine was running. The instructions clearly say the points need to lie on a single flow line because that flow line represents a single turbine housing
• Also, you absolutely can't try to plot the Garrett turbine flow lines onto the BW maps shown here. This BW turbine phi value = mass flow * (sqrt abs temp)/abs press. Garrett does corrected mass flow = mass flow * (sqrt (turbine inlet temp / Treference))/(turbine inlet pressure / Preference). So their flows are corrected differently.
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I did goof a bit in my initial match. During spool-up, the wastegate % should be near zero. I corrected it here. https://www.borgwarner.com/go/41PBWW

Borg Warner or Full-Race posted a series of videos on how to do turbo matching on matchbot way back in the day. You should go watch them.

 

This is Rob's FC dyno? Look at that, my turbo match using a close BW turbo, never having matched a rotary before, is within about 15%. I chose 17psi target because I vaguely remembered the 300hp number. My turbo match lines up fairly closely with orange line, the middle boost level run. My torque values are quite a bit off at 2k/3k rpms which means my assumptions on the BSFC and A/F are way off there. But hey, not too bad for spending like 30 minutes doing it and no reference point.


I just did a quick adjustment at 2k/3k on BSFC and AF to get the numbers more inline.

 

you can’t do that either on the turbine side, because physically they don’t equate at all due to the different design concepts.

for a given power output there’s a given mass flow out the exhaust. The G-series design moves that same flow through a smaller diameter impeller than the BW does. It’s not just a smaller diameter though, it’s the full configuration of the turbine impeller design that skins the cat a different way. Not just against the BW impellers, but the former Garrett GTX impellers as well as others.

which I noticed you don’t have any turbine data on your revised posting …

there’s no way they’re going to line up on the same phi line in the orderly fashion as indicated on your original posting. That particular phi line you used is way too low relative to potential output flow compared to the Garrett turbine we’re discussing.
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The primary issue on this is simple; the actual flow rate and horsepower potential of the turbine is being greatly underestimated. It’s the same thing I’ve been speaking about on this forum for the last two or more years regarding the Garrett G-series. It cannot be directly compared to other turbos by the dimensional diameter of the impellers. It’s not even directly comparable that way against the previous Garrett GTX series.

The other person attempting to work this on Matchbot has selected a BW 300 series turbine that’s an equivalent match to the G35 range rather than the G40. The closer BW equivalent for a G40 is the 400 series range, specifically between the BW S400 178855 with 83mm 1.10 turbine rated for 500-900 hp range and the BW SXE400 14009097006 with 87mm 0.90 turbine rated for 500-1000 hp range. These compressor maps are irrelevant, they just clarify which BW turbos I’m referencing:



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Which it just so happens that the G40 1.06 A/R T4 turbine map line I laid out on the BW Matchbot phi chart falls between them both. And no, I didn’t plan it that way. Which brings us to the contention that it can’t be done that way due to a difference in calculation methods or whatever. That’s simply a false claim by someone who hasn’t put it together yet. How do we come to this understanding?

First, you have to line up the turbine output points to match up on the specific turbine phi line. And what data actually defines it? This data; the Turbine Corrected Flow @ 59°F:


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And once you reach an understanding of how those flow rate values line up on the phi map, you can then also come to the understanding of how the Garrett turbine map flow line will also layout on it. Which also just happen to represent Turbine Corrected Flow @ 59°F
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This is another point I’ve been try to share with people on here who refuse to either hear or consider it. They can and do line up. Yet this initially wasn’t even how I came about understanding it. That occurred from me laying out many, many dyno results on Matchbot of both BW and Garrett turbos with the understanding of how they correlate relative to corrected turbine flow rate relative to hp and other variables. Because when you can do that, they all line up just as I’m showing you with Garrett turbine line plotted on the BW Matchbot phi chart. Garrett just lists them individually by frame size while BW put them all on the same page together in Matchbot. Which you can readily see on the phi chart how they overlap with a larger turbine impeller matched to a smaller A/R is on the same line as smaller turbine with larger A/R. With Garrett you have to pull up the smaller and larger frame turbine maps and then you can see how they overlap. Like a G25 0.92 A/R has the same approximate turbine flow line as a G30 0.83, and a G30 1.01 A/R has the same approximate turbine flow line as a G35 0.83, and so on. It's an important thing to understand.

The thing I’ve been saying over and over is that the A/R value isn’t what matters, it’s the flow rate potential. The A/R only designates the flow ranking hierarchy for a given turbine wheel. Which correlates the velocity through it relative to mass exhaust flow rate, which correlates to engine power output. So I’ve claimed several times that the person I’m contending with demonstrates a lack of familiarity of rotary engine dynamics. The words that admit to it are that he never tried to plot a rotary before, yet also wants to claim that his results are close, when they’re not. I’ve repeatedly stated that the 350 whp results demonstrate how poorly fitted the G40-900 1.06 T4 is for that.

Instead of going back to the video to confirm anything, numbers out of memory were used. The thing is, choosing a lower output to use on an oversized turbine is only going to be a worse result. Which many of the other things mentioned, like using too high of an SMIC efficiency rate, are only being made as not well thought out points of contention. Using a lower efficiency value only makes the numbers worse by putting the turbine output point further away from the turbine phi map line. Just as the claim that I need to go back and watch the Marchbot tutorials. The same tutorials that in part #2 and part #3 on youtube state that if the flow point can’t line up on the necessary phi line the wrong turbine has been selected. The reality is this; you can’t see the error of those claims if the wrong phi line is being used to plot incorrect output values. Particularly if the phi line selected is too low on the list, as was done.

Yet I’m not without error either. As mentioned, the turbine efficiency values I used in the previous plot are not proper. I’m not sure how that happened or how I didn’t notice it even. No excuses intended, but mapping these out is tedious and difficult, requiring many manual iterations by refining the inputs to match the outputs properly. Which we don’t have or know all of those data points. Some guesses and assumptions have to be made initially and then worked through. I’m not entirely sure what turbine efficiencies to use are in a case where the turbine is much larger than it should be. Regardless it’s not a point of contention for me. I’m going to use the same values he selected for my revised results below at the end.

Yet there are certain things that also have to line up properly. Of which, not only do the hp output values on Matchbot have to align with the dyno output values on the video screen shot I posted, but they also have to match up properly with the corrected compressor mass flow rates. That correlation has been put forth by Howard Coleman, which per his calculations specifically for the rotary engine equates to 1 lb/min corrected compressor mass flow equates to 7.52 rotary whp:


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The way you get there is by adjusting the input variables that aren’t known until it starts to line up properly. Which again comes about through tedious manual iterations. It’s not easy or simple, but it can be done. Mine aren’t within 15%, but within 1 or 2 hp. The contending result indicates 313.2 hp @ 45.37 lb/min, but that flow rate translates to 341.7 hp. So the input values are not matching the output values properly.

Further, a similar BW compressor map can’t be used, it is of no use at all when evaluating the Garrett turbo. No, you have to plot the corrected flow and compressor P-R values onto the Garrett compressor map and then use those efficiency island values in Matchbot. Which again, the wrong input value only generates an incorrect output value.



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So I went through this again. The revised turbine efficiency values do help put points 2 - 6 on the Garrett G40 1.06 T4 phi line. However that’s only 4500 - 6500 rpm and points 4 - 6 are stacked on top of each other as indicated in the turbine output data phi numbers. The WG sizing reveals how little control there must be due to the turbine being so oversized. Further, in order to get point 1 @ 4000 rpm to line up on the phi line requires an 85% turbine efficiency value; not going to happen. As stated, some of the contentions about incorrect values being used only generate a worse result. Which if the turbo selected was only intended as a 4500 - 6500 application then ok. Otherwise as stated by the BW engineer in the Matchbot tutorials; if the values don’t line up; and below 4500 rpm they don’t line up, the incorrect turbine has been selected.

Which is what I’ve been stating over and over again. You need to understand those turbine selections are for both the -900 compressor and the -1150 compressor. The rated output range for them is 500 - 1150 piston engine hp. Which again using Howards formulas translates to a 384 - 885 rotary hp range for those compressors. That in itself should shine a light on the turbine selection. When in fact a 350 hp result is below the stated power range, it’s not one of the larger turbines that should be selected. What have I been saying? This; it’s still too big for the application, but the smallest 0.84 A/R T4 turbine housing would be the much better choice.

That was without me running any numbers. Because again and again and again; once you obtain an understanding of what flow rate for what rotary hp and how that then lines up on the turbine flow map, you don’t have to run the numbers to have a general understanding of what the potential outcome is going to be. So as I stated before; a G35-900 1.04 T4 would have been a much better choice, but my personal choice would have been the G30-660 1.06 T4. Importantly stated though; don't get caught up that they all happen to be 1.06 A/R. In this particular case that's all just circumstance. Because on the G30 and G35, there is only one divided T4 option and it just happens to be that they're 1.06 A/R

Which is still not going to give the best response for a 13B making only 350 whp, but that’s the only divided T4 housing Garrett offers for the G30. However Pulsar does offer a 0.84 div T4 for their copycat version and it directly retrofits onto the Garrett. Likely the emap would be higher than they would prefer on pump gas though, but possibly still workable for only 350 whp. If I get the energy and inclination, I might just run estimated output for the G30-660 1.06 and post it up. It’d be a great choice imo for a low-mid 450 whp 13B on e-fuel with the boost cranked up in the low rpm range.



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respectfully …
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extremely minor nit, but missed a typo

1 lb/min corrected compressor flow = 7.532 rotary hp
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Where did I say I was trying to match a Garrett G40-900? I mean, I could match a G40 doing it the old fashioned way with hand calcs, but that's a relatively time consuming exercise compared to just using matchbot to illustrate the operating points of a turbo similar in size to the G40 on a 2-rotor. I matched a BW turbo with similar specs to the G40, not an actual G40. Have another look at post 66, I included a link there to my update. You just missed it.

 

To attempt to overlay BW and Garrett turbine maps, you must know these values:

For BW, you have to know the absolute temperature and pressure during the testing over the entire map.
BW turbine phi value = mass flow * (sqrt abs temp)/abs press.

For Garrett, you have to know the turbine inlet temp, turbine inlet pressure, and what Garrett uses from their reference temperatures and pressures.
Garrett does corrected mass flow = mass flow * (sqrt (turbine inlet temp / Treference))/(turbine inlet pressure / Preference).

You know the values for turbine inlet temp and pressure are not constant during a gas stand mapping right? So do you somehow have access to both BW and Garrett confidential gas stand test data?

 

At what operating point does this correlation work? Again, you show a lack of fundamental engine operation. Below is an example of a Brake Specific Fuel Consumption map which as you can see, the value varies greatly depending on load and RPM. It's not a constant value like your assumption of 1 lb/min = 7.532 hp for a rotary. And that values changes of course based on how the rotary is ported, etc.

 

That's a rough rule of thumb for what you can expect from a properly sized turbo and correct porting for that turbo. ~10hp/lb piston, ~7hp/lb rotary. It's not exact but it lines up quite well. If you're below it you aren't making full use of the turbo, and bless your setup and ability to bend physics if you are above it.

At 89lb/min, an EFR 8374 should be good for a max of 630hp crank, -15% gives us the advertised 550whp accepted maximum. As long as the turbo flow is the bottleneck, this is a reasonably true statement

 

89lb/min? Aren't they rated at an optimistic 80lb/min and a more attainable 70-75lb-min?