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throttle body question


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September 27th, 2010, 1:06 PM   #1  
throttle body question

I was lookin to put a BBK throttle body on my 01 silverado 5.3 but i was wonderin whats the difference between the 80mm and the 85mm that they offer? and is it actually worth gettin the throttle body or would it be just wastin money? i already plan to do electric fans with this also

 
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September 27th, 2010, 1:21 PM   #2  
The difference in size is a big difference in volume/air flow, but the problem is if you haven't done anything else to the motor ie. cam, bottom end, heads, headers etc. a bigger throttle body such as an 85mm may hurt your power band. what needs to be figured is the volumetric efficiency of your motor as it sits then decide what size throttle body actually is best suited for your engine(unfortunately I don't remember the formula off the top of my head and I don't have my cheat sheet on me either).

 
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September 27th, 2010, 3:40 PM   #3  
well all i have done to the truck is a CAI and a programmer then the electric fans are comin so would i just get the 80mm considerin i only have simple mods done to it? im just lookin to get a lil bit more power out with the fans and some more throttle response with the throttle body

 
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September 27th, 2010, 8:08 PM   #4  
I'm not sure how big the stock throttle body is but with only a CAI and some tuning done the 80mm would probably be your best bet. Something to do if you do upgrade is port your intake to match the throttle body. It will make the fair flow a lot smoother than if you just bolt on a bigger throttle body. Really the only thing the electric fans will do is eliminate the drag that you would normally have with a fan clutch.

 
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September 28th, 2010, 9:29 AM   #5  
how would i go about portin my intake to match the throttle body?

so the fans won't really help in the gas mileage department? thats my biggest concern to get some more mpg cause even drivin normal im only gettin about 14-15

 
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September 28th, 2010, 12:56 PM   #6  
When you install your throttle body center it by opening up the butterfly put it on finger tight then open up the butterfly again and mark how much of the intake needs to be taken out. The next step involves a dremel a rag and a very steady hand. You'll need to use a dremel with a mild grinding wheel/drum to grind out the area that overhangs past the throttle body, be extremely careful not to grind into any coolant passage that may or may not be around the opening(the rag gets stuffed into the intake to prevent debris from getting down there). I probably should have edited that statement about the fans, it will reduce the drag on the motor freeing up more power, it'll help aid in extending the life of your water pump and I've heard other guys that do it claim an increase in MPG but I haven't seen actual results nor done it myself yet so that much I'm not sure about. Mostly though guys replace the fan clutch with electric fans to free up the power that the clutch drags off the motor.

 
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September 29th, 2010, 12:18 PM   #7  
so all in all will the different throttle body add a little more power? or just do throttle response? or both with portin the intake to match it? and is it worth spending the money on the electric fans for that power and mpg gain?

 
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September 29th, 2010, 2:33 PM   #8  
A bigger throttle body increases air flow and volume which will increase horsepower and torque numbers and makes throttle response better, porting the intake to match aids in the increase in power by allowing the air to flow smoother into the intake. the power gain from switching to electric fans is IMO worth the price(that's the next step on my S-10).

On a side note one thing that a lot of people miss is the fact that you can't have performance and MPG, to get one you have to sacrifice the other.

 
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September 29th, 2010, 11:07 PM   #9  
I've heard that a throttle body spacer "adds 10 hp but eats gas." So from what I have heard, not something you want to do if you are looking to be more efficient.

 
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September 29th, 2010, 11:59 PM   #10  
well i kinda really want the power more than the mpg...i guess ill just sacrifice that. but from the sounds of it i'll be gettin a 80mm bbk throttle body and some dual electric fans then i'll try and either find someone to port my intake or do it myself(i have knowledge of these things but would rather someone who does it on a daily basis do it)

 
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