75mm vs 70mm TB

K

keisers1001

Registered User
I don't know why it is so hard to get info from the vendors, but I am trying to find out what the INLET OUTER diameter is on the 70mm vs 75mm throttle body...are they the same size??. I am going to purchase a POWER throttle body; I have head, valve, cam, intake, and exhaust mods. I am using a 73mm c&l mass air. Does the 75mm really make that big of a difference?? Please help!!

Thanks, John
 
i put a 65 mm on mine it feels slower below about 3000 rpm
for normal highway driving i dont think i would reccomend it, i wish i had the stock one back but i took a 65 mm plate from a newer crown vic and honed my stock throttle body out so it would fit, i still get over 30 mpg highway though
 
Last edited:
keisers1001 said:
I don't know why it is so hard to get info from the vendors, but I am trying to find out what the INLET OUTER diameter is on the 70mm vs 75mm throttle body...are they the same size??. I am going to purchase a POWER throttle body; I have head, valve, cam, intake, and exhaust mods. I am using a 73mm c&l mass air. Does the 75mm really make that big of a difference?? Please help!!

Thanks, John
Click to expand...
They both have 3" outlets. If you have a stock inlet then go no bigger than 70MM. The inlet cannot be ported enough to take proper advantage of a 75MM TB.
 
rlong said:
i put a 65 mm on mine it feels slower below about 3000 rpm
for normal highway driving i dont think i would reccomend it, i wish i had the stock one back but i took a 65 mm plate from a newer crown vic and honed my stock throttle body out so it would fit, i still get over 30 mpg highway though
Click to expand...

Did you re-calibrate your sensor?...maybe this would help
 
Good information Dave... I too have been trying to make the decision on which TB to go with the stock inlet. Now with that information, I will go with the 70mm. I have no future plans to upgrade the inlet other than porting it.

Thanks again

Bryan
 
I use a 3 1/4" (TB) to 3 1/2" (MAF) adapter hose on my 70mm, the 3" was just too tight.
 
OK, let me rephrase that. Both the 70 and 75mm Tb's have the same outer flange diameter as stock. It is 3.2" and I use (as do all aftermarket air tube kits) a 3" hose that is stretched slightly to fit. I wasn't aware of any 3.25" tubing. Where do you get it?
 
u can just use couplings for plumbing found at a hardware store, same thing, come with clamps and are made from rubber. just as a alternative.
 
Those turbo couplings are not the same as the couplings you find at hardware stores.

The air to air after cooler connections are made of a re-inforced silicon hose rated to deal with the heat that can be experienced at the outlet of a turbo charger. They are also much more structurally solid than what you'll find at the hardware stores.

Typically they are connected to the tubes by special screw clamps that feature a constant torque feature. The constant torque feature is needed to allow the clamps to be tight enough to deal with high boost pressures yet not to break when the heat of the intake gases expands the metal tubes.

For the connections ahead of the SC, the hardware parts likely are just fine. But for creating couplings after the SC outlet you'll need something more sturdy.

I worked with these types of connections extensively with Caterpillar 3406B 6 cylinder diesel engines with air to air aftercoolers used in over the road trucks.
 
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