yes I found this out 3 years ago when comparing sxe and efr compr maps. I talked to the nice people at BW and they sent me a sxe cover to try. The efr7670 was mounted into a modified S300 vgt housing off a john deere and used on a Audi 3.0 tdi. At that time we were very surge limited up to about 3000 rpm. The sxe cover fitted right on and we also didn't need the bov on a diesel and all surge was fixed without changing anything in the tune. The car is making about 600 hp for the last 2 years as a daily driver.

I then fed back the positive results to BW and in the next performance catalog they added the sxe housing pn onto the efr page.

the sxe housing ar wise and external diameter wise quite a bit larger. On the audi we had about 1mm clearance w the housing on

 

 

Interesting feedback, thank you.
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Axially its shorter

but due to the larger A/R its radially bigger.

 

But you lose the recirculation valve with the SXE cover, so transient response will suffer, and that's the whole point of an EFR

 

you can run an external BOV

 

it was my bad; in the video it shows a picture of each side by side (captured below), but the photo of the EFR cover is just larger than the photo of the SX-E cover, creating an optical illusion of it being larger in the few seconds it was shown. However, there is less space around the SX-E cover due to the larger diameter just as you noted:

 

Is that a documented thing?

 

The recirculation valve is built into the IWG EFR cover, swapping it for an SXE cover removes it entirely.

From Borg Warner press release-

EFR turbo compressor housings incorporate an integrated BOV. Yes, you read that right - the BOV is a recirculating style *built-in* to the Compressor Housing. The major performance advantage in this design is that it redirects the high-pressure compressed air from the outlet of the compressor wheel -> right at the low-pressure inlet of the turbo. This helps to keep the turbo spooled between shifts and offers cost savings/convenience while keeping MAF-based engine mgt happy. With this in place, there is no need for a BOV or flange on the charge piping. The only downside of this feature is the fact that it makes the compressor housing about 1" (~25mm) longer in axial length. For the hardcore racers who want to use an external traditional BOV, and for applications that can not fit or do not want to use the internal valve, we offer a disabling cover plate. This cover plate installs in place of the plastic cover and uses the original diaphragm to seal the port.

 

Have you watched any tech articles or viewed logs of turbine speed with/without? On a shift with closed throttle, the compressor does less work and absorbs less energy if not flowing through a BOV maintaining higher shaft speed.

What I was interested in was shaft speed at cruise in conditions where a BOV may be partially open against a part throttle- ie relevant to the use of the "response". Anecdotally I have heard people say roll on torque was better but I have never seem logged data.

 

I haven't reviewed logs, I'm just repeating BWs literature. I highly doubt they would make those claims without having the data to back it up. This is Borg Warner, a large respected OEM manufacturer, not some small company trying to make a name for themselves with new untested tech.

If you do have the means to test it, I would love to see the results

 

Imo you read too much into it. It works just like a recirculating BOV and accomplishes the same thing, and that’s all they’re saying. With a MAP based system you don’t need it to recirculate.

In the EFR7163 example I posted the owner reports no negative change at all, only improvement
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I was under the impression the boost pressure was routed towards the turbine to keep it spooled up, using the excess pressure in the system instead of wasting it. Maybe I've misunderstood their literature

 

I understand why you might see it that way. My feeling is the way it’s implied rather than actually stated is that you might be giving it much more weight than the magnitude in reality is. The channel is as open or more to the front as it is back to the impeller. In other words, it doesn’t hurt and a little something might be better than nothing, but perhaps not so easy to quantify in reality.

Otherwise my feeling is that the wording would be much more specific rather than stated as such a generic marketing point. They don’t say it keeps turbo speed high, but that it “helps” to. That sounds more like “kind of maybe” to me.

But you ought to go back and look at the difference in that one example again. There was a lot of performance gained with a cover change that shouldn’t be ignored.
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way less than ideal for a 13B; high boost low displacement piston engine application for sure

 

Maybe I’m reading it wrong. But isn’t that similar to the 7670 map but gives more flow?

 

so does an 8374, but more efficiently

it will make a great hairblower with all the hot air it will be kicking out below 2.8 Pr

but for reference, very few 13B-7670 power levels exceed 55 lb/min compressor flow, most are lower.





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The 7670 is the hot air blower , the 8370 actually addresses that and could be a great intermediate turbo (400-450 range) between 7670 and 8374 if used with the T4 divided 1.05 turbine housing.............. IMO

 

We'll yes, but you can say the same thing a 9180 will flow more and be more efficient than the 8374.

I'm just saying there are a lot of people torn between 7670 response and top end of 8374. Several threads on it, probably even discussed in this thread.

This this new hybrid not fit that purpose?

 

Exactly my what I was thinking

 

I think you’re both ignoring a lot of obvious points, but yeah it might do 65 lb/min with high emap and hot discharge temp.

but it seems to me neither of you gave any consideration how the loading is going to effect response and also the extra flow it will now be trying to stuff through a turbine housing that was already maxing out. What made it work on a 13B is exactly why piston engines would run it into overspeed easily. So for me, from a piston engine perspective, it makes a lot of sense. It was actually done on a custom basis for several years now fwiw.

1.05 A/R means little; the actual peak flow matters and it’s not that high on the 70 housing, you might as well put a tighter A/R on the 8374, which there is a divided 0.75 A/R aftermarket option available. Which again, Rotary101 for turbo sizing is that piston engines have a lower turbine flow requirement.

for 400-450whp, a Garrett G30-660 makes more sense to me, and it’s a much smaller packaging envelope
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On the compressor side at 65lb/min there is a 2% ish efficiency difference .... pretty insignificant.
On the turbine side :
The 70/1.05 combination flows the same as the 74/0.83 combo according to BW. (As you have pointed out the BW info doesn't show the 1.05 but it's easy to see where it should be)

So yeah , a little small on the turbine side for 450 maybe ...but ............. much better than the 7670 for low 400s. Ideal in the 375-425 range perhaps ?

With the added benefits from a much smaller compressor housing package

 

perhaps you lack discernment; the 70mm listings on Matchbot have been messed up from the beginning and nobody there ever bothered to straighten it out

I would suggest to you that the 1.05 housing belongs on the curve not listing anything, which has a flatline peak flow of 25 lb/min

 

I looked at that and my thought was always that the 70/ 0.80 was an obvious mistake .... and they meant to put the 70/1.05 there . But until someone gets that from the horses mouth ................ neither of us know for sure I guess.

 

look at the progression leading up to that, I would again suggest a possible lack of discernment