AST hose "pill" restrictor ? valve in heater hose for track days ?
06-23-10, 01:45 PM
#1
AST hose "pill" restrictor ? valve in heater hose for track days ?
I found the below, and was wondering if there really is a pill / restrictor in the hose from the coolant-filller-neck to the AST ?
I have the stock hose and never felt one. Was the restrictor in the plastic tank nipple ?
Does the Pettit aluminum AST have a restrictor built-in ?
Is it even necessary ?
Does anyone run the valve during track days ?
Thanks,
:-) neil
<SNIP>
RELATED TWEAKS:
Rad, heater core, and AST are mostly in parallel, so hot coolant will only pass thru one of these. Aluminum AST's should have a .07" pill in the inlet hose, like the oem ast restrictor, to reduce coolant bypassing the rad. Might also consider a manual valve in heater core hose, to nearly close off during summer track events and force more coolant through the rad, and thru the exh side of block (credit cam worth).
<SNIP>
I have the stock hose and never felt one. Was the restrictor in the plastic tank nipple ?
Does the Pettit aluminum AST have a restrictor built-in ?
Is it even necessary ?
Does anyone run the valve during track days ?
Thanks,
:-) neil
<SNIP>
RELATED TWEAKS:
Rad, heater core, and AST are mostly in parallel, so hot coolant will only pass thru one of these. Aluminum AST's should have a .07" pill in the inlet hose, like the oem ast restrictor, to reduce coolant bypassing the rad. Might also consider a manual valve in heater core hose, to nearly close off during summer track events and force more coolant through the rad, and thru the exh side of block (credit cam worth).
<SNIP>
06-23-10, 01:52 PM
#2
IIRC, the restriction was in the AST nipple. The concern was that aftermarket AST's did not have this restriction in their nipples for that line. I don't know if you'll "need" it. I have not know too many people who have added the restriction back in after going with an aftermarket AST.
06-23-10, 02:46 PM
#3
Wastegate John
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When I had a custom ast made I had the guy make the restrictor(exact diameter of original) and press it in the nipple for the ast. My thoughts are that "mazda took the time to mold that brass piece in it for a reason" I put brass in bold because I wonder why they just didnt make the hole of the nipple that diameter. I guess they wanted to make sure it is an exact diameter.
As far as the shut off valve it could be true maybe the factory heat valve does not close all the way or maybe with age they dont work properly. However I think if that was the case then the a/c would not be as cold as it is
. But I am just guessing.
John
As far as the shut off valve it could be true maybe the factory heat valve does not close all the way or maybe with age they dont work properly. However I think if that was the case then the a/c would not be as cold as it is
. But I am just guessing. John
06-23-10, 05:20 PM
#5
Racecar - Formula 2000
I found the below, and was wondering if there really is a pill / restrictor in the hose from the coolant-filller-neck to the AST ?
I have the stock hose and never felt one. Was the restrictor in the plastic tank nipple ?
Yes.
Does the Pettit aluminum AST have a restrictor built-in ?
No, it does not.
Is it even necessary ?
IMO, yes. Too much flow there does 2 bad things - 1) it allows some hot water to bypass the radiator, and 2) too fast a flow will carry the air with it, rather than allowing it to accumulate in the AST.
Does anyone run the valve during track days ?
Thanks,
:-) neil
I have the stock hose and never felt one. Was the restrictor in the plastic tank nipple ?
Yes.
Does the Pettit aluminum AST have a restrictor built-in ?
No, it does not.
Is it even necessary ?
IMO, yes. Too much flow there does 2 bad things - 1) it allows some hot water to bypass the radiator, and 2) too fast a flow will carry the air with it, rather than allowing it to accumulate in the AST.
Does anyone run the valve during track days ?
Thanks,
:-) neil
06-23-10, 07:20 PM
#7
Racecar - Formula 2000
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06-23-10, 07:34 PM
#8
Wastegate John
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This is just a thought... What if you took the stock plastic ast and broke the brass restrictor out of it and then put that in the hose so there is no need to make one.
This is assuming that you dont care about the stock ast and that the brass restrictor's O.D. is bigger than the I.D. of the hose. You could just file it down to fit properly.
John
This is assuming that you dont care about the stock ast and that the brass restrictor's O.D. is bigger than the I.D. of the hose. You could just file it down to fit properly.
John
06-24-10, 08:06 PM
#11
This is just a thought... What if you took the stock plastic ast and broke the brass restrictor out of it and then put that in the hose so there is no need to make one.
This is assuming that you dont care about the stock ast and that the brass restrictor's O.D. is bigger than the I.D. of the hose. You could just file it down to fit properly.
John
This is assuming that you dont care about the stock ast and that the brass restrictor's O.D. is bigger than the I.D. of the hose. You could just file it down to fit properly.
John
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