Which TB/Plenum???

Tank567, I took a look at your thread and saw your dyno sheets. Now you have real figures listed there, no doubt about it, and kudos to putting in the time and effort and money to do the experiment. But I have to ask the question because I saw no mention of it made. Did you have a proper tune for not only the TB/plenum combo, but a different and proper tune for the stock setup? Without independent tunes tailored to each setup, you introduce an uncontrolled variable because with only one tune, which setup does the tune on the favor? I'm not saying you stacked in favor of your argument, it's just something that could have been easily overlooked.

Regardless, I just can't buy into your philosophy, no offense intended.

The idea that ANY TB/Plenum could be considered a better mod on a stock NPI/PI car than either cams or gears, I can't agree with that. You have to consider where the most restrictive part of the intake system is. I think we can all agree that the cylinder heads are that part. When you come to that conclusion, it stands to reason that improving less restrictive parts first will not make anywhere near the same improvement. Furthermore, any modifications done prior to the most restrictive part will be less than optimal until said restriction is remedied.

Someone on this thread stated that you have to give up low end torque to gain top end power. Now that does occur when you get into more radical setups that are designed to promote high rpm cylinder fill. You give up low speed velocity by staging the intake valve opening earlier and the closing later. But there is plenty of room for growth beyond the PI cam profile without having to sacrifice any low end torque. As a matter of fact, stage one cams from companies like Comp, Crower, and several others lose nothing to stock cams at any point in the power band. In fact they provide significant gains in peak power and even more importantly post peak power. A simple Comp Cams XE262AH will give more than 20RWHP peak gain and as much as 44 RWHP post peak. Not only does that dwarf the TB/plenum power boost, but it extends your RPM range significantly as well.

Talking about gears, it's not about the power curve. It's about the increased mechanical advantage you have accross the entire RPM range. Going from 3.27 to 4.10 is a 25% increase in mechanical advantage regardless of RPM. Now compare that to your best figures from an ideal TB/plenum swap and you are still better off with gear depending on the change in ratios.

The idea that a TB/Plenum combo would benefit a stock car more than cams or gears only makes sense if you can install it yourself, are not tuning it, and have no intention of ever installing gears or modifying the cylinder heads. Once you commit to a tune, cams become a far superior option. Like many others have said, gears give the best bang for the buck performance on these cars...bar none. If you are not concerned with MPG, or highway RPM, they should be the first serious mod you consider and the only issue should be what ratio to select.

I'm not calling you out or trying to bash you, I just can't subscribe to the idea that a TB/plenum is a better mod than cams or gears given everything I personally have experienced or have ever been told by others. It's not listed in my sig but I was using a 75mm TB/Accufab in NA form before my current mods went on. To say I was sorely disappointed for the money and effort I put into the project would be an understatement.