Why block the coolant from the Intake Manifold??
Folks I noticed a few threads on how to block off the coolant from the manifold.
Why block the coolant passages in a stock manifold? Why is there coolant in there anyway? Does that apply for both 12A +13bA? FYI - I have an 85 12A Can I gain 10%HP or 20MPG by sticking in a couple quarters?? :Wconfused |
It is there to help warm the car up faster. By having a hot manifold the fuel does not atomize as well.
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coolant runs through the stock intake manifold to warm up the the manifold faster and make the car warm up faster...especially on cold days...one reason i sealed them.up is because with aftermarket manifolds the ports are actually welded shut..and you could put new o-rings...but i just optioned to bounce the coolant back sooner..by installing freeze plugs from pineapple racing...
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you can get the freeze plugs from any auto parts store, I used 20mmWx12mmD IIRC.
i blocked them off personally so i can change manifolds, without losing coolant/making a mess. isaac |
Quarters don't work that well. Get freeze plugs.
flight_of_pain, I hope you blocked off your ACV port too. Or hopefully you are using an aftermarket manifold. You do NOT want hot blasts of exhaust pulsating up into your manifold with no way to cool it. Yes, that is the other reason why Mazda has coolant flowing through the manifold, to keep it cool! I will not block off the coolant ports if the ACV port in the intermediate plate is active. You can shove a bunch of quick steel or devcon in there but it's a good idea to clean the carbon off first, which can be done with the engine in the car. If the car ever has to pass emissions, don't block anything. |
Another thing that the coolant passages do in the intake manifold is prevent intake icing. Ever notice how on piston powered planes they have a carburetor de-ice mechanism? this is because of the Venturi effect cooling the intake charge down below the freezing point, which at altitude can ice up the intake and choke the engine. I blocked mine because I hate the mess I make taking off the intake manifold with the ports enabled, and because I live in florida, where I'm always at sea level and it's hot as balls 24/7. :)
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Originally Posted by Jeff20B
(Post 8403377)
Quarters don't work that well. Get freeze plugs.
I beg to differ... Quarters worked well for me, and used slicone sealant to hold it in place. Granted I took them off a year later (after I went through a wrap-around side draft, to lake city side draft, to holly downdraft) for a nikki stripped and prepped carb. If given the choice between the two, definitely get the freeze plugs. Only reason I didn't was because all the shops around here didn't carry 20mm freezes. |
Originally Posted by Jeff20B
(Post 8403377)
Quarters don't work that well. Get freeze plugs.
flight_of_pain, I hope you blocked off your ACV port too. yep, that was taken care of before the engine went together :) isaac |
I wasn’t asking how (there are several threads) as much as Why or why not.
So far we have: Plus Side Warm the car up faster. To help vaporize the gas Prevent freeze up of the carb. Needed for ACV Minus Side Change manifold quicker easier There has to be a power gain or something for it to be common on the racetrack. |
You might want to do some re-reading because RX-7 Chris said the hot intake mani DOES NOT atomize the fuel as well. Also, how is being able to quickly swap manis a minus?
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Pros of blocking:
Colder air intake tepms make more power less mess Pros of leaving it alone: Faster warm up no carb icing needed when you have ACV That's all there is to it. |
Originally Posted by AverageJoe
(Post 8404771)
You might want to do some re-reading because RX-7 Chris said the hot intake mani DOES NOT atomize the fuel as well. Also, how is being able to quickly swap manis a minus?
If he meant that the coolant helps warm up the manifold but stops it from getting hot. Ok But the coolant is adding heat to the manifold after the engine warms up. So I think he mis-typed |
Regarding racing, a lot of folks do it because of protests. If you're in a class that requires stock porting and you get protested, you're going to have to remove the intake manifold in the pits, same day, and might have a race soon-after. Freeze plugs make the day MUCH easier.
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RX-7doc or Addict,
I wish you guys could chime in and give your opinions on this one :-) Mike |
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