Hi Everybody

https://www.facebook.com/Raceonlygar...149811/?type=1

Check It out.

Both run's are back to back on the same car and are at the same boost level.

This particular motor is maxxed out (It has less than 40 psi compression) so don't ask why the power figures are low.

Also the borgwarner was frying the tyres on the dyno hence the top end speed not being the same.

Once i have more time we will have it back on the dyno with the EFR and i will get a few guys to sit in the boot.

Power will probably go even higher.

No wheel spin on the 42 Though.

 

Nice! Looking forward to seeing further results specifically with a fresh engine

 

great work race only!

 

Maybe there's a language barrier and I'm misunderstanding what you're trying to say here but how do you even start and engine with 40psi compression and if you do get it running why would you dyno tune it?

 

It barely starts , sometimes it does not

As for why we would dyno it

Why the hell not ?
Motor is going in the bin anyway
Might as well get the rest of the car perfect and then put the good motor in
Which is what we are doing

Sometimes I wonder why I bother making these posts

 

Thanks for the info. It is very informative, for me at least. I like that the motor is still producing power. Thats more than im after thats for sure.

 

I think the point is that with a motor that weak, the car will need to be retuned once a fresh motor is installed. still awesome that it made those numbers with that low of compression!

 

I think the op is just trying to show some comparison results because the other threads on this efr turbo have fallen short with incomplete data. Regardless of compression, the dyno chart goes a long way to show the differences in these turbos responsiveness. Even with a much smaller exhaust A/R, that Gtx42 got it *** kicked.

Edit: Any idea what rpm full boost hits on boths turbos?

 

I have a GTX4294R and I get positive pressure at 2000rpm (sometimes 1800), and full boost (30psi) at 3600-4000rpm. I can't imagine the EFR9180 being that much faster but the sizing between the two turbos being compared isn't very closely matched IMO.

-EFR9180-
Compressor inducer: 67.7mm
Compressor exducer: 91mm
Turbine inducer: 80mm
Turbine exducer: ??mm

-GTX4202R-
Compressor inducer: 75.8mm
Compressor exducer: 102.3mm
Turbine inducer: 82mm
Turbine exducer: 75.1mm

A better comparison would be a GTX4294R with the smaller 67mm inducer.

-GTX4294R-
Compressor inducer: 70.3mm (67.8mm model this is only thing that changes)
Compressor exducer: 94mm
Turbine inducer: 82mm
Turbine exducer: 75.1mm

Maybe I'm missing something here?

Since the EFR is smaller, ofcourse it will come online sooner. The GTX is a bigger turbo so it's going to lag behind. The real comparison is when you put both turbos on an engine that can stress both turbos. The GTX is bigger so it will eventually make more power (assuming here). You can see the GTX is starting to curve up and would have eventually passed the EFR but the engine wasn't up to par.

I'm not defending the GTX by any means but the comparison test seems one sided. Were both dyno graphs done in the same gear? It looks like the EFR is in 3rd and the GTX is in 4th (FD gearing wise). It could just be that big of a difference but hard to believe it since my GTX performs wildly different.

 

Thanks for the results. I always like seeing comparisons.

 

I am not going to bother with any more replies
Anyone who cares to read my post will have their questions answered already


Anyone with real world experience will know that 30psi at 3600-4000rpm on a 13b Gtx4202 just doesn't happen on pump or e85
Maybe on meth

Although I'm sure you would be happy to provide a video of your dash showing 30psi at 3600-4000rpm

 

it also had a 1.45 AR, pretty impressive

 

I don't have a GTX4204, although I do have a GTX4294.

The 3600 - 30psi pull would be 5th gear so I'll admit that's unrealistic, so I shouldn't have put that. The 4000rpm pull however is real.

Never the less, the EFR is a very nice turbo. I hope to see more information posted on it with a good engine. I only offer my experience as a comparison, I hope it helps.

Have a look at my engine log and a corresponding dyno later that day:

 

Some people think with restrictions, while others believe in infinity.

 

im wondering the difference is drastic because the engine has low compression. Im thinking the efr will still have better results on a fresh engine, but hopefully the gtx42 might be able to close the gap a little

 

Both test were done on the same engine with the same compression so the results are fair.

 

I'm just wondering that since the engine is so low on compression and since the efr has a lighter turbine. The gt42 is way to much turbo for a rotary. Maybe that's why the response is that far apart. Just a thought, but I would like to see the results on a healthy engine.

 

I understand what you're saying. Since the turbines are exhaust driven a low compression motor can't push the turbine as well, so the bw will clearly shine over the garret. Perhaps on a healthier motor, the gap would be less. Who knows? We'll have to wait and see.

 

All these threads on the efr make me want to sell everything I own for one. I used to think just a ball bearing turbo was enough

 

EFR will spoll the same given the exhaust flow is the same. same with the larger turbo. The delta is exactly the same in terms of spool characteristics. So you guys are wondering if the difference would be less because a healthier engine can increase exhaust output quickier? If that is the same, I would think the delta to still be close to the same, perhaps maybe a little compressed, but the BW will just spool even earlier.

 

Probably true, but it sure will be nice when we get a comparison on a healthy engine.

I noticed on Subarus in particular the EFR had no advantage in spool since the EFR line has generous hotside dimensions and the Subaru has very very weak exhaust output due to long primary header lengths and so require a very small hotside dimension to get good spool (like GT turbo line).

Finally the Subaru guys found an EFR that spools ok with the new mixed Radial/Axial flow exhaust wheel and larger compressor to exhaust wheel dimensions on the EFR 7163.

Anyways- just a note to point out the EFRs aren't a universal panacea against turbo lag. They do seem to work particularly well on the rotary!

 

All things being equal, the lower mass turbine will spin sooner and wind up much faster. That's just plain physics. With a healthy engine, the gap could easily widen as the efr will react sooner due to the lightness of the turbine. The Garrett will respond sooner as well but, it wont react as quickly. The sooner the air enters the engine, the faster it has to leave the engine which will continue to spin the turbine even faster. It's very possible that the gap could widen with a healthy engine.

 

All things being equal, the lower mass turbine will spin sooner and wind up much faster. That's just plain physics.

My Subaru example was exactly to point out that no, there are more forces at work than just the exhaust wheel mass.

All things being equal is the key.

No sideseal rotary versus sideseals functioning rotary are not necessarily equal.

Or perhaps the low compression rotary is soft on one face causing a missfire- again not an equal scenario as it involves dumping more air/fuel into the exhaust which I believe has more of a positive affect on the larger diameter/lighter exhaust wheel turbo.

-------------

To illustrate, back to my Subaru vs rotary example-

The Subaru with its long primary headers has a very cool, more constant lower velocity exhaust gas spooling the turbo primarily with exhaust gas flow alone. Much like a model of a positive displacement pump spinning a turbine taking only fluid displacement into account.

The rotaries on the other hand has more pulsating very high blowdown exhaust velocity and lower velocity, very high kinetic exhaust component (expressed as sonic wave), very high gas temperatures (higher expanding volume of gas) and a resulting very high manifold to downpipe pressure delta.

The larger diameter and reduced exhaust wheel mass of the EFR seems to be very much more of a factor with the dynamic (many factors) rotary exhaust model compared to the more static (flow based) Subaru model.

I think we agree on that.

------------------

Now, see my point above about misfire events dumping more air/fuel into the exhaust making even a damaged rotary vs healthy rotary comparison biased more toward the larger diamter, lighter exhaust wheel turbo.

Anyways... just typing drivel while we await more results with a healthy engine.

Its all speculation regarding the state of the engine that was tested in this thread.

 

respectfully disagree, These turbos have worked so well on subie's that Subaru is our most popular platform for EFR turbos over the last few years. from our site here:

"Just switched out our Redline Time Attack Street Class 06 STI from the stock VF39 to an EFR 6258. Added a reverse intake manifold FMIC, the turbo and retuned. Bone stock unopened long block. E85 fuel. Results speak for themselves. 2013 Street AWD and Overall Street Class Championship specs:

Bone stock (never opened) longblock 60K miles
Reversed intake manifold FMIC w/ TGV deletes and 3" CAI
Full-Race stock location up pipe, lower manifold and catless turboback exhaust
pump E85 Fuel
Boost level: 24.5 psi on both in the midrange. EFR6258 tapers to about 20 psi. VF39 tapered to about 13.5 psi *note VF39 used stock TMIC"



definitely agree with you there, the 7163 is the hotness for a stock location EFR subaru!

 

I am no Subaru expert, but I was looking into turbo sizing on them for my friends who autocross.

In your example you show an

EFR 6258 with supporting mods "Added a reverse intake manifold FMIC, the turbo and retuned"


versus a STOCK VF39

I don't think that shows it was the Gamma Ti exhaust wheel that created those gains in spool alone.

From what I saw the tiny hotside EFRs are the ones that showed gains on Subarus and BW themselves say the impact of the Gamma Ti is much less a factor on these small hotsides.

EFR 7163 makes more power (peak and power under the curve I believe) on a Subaru than a EFR 7670 because the Subaru does not have the exhaust energy to drive the larger turbine despite the advantages of the Gamma Ti exhaust wheel.

I talked my friend with an STi into buying an EFR 7163 (when I couldn't talk him into selling Subaru for a Mitsubishi).

Yes, certain EFR turbos are still the best turbo on Subarus, but I don't think it has nearly as much to do with the Gamma Ti exhaust wheel as on the rotary application.

Anyways, one thing they have in common is Subaru boxers like rotaries are garbage so I try to talk my friends out of them before they get one because they are both easy to get addicted to as well.