If you want the power of a bigger turbo at low boost than why not just run a smaller turbo? Operating a big turbo in surge is probably going to be worse in the long run than maintaining more boost inside the efficiency range of a smaller turbo.

 

From what I have seen the surge on the 8374 is when you try to run high boost in the low rpms though. Like 22psi or more at 3,000rpm.

I imagine the EFR 8474 would about the same surge zone, just at a little lower boost.

Running low boost off the wastegate and boost creeping up to medium boost shouldnt manage to get you into the surge line.

Why to do it?
Easier on engine at the cost of slightly less response is why road race and track day guys usually do it.
Lower IAT and EGT means more laps under full power.

Several Japanese actually ran T04Z on low boost which is similar sized turbo. Even Feed did on their touge monster FD where you would think the response of a T04S kit would be preferred.

Feed went to a new GTW turbo on that car more recently and the hectic boost onset actually looked way harder for even the professional race drivers to handle over the progressive but less responsive T04Z boost onset.

Ofc, with smaller EFR like my 7670 I know that wasnt the case. The boost came on so fast it was like the boost gauge needle was tied to throttle pedal and torque dropped so fast after 5,000rpm it was easy to modulate wheelspin. The high rpm drop in torque made wheelspin self correct in a way.

 

Back in the days before E85 where premium unleaded was the highest octane fuel that was readily available and ECUs didn't have engine protection features, bigger turbo with lower boost was the only way to go unless you used water injection. It was very common in Australia to see 13Bs running with large truck turbos at only around 8-10psi. They weren't responsive at all but they still made a lot of top end power and safely. To a degree, running a larger turbo at lower boost is still much safer than a smaller turbo running at the edge for reasons that BLUE TII has stated.

 

It's a stock port motor with M2 large SMIC that I'm considering trying to convert it to V-mount.
I plan to run 93 with water injection. The car is mostly used for track days and Auto-X.
I would like to run around 15 psi but might be OK if it creeps a couple of psi at high rpm. I guess i will find out when I get it all put together.
Ran the 99 spec twins at 14psi with 370hp at the wheels.

 

Any more updates / experience with the 8474?

 

Two weeks out from the HPA dyno;

https://www.facebook.com/HPAcademy/videos/1112742225772758/UzpfSTE4NDkyNDI0ODY4NDoxMDE1ODIyNzI0MzE5MzY4NQ/

 

Finally opened the boxes and looked at the turbo. Not impressed.

Can anyone say if this looks normal.

The inlet has very thin flashing on one side that to me looks as if it could brake loose from vibration or just air rushing in,
Also I was considering porting the wastegate but the flapper is so far out of center that it barely catches the edge on one side


Thin Flashing not fully machined out on left side

Flap 3mm out of center

 

Seen a couple like that out of the box. Take a small file and clean it up.

 

I don't think that will have any effect on performance, but paying $2,500 for a top of the line turbo you shouldn't have to deal with those issues. All of the extra flashing on the inlet should have been cleaned up before assembly.

I would send those pictures to BW customer service and see if they will make it right....

I just bought a 369SXE and it came with casting mark on the compressor housing that could have been fixed with die grinder and about 15 seconds of extra work. I initially thought it was a crack, but its just surficial mark.

 

I would bring that to BW’s attention if only to make sure they’re aware of the situation because it’s not unheard of for the production shop to be shipping out things the engineering office might not be aware of (yet). I would rather have them tell me it’s ok to take a file to it rather than have a problem and then be told you modified and ruined it.

 

Send it back. That level of finish is unacceptable IMO. That ************ cost 3 weeks wages and should be aerospace quality.

 

I wouldn't be getting my hopes up that a replacement would be any better, it's commonplace with these and dressing the defect might be easier. https://www.sau.com.au/forums/topic/...v-20/page/122/ The wastegate flap, as long as it's fully seated, that's 99.9% of the concern.

 

What I see here is lack of attention to detail. When it's so blatant, you have to ask yourself, what about the parts I can't see?
I'd contact the manufacturer and see if may be they could at least provide you with something that looks finished.

 

It's common with the Black series EFR turbos. A file will clean it up quickly. That said, you're right for a $2000+ turbo it shouldn't be there.

 

We have still yet to see an EFR fail, only had one in for warranty and it was FOD in the oil system ( freshly rebuilt porsche engine). I've never seen a more reliable turbo in my entire career( that is 20+ years).

 

I'm not suggesting that there are failures in this product line, only that obvious quality control issues should raise concerns. It would seem that as a Borg Warner vendor, it would be in your interest to see these issues resolved.

 

Elliot isn't an actual dealer/vendor for BW as I understand it, he buys his turbos from full-race and sends them on. He would have as much weight as you or me if he complained to BW about the casting.

That's not to say that any turbo purchased from him is necessarily subpar, simply that if you had issues then he would be a middle man between the customer, the dealer (full-race) and the manufacturer. I realized that this past winter when the shop my car is at ordered me an EFR from BW and was given like a 3 month lead on availability. I mentioned turbos being available from Elliot and they declined due to him *not* being a part of the BW dealer network.

 

High Performance Academy has got some preliminary dyno results on the EFR 8474 FD;