Do you mean Strut tower bar or really the sway bar.

 

Agreed!
He is referring to the bar that crosses over the top of the engine bay. From Shock Tower to Shock Tower.

 

Actually the MD 1/2 puts out about 1 HP more than the 5/16 and u dont have to replace the strut bar with the 5/16

 

What about the crawford or aap full replacement plenums. More hp?

 

No ----Motordyne. $$$$$ spent and HP gained its the way to go.

 

How is it possible that a simple spacer gains more hp than a full replacement plenum that is polished and smooth.

 

someone chime in and correct me if i'm wrong here. the plenum mod; be it spacer or replacement upper plenum is more about getting air to the cylinders. period. the gains from the plenum mod are more focused on redistributing the air flow to get more air to the front two cylinders. so as long as this is accomplished you should see the gains with either.

the crawford and kinetix plenum mods you are referring to are not full replacement plenums. they simply replace the upper plenum versus retaining it and sandwiching a spacer between the upper and lower plenum. in both cases the lower oem plenum remains intact. also i don't believe the polished crawford plenum is polished on both surfaces. the outer surface is polished and the inside is not.

so the concept between the two and a spacer is essentially the same. also there is a saturation point where increased volume made by the plenum mod will not = more hp/tq. a perfect example of this is going through some of the older Motordyne threads where Tony discusses the differences between the 5/16" and 1/2" plenum spacer.

 

Check out 350Z/G35 Plenum/Spacer Shootout Dyno tests in SportZ Mag winter 2006 issue