58mm vs. 52mm TB
Thread Starter
Le Mans Master
Joined: Jul 2001
Posts: 6,252
Likes: 2
From: Silicon Valley Kalifornia
58mm vs. 52mm TB
I'm installing my Carroll kit (12 lb) and am wondering what advantage a 58mm throtle body has over a 52mm? Any real gain in a SC application?
TIA!~
TIA!~
Thread Starter
Le Mans Master
Joined: Jul 2001
Posts: 6,252
Likes: 2
From: Silicon Valley Kalifornia
Safety Car
Joined: Apr 2001
Posts: 3,525
Likes: 2
From: Houston TX
If your boost guage was accurate enough, the 58MM TB would show a slight decrease in boost (boost is engine's resistance to move the air that is being fed), but the flow should remain fairly constant (if not go up slightly). Power gain with the 58MM TB would be negligible with the mods you have listed.
Aaron
Aaron
Melting Slicks
Joined: Jan 2002
Posts: 3,293
Likes: 79
From: Jackson MI
I'm not so sure I agree. Boost is an engines resistance to airflow, yes, but the problem is that you are measuring the boost inside the manifold. If you are maxing out the flow rate of the TB then you are going to get a drop in boost across the TB. So by increasing the TB size you can actually increase boost.
This falls under the same principle as an intercooler. If it becomes a restriction in the intake track then you will get less boost on the other side of the intercooler than if it is a larger diameter/higher flowing IC.
This falls under the same principle as an intercooler. If it becomes a restriction in the intake track then you will get less boost on the other side of the intercooler than if it is a larger diameter/higher flowing IC.
Safety Car
Joined: Apr 2001
Posts: 3,525
Likes: 2
From: Houston TX
It is going to have to be at considerably higher boost / airflow for the TB to become a significant restrictor to boost. I stand by my original statement that there will be little, if any, change.
Aaron
Aaron
Burning Brakes
Joined: Aug 2006
Posts: 1,061
Likes: 99
From: Seattle WA
A stock MAF on an '87 will flow less than a stock 48mm TB so that will become your bottleneck in flow. Going to a larger TB will have little to no effect. Also, keep in mind that stated CFM flow rates are usually standardized to a particular vacuum level applicable for NA cars. Under boost, the flow numbers of any particular component will be much higher.
Le Mans Master
Joined: Apr 2005
Posts: 8,077
Likes: 4
From: Scarborough ONTARIO
I would recommend 58mm TB regardless of engine CID, if u dont get benefit than u wont loose either atleast, check golenengineservice.com and use thier calculater to evaluate if u need bigger TB.
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