ha ha ha ha

 

The mixing aspect of a TB spacer really isn't where the increase in power (torque) is from. Basically, the way a spacer works (regardless whether it is under a carb, TBI, or on a MPI manifold) is by increasing the volume of air between the throttle and the cylinders. What this increase in volume does is shifts the torque curve down lower in the rpm range. Think of it this way. What is the difference between run-of-the-mill dual plane intakes and single plane intakes in terms of their respective power-band? The dual plane intakes have power bands much lower in the rpm range than the single planes because of the added volume of air. By adding a spacer, you are increasing this volume of air and shifting the torque curve down. So say you have 285 ftlbs of peak torque at 3500rpm. With a 1" spacer, you may now have 285ftlbs peak torque, but it may now be down at 2700rpm. By shifting the peak torque lower, you boosted the torque (mind you that the actual torque curve changes very little with a spacer - the entire curve shifts) from off idle to the new peak rpm, but after the new peak rpm, the torque has fallen off.

Here's an illustration:


Now, here's where the mileage increase comes in. If you very rarely get up in the rpm range (past peak torque), then by shifting the curve lower in the rpm range you are decreasing the throttle required to reach the same speed as without the spacer.

Back to the discussion on the 'spiral bore' of many of the aftermarket available spacers. This spiral does NOTHING. Every little bit that it protrudes into the air stream slows down the main stream velocity, thus hindering performance. Many of these designs don't impinge on the air stream at all and if they don't get out into the air stream, then how can they influence the airflow much?

I produced a limited run of throttle body spacers for the Dodge Intrepid 3.3L & 3.5L engines for DodgeIntrepid.net members and EVERY single person that purchased a kit from me noticed atleast 2mpg better fuel mileage. One member even dyno'd his 3.5L with my spacers (smooth bore), PowerAids spacers (spiral bore), and bone stock. His dyno showed a 500rpm decrease in peak torque rpm level with both of the spacers (only difference between the two spacers was the bore design). Nothing else changed. Peak horsepower was the same and at the same rpm and peak torque remained the same.

Take everything that you have read with a grain of salt, but I speak from actual first hand experience. I know for a fact that on my Chevelle, my 1" 4-hole spacer makes a huge difference with it in than with it out on top of my Edelbrock Torquer 2 single plane manifold. But I never did dyno it to figure out exactly what the difference was. The car pulls much better in the lower rpm with it and it was free so I decided to leave it on.

 

Thanks for the info. Very well explained. I do tow a small boat, 3500lbs, every weekend. It would be interesting to see what improvements can be felt. Thanks.