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Throttle body opening more than 90 degrees

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Old 03-24-2008, 03:02 AM
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Default Throttle body opening more than 90 degrees

So.. I heard that the throttle body blade opening a few more degrees over 90* is actually very normal and can make a little more horsepower.

Discuss.
Old 03-24-2008, 04:38 AM
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Think about what you just said. You have a round opening. You have a blade in the middle of it. If you go past horizontal you are restricting again by putting the backside of the blade into the way.
Old 03-24-2008, 04:58 AM
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like blanco said .. anything above 90 (or below) is going to put a blade surface back in the airstream.

Also consider the TPS signal. It reads in mili-volts. I'm just not sure what would be the consequences, in computer response, if you exceed the max amount (by opening the blade too far).
Old 03-24-2008, 05:33 AM
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Tell us where you heard this from. I am curious.
Old 03-24-2008, 06:20 AM
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Originally Posted by orangeapeel
Tell us where you heard this from. I am curious.
Most likely from someone who isn't familiar with most fuel injection systems. Modifying the air valve to allow 95* of opening is a popular thing to do with carbs. It helps the cylinders at the ends of the manifold to get as much air as the center cylinders.
Old 03-24-2008, 04:13 PM
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Originally Posted by orangeapeel
Tell us where you heard this from. I am curious.
Originally Posted by Marc 85Z28
Most likely from someone who isn't familiar with most fuel injection systems. Modifying the air valve to allow 95* of opening is a popular thing to do with carbs. It helps the cylinders at the ends of the manifold to get as much air as the center cylinders.
Just for clarification... I know that opening more than 90* is not good and will throw codes...it did it on my friends car. (his TPS voltage was 4.94..far over the limit of 4.71)

But, this is straight from a sponsor...


You should be able to open that blade far past 90 with no issue , it is not uncommon to go past 90 a little bit , we intentionally do this so the blade angle matches the air entry angle because the ls1 fbody induction system has the air entering on an angle . I don't see it possible that this can cause the problem you are having


I am not talking about it going up to the sky , but a few degrees past 90 is normal and will make a little bit more hp . That is one of the ways the FRE 91mm tb we sell makes more power than other tbs . I am not going to argue with you about this , we've done over 1000 throttle bodies in the last 5 yrs and you are the first person to ever mention a scenario like this to me.

Last edited by jetlag; 03-24-2008 at 04:25 PM.
Old 03-25-2008, 08:26 AM
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If you look down the bore of the MAF you can see the air is
coming into the TB from the top and you don't see the throttle
blade edge-on at 90 degrees. A bit over center would be closer
to airflow-parallel.

But TPS over 4.75V will bother the PCM, even if you don't set
a code it can mess up your WOT shift behavior on automatics.
If you want over-center throttle blade angle you have to deal
with that somehow.




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