Street Port MPG?
01-15-09, 07:47 AM
#26
Porting the engine allows more air flow. More air means that you need to add more fuel or it will run lean. Same holds true for turning up the boost, if you are pushing more air you need to add more fuel.
Anyone can get decent fuel economy if they are tuned lean, do not go WOT, and not exceding 3500rpm so that the secondaries never come on. You will also not make any power. If this is how you plan on driving the car then there is no need for any porting, it will actually hurt performance as the power band will be moved higher in the RPM range. If you want to just putter around then leave the engine ports stock so that you do not hurt the low end torque.
Anyone can get decent fuel economy if they are tuned lean, do not go WOT, and not exceding 3500rpm so that the secondaries never come on. You will also not make any power. If this is how you plan on driving the car then there is no need for any porting, it will actually hurt performance as the power band will be moved higher in the RPM range. If you want to just putter around then leave the engine ports stock so that you do not hurt the low end torque.
01-15-09, 08:10 AM
#27
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Bascially Im trying to get to the 200whp number. I saw dyno numbers from an 88 n/a with aggressive street port done at Banzai Racing and it hit 188 without fuel management. Im hoping with the same port and an afc neo i can get to at least 195whp.
Okay so Ive got responses ranging from 26 mpg to 13. If I average those numbers Id be very content. Do the turbos get better or worse mileage in general?
Okay so Ive got responses ranging from 26 mpg to 13. If I average those numbers Id be very content. Do the turbos get better or worse mileage in general?
01-15-09, 09:25 AM
#28
There you have it, I would consider that pretty good MPG for highway. Stop and go, around town and high RPM driving will guzzle considerably more fuel. In our 13b-re single turbo vert, we see 22-26 MPG on the highway and 8-10 MPG when having fun....basically any time the secondary injectors come on line the gas gauge drops noticeably 
01-15-09, 01:24 PM
#29
Black Beast
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well with my car being a daily driver keeping it below 3500 is no problem going to work and back... i mainly want the port for weekend fun.
lots of good information
lots of good information
01-15-09, 03:11 PM
#31
https://www.rx7club.com/naturally-aspirated-performance-forum-220/my-bridgeport-project-754841/
e's making 30+ highway with a Bridgie, Itb's n Megasquirt
e's making 30+ highway with a Bridgie, Itb's n Megasquirt
01-15-09, 05:05 PM
#33
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01-15-09, 05:58 PM
#34
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Pumping mean effective pressure (pmep) should reduce giving greater Brake mean effect pressure (bmep) so in theroy should make the engine more efficient, but larger ports will have greater thermal losses therefore reducing efficiency. Swings and Roundabouts.
To conclude the ECU is putting the same AFR into the engine but the larger port allows more charge in but only if you demand it. Personnally I dont think a Street port would change they mpg if driven in the same manor, But under WOT the ported engine will use more fuel than a un ported engine.
To conclude the ECU is putting the same AFR into the engine but the larger port allows more charge in but only if you demand it. Personnally I dont think a Street port would change they mpg if driven in the same manor, But under WOT the ported engine will use more fuel than a un ported engine.
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