no - not port the throttle butterfly, replsace it once ported. also - i remember GUDE had one where it was stepped ( for velocity ) before the butterfly -

 

guys... please don't let the thread make a lateral transition... There is a BUNCH of quality info is this thread...

I'm hopping this doesn't become another "under-drive pulley" debate - but... today I received from viable source that another look/feel might be valued.

I must reiterate - my previous "testing" was solely dyno. I didn’t even drive my car with the TB spacer on...

To preface - I am as analytical as anyone you will know... my car is paid for by my over-analytical persuasion... I have no bias one way or another to this mod - BUT... the recent info I have received warrants further trial evaluation.

Admittedly I shut the door pre-maturely after concluding dyno tests... And I (of all people) should know there is more to testing than machine and numbers... Therefore, I will be re-installing (for a third time) to get/give driving impressions... Please understand I am not suggesting I'm an authority in evaluation - however an extremely viable, knowledgeable and trustworthy resource has advise that I give it a "Driving Impression" before final judgment.

Pre-Comments: I was told I "will feel torque"... This is a very intriguing and perplexing puzzle to me - only because the recourses I am utilizing are premiere industry entities.

With no endorsement, results, opinions, bias, or concern… the "resources" I have utilized are Ace Precision, Church Automotive, Motordyne Engineering, and Nissan Sport Magazine....

I hope I haven’t killed my friendship/relationship with any of them - but this has become a very compelling task for me because I trust and value each mentioned resource - but they all vary.

If any of you are like me you will not accept any answer without explanation... more so no explanation without reason... WTF!!!! This mod is bizarre! YOU MUST READ THE POST THAT EXPLAINS WHY CHURCHES SAYS IT WORKS... please don’t throw flame theory without understanding the time, level and dedication to this research…

Words in bold are for those that think this is old school slap a swirly under a carburetor to throw a tornado in the combustion chamber - that is not what this is... However it may be nothing more… f-ing pisses me off because it’s too possible that there might be something more ~

I don’t know what this is... but follow the thread for "possible vs (and/or) probable)...

More to follow...

 

*Long post, but I think there's some valuable information here...

I was a little skeptical of this mod at first, but the theory in this thread intrigued me, so I got a TB spacer made by Street & Performance Electronics, listed for the 03-05 350Z. A number of vendors sell them, easy to find on google, runs for about $100.

A little about my car, I've got an 06 5AT coupe, with a pop-charger, z-tube, and MD 5/16" plenum spacer. The TB spacer was a relatively quick install, took about 30 minutes (pics of the kit and installation are attached). One important thing to note, I did reset the ECU.

I've been driving the car for 4 days with the TB spacer on. I've broken down my observations into two categories, subjective (opinions) and objective (factual).

Subjective Observations:

I think that the TB spacer I bought alters the airflow differently than the Ace Precision (swirl) model mentioned in this thread. The Street Performance model is 1 inch thick and has deep grooves (facing the throttle body) that channel the air toward a small lip at the back. Just looking at it you can see that it will create more turbulence than a simple swirl.

After the install, I reconnected the negative battery terminal and took the car for a test drive. It definitely felt more peppy. It seemed like the car had more torque and power across the whole RPM band.

One thing I've learned about my 5AT is that it has (at least) two "sweet spots" for acceleration. The first one is gunning it from a stop or a slow roll up to about 8 MPH, the second one is gunning it from a roll at about 41-42 MPH. If I gun it from a roll outside of those ranges, the car falls on its a$$.

But after the TB spacer, gunning it from a roll, especially between 20-30 MPH resulted in significantly faster acceleration - the butt dyno felt more torque.

I purposely test drove the mod for 4 days before posting because I was interested in the theory about ECU resets resulting in a performance mode that diminishes over time. I think there may be some truth to that, because the car is not quite as peppy as it was on the day of the install. But that said, it still seems to have more pep than it did pre-spacer. And to make it even more interesting, I've been driving the car in 90 degree, humid weather, but it pulls like a champ.


Objective Observations:

The TB spacer has definitely altered the airflow into the engine. Before the install, my pop-charger would only whistle at ~4000 RPM. Now it whistles across a much wider RPM range and with higher pitch, most notably at lower RPMs (i.e. 1500-2500). If I moderately accelerate from a stop to 40 MPH, the pop-charger whistles until I let off the gas. And even more interesting, it almost sounds like a blow-off valve when I let off the gas. You can clearly here a "pssssssst".

At first I was thinking that I had a vacuum leak, so I made my brother sit in the car and repeatedly rev it while I listened to the engine bay. The sound is definitely coming from the pop-charger.

So my conclusions are that in my application (5AT coupe with listed mods), the Street Performance TB spacer has definitely altered (and possibly increased) airflow into the engine. The car feels more powerful and sounds bada$$. I think it was worth the $100.

EDIT:

Street Performance claims a gain of 8 hp/10 ft-lbs.

I like this TB spacer kit because it came with a 1 inch extension for the intake tube connection. The z-tube was easy to bolt up and I was able to rotate the pop-charger slightly and use the existing connection.

As for the perceived gains, it's day 5 now and the car is still pulling strong.
I have a theory that may help explain what's going on. It's a mixture of Newtonian physics and modern aerodynamics. Someone mentioned that since the TB spacer should only interfere with the fringes of the air mass traveling into the plenum, it shouldn't have much effect on power. But I think that phenomenon may actually be the key - only a portion of the air mass should be disrupted. Take a look at the diagram I whipped up (attached). Most of the air mass should travel through the center of the spacer unscathed, but the outer fringes of it will travel through the grooves in the spacer and impact the small lip at the back, reducing the velocity of some air molecules. This should, theoretically, produce two airflows, one streamlined flow through the middle (with higher velocity), and one turbulent flow around the streamlined flow (with lower velocity and more randomness). Hypothetically, the molecules with more chaotic behavior should impact the streamlined flow and impart energy on it. Additional energy imparted on gas molecules = higher velocity. This could result in a faster streamlined flow. Just some thoughts.

Also, I have a feeling that the effects I'm noticing are a result of all of my intake mods working in tandem.

 

Sorry to revive an old subject, but could it be that they had to angle it to once again fit into the '07 Z that is also now running an VQ35HR? Maybe that will change shortly. Is the VQ37HR also angled?

 

I'm no expert in the matter by any means, but I was just wondering if the benefits/effects of this mod are somewhat negated by the plenum spacers that happened to be on both test cars. It's obvious that a plenum spacer has improved gains due to increase airflow, however is there a limit to the benefits that can be realized w/ regards to increasing airflow without a proper A/F adjustment? So is it possible that more consistent benefits can be realized/measured/proven on cars that don't have any plenum mods?

Again, I'm no techobraniac here, but the question came up because my recent research into getting a spacer for myself and seeing that the 1/2" did not gain much more over a 5/16". Are we seeing a similar effect here?

 

No. The A/F was unchanged.

The throttle body spacers just don't work. I tested it and tested it and it did zero up or down.

 

Have any of you guys tested the model I bought from Street Performance (w/deep grooves leading into a lip, as opposed to the swirls)? I have to admit that my "subjective" observations could be psychological, but what can explain why my pop-charger is whistling like a bottle rocket?

 

I have little doubt that these TB spacers alter the air flow in some way as it enters the upper intake plenum. This would account for the whistling sound you have described.

The question is does this air flow change result in any measurable, repeatable performance gains? I have to side with Hydrazine on this one. Throttle body spacers just don't seem to increase performance in our engines.

 

Where did you purchase your tb spacer from? I found their site but do you have to email them to buy one?

 

I got mine from amazon.

What's perplexing me about this thing is that the change in pop-charger whistling suggests that more air is flowing through the intake system. Pre-spacer, the filter would only whistle slightly around 4K RPM. Now the thing sounds insane, if i tap the gas it's louder at 1.5K than it was at 4K. Seems like the only explanation for that is more airflow.

 

Well, if its whistling like a bottle rocket that may be kinda cool. (at least for some) but the whistle isn't necessarily indicative of more flow.

 

Carb spacers have an effect that works but Trottle Body Spacers are a waste of time and money........it's kinda like those adds in back of most car
mags that claim they can supercharge any car for $49.99!

 

I may actually be in a position to get some dyno numbers for the street performance model. I'm taking my car to altered atmosphere next week to get a tune, so I could ask them to dyno the car with and without the spacer. Just don't know if it's worth the extra $175.

It sounds like you guys have some pretty solid evidence for the swirl model not working, but I'd like to see more hard data on the groove/lip model.

 

That's the point I was trying to make. Perhaps the A/F was not optimized. I was told by someone that getting an MD 1/2 would barely give me more performance than the 5/16 unless the car was 'dialed in' for the additional air coming in. So again I'm wondering has this been test and measured on a completely bone stock car?

 

Not necessarily so... There is very solid evidence from Shawn Church’s testing that it worked on his application... Additionally further types of testing on multiple cars have been in the works for last several weeks - with surprising observations.

When more concrete information is ready I will pass on the findings. As of now I can tell you the "definitive" is not concluded. There could be something here for sure.