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BSFC number for stock EJ22T in a USDM 91-94 Legacy Turbo

Posted: Fri Jun 05, 2009 12:36 am
by baddriver
Would anyone know what the stock BSFC (brake specific fuel consumption) number is for a stock Legacy sport sedan?
(I did search both NASIOC and here before asking this)

Posted: Fri Jun 05, 2009 5:46 pm
by Legacy777
If it's anywhere, it's here

www.surrealmirage.com/subaru/files/SAE_boxer.pdf

I haven't had a chance to look through it in a while.

Posted: Fri Jun 05, 2009 5:50 pm
by asc_up

Posted: Fri Jun 05, 2009 5:51 pm
by Legacy777
Thanks....missed that.

Fixed mine too :)

Posted: Fri Jun 05, 2009 6:14 pm
by baddriver
Thanks for the link.

Although I didn't see specific BSFC info in there, but it's full
of good information.

Posted: Fri Jun 05, 2009 11:53 pm
by Matt Monson
I don't think Subaru ever published that. You would have to calculate it.

Posted: Tue Jun 16, 2009 7:07 pm
by samandw
Probably the best way to measure that is to buy some time on the Dyno, they can usually measure BSFC. Keep in mind though, that's usually WOT BSFC, which is very different than say cruise BSFC. If you want to calculate BSFC at say 60 mph on level ground, you can perform coast-down tests to determine the hp required to maintain 60 mph, and then compare that to the mpg you get to come up with a decent BSFC estimate.

BSFC can vary significantly dependent on throttle position and RPM. Making a TPS/RPM/BSFC or maybe a more useful hp/RPM/BSFC map would take a while on the dyno, but would be very doable. Either way, you're looking at creating a 3-dimensional plot.

Posted: Wed Jun 17, 2009 12:52 am
by 93forestpearl
All I know is that it is pretty high. 650cc injectors did not get me nearly as far as they would with the more modern heads and combustion chambers, even with hotter cams.

Posted: Wed Jun 17, 2009 8:12 pm
by baddriver
93forestpearl wrote:All I know is that it is pretty high. 650cc injectors did not get me nearly as far as they would with the more modern heads and combustion chambers, even with hotter cams.
Yeah, my car came with some extra MY98 2.5L DOHC heads in the trunk, and I've thought about putting these on or looking for 20g or 20k heads to make the motor more efficient.

I don't have the intake manifold though for the freebie heads, and I need to get them tested.