The vid in the link I provided, though a year old does a good job at explaining the differences in this particular size of EFR and G series. More importantly, it shows that claimed efficiency isn't always the case.

Turbine speed seems to be the factor here and is most likely the reason that emap logs from various sources in at least 2 sizes of the latest EFR models with larger compressor wheels haven't been an issue.

 

Some epic fails in accounting for different flow rates mapped at low boost and not matching speed lines to the flow/pressure point at high boost.

If he actually picked the closest speed line at 3.5 PR on the BW as the garrett they would have been near dead on fir both flow and shaft speed.

I think a back to back on the same engine with runs targeting equal intake pressure and also equal torque at rpm with back pressure would tell you a lot more on real world performance.

 

if you read in the comment section of that vid one of the first few posts has a back to back with these 2 turbos on the same engine / set up. Not only did the EFR out perform the G series, the Garret had and caused unwanted issues.He has all of the logs as well.

 

Both turbos have advantages and disadvantages that will apply or not to various applications.

I surely hope the G series Garrett can exceed the amazing EFR series on the rotary. We would all win.

But my money is on EFR on a 2 rotor after my experience with EFR 7670 and Borg Warner's focus on reliabilty over packaging concerns.
Though he tries to gloss it over many times that BW center bearing cartridge is longer than Garrett's and the BW full back exhaust wheel was done to make the relatively "fragile" when cold Titanium Aluminide exhaust wheel more robust.

The Mar M G series exhaust wheel shape and sizing is Garret's effort to likewise lower exhaust wheel mass while not sacrificing flow. Like all metals even a "super alloy" will be stronger cold and weaker hot unlike a cerametallic compound like TiAl.

Powder metal plus 2ndary processing technology as used in aerospace and F1 (and Indy, thank you BW EFR 7163).

https://www.sciencedirect.com/topics...nium-aluminide

 

In his 2 part g series vs EFR videos he breaks down all the differences. Basically says EFR is superior, unless the largest EFR won’t support the power you want, then go to a G series.

EFR: larger cartridge bearing, lighter turbine wheel, fullback turbine wheel (like full motorsports spec g series), better response, better water cooling channels, etc. But of course it comes at a cost

 

I was looking at the G42 1450 and was actually considering it to replace my 9280(which we havent even got to test yet).

After seeing Dahm push that unit on his 20b and hearing him talk about the massive EMAP I'll pass...

If i.was considering a Garrett, I'd run a gt55 and make more power. Alot more. Those compressor maps from Garrett on the G series are too optimistic to say the least.

 

The older EFR simply cannot be superior in ALL ways to the newer G series.

That isnt how it works.

Superior for your or my application. Possibly.

Example, if a 1,000hp EFR 9280 doesnt fit in your car's engine bay ... a 1,000hp G- series that does fit is going to be the superior turbo.

Comp or Precision turbos.
The turbo you can afford or is allowed in the racing class sponsored by them will make more power than no turbo.

Lets not forget Garrett bankrupted itself giving free turbos to Youtube influencers. Thank you for the turbos!

Lets hope Garrett rises like a Phoenix!

 

Take it from someone who worked in turbocharger development projects for a couple OEMs.

The Y axis of a compressor map is the pressure ratio between the compressor inlet and the compressor outlet, known as p1 and p2, where p3 is the turbine inlet pressure and p4 is the turbine outlet pressure.

The Y axis is NOT the pressure ratio between the atmosphere and the intake manifold. That matters more than you think. The level of restriction across the intake (air filter and any ducting) determines the slope of the mass airflow vs p1 relationship. p1 decreases with boost. There's effectively a pressure drop as you increase airflow.

p2 is the compressor outlet pressure, not the intake manifold pressure. So it doesn't take into account pressure drops across the intercooler and piping. Remember, compressor maps are made on a gas stand (Basically a gas burner) at the turbo suppliers lab, not on a real firing engine with exhaust and intake pulsation. The maps are not always reflecting real world performance, or even engine test stand performance. If you're running 10psi in the intake manifold, you're most likely NOT at 1.7 pressure ratio, but somewhere higher than that. In that case you're probably running in the less efficient area of the map if your boost is high enough.




Bottom line, the edges of the compressor maps aren't fully accurate because they aren't developed on real engines, and the pressure ratio to consider is higher than you think. Also, exhaust manifold pressure (roughly corresponds to p3 on a turbine map) is only indirectly related to the compressor map. It depends on a lot of factors like manifold design, turbine housing A/R, and the exhaust event timing (porting on a rotary or valve timing on a piston engine).

 

Also, regarding Garrett bankruptcy - automotive suppliers are driven on volumes, and internal combustion engine volumes have not been growing for a long time. Most new engine development has stopped and tons of people have been laid off, retired, or reassigned. A good friend of mine was a turbocharger application engineer at one of the big turbocharger manufacturers and the whole enterprise was massively downsized years ago.

Aftermarket turbos are a drop in the bucket. The volumes are low, but the margins are huge in comparison.

 

i'm surprised that nobody has built a box or something to log this, i thought about it, but by the time you add the temps in, its more complex than i was willing to do. (i was picturing something modular)

 

Watch the breakdown videos and tell me what you think. More money spent on production can mean a better overall product. The EFRs seem to have a lot of features the full motorsport Garrett turbos have, but those aren't exactly available to people like you and me.

But sure, a lot of the time it comes down to fit or budget or specific power goals, in which case an old kei truck turbo might be best for whatever you are working on.

 

The G42-1450 is a poor match with 98mm compressor exducer on the 79mm inducer G42 turbine. What would be an awesome match is you take that same 98mm exducer compressor and put it on the G45 turbine. That combination would rock. The G42-1200 is a pretty good combo with the 91mm exducer compressor. The G40 is a really good combo with the 88mm exducer on the 77mm inducer turbine. I think Garrett went too small on the trim of the compressor for the G40-900. They should have made it a G40-1000 in my opinion. The G35-1050 is so-so, they went a bit too big on the compressor diameter for that turbine wheel. Not horrendously too big, unlike the G45s, but fairly far out of optimal. Out of these bigger turbos, the G40 is the rock star. I'd avoid the G45s completely; the compressor diameters are too big for that turbine wheel. If using a G35, the G35-900 is the one to get. Want more power? G40-1150. The compressor maps are legit. What you're not seeing are the turbine maps. When you pair too big of a diameter compressor for a given diameter turbine, you end up with a poor blade speed ratio. That results in poor turbine efficiency. Poor turbine efficiency end result is high turbine pressure ratio, i.e. EMAP.

 

Garrett declared bankruptcy because Honeywell saddled Garrett with a $2 BILLION dollar liability for asbestos when Honeywell spun off Garrett. Go back a bit in history, Garrett was part of the Honeywell Transportation division which included Fram, Prestone, and Bendix Brake Pads. Honeywell sold off all those business groups leaving just Garrett. However, there was no way Honeywell would have been able to sell Bendix with its $2 Billion asbestos liability because Bendix was way too small. Garrett was the last company standing in the Transportation group and when Honeywell decided to get rid of Garrett, they saddled them with the $2 billlion liability that was attached to what was the Transportation group.

https://www.businesswire.com/news/ho...Indemnity-Suit

 

The MarM material of the Garrett G-series, same material as used in Garrett motorsports turbos, is rated for 1050degC. TiAl is only good for around 980degC. The Ferrari 488 has IHI turbos I believe with TiAl turbine wheels and those are falling apart in their Challenge cars. Keep in mind Garrett turbos have been on every 24 Hour of Le Mans winner for the past two decades. And every WRC car for two decades. And all the current German DTMs and Japanese Super GTs. And Ferrari F1. And first to market with an e-turbo on a gasoline engine. Garrett has typically been the largest OEM supplier followed by Borg Warner. Then you have the next batch of players like Cummins/Holset, MHI, and IHI.

 

the G series has a longer (deeper? taller wheel?) so that relationship is going to be different than the older stuff.

 

as we all know, the OE market is the 100% driver for turbos.

we are very close to a revolution as to OE turbos.

the revolution is E turbos and Garrett is at the head of the revolution. the concept is smaller displacement gas motors with large turbos. turbos of the size that the motor would not normally be able to spool. enter the electric motor on the back of the turbo and either 48 or 96 volt systems to drive the turbo..the E motor primarily works in spool and transforms to become a charger under cruise when the exhaust powers the turbo.

consequently the volume of turbos will explode. this is why Garrett has been aggressively working on their hardware. Garrett merged with Honeywell a few years ago and has used (and is now using) Honeywell's vast aero/aerospace resources to redesign their turbos. Honeywell spun off Garrett but holds a significant equity position. Mercedes/AMG currently have a number of Garrett E turbos out on the streets doing initial real world R&D.

since the Jan 4 top in the market the S&P 500 is down 17.2%, Borg Warner is down 21.3% and Garrett is down 12.2%... less than the market and almost half of the BW decline. and yes i know that BW is a 10 billion dollar topline company and there are other factors of influence. Garrett, OTOH, is a pure turbo play and the outlook is stronger than the general market ATM.

i have always held Garrett turbos in esteem. i ran a GT4094r for my first, and only to this point, Texas Mile attempt. i needed about 575 to accomplish my goal... just under 80 lbs per minute. no problem. the neat thing was that the GT4094r was a hybrid sizewise. 80 pounds per minute on a smaller frame. we all remember the GT3582r, the precursor to all the modern turbos today.

then came the Borg revolution, especially a good fit for our rotaries. lots of exhaust flow and loads of options especially the EFR line. i ran an EFR 9180 and thoroughly tested an SXE 62. good stuff.

over the years two considerations have opened my mind to consider other options.

i had the good fortune of spending a day with Dan Barlog. Dan is the ultimate brain behind Precision Turbo. as we were touring their ever expanding facility we arrived at the turbine wheel area. he was explaining the difference in shape between the Precison and EFR hotside wheels. i asked him if they had ever evaluated the titanium aluminide material for their turbos. he replied, "yes. we decided to pick flow over weight." i asked him to elaborate. he said that because of the material's properties they were unable to form it into the shape they needed for max flow. of course that could be BS or not. having a feel for Dan at that point i vote not.

Titanium-Alumnide is primarily used for the fan blades on the GE's awesome bypass jet engines.

the second consideration also relates to the hotside wheel on the EFR. i was at the Tail of the Dragon last year and attended a BW lecture. during the lecture Brian Rheinhart casually mentioned that EGTs should not go above 1765 (!). huh? that's the first time i heard this. after his presentation i buttonholed him and pursued the matter. he said, he thought it was in the 120 page PDF on the EFR turbos. maybe i missed it, but have yet to find it. perhaps it is other later materials. rotaries run at least 200 F more egt than piston engines. i often see mid 1800 egts around 9000 and 600 rwhp. i do realise that i haven't seen anyone "melting" their wheels but Brian was dead serious about Gamma Ti "changing state above 1765." i take what he said seriously. he said it seriously. he is a BW design engineer.

the weight advantage is not as clear cut as it may seem. while the material is significantly lighter V inconel per volume i suspect there are a number of offsets. the PDF goes into great detail as to how hard it is to cast. i suspect the fullback section of the wheel functions more as structual support for the vanes. Garrett's wheel does not have this added mass. further both the compressor and hotside wheel have more vane and less non-working centers. here's a comparative picture i took of my 9180 and my new Garrett G40-1150. take a very close look at the vanes. the picture proves out Dan Barlog:.




notice how thick the EFR vanes are as well as not being as complex a shape. notice the relative mass of the wheels. notice the scallops between the vanes on the Garrett. less mass. i believe the additional "fullback" on the BW is probably more for support than flow. more mass. finally, on both the compressor and the hot wheel, the center is significantly larger on the BW. the diameter of the center on the BW hotside is .965 whereas the Garrett is .87. centers do no work and to the extent they exist they remove vane length.

then there's the big balance nub on the end of the wheel. compare. note also the mass of the fullback section which doesn't exist on the Garrett:

BW


here's my Garrett G40-1150:



this post is not meant to be a thumbs down on BW. there are many wonderful aspects of both the EFR and SXE line of turbos. much of turbo selection comes down to specific needs and each of us is different. for many the EFR8374 is a great fit. for me the G40-1150 was the best fit. i picked it for.... Efficiency as number one need. around the 80 pound area it is awesome. i am after lower IATs.

i look at relative efficiency island placement and width.

at 26 psi and 68% efficiency:

G40-1150 50.5-102 pounds per minute 51.5 total width
EFR 9180 50-84 34 width
G40-900 36-76 40
G35-1050 51-90 39
EFR 9280 53-86 33
EFR 8373 32-67 35
EFR 8474 42-51 39

i will be generating some comparative data soon.

 

And Borg Warner sold its asbestos liability to an insurance company...

But my humor...

_____
Those material data temperature ratings.

Before anyone gets scared the TiAl cant handle rotary heat.

I put ~40,000 miles on regular Garrett Inconel P-trim exhaust wheels with 1,000c egt cruise, 800c on tip in and climb ~900c 4th/5th pulls .

I switched directly to EFR 7670 with only an additive tune and no issues there either.

 

My opinion:
The battle between BW and Garrett over this little hobby "motorsports" market for turbos is real. Dont let them try to downplay it.

When BW had early production teething issues with TiAl turbine wheel reliability 10 years ago Garrett was aggressive in trying to exploit that on the consumer level.

Litterally trying to give away Garrett turbos away to anyone with a failed EFR.

Like they give the new G series turbos to social influencers now.

BW will make you pay full price for your turbo and you will probably have to wait a long time.

Hmmmn...

 

"no issues"

not disputing that so far all is fine w the heat/EFR hotsides.

when i eventually do get back to the Texas Mile it will be 30 seconds at 575+ ending in 6th gear at 7000+ almost static rpm. IMO, this will be a serious test and i would rather not speculate. plus i will be seeing lower IATs w the G40.

 

Howard, what fuel will you run? There is a significant difference in EGT from race gas vs E. Trying to figure out why you "need" to hang around that 68% efficiency island.

My initial goals are making standing half mile hits, 16 seconds at 780+ in 5th gear at 8300+.

Also rolling 60mph TX2k and SCT.

The 9280 at 2.4 bar (on the car not map) on Ethanol One should be good and not on the bubble.

Of course real world has it's own reality, we will see if it agrees with this.

 

"16 seconds at 780+"

time is a big deal, primarily but not exclusively due to intercooler heatsoak. easily above 75 rwhp in 30 seconds just from heatsoak.

30 seconds is a lot of time to roast everything. also, if i don't do the 200 at 575 i will be turning up the boost.

not in any way diminishing your challenge which is significant but fun.. i hope we both get out on track to meet the real world soon.

 

Coming from the motorcycle world , the mile was the big deal, even 1.5 mile at Loring where a Busa broke 311. But man was it dangerous. Cars and bikes are so fast now as technology has progressed, you don't really need to stretch it out.

Now that the runway racing has kicked in with side by side racing shorter distance, roll racing at 1/4 mile venues and land speed is half mile now primarily, it only makes sense to have a well rounded set up. I think even for the rotary engine, tuning tech, safeguards and traction control has caught up and is now available. Even DCT.

Ethenal One really allows the big power.

Definitely would like to meet you at one of these.

 

The Turbodirect videos weigh the wheels, the EFR is significantly lighter despite having a fullback design, and the G series full motorsports turbos use a fullback design even though it might add weight. But I don't see any benefit to a lighter wheel in a 200+ speed run anyhow.

 

Regarding the design specs for the thermal limits:

Generally speaking those specs are at steady state on an engine dyno. Like running for hours on a durability torture test stand. So when he says 1765F or ~960C, it's not for a few WOT pulls or even for a few laps. It's for like... a few days. A 100 hour durability test might be running at steady peak power WOT on an engine for a certain number of hours, change the oil, and run again, until 100 hours are reached and the engine is torn down. In the various turbo matching activities I was working on about 8 years ago for OEMs we would target in that 960-980C steady state range (exhaust inlet temperature), with the understanding that it would spike higher occasionally in severe situations like towing. Those exotic alloys aren't common in high volume applications.

Another possible misunderstanding is that he may be referring to a specific thermal point of the metal itself, not the exhaust inlet temperature. That temperature may not be possible to measure without a special test stand, or it can only be calculated with simulation software. For example I had one project I worked on where we were comparing the calculated temperature in the cast-in integrated exhaust manifold of an engine to a simulation result. The drilling and wiring required wouldn't fit into a vehicle and would be reserved for test stands only.

 

"Howard, what fuel will you run?"
75% VP X85... (85% ethanol, 25% 110 octane gasoline)
25% VP Q16

ethanol for octane and lower egts, Q16 for the oxygen and BTUs.

"Trying to figure out why you "need" to hang around that 68% efficiency island."

sorry for any confusion. the 68% island has nothing to do w where i will be running on the map. it is simply an island i picked so i can compare compressor maps.

"EFR is significantly lighter"

it may be lighter but a simple look at the vanes shows they had to compromise flow for durability. they are significantly thicker near the hub and the hub is larger than the Garrett. i think i have a picture of the compressors and it is very clear the BW compressor hub is also larger than the Garrett. of course i am only referring to the two turbos i owned, the EFR 9180 and the G40-1150.

"he may be referring to a specific thermal point of the metal itself"

i agree w your post and it could be he simply mispoke. when he first mentioned 1765 it was in regard to egts. "don't run over 1765..." when i spoke with him afterwards i asked him why. he answered because the material changes state above that temp. i mentioned that the EFRs had been out for 8 years and the caution was new to me. i was stunned. he said it was in the EFR literature. i did a very brief review of the 120 page EFR PDF today and found nothing nor anything in the new catalog. i do think it isn't much of an issue but i highly regard Brian and it was just weird. if i was still running the turbo i would email or call him... but considering there have been zero melted hotside wheels it is probably much ado about nothing. i probably shouldn't have brought it up.