Excellent review of BW EFR turbo(s) vs GTX - data, review, feedback

[5mall5nail5]

I am mirroring this from NASIOC. Its definitely a worth while read even if not considering this turbo.

Borg Warner EFR Turbos


EFR7670

Like a lot of guys out there, we have been waiting for an EFR to play with for a long time!
Someone took this picture of me about a month ago waiting. Ok not really it was from today, but it sure feels like i have been waiting forever.




I know there is no proven power yet, but very very soon. Maybe Nasioc can make a new Turbo section for things like this... Like the GTX thread i started there will be great data to surf through. Lets start with simple things like pics.

I have a bunch more coming don't worry!



Even the badge is way nicer!




The compressor wheel is amazing looking just wait until the shroud comes off.




EFR is 3.25" taller overall and like others have said, this is going to be a challenge to fit into the car for sure!






This is probably my favorite part of the whole turbo. The SS housing is very high quality and the internal wastegate routing is very cool. The angle of the exit is angled perfectly off the inlet. VERY cool.






Another angle showing the turbine.






One of the things i was looking forward is the BOV and how its integrated. It just like the Mini coopers we deal with that have a very similar style. The pressure port is tiny, the spring is pretty weak, but small port means less overall force acting upon it. I know guys are going to be concerned that the port is too small to dump the boost it might see, but it works fine on Minis running 24psi, as well as a bunch of other euro cars. There are stiffer springs available for them but we will have to see how these work first.




The EFR compressor housing is smaller OD than the Garrett. Also has a smaller inlet, which is great for fittment reasons and shouldn't hinder HP at all.






HEre is a side by side of the EFR and the Garrett housings. You can see which one is much nicer. The EFR casting is smooth, not dinged up as though its been thrown across the floor a few times.

Here are the other important things to compare. I tried to take a picture showing the finish of the two wheels. I think it came out pretty good. The EFR wheel is a machined forging and you can see the feed rate of the machining is very slow making these pretty much polished!






Compare the GTX wheel and you can see how much faster they machine the part by the deeper grooves. Borg Warner really took their time making these new turbos really nice.



Its hard to see in this pictures, but the GTX wheels are much shorter compared to the EFR compressor wheels. Its very interesting up close as they shape of the fins are very very different. Its like comparing fins on a ceiling fan to fins on a jet engine.






The one part that i think really make people go crazy is the Gamma Titanium turbine wheel. Its finish is very very nice. The flat bottom of the turbine wheel makes it very strong and also more aerodynamic compared to the split Garrett type. Again the turbine wheel fin design is different.





The Garrett turbine wheel is shaped different, and also has a much thinner cross section. You can almost make it out in the pics. Brock at Borg Warner told me that you have to go up a size in the EFR turbine wheel OD, to compare against a Garrett. In this case 70mm EFR will be similar to the 60mm GTX. Which this makes more sense base on the overall volume the turbine wheel being slightly less with an EFR of the same given OD as a Garrett.




Beside that stuff here are some other cool pics from BWTS.







This cross section shows why the turbo is so much longer. The dual caged ceramic ball bearings are spread far apart for stability, notice the 4 oil seals (Garrett has 2), the oiling mechanism is designed to push oil to the front and back bearings, the coolant jacket spreads deep into the turbine wheel area, the really cool BOV return port and all the other really cool stuff. You can really tell this is over built and designed for abuse.






Here is the GT3076R. You can't see the bearings in this but you get the idea.They don't recommend going 20 degrees of kilter with the EFR, but with the better oil slinger and dual seals on both ends, i bet you could do close to 45 degrees.






These are the 3 main castings used on all the current models of the turbos.











Now the fun begins trying to make this fit!



EFR Turbo Technical Brief


Here is a very in depth article about the EFR turbos and how they came to be. This article is what really got me going on these turbos. Never before has turbo company done this kind of public documentation.

Click Here to Download EFR Turbo Technical breif.pdf

I know, its been a while since i posted, but there was tons to compile and just not enough time in the day to complete this. Anyway here you go! I will repsond to some of the customer posts in just a few!

The Build and the Results

Installing the EFR, or should i say building a turbo kit surrounding this turbo wasn't too hard, it just took some time and planning. I spent alot of time placing the turbo in an area that balanced clearing everything, while still providing a decent intake path and downpipe path. At the time i didn't have the larger EFR8374 or something representing the size of it. On BW's website there were no dimensions that showed the overall size of the bigger turbos, so i resulted to figuring out the scale of the pics in relationship to the part i had. Hoping that the larger turbos would still fit with my initial design, i finished up the upppipe and downpipe and started the install. Below is a pic showing it all mounted up.



As many of you know I had had somewhat of a wasted dyno session/weekend dealing with the medium pressure actuator for the EFR. Essentially what it comes down to is our Subarus run high enough exhaust backpressure that some autowastegating occurs. This is when the exhaust pressure is pushing open the wastegate door not the wastegate actuator. While BW says the Medium canister cracks at various pressures, in my testing I found these don't pertain to actual boost pressures found. Meaning, BW says the Medium canister with 10mm of preload (plus the 2mm added at the factory) will crack open at 14psi of pressure. I found to actually crack open around 12psi and on the car ran about 11psi of boost. Even though I found contradicting info there is no need to go over my wasted efforts in trying to make this Medium Canister work.

So while the Medium Canisters the OE wastgates for these turbos, for our car, you need the high pressure one which is rated 17psi to 32psi. I have now been able to do a bunch more testing on these and I found 32 is not hard to hit! Yes, the simple solution is the BW high pressure wastegate canister. A more complicated answer is using a push/pull setup like this PERRIN prototype we built a few years back.



Amongst all my troubles with the High Pressure Wastegate Actuator, Full-Race sent me an EFR9180 to test out. This thing is freaking huge! I only had it for a couple of days and didn't get to dyno it as they needed it back, only to ship me an EFR8374! But anyway I will eventually toss this on to see how the spool characteristics are. I know it will make huge power with the right boost, but when will it reach 20psi, that is the question. And yes it did fit! Luckily i made a second uppipe and left it installed on our 2011 STI so i could just drop this into place. Sure enough there was tons of room!

More details will follow on our prototype kit and its design over the next few months, but there are a couple of really cool tricks and things that i think will make customers really like the install of this, IF we make kits surrounding the EFR.

Before I made time to dyno my car with the new actuator, I did some road testing and while this isn't an exact test, it does show how much more responsive the EFR is compared to the Garrett GTX. IF you look at this 2 second window comparing the GTX3076R w/.82 to the EFR7670 w/83, both reached the same boost level at the same time, but the EFR was floored about .5seconds later and about 200-300RPM later. This is a great example of the light weight CHRA coming into play.



In this diagram the Green line is a run on the GTX, and the red line is the one done on the EFR. You can see the sharp vertical line that represents throttle position. You can see how the EFR was floored later.

I did some other road comparisons and I was getting excited to see how this performed on the dyno. On the road, with the new high pressure actuator installed, I was noticing that the EFR was much snappier feeling. Cruising at 3000, I would floor it and it really felt alive as the boost started building. This is different compared to the GT or GTX3076 turbo, which turbos have much less response off throttle, and also at those lower RPM full throttle areas where the turbo is building boost. But when they come on boost, they hit pretty hard which makes them feel fast.

If a turbo feels fast that doesn't mean its really that fast right??

That is one of those things that is hard to describe to customers when talking about turbos. I hear customers say they were in their friends GT35 powered car and it felt so fast. It was because of that huge lag then huge hit of power. This makes cars feel faster than they really are. The reason why I mention that is the EFR actually doesn't have that huge hit power on the road like the GT turbos, especially the GT35.

Its like saying a Z06 Corvette feels slow compared to Rotated turbo kit STI. I have driven them back to back and the Vette with the flat TQ and linear HP curve actually feels slower, until you look at the speedo! This is the same with the EFR. On full throttle 2-4th gear runs, it doesn't have that huge hit of power, but when you look at the speedo you realize it's time to hit the brakes all of a sudden.

So, that is how I "Feel" about the EFR7670 with high pressure canister so far, not knowing how the EFR spools on the dyno. Until this point I had only dynoed the EFR7670 w/.83 with the medium canister and found it was slower spooling than the GTX3076R w/.82 housing by about 400RPM.

Hot Headers and Cold Headers

Below is a graph showing hot and cold runs. This is an important thing to understand because hot headers versus cold headers, makes a huge difference when the turbo spools up. The EFR7670 is the red and yellow lines from one set of runs at 25psi, and the green and blue are a set from the GTX3076. I consider the cold runs to be typical tuning runs where a run is made, a few things may be adjusted, and 30 seconds to 1 minute later another run is done. During this time, the header cools off as well as the turbine housing. A hot run I consider when a second run is done 10seconds or so after a run. During this time the header is still plenty hot as well as the turbine housing. The reason why it spools the turbo faster is that less of the exhaust energy/heat gets sucked out of cold headers which slows down exhaust velocity. When they are already hot, that energy/heat stays in the tubing and the exhaust velocity stays the same. The header on this car is not wrapped but wrapping would help this out between runs. This is also the same un wrapped header as used on the GT/GTX test so it a valid test as far as that goes.



If we use the 20psi mark, you can see that the EFR7670 with cool header crosses that point at just past 4000. But when hot, the change is pretty significant and decreases the spool point just past 3750. That is a 250RPM increase. The GT or GTX when cold was hitting 20psi at 3750,and when hot it would only decrease this RPM about 125 RPM. Either way all runs shown from here on out are done with the GTX or GT turbos with a cool header as well as the EFR with a cool header. All these runs
Before we start with the dynos let talk about the car, the dyno and all that stuff. I am sure many have see our GTX vs GT testing we did and while that info is still the same I know, not all of you, know about the car or dyno. So here we go.

The Car and The Setup

My 08 STI was used for these tests and its setup like a typical PERRIN GT rotated turbo kit car would be.

Parts installed: PERRIN Headers, PERRIN EFR Turbo kit, PERRIN FMIC, PERRIN Catback, and our PWI-2 Methanol Injection kit, PERRIN EBCS Pro, Deatchwerks 850cc injectors and Walbro 255lph pump. The engine is built with Cosworth Rods, Pistons and bearings, and ARP Studs. Things to take special notes on are: Stock heads, Stock Cams, OEM head gaskets, OEM TGV housings in place and functioning and stock fuel rails with PERRIN Stumble fix installed.

We use 92 ocatane fuel here in Oregon, but like any big power car running on pump gas, we run 50/50 methanol. The kit is setup to flow around 800cc's per minute. But can go up to 1200cc's.

Tuning duties are controlled by a Cosworth ECPro standalone ECU. An Innovate Wide Band, and EGT is integrated into the ECU as well as into the dash so i can visually watch AFR along with logging it.

The Dyno

Setup: Dyno we are using is our awesome Dynapack Dyno. Car is setup to run in 4th gear, starting at 2000 RPM and ending at 6900RPM. We use a settle time of 4 seconds, which means, the dyno holds the RPMS at 2000RPM for 4 seconds before the run starts. During these 4 seconds, we have the car at 100% throttle for about 2-3 seconds. The fans we use are not super crazy fans that flow 100MPH wind, but each fan flows exactly 28MPH (measured with our anemometer) and both are aimed at (not on) the intercooler). This doesn't provide perfect airflow to the intercooler compared to driving on the street, but it does provide very accurate and repeatable results and if anything lower HP that you may see on the road. Since the dyno has a pretty heavy load, it does provide pretty much the ultimate RPM for which a turbo will spool. So in these tests you will see ZERO benefit from the Titanium Aluminide Turbine wheel. Also all dyno readings are in Wheel HP not flywheel. Stock STI's make about 230-240WHP on our dyno as a reference.

All runs were done with the ECU reading about 30C intake temps, and this was very consistent. The dyno temp measured 60-65F. The dyno runs were done with about the same amount of time between them as well as coolant temps were always at 90C. The idea is we did it consistently to eliminate as many variables as possible. These same exact things were done with the GTX and GT tests a few weeks back and of course we did it on the EFR to ensure that the results were the same.

Tuning

Regarding the tuning. Like the other GT/GTX tests, I tried not to do any tuning beyond AFR. I of course tuned for boost to be able to match the same 1.2 bar, 1.5bar, 1.7bar and 1.9bar runs I did with the GTX test. For sure the AFR needed tuning between these turbos and in fact I found that I needed to add fuel compared to previous runs. But I started with the same ignition timing as used on the other tests. The idea is to ensure that no unfair tuning was done to increase HP or TQ beyond a normal level. Keep in mind the whole idea here is that these are tests for PERRIN to determine if the EFR turbo is something we are interested in making kits for. There is no reason for us to fudge results, or make one turbo look better than the other.

Engine Demand

On last thing to hit on is, engine demand. Using engine airflow calculators, or the Borg Warner Matchbot program, you can see what your engine requires for air flow for a given boost level and redline. The next thing to look at is if a turbo fits these demands and if it does it efficiently. If you compare this against some of the popular turbo upgrades you will see that in most cases customers are running off the compressor map but getting great power. So its not always 100% important that your engine airflow needs fit within the boundary of the turbos compressor map. Far too often I get calls from customers that look way to deep into this and try to match their power goals to perfectly on the compressor map.

EFR7670 vs GT3076R

This is the turbo that BW said it compared to the most, but should make more power. After the first few pulls I noticed that I was getting a bit more engine noise that previously. I ended up pulling timing around the 5500-6000 range to keep some of the noise down. In the end this didn't change power at all. First let's compare the GT3076R w/.82 housing. In this test you can see the EFR is slower spooling on the dyno. Keep in mind these are cool runs and hot runs were faster spooling as well as heavy load on the road showed better performance, but none the less its consistent.



The green line shows the GT3076r w/.82 housing making more TQ at 4000 because it was making more boost there., but as soon as the EFR and the GT cross the same boost path the more efficient compressor wheel starts to kick in. Even at 1.7 bar of boost the EFR was showing a pretty solid 20WHP gain over the GT. In this case it's easy to see that the slightly laggier nature of the EFR was worth the trade off in HP. The "Area Under the Curve" the EFR has, outweighs the GT easily. I feel this is the best boost (1.7bar/25psi) to test all these turbos at because this is a very common boost run on Subaru's. Of course you see more, but when it comes down to boost being used on the street, 25psi or less is pretty common.



Now on to the comparison of the 1.9 bar runs. Even at 1.7bar, the GT3076R is running out of in relationship to the compressor map, but at 1.9 it really starts to. I remember in previous dyno runs with the GT, I had to pull timing out to ensure it was ok. With the EFR, it was way happier. As you can see, its making 20-30 more WHP at the same boost. There is only one thing with the GT3076 run, it's that it was on the hotter side of things and it was spooling faster than the other. For some reason when I did the 1.9bar GT runs, I spent the first few runs dialing in boost and this purple line ended up being on the hotter side of things. Either way you get the idea on HP gained, and from the other results you will get and idea on the spool.

I did do the other 1.2 bar and 1.5 bar runs but no need to show you the same basic gains of about 20WHP.

EFR7670 vs. GTX3076R

As I had shown before the GTX turbos spool the same as the GT turbos. So its not a question if GTX is going to spool faster than the EFR, it's a question of how much power will the GTX3076R w/.82 make. As I had show the GTX3076 made about 20WHP over the GT3076 and you can see here that it's still not quite enough to overcome the EFR7670 HP. Looking at the purple line showing 1.5 bar of boost, you can see a bump in power at 4000, but that is where the EFR was running a bit more boost than it was supposed to. Besides that you can see they make about the same power until redline. Why is that??



Below are the 1.7bar runs and it shows about the same thing. The GTX and EFR make very similar power until 6000 RPM where the EFR starts to pull away. The blue line in the below graphs shows also that the area under the curve on the EFR most likely outweighs the 250 RPM slower spooling. That and the fact on the street the EFR is more responsive between shifts but more on that later.





Now if you compare the EFR7670 compressor map to the GTX3076R compressor map you will see how the GTX is more efficient higher up on the pressure scale, but not by much. In the grand scheme of things a few points in efficiency here or there doesn't really matter. This could be why the GTX3076 and the EFR7670 both made similar power at this boost level. At this level both are starting to run out of air and become less efficient. During the EFR7670 tuning I ended up getting some engine noise that I felt needed some timing removed. No I never hear knock but I pulled .5 to 1 degree at 6000 as it just wasn't perfectly happy. Again trying to keep thing consistent I was not experiencing this on the GTX tests. I had a target for engine noise on these runs and it was being exceeded. This is a one of the logs, and you can see how I use the individual cylinder noise as a guide to what is going on.



This is one of the runs that you can see I got some spiking in engine noise. It crossed the threshold for knock (that I set) and it pulled timing. But anyway in keeping things consistent, and while this didn't loose power or cause audible knock, I lowered timing to keep things consistent between the GTX and EFR tests.

Some might come to the conclusion that this turbo is less efficient than the GTX which is why I got knock. Well yes and no. The compressor wheel is less efficient, but my Methanol injection masks a lot of that. But as the engine becomes more and more efficient, the combustion chamber also does. A more efficient combustion chamber typically has faster, more controlled flame burn rates. This in turn means you need less ignition timing to get the same peak cylinder pressure. Is this what was happening because of the freer flowing nature of the turbine housing and wheel?

And finally here is the 1.9 bar results still show great Wheel HP and 480WHP is nothing to complain about that is for sure. Keep in mind that If I remove my TGV's, maybe wrap the header, there is more power to be had for sure. Is there 500WHP to be had here?? I say yes on an engine with heads and cams, and with a higher redline.

Ok

[5mall5nail5]

Why is the turbo not making more power than the GTX3076r? Here is the compressor map for the EFR using my engine data plotted on it. You can see that at 7000 we are off the compressor map. This also is true for the GTX3076r and GT3582R. But still this is making great power and for sure there is more on tap with the use of race fuel, higher boost, heads, cams....



EFR7670 vs. GTX3582R

So now lets compare the GTX3582R to this turbo. First up is the GTX3582R w/.63 housing. In this case the EFR blows it out of the water. It spools the same but it makes about 20more WHP everywhere. This is because the EFR has a much freer flowing exhaust housing/turbine wheel. According to Garrett's site this combo only has 22.5lbs/min of turbine flow capability. The EFR flows 24.5 lbs/min. That change in 2 lbs-min is 20WHP! So in this case the GTX3582R w/.63 housing is no longer a match for the EFR7670 with .83 housing. You can see below the blue line makes a lot more power everywhere.



I didn't put up the GTX3582R w/.63 and 1.9 bar as it shows the same thing. The EFR makes more power. But below you can see when we compare this to the GTX3582R with .82 housing, things start to change....



Now you can see this comparison look like the EFR7670 vs the GTX3076R, but this is the GTX3582R w/.82 vs the EFR7670 w/.83. If you think this is the more comparable turbo to the EFR7670, you would be correct. In this case, the EFR spools much faster and makes pretty much the same HP. At this 1.7 bar level, its obvious what turbo is best for you. Looking at the plot above, you can see at 1.9Bar of boost, the EFR efficiency starts to fall off at redline. Don't jump to conclusions that this is bad because GT3076 customers are constantly running WAY off the map. Here is a GT3076 compressor map plotted at different boost levels. Now don't forget I ran the GT3076 at all these levels and it made plenty of power.



Here is the GTX3076R with the same boost plotted and you can see how this matches pretty close to the EFR7670 where it just starts to run off the map at 1.9Bar and redline. Again we were running this off the map and it was still making lots of HP, so its not bad to run it off the map necessarily.



One more comparison is the GTX3582R w/,82 AR. You can see that the GTX compressor map is much more efficient at these boost and RPM levels compared to the EFR7670. But really the GTX3582 compares closer to the EFR8374 but we are not testing that turbo here, but soon! But this graph is more for comparison purposes and may explain why the GTX3582R made a tiny bit more power.

While the above graphs show the EFR7670 runs off the map at redline, and still makes great power. Check this out!



The EFR being quite a bit smaller than the GT3582R (in the compressor map department) it easily holds it own with the GTX3582. The faster spooling nature the fact it easily keeps up until 6000, I say the EFR7670 is worth a measly loss of 15WHP. Also during these tuning sessions, I had pulled some timing from the map because I was getting some increased engine noise as I was during the 1.7bar runs. I suspect that had the runs been done with race fuel, I would guess that the spread in HP would have been almost nothing. But as I said before, these tests were done to represent what most customers do with their cars.

And I bet that if I did a drag race with both the faster respooling nature of the EFR is going to make it a faster car. If you are running to 8000rpm or a lot more boost, then the GTX3582 comes into play, or the EFR8374. But in this case the EFR7670 is versus the GTX3582R w/.82 I would still pick the EFR7670 as on the road, this turbo feels significantly faster off boost and also between shifts.

On the Dyno Conclusions

The EFR7670 is a turbo that I personally feel compares more like A GT3582R, but spools faster on the dyno (like a GT or GTX3582R w/.63Ar). Comparing the EFR7670 to a GTX3076, its slightly laggier, but that lag is a trade off for more power. Since the GTX3076R and EFR7670 have very similar compressor maps, the HP gained is do to the higher flowing turbine housing/wheel. Since the dyno is very controlled, and a high loaded run, in all these tests the super light Titanium Aluminide turbine wheel doesn't come into play at all. What this does show is the turbine wheel and compressor wheel design is a notch up over the Garrett GTX stuff. From what I have seen Borg Warner has designed a turbo that does what they say it should. It makes more power and spools faster than the GT3582R.

On the Road Conclusions

My conclusions are this. The dyno conclusions do not match what I "feel" on the road. On the road, I feel like this is much more lively than the GT or GTX3076R. Its interesting as in some road tests the EFR7670 shows the same spool up RPM as the GTX3076 w.82ar, but it feels so much snappier between shifts light load low RPM shifts. Meaning the normal day to day 2000-4000RPM shifting is about 50% better than it was before. In some logs I notice that the GTX would show say 2-3psi of boost at these really low RPM's, where the EFR is showing about 5psi. Its only a couple PSI but that makes huge difference in how it feels. You can see this on the dyno graphs where the EFR is making more TQ at 2000-2500.

Under full throttle high RPM acceleration, again the car feels a bit faster. It feels like Its right back on the power. When comparing this to the GTX3582R graphs I have, it blows it out of the water. When comparing it to the GTX3076, its very close in respool time, but there is this thing that just "feels" better.

I am compiling some road going plots of the GTX3076R and EFR and I think this will show what I am feeling.

Final Conclusions

I used to think that there are lots of turbos out there, depending on the size of the turbine, its going to spool at a particular RPM, depending on the compressor wheel used, your redline and boost, its going to make a given HP. So then it was a matter of what size wheels Garrett and others used to create a given turbo and it was a balancing act of spool and HP. But Borg Warner has proven that there is some magic left in its turbos in that it actually spools faster than its comparable GTX/GT3582R turbo and makes almost the same power, if not more on the GT3582R.

PERRIN Performance will hold off on making conclusions about the entire EFR line when we are able to test an EFR7064 and the 8374. After seeing when these spool up, and the HP they make, I think we and other customers can decide if the EFR is here to stay. What I suspect is that the other EFR turbos are going perform better in one way or another to the Garrett product but will fall in between Garret part numbers in some way. That is not bad as it will make for a big balancing act of price, spool, HP, durability, features and feel.

What is next? I am going to beg and beg to get a test EFR 7064 turbo and in the mean time, I should have the test 8374 turbo from Full-Race any day and that will be bolted on and dynoed. I think this turbo will make more power, but I hate to say, I am not going to be running it high enough boost or high enough redline to really see where it kicks butt. For these tests I will be dynoing it purely to see when it builds boost. I will do the 1.7bar and 1.9 bar runs just for fun, but its not going to be making that much more power.....right???

Over the last couple of weeks I have been asked: Are we giving up on Garrett? No way! These turbos are very well proven and while they sometimes have a bad name in the quality department, I can say over the last 2 years we have had 3 warranty issues come up. Relative to how many we have sold, that % is very very low. I see that they will always have their place and customers will always want a Garrett turbo with an external wastegate.

Lots of fun stuff to come over the next few months!

Read it. Its an excellent review of the unit(s).

[Duskin]

very interesting! from reading it, the overall feel seems that he is leaning towards the EFR. Time to go check pricing

[M3 Muscle]

Great read, thanks for posting Jon! I wish more people did reviews like this!

[jfdmas]

ugh, cliffs?

[Lurker27]

GT spools faster but is slightly less efficient (less top end power).

EFR has a nicer internal wastegate and integrated blow off valve.

I do like the attention to detail in the EFR build (longitudinal stability in the bearings to prevent oil leaks gets high marks from me).

I'd probably buy whatever ends up being cheaper between the 2, honestly. Of course, I have a $250 rebuilt hx40, so don't mind me.

[flexer]

On his Dyno The GTX30R made 479.4 @ 27 psi

AND
The GTX35R made 488.9 @ 27 psi

So let me get this straight..... the difference between a x30R and x35R is 10 hp!??!?!?!?!?!

Anyone else seem to have a problem with this?

[rt turbo]

So, the efr 7670 makes the same/or better power than the gtx3582 w/.63 housing and spools the same. Makes better torque that the gtx with the .82 housing. I would love to try this turbo but without the gadgets. That bov just doesnt look like it can handle the surge. They need to make these with external WG, bov, etc. Based on these numbers I would switch over.

[rt turbo]

On his Dyno The GTX30R made 479.4 @ 27 psi

AND
The GTX35R made 488.9 @ 27 psi

So let me get this straight..... the difference between a x30R and x35R is 10 hp!??!?!?!?!?!

Anyone else seem to have a problem with this?

Good find, I didnt notice that. Maybe some bias and numbers massaging here?

[jonesmechanical]

On his Dyno The GTX30R made 479.4 @ 27 psi

AND
The GTX35R made 488.9 @ 27 psi

So let me get this straight..... the difference between a x30R and x35R is 10 hp!??!?!?!?!?!

Anyone else seem to have a problem with this?

Sounds like we need to get this guy to balance the national budget. Very scientific approach. Spend all day measuring with a micrometer and then cut everything with a chain saw. Doesn't do much for all that hard work typing. Obviously a GTX35 would make more power than a GTX30 any day of the week, and there is going to be a difference in power curve also. On this application, is the 30 overstated, the 35 understated, a bit of both?

[jonesmechanical]

Hey, I am just remembering the Cosworth booth at SEMA. They had a beautiful head/intake manifold setup that addressed a tremendous high flow restriction on the stock STI's. If I remember right, the difference starts happening right around 450-500 wheel.

This could explain. This car tested could be reaching critical mass as far as his stock head/cam/intake manifold capacity. The smaller turbo could have more ability to work against that restriction ?

I guess that the problem with such a wide variety of boost levels and not tailoring important supporting mods to a specific turbo. All of us always want to see straight up comparisons like for like with different turbos for the sake of argument. I guess that opens the door for more argument.

[black bnr32]

try reading the entire original thread if you guys can...there is lots of data and comments from the tester to sift through.

[flexer]

try reading the entire original thread if you guys can...there is lots of data and comments from the tester to sift through.

I have no idea what this has to do with what we are talking about above. I've read the whole thread and no where does he mention any short comings to back up the idea that the X30R only dyno'd 10 hp more than a X35R. THERE IS OBVIOUSLY SOMETHING going wrong there with that. One every other regular, non-boxer engine that dyno's and goes from a 30R to a 35R, the gain is usually 50-100 HP gain depending on boost. At lower boost a difference of 30-50 hp is seen, but at 30+ psi....the 35R will make 100+ HP over the 30R since you are WAY out of the flow of the map on a 30R at that boost.

JR

[wazzu70]

I agree if you read through things there is a decent amount of commentary.

The boost levels were not changed, and he said timing was not changed from one to the other (unless timing needed to be pulled). Obviously if you do not optimize the timing map, you are leaving a ton of power on the table.

Since most people just get an off the shelf tune, this kind of comparison is probably more useful (unfortunately).

Would be nice to see what the different turbos could do with a remap of the timing to suit the turbo. I think it would widen the gap considerably.

[black bnr32]

I have no idea what this has to do with what we are talking about above. I've read the whole thread and no where does he mention any short comings to back up the idea that the X30R only dyno'd 10 hp more than a X35R. THERE IS OBVIOUSLY SOMETHING going wrong there with that. One every other regular, non-boxer engine that dyno's and goes from a 30R to a 35R, the gain is usually 50-100 HP gain depending on boost. At lower boost a difference of 30-50 hp is seen, but at 30+ psi....the 35R will make 100+ HP over the 30R since you are WAY out of the flow of the map on a 30R at that boost.

JR

i wasn't referring to anything in particular

[flexer]

I agree if you read through things there is a decent amount of commentary.

The boost levels were not changed, and he said timing was not changed from one to the other (unless timing needed to be pulled). Obviously if you do not optimize the timing map, you are leaving a ton of power on the table.

Since most people just get an off the shelf tune, this kind of comparison is probably more useful (unfortunately).

Would be nice to see what the different turbos could do with a remap of the timing to suit the turbo. I think it would widen the gap considerably.

I agree. If the timing was fully mapped we MIGHT have seen more of a gain with the 35R......BUT EVEN STILL.....Look at most comparitive turbo threads and you will see that even when they max out the VE timing curve with the new turbo.....your talking about a 1-3 degree timing change, at any given RPM. So again you talking about gaining another 10-25 HP from adding this timing in.

Bringing in the fact that he didn't change the timing is fine and noted, but STILL DOESN'T ACCOUNT for the terrible performance of the X35R over the X30R.

Also note....there are several other cars that have dyno'd at the 27 PSI level that this car also dyno'd the X35R at and they are making 550 HP+. On one S2000 dyno I saw that at 28 PSI the X35R made over 600whp. To be fair this one on a dynojet, so inflated numbers, but still.

Someone help me understand how the X35R only gained 10 hp on that freaking car!

JR

[flexer]

OK I posted over there. I think I understand. Got a good response. I guess it turns out that the 2.5 Subaru boxer motor is terribly in-efficient and has a lot of short falls. This is why they dyno like crap compared to EVO motors. I actually googled and read a lot on the 2.5 motor, and like jonesmechanical said above. The intake manifolds are CRAP I guess. The heads are CRAP I guess, and the stock cams are VERY restrictive....

So now this makes sense. The reason why the X35R didn't gain much power is that the restriction is not the turbo in any way, shape, or form. ITS THE MOTOR.

What sucks about that is NOW I CAN'T COME TO ANY CONCLUSION what so ever from reading something on nasiac because the motor isn't comparable VE wise to a standard....non-boxer motor.

Anway, here is the response they wrote me over there:

"

So your saying that A/R is the reason why a GTX30/76R and GTX35/82R made only a 10 HP difference. I admit that I have seen a A/R change add HP in major ways.....but still.

WOW. And so just with that offset in A/R you don't find it odd at all that the X35R STILL ONLY MADE 10 hp more?

Is it the Motor? Since I am not a pro at the 2.5 in the STI is there some other restriction that I don't find in the non boxer engines. In other engines The 35R offers HUGE gains of 50-60 hp at lower boost levels.....and upwards of 100 HP gains above 30 PSI when compared to a 30R.

But no one finds the 10 hp gain to be odd?

JR"

REPLY:

The 2.5L STI engine is relatively poor flowing as compared to Hondas (K20, F20, etc) or Evo 4b11t. Jeff's engine is pretty much stock besides the turbo setup. So no TGV deletes, stock cams, etc. So a lot of various flow restrictions which serve to bottle neck the bigger turbo. As an example, if you put a 30mm inlet restrictor on a GT30 and GT35, they're going to make nearly the same power.

[wazzu70]

Glad you posted and got an answer. That is what I would have guessed, but it would have been nothing more than a guess.

Makes a lot mroe sense though considering the other hardware needed to take advantage of serious airflow is not present. would be interesting to see the restuls after some of the bottlenecks were relieved. I can't imagine adding such a nice turbo to an engine that still was otherwise stock.

[rt turbo]

That does kinda void the validity of this test though. It needs to be done on a motor that can actually breath. Maybe the BW turbo works better on an engine with more restriction? Too many variables now.

[tptrsn]

Seems like the author harbors a tremendous predisposition toward the EFRs, doesn't he? When he's comparing a GTX that spools sooner to a EFR that makes more power, the EFR is great. Compare a EFR that spools sooner to a GTX that makes a bit more power, and the EFR is great.....

And none of the differences are real big, as mentioned already.

I'm a bit confused, but I find the EFR packaging to be unwieldy, so maybe I'm predisposed in the opposite direction of the author.

And then the truth is that I love my Precision billet wheel 6265, so I supposed I'm completely unqualified to have an opinion on this topic.

[LukeG]

That does kinda void the validity of this test though. It needs to be done on a motor that can actually breath. Maybe the BW turbo works better on an engine with more restriction? Too many variables now.

Hopefully we'll be getting a review via .140"mls m52 with s52 cams in the near future.

I placed the order over a month ago and still waiting for it to ship. The last promise ship date I'll deal with is the may 1st promise. If it still doesn't ship I'll be getting a refund and going with something else

[wazzu70]

As mentioned in the thread, the dyno only shows part of the story. "Real world" conditions make the EFR a better match for drivability.

The integrated wastegate can save you a lot of room and complex plumbing as long as its big enough to control your flow properly. I'm not sure about the integrated bypass valve, looks kinda cheezy and for packaging its easy to locate elsewhere. I know you can get the turbo without integrated wastegate, but not sure about the bypass.

[psyber0ptix]

they sell a kit that blocks off the integrated bypass valve. It's called the Compressor Recirculation Valve (CRV) Kit and includes:

Plastic cover with hose nipple
CRV Disabling blockoff plate
CRV Diaphragm and piston assembly
CRV Spring
Cover Plate bolts with locking compound

Here's some good info on these particular turbos from full-race

http://www.full-race.com/articles/efrturbotechbrief.pdf



I find that this turbo definitely accomplishes a lot in a complete package. Can you spend your money elsewhere to satisfy your needs? definitely. But taking a look at the design, the 4 ball bearings with metal bearing cages, the option to watercool, and integrated less-hassle wastegate and bypass for those who dont live for the noise; i definitely appreciate the time that went into the design.

One thing I will complain about, is it's large, standing at a 3.5" longer assembly over the GTX3076R. It might be difficult for us 24v e30 folks to find a good way to fit such a lengthy assembly, dependent on the way the manifold is constructed.

but overall, i like it. i do dream of a 7064 or a 7670 providing some air to my s50 swapped e30 someday.

[BadBoostedBmwM3]

So, the efr 7670 makes the same/or better power than the gtx3582 w/.63 housing and spools the same. Makes better torque that the gtx with the .82 housing. I would love to try this turbo but without the gadgets. That bov just doesnt look like it can handle the surge. They need to make these with external WG, bov, etc. Based on these numbers I would switch over.

Check out treadstone performance... they are working on something for you.

[Def]

The integrated bypass valve looks like a total POS. It's not even the size of it, but the cheap rubber diaphram that just will not hold up in the long term. It's been proven on OEM bypass valves of this type over and over.


It wouldn't have really added much cost to use a simple machined aluminum piston with o-rings that would probably last longer than the diaphram and provide better sealing.


The power potential is cool, and I love the stainless steel turbine housings, but I feel like they held back just a bit on their design to try to save that extra $20-30 off their production cost.