3.25 or 3.5 tmic which one would u choose

andre0121

Member
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mazdaspeed 3
im not sure which one to go with i heard the 3.5 is too big yet people say its good...also i was told i should upgrade motor mount before if not my engine will toss the intercooler too much ?
 
i have the 3.25" and it works great, but its true, cooling air doesnt flow as well as with the stocker, but half of that could be due to the alumn surround on it not fitting very well on the 3 (its not big enough to seal with the shroud). But in the end, it doesnt heat soak while driving down the road, so there is alot of false info out there.
 
im not sure which one to go with i heard the 3.5 is too big yet people say its good...also i was told i should upgrade motor mount before if not my engine will toss the intercooler too much ?

if u dont get a motor mount u can just cut a bit off the intercooler so it wont rub... i remember hearing that 3.5 was too big and that the air ducts didnt cover the entire intercooler. 3.25 would be a good upgrade but you should search and look at dyno graphs with before and after of each.
 
a dyno wont show a direct indication of change from stock to aftermarket ic because of the relatively weak airflow from the fans on ic compared to wind while rolling down the road. A better indication would be to know how much timing the engine is running under identical circustances to compare the cooling efficiency. the most prime time for this comparpson is after the car has been sitting and idling for a while, timing is changed to compensate for the hotter intake charge to prevent knock. How quick the timing returns to normal after driving is proof of how efficient the ic is. msd dashhawks have the abilitly to monitor timing but not post ic intake temps. Anyone with msd dh willing to test different ic?
 
the 3.5 is the best. to the guy that said 3inch. you my friend are confused and should not post useless info. 3.25will work just fine. the 3.5 flows better, plain and simple.
 
the 3.5 is the best. to the guy that said 3inch. you my friend are confused and should not post useless info. 3.25will work just fine. the 3.5 flows better, plain and simple.

3.5 core = more volumetric mass of air being cooled. to the dude that said 3 is enough that might be tru, but if the stock turbo is able to run 20psi the larger core will come in handy. It will produce more lag when you punch it but you will also get a harder pull and feel once the cool air is pushed out of the IC and into the engine. more mass = more lag, but cooler air = efficient power
 
He actually is saying that the 3inch is better than the 3.5. Im saying that is crazy talk. 3.5 with flow more volume and have better cooling capabilities in turn making more power. Especially at the higher boost levels on small turbod cars. Spool up is not issue on this car and if you are gonna go big tmic I would say 3.25 bare minimun. FOR SURE!
 
I've read that anything greater than 3 inch makes no discernible difference in power. The stock is 2 inch I believe. I have a 3.25 and am pleased with the results. The Autoexe is 3 inch I believe.
 
I believe if you shim up the bottom of your intercooler like mine is, you will get more airflow through the thicker core. I raised mine about a 1/4 inch. Anything is better than that stock piece, ill tell you that.
 
tmic ets 3.25 or 3.50

I believe if you shim up the bottom of your intercooler like mine is, you will get more airflow through the thicker core. I raised mine about a 1/4 inch. Anything is better than that stock piece, ill tell you that.

the sizes are 3.25 or 3.50 the 3.50 will only fit with a vented hood. SU also sells 2 different cf hoods ones vented for ms3.
 
I believe if you shim up the bottom of your intercooler like mine is, you will get more airflow through the thicker core. I raised mine about a 1/4 inch. Anything is better than that stock piece, ill tell you that.

It sure would be nice if someone would just offer an aftermarket hood in which the primary gain is raising the already stock raised section to accomadate a larger TMIC and more space between the valve cover and the IC.
Every After market hood is focusing on weight savings. Weight savings on this hood is a joke cause it only weighs 39 lbs as is. Not much more to save there, but space.....
 

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