Aux port delete for FI discussion
Open them just before they become a restriction to flow....
The best way to test it is start with stock and - do WOT pulls every 100 RPMs, and compare g/sec readings.... look for the best curve.
The best way to test it is start with stock and - do WOT pulls every 100 RPMs, and compare g/sec readings.... look for the best curve.
I divide by zero
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From: Y-cat-o NZ
/\ agree with Kane . FWIW I've played with that a LOT and eventually came to the conclusion that anything below 6000 was too early and it was swings and roundabouts between 6000-7000 .
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The issue of the lean spike when they open needs to be discussed as well i think . I came to the conclusion that the spike is acceptable so long as it was not lean either side of the spike . Any advance on that ?
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OK . Found the correct formula (i think) for calculating temp of compression :
(PR^0.28-1) x T absolute x 1/turbo efficiency x intercooler eficiency (say 50%)
So for my example we get
@10psi UIM and 14.5psi post turbo, 60% turbo efficiency and 20C ambient(=293Kelvin) :
(1.99^0.28-1) x 293K x 1/0.6 x 50/100 = 51.8C
So a rise in temp of 31.8C
@7.5psi UIM and 12psi post turbo , 55%turbo efficiency and 20C ambient:
(1.82^0.28-1) x 293K x 1/0.55 x 50/100 =48.6 C
Rise in temp of 28.6C
So for my setup I'm better off staying with ports open .
There would have to be a turbo efficiency increase of 12% to make NOT opening the ports worthwhile ...
(PR^0.28-1) x T absolute x 1/turbo efficiency x intercooler eficiency (say 50%)
So for my example we get
@10psi UIM and 14.5psi post turbo, 60% turbo efficiency and 20C ambient(=293Kelvin) :
(1.99^0.28-1) x 293K x 1/0.6 x 50/100 = 51.8C
So a rise in temp of 31.8C
@7.5psi UIM and 12psi post turbo , 55%turbo efficiency and 20C ambient:
(1.82^0.28-1) x 293K x 1/0.55 x 50/100 =48.6 C
Rise in temp of 28.6C
So for my setup I'm better off staying with ports open .
There would have to be a turbo efficiency increase of 12% to make NOT opening the ports worthwhile ...
Does change things a bit but does not change the concluision .....
As the boost pressure gets higher however -it becomes interesting because the %difference in boost is a lot less and the difference in turbo efficiency may be higher for the same flow .
Brain Exploding .................................................. .....................................
NOW !
Last edited by Brettus; Feb 12, 2010 at 05:38 PM.
well just found out that my 334 g/sec at 6981 rpms was with the apv CLOSED.
The gear on the manifold side had come loose and the gear was just hanging there--i was getting apv obd 2 code also.
HMMMMM---since my redline is max at 7.5K maybe its best to leave them closed for me>.
The gear on the manifold side had come loose and the gear was just hanging there--i was getting apv obd 2 code also.
HMMMMM---since my redline is max at 7.5K maybe its best to leave them closed for me>.
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well just found out that my 334 g/sec at 6981 rpms was with the apv CLOSED.
The gear on the manifold side had come loose and the gear was just hanging there--i was getting apv obd 2 code also.
HMMMMM---since my redline is max at 7.5K maybe its best to leave them closed for me>.
The gear on the manifold side had come loose and the gear was just hanging there--i was getting apv obd 2 code also.
HMMMMM---since my redline is max at 7.5K maybe its best to leave them closed for me>.
You just need to pull the DC motor plug to stop them opening ....
I would think more flow with them open but till you do the log ..............
Last edited by Brettus; Mar 1, 2010 at 08:29 PM.
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IAT from just before throttle plate
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 ......
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 ......
Aux ports open
Max MAF 320 (sitting around 315 for same range as above)
Boost pressure : 10psi to 6300 dropping away to 7psi approx. from there)
ambient temp : 21C
Start IAT temp : 35C
End IAT temp : 38.5C
So - not exactly an equal comparison test but interesting to see that even though MAF is 5% higher for the 2nd test , temp rise is only slightly more.
Too little data to make a conclusion but it leans towards aux port open as being the better way to go .
Last edited by Brettus; May 14, 2010 at 12:02 AM.
Coupla things:
1) @ 21°C ambient you are seeing charge temps of 38.5°C ?!?!? What is going on there? AT 21°C, my charge temps wont go above 30°C MAXIMUM.
2) How do you draw a conclusion about the AUX ports with that data? g/sec max? At what RPM does that happen? You state that your manifold pressure drops by 30%, but your flow goes up, yet your intake charge temps are >15°C delta?
1) @ 21°C ambient you are seeing charge temps of 38.5°C ?!?!? What is going on there? AT 21°C, my charge temps wont go above 30°C MAXIMUM.
2) How do you draw a conclusion about the AUX ports with that data? g/sec max? At what RPM does that happen? You state that your manifold pressure drops by 30%, but your flow goes up, yet your intake charge temps are >15°C delta?
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I really didn't have the inclination to test this further as I can see that either way - there is not a lot in it .My flow does not go up - it stays approx. level at 315ish g/s from 7000 onwards . See chart below for example .I'm just reporting what I see . Not sure what point you are making ?
Last edited by Brettus; May 14, 2010 at 04:07 PM.
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this is interesting,,...i have had the turbo for more than 20 K, and my APV was always openned....LOL....we kept it openned, so my turbo can get in, LOL....
it's tru and low RPM is ****, until it hits 4K.....LOL...
now i know how it works....
good job
steven
it's tru and low RPM is ****, until it hits 4K.....LOL...
now i know how it works....
good job
steven
reviving old thread.
I will be doing some caveman data collection with my apvs open this w/e ( i have the Pettit kit)
I have 8.5# of boost available at 2.5--2.7K. and i have modified the lim to maximize as best I could smoother flow. I removed all internal casting marks, thrumpheted the runners as best I could, port matched, and premently removed and sealed the vdi /area. I also have a drilled TB.
We shall see.
I have already just cranked it up and my a/f's were ok in closed loop.
OD
I will be doing some caveman data collection with my apvs open this w/e ( i have the Pettit kit)
I have 8.5# of boost available at 2.5--2.7K. and i have modified the lim to maximize as best I could smoother flow. I removed all internal casting marks, thrumpheted the runners as best I could, port matched, and premently removed and sealed the vdi /area. I also have a drilled TB.
We shall see.
I have already just cranked it up and my a/f's were ok in closed loop.
OD
i dont know if I will clear anything up or not?
My goal for my set up seems to be a little different from many others.
For instance--i have never though this engine was stout/balanced enough for a 9K+ redline and to have a 75K life expectancy. So I self lowered mine to 7.5K and I never exceed (if i can help it) 8K. I have been told by multiple established and reputable people--including Cam /Pettit, Paul, Rick E/Mazmart etc that a standard build na engine would probably be good to 8.2K
So if 7.5 is my most used redline what good is an intake valve that opens at over 6K? Not much.
As said I have over 8 lbs boost just off idle ( we idle at 1.2K). I have good maf readings (365 g/sec) below 8K. So what I am looking for is to expand the power available "under the curve" so to speak. I would like to increase that area from 3.5 to7K.
Bret did some good work exploring this and he found the best solution for his car. My car and goals are different from his.
Heck I may even play with consistant partial openings of the apv. Say 75% versus 100%--you get the idea.
My gut thinks that the apv can be more utilized in fine tuning the car. I may be wrong, but in the least I will probably learn first hand what NOT to do!
OD
My goal for my set up seems to be a little different from many others.
For instance--i have never though this engine was stout/balanced enough for a 9K+ redline and to have a 75K life expectancy. So I self lowered mine to 7.5K and I never exceed (if i can help it) 8K. I have been told by multiple established and reputable people--including Cam /Pettit, Paul, Rick E/Mazmart etc that a standard build na engine would probably be good to 8.2K
So if 7.5 is my most used redline what good is an intake valve that opens at over 6K? Not much.
As said I have over 8 lbs boost just off idle ( we idle at 1.2K). I have good maf readings (365 g/sec) below 8K. So what I am looking for is to expand the power available "under the curve" so to speak. I would like to increase that area from 3.5 to7K.
Bret did some good work exploring this and he found the best solution for his car. My car and goals are different from his.
Heck I may even play with consistant partial openings of the apv. Say 75% versus 100%--you get the idea.
My gut thinks that the apv can be more utilized in fine tuning the car. I may be wrong, but in the least I will probably learn first hand what NOT to do!
OD
