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threestar40 · 03-13-2008

This is a re post from 5/06 on that other site...the reason I still have my secondaries...and I hate extra complicated equipment as well, so I own a ZR1

I did do coil overs with an FX3 delete though...so I got that going for me.

When I read lingenfelters book on modifying small block chevy's, he talked a lot about intake velocity.

At the lower RPMs, smaller passages=more intake velocity thus making more power and torque and at the higher RPM's you want more volumetric area as the motor is pulling all the air it can and intake velocity for cylinder filling is not as much an issue.

I thought that was the idea behind how our stock throttle bodies' work as well. Have ya'll looked at how small that little primary butterfly is?

It's tiny...I think we need to keep our eye on the ball here.

Let me quote John.

"Intake runner length is one of the critical decisions in engine building since it contributes significantly to the shape of the power curve"

"Condensing this very complex subject down to it's basic concepts, increasing runner length tends to improve torque at the lower RPM levels while simultaneously lowering the peak torque RPM point"

Now I realize that he is speaking about a different motor, but there is knowledge to be gained here.

"The other half of the intake manifold design process, cross-sectional area of the port, also plays an important role. Generally a smaller runner area increases intake charge velocity, speeding up the inlet charge, which improves cylinder filling at lower RPM levels. Conversely, huge intake manifold port runners contribute to slowing the intake gas speed at lower RPM levels, hurting power below peak torque while contributing to improved cylinder filling at RPM levels closer to peak horsepower."

One more thing which I feel is a jewel should be mentioned here.

On a section titled "manifold destinies" (Love it, Every ZR1 owner should albeit bittersweet)

"As you can see, there are several intake tuning factors that remain constant...Intake runner size is perhaps the most important. Small runners generate great low speed torque but tend to limit top end power. Runners that are too large will be lazy at street engine speeds and contribute to exhaust dilution/reversion in the intake. Short length runners tend to emphasize top-end power while longer runners tend to increase mid-range torque at some sacrifice of top-end RPM power potential. This is about as concise as you can get yet there are plenty of questions still to be answered. The future of induction tuning will address all of these factors plus a dozen more." NOW THIS IS TH IMPORTANT PART. PAY ATTENTION "How about a variable-length, variable-diameter intake that could be long and small for good low-end power and short and fat for top end power? If that sounds too much like Buck Rogers, it's already happenend in Formula 1. Perhaps some enterprising Hot Rodder will someday build as practical and affordable and intake for the small block Chevy! Think about it."

The bastards should have designed it better so it doesn't break all the time.

Eyes on the ball.

Rick

03-13-2008	#23
threestar40 Join Date: Jan 2005 Posts: 148	Re: secondary removal how do you go...... This is a re post from 5/06 on that other site...the reason I still have my secondaries...and I hate extra complicated equipment as well, so I own a ZR1 I did do coil overs with an FX3 delete though...so I got that going for me. When I read lingenfelters book on modifying small block chevy's, he talked a lot about intake velocity. At the lower RPMs, smaller passages=more intake velocity thus making more power and torque and at the higher RPM's you want more volumetric area as the motor is pulling all the air it can and intake velocity for cylinder filling is not as much an issue. I thought that was the idea behind how our stock throttle bodies' work as well. Have ya'll looked at how small that little primary butterfly is? It's tiny...I think we need to keep our eye on the ball here. Let me quote John. "Intake runner length is one of the critical decisions in engine building since it contributes significantly to the shape of the power curve" "Condensing this very complex subject down to it's basic concepts, increasing runner length tends to improve torque at the lower RPM levels while simultaneously lowering the peak torque RPM point" Now I realize that he is speaking about a different motor, but there is knowledge to be gained here. "The other half of the intake manifold design process, cross-sectional area of the port, also plays an important role. Generally a smaller runner area increases intake charge velocity, speeding up the inlet charge, which improves cylinder filling at lower RPM levels. Conversely, huge intake manifold port runners contribute to slowing the intake gas speed at lower RPM levels, hurting power below peak torque while contributing to improved cylinder filling at RPM levels closer to peak horsepower." One more thing which I feel is a jewel should be mentioned here. On a section titled "manifold destinies" (Love it, Every ZR1 owner should albeit bittersweet) "As you can see, there are several intake tuning factors that remain constant...Intake runner size is perhaps the most important. Small runners generate great low speed torque but tend to limit top end power. Runners that are too large will be lazy at street engine speeds and contribute to exhaust dilution/reversion in the intake. Short length runners tend to emphasize top-end power while longer runners tend to increase mid-range torque at some sacrifice of top-end RPM power potential. This is about as concise as you can get yet there are plenty of questions still to be answered. The future of induction tuning will address all of these factors plus a dozen more." NOW THIS IS TH IMPORTANT PART. PAY ATTENTION "How about a variable-length, variable-diameter intake that could be long and small for good low-end power and short and fat for top end power? If that sounds too much like Buck Rogers, it's already happenend in Formula 1. Perhaps some enterprising Hot Rodder will someday build as practical and affordable and intake for the small block Chevy! Think about it." The bastards should have designed it better so it doesn't break all the time. Eyes on the ball. Rick Last edited by threestar40; 03-13-2008 at 08:04 PM.