62 mm vs. 70 mm t/bodies

[ESP Products]

Very well said.

 

[VadersV6]

I was also thinking that velocity through the TB would decrease with the bigger TB, and maybe that would help air distribution to the front cylinders. Right now its shooting through like a firehose toward the back of the plenum.

 

[Slo86GN]

One thing I am going to try is port matching the stock tb with the plenum. I had it apart for a good cleaning and noticed the tb opening is offset slightly from the opening in the upper plenum. That has to produce some odd turbulence as the air passes from the tb into the plenum. I'm also going to slightly radius the back side of the tb opening. May not do much, but every little bit helps...... :biggrin:

 

[turbo2nr]

Back in 1997 Kenne Bell wrote an article on power adders. With a stock motor heads and injectors. Motor started out with 200 rwhp add chip 31hp 14 hp with full exhaust 13hp with ram air kit. dual stage header were worth 29hp.He then added a Big Boy front mount intercooler and was up to 307hp at the rear wheels. The next step was adding a 70mm Throttle Body this add on brought the rwhp up to 332. He wrote a bigger throttle body will allow more air flow but won't the pressure loss mean a sacrifice in low-end torpue? Isn't turbo lag a bad enough penalty already? We found zero pressure loss throughout all these tests due to this throttle body,and the whole system would make a ton less power with out it. just putting on the throttle body brought up the boost by four pounds. Thought I would share this with you it is only what was written for Popular Hot Rodding in October 1997.

Read the fine print! They noted a 3PSI rise in boost. Ahh, so that's where the power came from. Well, keep the stock TB and raise boost 3PSI and you get the same thing! They just pulled the wool over our eyes.

 

[Momar]

Read the fine print! They noted a 3PSI rise in boost. Ahh, so that's where the power came from. Well, keep the stock TB and raise boost 3PSI and you get the same thing! They just pulled the wool over our eyes.

Thats probably true, and I agree that this is not a mod that should be one of the first, but for the boost to rise 3 psi when you changed it, wouldnt that suggest a restriction?

Ben

 

[Ormand]

I have my doubts about gaining 3 lbs from changing the throttle body. The air flow is just too low. Unless they tested the throttle bodies on a 400 cubic inch engine! With the 231 V6, air flow is going to be only 400 cfm, more or less, at the throttle body. Maybe 1000 cfm into the turbo intake, but that's another issue. At 400 cfm, there just won't be a big pressure drop across the throttle body, IF the throttle body is set up right. On the other hand, if they had a stock TB that was not opening all the way... but surely KB wouldn't "rig" a test to tilt the results? But I agree with Vader's idea, that slowing down the velocity at the throttle body might help solve the flow distribution problem. Sure would be nice to see some air flow tests, from somebody "neutral".

 

[turbo2nr]

I can clap my hands and get 30HP and see a magic 3PSI appear.

I don't know when the 70mm helps. It sure looks better than the ugly stock unit.

 

[Ormand]

The modified stocker that Stevemon provides looks better, and will eliminate much of the flow restriction. And it will fit the stock doghouse, too. The bigger throttle bodies require changing more things, and just don't seem like the "smart" way to spend money. Of course, for those who have so much money that getting the best value for a dollar is not important, then I guess that's not a consideration.