TB and Plenum?
08-01-2006, 09:40 PM
#6
5th Gear Member
Join Date: Apr 2004
Location: CA
Posts: 3,023
RE: TB and Plenum?
i ve seen F/I with 65mm and i asked the guy shouldnt he upgrade and he told me no it was plenty. but he was an older guy , so idk if that mean he DOES or DOESNOT know what he is talking about, car ran 12s.
08-01-2006, 09:47 PM
#7
4th Gear Member
Join Date: Jul 2006
Location:
Posts: 1,495
RE: TB and Plenum?
TB/Plenum may only add a couple hp..... Im on the stock one for now. I heard that the TB/Plenum combos can lean out your a/f ratio up to 30%, so I wanna stay nice and rich for the n20. Maybe when I get a tuner, ill throw in the combo, and add fuel...
08-01-2006, 10:06 PM
#8
5th Gear Member
Thread Starter
Join Date: Mar 2004
Location:
Posts: 2,284
RE: TB and Plenum?
ok, I already have the combo accufab 70 mm. Was just thinking about upgrading to the 75 mm is all. I'm thinking I'm not not going to, lol. Back and forth. In fact, I think I'm going to go out right now in the 100 heat and take all the plugs out and check them for carbon buildup. She was running pretty rich before my tune, so they may be black on the diode. Get back on here later.
08-01-2006, 10:20 PM
#9
3rd Gear Member
Join Date: Jan 2006
Location:
Posts: 505
RE: TB and Plenum?
ORIGINAL: Frostbitten
TB/Plenum may only add a couple hp..... Im on the stock one for now. I heard that the TB/Plenum combos can lean out your a/f ratio up to 30%, so I wanna stay nice and rich for the n20. Maybe when I get a tuner, ill throw in the combo, and add fuel...
TB/Plenum may only add a couple hp..... Im on the stock one for now. I heard that the TB/Plenum combos can lean out your a/f ratio up to 30%, so I wanna stay nice and rich for the n20. Maybe when I get a tuner, ill throw in the combo, and add fuel...
08-01-2006, 10:38 PM
#10
5th Gear Member
Join Date: Feb 2005
Location:
Posts: 2,034
RE: TB and Plenum?
If I were you I would stay with the 70mm TB you have.. Reason why is I bought this book.... http://www.amazon.com/gp/product/193...e=UTF8&s=books
Its very good it answers alot of questions people have on here, its new it just came out so it has alot of the products out there now... Anyways. They tested a NA 4.6 2v with a Accufab TB and plenum. The 75mm TB made 5 more hp than the 70mm one. But the motor was making 406hp. Then they tested it on a Supercharged 4.6 2v. Same accufab TB's and plenum. the 70mm TB made 11hp more than the 75mm TB. But this motore was making 633hp. So its up to you, I would stick with what you got, smaller seems to work better with FI motors.
It all goes back to Bernoulli's Principle of Aerodynamics. You think when you take a big tube and funnel it into a smaller tube you would increase the velocity and pressure of the air... No thats not how it works... Thats how I thought it was, but the correct thing is this... Fool around with that pipe demo in the web link here, you will see how the velocity and pressure is affected based on inlet size and shape..... http://home.earthlink.net/~mmc1919/venturi.html
If you go from a large opening like and intake tube and then funnel it into a smaller opening at the end you will increase the velocity of the air and decrease the pressure of the air. But if you start of with a small opening at one end of the tube and widen it to a larger opening at the other end you will decrease the velocity of the air and increase the pressure. Make sense? So bigger is not always better. Thats why I am thinking I have way to big of a MAF anf TB on my motor. I am thinking about getting a 73mm MAF and 70mm TB....
Its very good it answers alot of questions people have on here, its new it just came out so it has alot of the products out there now... Anyways. They tested a NA 4.6 2v with a Accufab TB and plenum. The 75mm TB made 5 more hp than the 70mm one. But the motor was making 406hp. Then they tested it on a Supercharged 4.6 2v. Same accufab TB's and plenum. the 70mm TB made 11hp more than the 75mm TB. But this motore was making 633hp. So its up to you, I would stick with what you got, smaller seems to work better with FI motors.
It all goes back to Bernoulli's Principle of Aerodynamics. You think when you take a big tube and funnel it into a smaller tube you would increase the velocity and pressure of the air... No thats not how it works... Thats how I thought it was, but the correct thing is this... Fool around with that pipe demo in the web link here, you will see how the velocity and pressure is affected based on inlet size and shape..... http://home.earthlink.net/~mmc1919/venturi.html
If you go from a large opening like and intake tube and then funnel it into a smaller opening at the end you will increase the velocity of the air and decrease the pressure of the air. But if you start of with a small opening at one end of the tube and widen it to a larger opening at the other end you will decrease the velocity of the air and increase the pressure. Make sense? So bigger is not always better. Thats why I am thinking I have way to big of a MAF anf TB on my motor. I am thinking about getting a 73mm MAF and 70mm TB....