Aluminum AST comparison?
#1
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Aluminum AST comparison?
Which is "better", the Pettit unit or the one from Tri-Point Engineering? I am going to need one, or find a good stock unit, as I broke mine when I took it off to remove the engine.
#2
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Doubt if there has ever been a comparison one. But I use the Pettit one. Pettit is, as im sure you know, known for their high-quality parts. That reason alone is why i went with Pettit. Plus its an AST, as long as its not plastic you'll be ok.
#4
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Somewhere in the deep, dark recesses of the 'Net, in one of the numerous pages of things I read on FD reliability, I seem to recall that someone had related that only the factory AST did the job as intended, i.e. creating a stagnant coolant zone that actually separated the air out, and that aftermarket ones only imitated the design of the original. Something about the plastic ones having a special inner-chamber found lacking in the aftermarket ones?
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Originally Posted by bajaman
Somewhere in the deep, dark recesses of the 'Net, in one of the numerous pages of things I read on FD reliability, I seem to recall that someone had related that only the factory AST did the job as intended, i.e. creating a stagnant coolant zone that actually separated the air out, and that aftermarket ones only imitated the design of the original. Something about the plastic ones having a special inner-chamber found lacking in the aftermarket ones?
Originally Posted by KevinK2
>The inlet (from the hot side of the radiator) is restricted:
That is the ast outlet at the bottom with .086" dia restrictor, going to the lower tank. by deleting this restrictor, aftermarket pettit and other asts look good, but bypass the rad with the hottest coolant that needs to be cooled.
That is the ast outlet at the bottom with .086" dia restrictor, going to the lower tank. by deleting this restrictor, aftermarket pettit and other asts look good, but bypass the rad with the hottest coolant that needs to be cooled.
https://www.rx7club.com/3rd-generation-specific-1993-2002-16/ast-dissected-433610/
As far as I know all aftermarket ASTs remove this restriction so an aluminum AST that maintains this restriction is the "best" AST, if one exists.
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#8
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Originally Posted by bajaman
Something about the plastic ones having a special inner-chamber found lacking in the aftermarket ones?
Given the fact that coolant enters from the side of the tank and exits from the bottom any air bubbles tend to stay in the tank since they can't exit out the bottom hose; they always float to the top.
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Originally Posted by bajaman
Thanks, BlueRex! I guess that answers THAT question regarding the stock unit, huh?
I wonder who makes that aluminum one shown in the thread post #10, by EFS.O?
I wonder who makes that aluminum one shown in the thread post #10, by EFS.O?
#13
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i had the same problem with my pettit ast. The neck for the pressure cap would not hold more that 7psi. My coolant would sometimes come out the over flow when i turn off the engine. I tested the pressure cap twice and it was fine, it was the stupid neck on the ast. It would be an easy fix if knew how to weld, you could order a billet al filler neck from summit for around $25.
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Originally Posted by bajaman
Which is "better", the Pettit unit or the one from Tri-Point Engineering? I am going to need one, or find a good stock unit, as I broke mine when I took it off to remove the engine.
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i believe the pettit uses a larger cap than stock. my tripoint used the stock cap and had a restrictor in the bottom connection. the tripoints are also anodized black while the petit is greyish powder coat.
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I got my metal AST from RX7.com too and has worked out great for me. Reason why the metal one is better, is that the stock plastic ones have the tendancy to melt and leak.
#17
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[QUOTE=RX-7racer88]I got my metal AST from RX7.com too and has worked out great for me.
He wasn't asking why the metal one was beter than factory, he wanted to know the differences between the pettit and the tri-power AST's
Originally Posted by RX-7racer88
Reason why the metal one is better, is that the stock plastic ones have the tendancy to melt and leak.
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Picture of my Tri-point AST, not the factory small cap. The neck is much stouter than the Pettit (billit I believe) and the neck doesn't bend or move when your pushing down ton the cap to install or remove it. JAck
Here is the Pettit AST note the lever style and larger cap
Here is the Pettit AST note the lever style and larger cap
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Originally Posted by sevensix
i have that same purple tripoint ast. but it has a different cap.. is your cap oem?
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Originally Posted by eo2am
has any body tried the Greddy AST tank?