Yes, they are. My guess is he got the 9180 map mixed up.

 

I’m not even getting into it anymore beyond this final post

one day he’s on here recommending to the guy making 415 whp @ 16 psig on a Renesis 13BSP with a Garrett G30-660 1.01AR V-band to size down to the 0.83 AR. This turbo is equivalent to the old GT35R with same AR wrt compressor and turbine flow, just more efficient and less MOI to spool up, but with open-scroll turbine since the Renesis has co-shared exhaust ports.

https://www.rx7club.com/rotary-car-p...-dyno-1154187/


and here a guy is asking for the best turbo choice in the 350 - 400 whp for a single-turbo FD and he recommended a G40-900 0.94 AR. That’s a terrible choice, really awful compared to the 7670/8374 EFRs or even the old GTR35 or HKS turbos the shop was pushing.

https://www.rx7club.com/single-turbo.../#post12526548


and he’s in this thread now attempting to defend a G40-900 1.06 T4 on a choked up FC 13B barely able to hit 350 whp with it when Rob Dahm himself admits what a bad choice it was at the end of the final dyno session. I predicted what would happen before he ever got to tuning it.

https://www.rx7club.com/3rd-generati.../#post12499685


yet, I wasn’t as confident then as now



Go to those Garrett maps and compare the flow ratings. It doesn’t make much sense. What does make sense is that Renesis result in the first link above. That G30-660 with 1.06 div T4 turbine is exactly what the other two cars should have. It’s the next-generation equivalent to the GT35R. This is what he’s arguing against, with the equivalent of a Borg Warner S400 sized turbo.
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Yes my mistake on the 8374 flow. They are rated at 79lb/min. Making the 7.5hp/lb more attainable.

 

about 575 or so is the most I’ve seen and rarely at that; 560 is more common and theoretical is 590ish, but the efficiency out there is falling off rapidly. Which has to be considered some. IMO all the EFRs are a bit overrated wrt compressor map peak flow potential for that reason. So ~75 lb/min is a bit more reasonable as seen below.


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Hopefully I've taught you some things like:

• how a throttle body changes pressure in the intake manifold and the throttle body's relative restriction in the intake side based on position
• how different types of BOVs work
• what a control volume analysis involves
• what a ported shroud does
• how you can't compare BW to Garrett turbine maps because they calculate corrected flow differently
• pressure drop in intake and exhaust systems increase is a function of mass flow rate squared
• I linked you to a whole engineering grad level book on turbochargers
  • did you read it?
  • if so, you'd have an understanding of compressor to turbine wheel size matching, effect on blade speed ratio and the resulting effect on turbine efficiency. And turbine efficiency effect on spool-up and power.
    • based on your recent comment, it does not seem you have read the book and therefore haven't learned anything
• when doing a turbo matching exercise, all the turbine operating points have to actually be on the same flow line
• BSFC is not a constant value, but actually a map

Rules of thumb for BSFC are great for estimating the peak power 'potential' of a turbo. I use them all the time. 9whp per lb/min airflow with E85 on a piston engine. 8whp for 93 octane. 7whp for 91 oct. It's a rough ballpark, +/-10%, for peak power estimation. It's no better than that because: different intake setups, different exhaust setups (test pipe? cat?), cam profiles (porting on a rotary), port injection vs direct injection, etc. It's definitely not accurate to 4 significant figures. And the rule of thumb is again really just for peak power estimation. When you're trying to do a match that looks at the full rpm range of operation at WOT, you need more accurate BSFC values at each rpm.

On the topic of the G30-660 on the Renesis. Weren't you the one saying the G25-660 with 0.92 would be a better match because you were only looking at turbine flow? And then the testing showed the G30-660 with 0.83 did as I predicted which was spool faster and make more power.

As for Rob Dahm testing using the G40-900. Is it the ideal turbo for 350whp? Certainly not. Why do you think he tested it? Maybe it's because Garrett was launching it at SEMA that year and they needed to promote it. Of course he's going to be power limited because of the stock intercooler. Duh. But when Garrett give you a free turbo to test, you test it. Why didn't he put on different intercooler parts? Maybe because that's time and money he didn't have; i.e. use what's laying around to make it work.

 

You still didn’t figure out that flow-wise a G40-900 with 1.06 T4 is equivalent to a Borg Warner S467 178855 with 0.91 A/R housing on an otherwise bone-stock FC3 engine including the factory intercooler yet? Even Rob Dahm was big enough to admit it was a mistake in his final analysis. Hopefully one day you’ll come to his eventual understanding on it as well.
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Rob wanted to test the factory intercooler with that setup and see how it would work. It didn't work and that's part of testing and learning. He wanted to do things one at a time because he was interested in finding out the results and sharing the journey, rather than just posting successes. I wouldn't knock him for that.

 

you’re completely off the mark. The entire issue is that the turbo is woefully mismatched for the application regardless of what intercooler is used, especially the turbine side of it. It’s still a factory S5 engine with factory ports, intake, and throttle body.

WRT a 13B, the G40 1.06 A/R turbine selection is needed for 100+ lbs/min compressor flow, yet the -900 compressor is only rated for 80 lbs/min at max allowable shaft speed, and the 350 whp the application made is only ~47 lbs/min.

It has nothing to do with beating anyone down. The only way to help people understand why it’s the wrong selection is to bring them to that understanding. If anything, Rob probably understands this better than anyone else.

don’t take my word on it though


so my recommendation would be a Garrett G30-660 with 1.06 A/R div T4. Which is a 60 lbs/min compressor at max allowable shaft speed, and the G30 1.06 A/R turbine supports 70 - 75 lbs/min compressor flow. Which makes it not too hyper for pump gas, yet still good low end and off/on throttle response. If you wanted something a bit more punchy with e-fuel and/or AI, then a G30 0.85 - 0.92 A/R housing is a better choice
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an acquaintance of mine recently reworked his single turbo REW setup and was recommended and purchased a G40-900 1.06 div T4 turbo. This is a dedicated track setup with a fairly standard single-turbo configuration; 13BREW, Large Street/Race Port, Xcessive LIM, E85 fuel., forward top mount manifold with twin WGs. Unfortunately he had already purchased the turbo before we hooked up about it. Because as I’ve tried to explain here several times; the G40 1.06 turbine housing flow capacity is very oversized for a 13B and suited more for a PP port etc. intake configuration that needs very low emap to minimize exhaust reversion.

He shared the the best run out of the initial dyno session with me privately so I’m not going to post it up, but I pulled the data posted below by approximating points off the graph and then also plotted it out on the compressor map to emphasize the point m; the G40 1.06 div T4 turbine housing peaks at ~39 lb/min and is too big for this compressor on a 13B!

. -26 psi setpoint from start -

3000 130 ft-lbs, 75 whp, 2 psig

3500 175 ft-lbs, 125 whp, 3 psig

4000 240 ft-lbs, 180 whp, 5 psig

4500 340 ft-lbs, 295 whp, 8 psig

5000 435 ft-lbs, 415 whp, 13 psig

5500 470 ft-lbs, 490 whp, 23 psig

6000 460 ft-lbs, 520 whp, 28 psig

. - leaning out 6000 rpm, cut boost to 21 psi setpoint -

6500 380 ft-lbs, 470 whp, 24 psig

7000 320 ft-lbs, 425 whp, 20.5 psig

7250 300 ft-lbs, 415 whp, 18.5 psig


Side notes; this was on a Dynojet dyno, peak values were 522 whp @ 5,900 rpm but it started to lean out there and despite the 80+ psi fuel pressure and total injector CC theoretically being enough (8600cc rating from FIC) it seemed to be running out of injector. So they cut boost 5 psi to keep AFR in range. Peak torque was 471 ft-lbs @ 5,590 rpm, but didn’t cross 300 ft-lbs until 4,300 rpm. No EMAP sensor, but it wouldn’t surprise me if it was was less than 1 for most, if not all, of the run. He’s looking at increasing the injector size and dropping back to the 0.95 A/R div-T4 housing and trying again. It really needs the 0.84 A/R div-T4 imo.

I didn’t plot out past 6500 rpm because those points will be backing up on the previous ones as indicated below and be visually confusing:



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You're a smart guy, so I'm going to let you off the hook on this one...

This is a tuning/configuration/mechanical issue somewhere as the turbo is nowhere near it's surge line and should NOT be acting that laggy. Someone needs to slap that tuner upside the head and replace them immediately.

G42-1200 I have 20psi by 3750 RPM on three cars. Here's one at only 10psi, but it does go STRAIGHT UP from here. This car is running an Aderptronic and only firing on trailing coils currently... Still works better than your buddy's car.



The G40-900 would be running out of compressor flow by 26psi on his engine by redline.

The Turbine Side is not oversized; there's a mechanical issue here. This turbo will continue to WIDEN powerband with the 1.15 and 1.28 A/R Housings on even a Stockport REW block on Pump Gas Boost Levels.

 

What's the setup for 20psi by 3750 rpm? There's no way they can spool that fast? are you on a rolling launch?

Even the G40-1150s t4 twin scroll divided mani's on a bp and with e85 are coming online at 4500rpm with some of the data race only shared. How are you getting 750rpm of better spool on a bigger turbo?

 

Firing only on trailing plugs will cause fast spool at lower rpm but also a lack of power.

I learned this when my ignition went out and was unknowingly running only trailings and started overboosting and creeping but with a slower car...

 

there could be other issues because I’m not there and am only getting information as it’s provided. Which as of last week it’s overboosting on the controller, but not on the WG spring so there obviously is an issue with that. The highest boost recorded was over 30 psi. Which is going to be porting dependent btw, but I’m sure you’re a smart guy too so it is what it is.

the thing is, that compressor is not much different than the EFR8374 wrt output potential, but the G40 1.06 turbine housing is larger flow capacity than the EFR 91/9280 1.45 turbine housing. Which kind of makes sense wrt to it also fitting the G40-1150 compressor, where it would be more applicable imo. However, who would think that they would put that EFR83xx compressor and EFRxx80 1.45 turbine combo together and have it work better than the EFR8374 down low?

But if you don’t trust the EFR comparison since you don’t have a straight up turbine flow map, then let’s reference a Garrett instead. The G-series 900 compressor is about equal to GTX3582 compressor and the Garrett xx82 1.06 turbine combo is equivalent to the EFRxx74 1.05 turbine, but the G40 1.06 turbine is an ~25% jump up in flow.

I’m making these comparisons because the GTX3582 and EFR8374 turbos are known and established for the ~550 whp range on a 13B, but again who here thinks they’re going to make a big jump in turbine capacity and not suffer down low on either one?

We don’t even have to guess, because BW does offer a 1.45 turbine housing for the EFR8374 and it’s been tried:

https://www.rx7club.com/single-turbo.../#post12552782

so again, I’m not a merchandiser of men and don’t need to resort to the forum tactics of vendors and glory seekers. I have nothing to sell, not even myself, or gain in either regard. I’m not a smart guy imo, neither handsome, nor rich, and have the social skills of a bull in a china shop. Which added up more or less means I’m no Don Juan either (did I leave anything out?). I don’t cheat, steal, or murder though and do my best to not intentionally lie or covet things I’m without. Nothing special at all.

However, if it doesn’t add up then it doesn’t add up and regardless of who you are or even if the mistake is my own lack of understanding then I’m going to question it. If for no other reason than to figure out how I got it wrong. Which I did leave out about having been wrong plenty over the years too.
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Thanks for clarifying. Your egts must also have been skyrocketing if the leadings failed.

 

Welp, I cannot seem to find the log I was looking for and don't look forward to converting .ALG to .CSV for these purposes when Aderptronic fails to do that properly half the time.

This one would be the average for a G42-1200 with 1.28 A/R on pump gas, on a motor that has large, slow responding ports by a questionable (at best) engine builder. This is more like what you guys are seeing.

Let's all remember how large of a variance there are from builder to builder on port design. Some engine builders "get it" and most (95% or so), haven't a clue what the hell these engines really want.

In that same chord, Noel in Alaska with a 9180 EFR on a Streetport that idles at 900 RPM will have full boost (14.5psi) by 2950 RPM. WHY? Because his engine builder understands something that the majority of folks do not.

I'll be the first one to ask, "What is your usage and application for the vehicle?" and really grind it home that this is a broad spectrum of usage.

 

EGTs are astronomical when like this. Yes.

 

just want to make sure you meant builder rather than tuner? With the build that’d seem to be more a result of the porting configuration as compared to the fueling/timing strategy of the tuner

I hear what you’re saying though. However the G35-900 1.06 is on par with the GTX3582 1.06 with a little better turbine flow (same for the BW EFR8374 1.05), while the G40 1.06 turbine combo is still going to be a bit more than a 20% hot side increase.

So based on what you’re saying the G35-900 should come on just that much harder than the G40-900 under the same conditions, right? On something more sensitive to emap the G40-900 1.06 might be the better option. Which I’ve been saying that all along.

There are 0.84 and 0.95 div T4 options on the G40. The 0.84 starts just past the G35 1.06 flow. So again I’ve also been saying people need to be studying the situation some and considering the tighter hot side housings if looking at the G40-900 on a 13B.
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Builders and Tuners are both huge factors here, but I did specifically mean Builders.

You're right when it comes to turbine flow; I wasn't questioning that at all. The perk of the G40-900 is that gorgeous compressor map compared to any of the G35 Series. One of the next cars I have is doing the 0.85 A/R T4 G40-900, so I'll have specific data on that. He was between that and an EFR8374, and personally, I'd prefer the Garrett Compressor map over the midrange response-king. It's always a give and take.

I am heavily reliant on compressor map, turbine efficiency, and surge line vs. lightweight rotating assembly in the situation where someone wants to later run e85 and push things hard. The EFRs are sadly unreliable over 32psi or so due to what makes them so great (and up here is where turbine efficiency and total flow come into play).

So I suppose if we know a car is staying on pump gas and moderate boost, EFR should win out, but future proofing for more power, I have more confidence in the reliability of the G-Series. Don't get me wrong, BorgWarner is the king of reliability with their SX-E lineup. Lightweighted-ness makes things more fragile, just a simple fact.

The G-Series will dump less heat into the system regardless of boost pressure, so that needs to be taken into account. If a car has a smaller intercooler setup or a drift configuration where airflow is harder to come-by, then efficiency should be prioritized over response, in my opinion.

Love em all. They all have their place in the industry given the application's true intentions.

Great thread.






G35-900 is a total piece of **** compared to the G40-900... I've avoided running these. G40 or G42 for Rotary 13Bs.

 

Not sure why Howard Coleman's post isn't showing up, but here's what he wrote:

 

"Not sure why Howard Coleman's post isn't showing up, but here's what he wrote:"

parts of the post are confusing so i deleted it and haven't had time to re-write...

 

this is the good part:

"my big deal is width of efficiency islands:

at 2.5 pressure ratios... 21.75 psi at 76% efficiency:

G35-900 47 to 66 pounds width 19 pounds
G40-900 40.5 to 70 pounds width 29.5 WOW
EFR 8374 37.5 to 57.5 width 20 pounds

so an interior look at the map does support a positive view of the G40-900."

 

in typical forum style; it’s was all discussed in other threads and the beginning of this one as well


it’s worth going back to read the entire post:

https://www.rx7club.com/single-turbo.../#post12531914


for continuous WOT such as top speed runs and long tracks, or lower grade fuel like pump gas that’s fine, but it is’t going to do anything to get the jump out of a slower corner at an autocross etc. where you’re only running 60 - 90 seconds on and off the throttle. Which Arghx brought that up on the first page of this thread as well; there’s always a price to pay between response or efficiency. So as per the recent comment by Gucci; it’s best not to overlook that the application matters.
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Experimenting with using Matchbot to generate match data, then create an overlay fit in Excel for a G35-900 1.06A/R on my Cosmo 13B Streetport on pump gas with 10-17psi. Looking for a low emap fit with minimal lag and efficient mid to top end. How do these results look? If I didn't screw anything up it appears to flow like something between an efr 9180 and an efr 8374.

Link to Matchbot Data ==> https://www.borgwarner.com/go/0O6AWJ

Data overlayed on G35-900 maps:

 

Beautifully done. Great way to showcase and share the data as well.

 

an 8374 maybe

it really has to be aligned properly on the Matchbot phi turbine map as I’ve posted on previously, without that it might be questionable, or at least not verifiable. Because I’d expect the compressor map to be shaped differently than indicated.
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