85 Throttle body vacuum/Coolant port help
#1
85 Throttle body vacuum/Coolant port help
So short story long... I wanted to upgrade my 85's throttle body.. just
because.. I bought a Summit racing model #SUM-228707. My stock TB has (on the passenger side) one upper port going to my passenger side valve cover and one lower port (IAC housing) going to heater core...
So I swap everything out.. and the new TB has 3 ports on the passenger side.. what the crap. what does the other port go to? So I began looking at other throttle bodies and they all seem to have 3 ports.. So maybe my 85 stocker is the odd ball out...Any help in clarifying what I need to do with this extra port would be greatly appreciated.
- Mark
because.. I bought a Summit racing model #SUM-228707. My stock TB has (on the passenger side) one upper port going to my passenger side valve cover and one lower port (IAC housing) going to heater core...
So I swap everything out.. and the new TB has 3 ports on the passenger side.. what the crap. what does the other port go to? So I began looking at other throttle bodies and they all seem to have 3 ports.. So maybe my 85 stocker is the odd ball out...Any help in clarifying what I need to do with this extra port would be greatly appreciated.
- Mark
#2
Team Owner
So short story long... I wanted to upgrade my 85's throttle body.. just
because.. I bought a Summit racing model #SUM-228707. My stock TB has (on the passenger side) one upper port going to my passenger side valve cover and one lower port (IAC housing) going to heater core...
So I swap everything out.. and the new TB has 3 ports on the passenger side.. what the crap. what does the other port go to? So I began looking at other throttle bodies and they all seem to have 3 ports.. So maybe my 85 stocker is the odd ball out...Any help in clarifying what I need to do with this extra port would be greatly appreciated.
- Mark
because.. I bought a Summit racing model #SUM-228707. My stock TB has (on the passenger side) one upper port going to my passenger side valve cover and one lower port (IAC housing) going to heater core...
So I swap everything out.. and the new TB has 3 ports on the passenger side.. what the crap. what does the other port go to? So I began looking at other throttle bodies and they all seem to have 3 ports.. So maybe my 85 stocker is the odd ball out...Any help in clarifying what I need to do with this extra port would be greatly appreciated.
- Mark
If they are vacuum ports, cap them off if you are not using.
#3
You guys havent steered me wrong yet. Let me know!
Last edited by Markever234; 05-15-2018 at 11:20 PM.
#4
Team Owner
An upgrade? hmm... its not 30 years old.. and thats probably about it. Its a twin 58mm, but there isnt really any mods done to the car yet to take advantage of the increased size. I'm planning long tubes and straight-piped 2.5inch exhaust. I might see a few horses then.
Going back to the capping. I could be wrong but wouldnt capping(especially at the TB) increases turbulant air going into the runners thus reducing flow/HP?
You guys havent steered me wrong yet. Let me know!
Going back to the capping. I could be wrong but wouldnt capping(especially at the TB) increases turbulant air going into the runners thus reducing flow/HP?
You guys havent steered me wrong yet. Let me know!
If you don't cap it, there will be a vacuum leak and that will cause problems. I doubt it will do anything bad if you cap it.
The following users liked this post:
Markever234 (05-16-2018)
#5
58 mm is too big for your stock 85.
52 mm is probably even too large.
Your best bet is too clean your stock TB (including the IAC housing) and reinstall.
Sell the 58 mm on ebay or CL; your preferred method or here in the For Sale section.
52 mm is probably even too large.
Your best bet is too clean your stock TB (including the IAC housing) and reinstall.
Sell the 58 mm on ebay or CL; your preferred method or here in the For Sale section.
The following users liked this post:
Markever234 (05-16-2018)
#6
Team Owner
Or if he just purchased it, return it
The following users liked this post:
Markever234 (05-16-2018)
#7
The stock TB is 700 - 750ish CFM, right? 6k rpm (higher than my or most other TPIs get) with a 383 can only suck down about 730, assuming everything is ported well. I had thought about getting a bigger TB, but the given the math and the cost, I decided against it. If you have a big cam, and 383+ cubes, then you might need it. But the stock TB will support plenty of power, I still run my stock one and I have no complaints about it.
#8
Team Owner
The stock TB is 700 - 750ish CFM, right? 6k rpm (higher than my or most other TPIs get) with a 383 can only suck down about 730, assuming everything is ported well. I had thought about getting a bigger TB, but the given the math and the cost, I decided against it. If you have a big cam, and 383+ cubes, then you might need it. But the stock TB will support plenty of power, I still run my stock one and I have no complaints about it.
#9
My brother understands fluid dynamics better than me, but we ran through the math, and having a larger than necessary throttle body will decrease air velocity, as well as introduce turbulence at WOT due to pockets of inconsistent air pressure. However, a bigger TB will feel faster, because your new 1/4 throttle is now much more air than before. You just top out at 3/4 throttle, and anything past that creates more turbulence.
#10
Team Owner
My brother understands fluid dynamics better than me, but we ran through the math, and having a larger than necessary throttle body will decrease air velocity, as well as introduce turbulence at WOT due to pockets of inconsistent air pressure. However, a bigger TB will feel faster, because your new 1/4 throttle is now much more air than before. You just top out at 3/4 throttle, and anything past that creates more turbulence.