Aux port delete for FI discussion
I think you are just bringing too much irrelevant info (for this particular discussion) to the table.
Port timing and volume is interesting and all, but in this instance, I think all we are looking for is hard data for this particular scenario.
Port timing and volume is interesting and all, but in this instance, I think all we are looking for is hard data for this particular scenario.
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Boosted Kiwi
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From: Y-cat-o NZ
some readings from first test
3000 rpm in 2nd gear through 3rd and to 8000rpm in 4th -( if any one has a better test that is easy to do on public roads i'm all ears)
Aux ports closed
Max MAF : 300g/s (sits at 295 from 6800 right through to 8000rpm)
Boost pressure : 9.5psi constant
ambient temp : 25C
Start IAT temp : 40C
end IAT temp : 43C
What I was going to compare was the speed of temp change hopefully at same maf , ambient and start temp ......
Last edited by Brettus; Feb 1, 2010 at 12:36 PM.
isnt your intercooler more efficent the hotter it gets? Just trying to think of this as apples to apples.
Wouldnt the intercooler efficentcy have to be a constant?
This is interesting. Especially if the 2nd run with the ports open shows no temp change.
Whats the bet gentleman? ---significant change are no significant change?
Arggggh---Thanks to your info i certainly have a better understanding of why MM has advocated the use of bigger injectors in the P1 spots instead of the P2's. Appreciate that.
Wouldnt the intercooler efficentcy have to be a constant?
This is interesting. Especially if the 2nd run with the ports open shows no temp change.
Whats the bet gentleman? ---significant change are no significant change?
Arggggh---Thanks to your info i certainly have a better understanding of why MM has advocated the use of bigger injectors in the P1 spots instead of the P2's. Appreciate that.
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Tried to do the second run yesterday but ran into laptop/software issues and was unable to measure IAT . 
Wish Hymee would get IAT onto dudelogger - would make it much easier for me ....

Wish Hymee would get IAT onto dudelogger - would make it much easier for me ....
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I did manage to get MAF info however which demonstrates the loss of power that happens when aux ports open .
I believe more power is lost than what we see on a dyno because dynos typically get their readings at a much slower acceleration rate than what we see on the road ....
I believe more power is lost than what we see on a dyno because dynos typically get their readings at a much slower acceleration rate than what we see on the road ....
Last edited by Brettus; Feb 2, 2010 at 01:38 PM.
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the point of the exercise was to see what the delta T was with the same MAF . I can fiddle the wastegate to achieve identical maf from 7000 onwards with either setup .
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Kane made a very good point which throws doubt into my mind - I don't mind if I end up proving myself (and MM) wrong if I at least learn something from it .
Last edited by Brettus; Feb 2, 2010 at 03:26 PM.
Learning--sometimes is half the fun of it all.
I wish I had a fully equipped garage/lab to do a lot of the tests I would like to do--properly.
Best i can come up with is a multi tester, stethoscope, timing light, thermometer ,vacuum/boost , obd2 stuff and a somewhat understanding tolerant wife.
OD
I wish I had a fully equipped garage/lab to do a lot of the tests I would like to do--properly.
Best i can come up with is a multi tester, stethoscope, timing light, thermometer ,vacuum/boost , obd2 stuff and a somewhat understanding tolerant wife.
OD
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I maybe started off the thread over enthusiastically but at least I did label it "discussion" .......
FWIW : I have looked back on previous logs I did (aux. ports open) some time ago which show a very similar delta T to the aux ports closed test I did so I'm not expecting any great ZOMG revalation from any testing that I do.
Last edited by Brettus; Feb 3, 2010 at 04:24 PM.
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I did a little digging and came up with this formula for calculating the temp diff.
I'm not 100% sure this is correct but i'll plug in the numbers anyway :
T1 x (P2/P1) x (1/ compressor efficiency) = T2
So for my particular example taking the pressure at the turbo outlet ,reading efficiency off the chart in my first post (not 100 % correct because It is off the chart but the difference should be about right ) and keeping MAF the same :
Aux ports open
25C x (26.7/14.7) x (1/0.65) = 69C
Aux ports closed
25C x (29.2/14.7) x (1/0.60) = 82C
From this it seems it is better for me to leave them open ......
I'm not 100% sure this is correct but i'll plug in the numbers anyway :
T1 x (P2/P1) x (1/ compressor efficiency) = T2
So for my particular example taking the pressure at the turbo outlet ,reading efficiency off the chart in my first post (not 100 % correct because It is off the chart but the difference should be about right ) and keeping MAF the same :
Aux ports open
25C x (26.7/14.7) x (1/0.65) = 69C
Aux ports closed
25C x (29.2/14.7) x (1/0.60) = 82C
From this it seems it is better for me to leave them open ......
Last edited by Brettus; Feb 6, 2010 at 03:00 PM.
So let me get this straight for all the people that want a simple logical answer. Your saying instead of closing off the aux ports its better to simply run them always open for better efficiency and lower temps. Is this correct?
No, it just means that more flow at a lower PSI is overall better temperature wise.
You still have to tune around it, which can be hard.
If you leave them open all the time you lose a lot of air velocity down low.
You still have to tune around it, which can be hard.
If you leave them open all the time you lose a lot of air velocity down low.



