Originally Posted by DocJohn

I understand what you are saying, but it is just difficult for me to believe that adding some vanes or "rifling" to the inner surface of a ¾” TB spacer to produce swirling of the intake air to help it flow around the curve of the plenum can produce a 8 WHP gain. I would really like to see some verified repeatable dyno results (same day, same car, same conditons) of this TB spacer. If it worked as good as claimed I would buy one myself.

Originally Posted by DocJohn

I understand what you are saying, but it is just difficult for me to believe that adding some vanes or "rifling" to the inner surface of a ¾” TB spacer to produce swirling of the intake air to help it flow around the curve of the plenum can produce a 8 WHP gain. I would really like to see some verified repeatable dyno results (same day, same car, same conditons) of this TB spacer. If it worked as good as claimed I would buy one myself.

Originally Posted by Jeff92se

I have to agree. Even if the air was "swirling" when it left that spacer, I highly doubt it would "swirling" by the time it took the turn into each lower plenom bore, down into the head's intake track, and past/around the intake valve.

A hp increase of 8hp is pretty damned big. ie.. motodyne spacer big.

Originally Posted by Jeff92se

Plus you also have to ask yourself, since the only the edges of the spacer are swirled, then how much air is actually being "swirled"??? A far bigger area of the TB is represented by the inside of the TB

Originally Posted by Jeff92se

You also have to consider that only a very little of the total airflow though the TB is actually touching the surface of the TB. In fact, one could also argue that the ridges are a moot point. As air has a habit of creating a "boundary layer" inbetween what it touches.

Originally Posted by ballisticus

Actually, if you look at the new plenum, it is angled down in the front as well. Look at the distance from the center gap between the 2 pieces in the front vs. the rear. That whole front 2 cylinder air starvation myth was started by Crawford with their flowbench "study". It had nothing to do with how an engine operates in reality. Show me a real study indicating rich ratios using a multi-channel exhaust gas analyzer in each header tube and then I'll believe it. Nissan did not angle the plenum to clear anything. If they did, then why is it angled on the new G with no strut bar?

Originally Posted by OCG35

I just got off the phone with Shawn Church (owner of Church Automotive Testing)… he indeed did dyno a prototype TB spacer from a company called Ace Precision… he confirmed that it dyno’d about 8 hp on the upper end (5500rmp range)… I asked him in theory what could possibly be the cause and he explained that the one he testing had rifling on the inside edge – you have to install it one way only… it alters the airflow in a way – unlike the Tabulator that swirls the air prior to the TB and does basically nothing, this apparently helps the airflow make the turn on our curve (from TB to plenum)… he said it did nothing on cars that have a straight intake/TB to collector.

So in theory it’s not the added volume, it the altered airflow helping the air flow around the curve after the TB.

Seems a little hokey, but I fully believe Shawn. He wouldn’t state false claims of gains. I asked about clearance (he ran a ¾” spacer) – he has stock intake tube and said it fit but the accordion flex was collapsed all the way.

I don’t know if all manufacturers have the rifling – it looks like AAMs has functionality more for adapting other components – the rifling one might be worth looking into further. I tried doing a Google search and there are tons or Ace Precisions – so I’m not sure which one makes this particular TB spacer or if it’s even production ready… I will start researching some of the others though. Now that I know there is something other than added volume (which in theory is a bogus claim) it might be worth it?

Originally Posted by ISMSOLUTIONS

I knew I wasn't dreaming

Originally Posted by speedracerg35

i'm pretty sure there are substantiated gains for throttle body spacers for other cars. i've read a few articles about how they are akin to velocity stacks (for the old timers) and carburator spacers (pre fuel injection days).

they are supposed to alter airflow and increase torque more than hp. this shouldn't be expensive or difficult to put in, so someone should try it and post up. i'll be more than happy to do it if no one wants to--let me know where i can get the one pictured above.