is there a difference between those two spacers...
looks to me the only difference is that the one from Hydrazine is 1/4 thick evenly
and the one from AAM is thicker in the front..

dyno mumbers look good for both of them

wich one do you thinks is the best buy

http://www.350zmotoring.com/forums/s...5&pagenumber=1

 

We will have to see. Its amazing that such a thing would change power like that. Especailly since its area under the curve and not peak power.

 

according to the dynos, it seems hydrazine's made more power. but everyone is saying those dynos are bunk. who knows.

 

If I knew the thickness I could make one myself and do a test.

 

thickness is 1/4 all around...

 

I am looking at the AAM? one; thats more thick in the front.

 

He's also done 3/8, 1/2 and 3/4 inch. Some of the guys are going to compare the 1/4 inch with some of the thicker ones pretty soon (dyno).

 

why doesn't someone build this spacer out of teflon or something heat resistant to bring down the temp of air going in?

 

because the lower plenum is still going to get heatsoaked anyways.


i dunno... in theory, these spacers should be doing what they're doing according to their dynos.

it's similar to boring out your throttlebody to increase the volume and decrease the turbulence of air going in. also follows the design principle of allowing the intake runners to get equal amounts of air, therefore allowing each individual cylinder to perform as identical as possible.... this is especially true with the AAM's slant design to increase the volume in the front of the plenum, where the front two cylinders are normally the most starved due to the long distance the air must travel from the throttlebody, and are also disadvantaged by the other intake runners to compete for the same air.

it's why individual throttlebodies are such a performance enhancement... each cylinder gets equal air and fuel, therefore each cylinder performs nearly as efficient as the others.

i'm sure if you were to analyze the exhaust between the stock plenum and a properly designed plenum or spacer like the AAM, you'd find the stock plenum to feature the front two cylinders reading a tad rich and the rearmost a tad lean, with the middle two being spot on... while you'll find the same thing on the aftermarket stuff, it wont be nearly as dramatic a difference from the front two to the rearmost two. it's just simply due to the plenum design allowing better feed to the runners/cylinders closest to the throttlebody. as far as i can see, the Crawford plenum increases volume in the front and throughout the plenum. the AAM does this too by design... but still maintaining the stock plenum upper. the only thing these two can argue about is who thinks their total volume is more effective as they both competently address the starvation problem... as total volume is important since too much volume can reduce intake velocity (bad), and too little volume reduces response (bad).

if a whole new plenum wanted to really be more effective, relocate the throttlebody so the runners get a better chance for even distribution of intake air... the top would be ideal for a single throttlebody. a setup of triples would be better. individuals would be optimum, but unreasonable on a street car... but none of these suggestions would fit under a stock hood.

more so, design a lower plenum with better flow characteristics... flow is just as important as volume. rearrange the runner positions to keep them as equal length as possible, but have equal opportunity for intake air. or you can have uneven runners, but relocate them and vary inner diameters as necessary to change intake velocities for each runner to help maintain equal volume.

and that's my observation as to why i believe the theory behind spacers is pretty much the same as the one for a whole new plenum. i also believe the AAM slant type to be superior simply by design over the Hydrazine spacer due to it's attempt to increase volume where it's needed the most.



now here's my only ***** about both... no one has addressed Nissan's retarded (or space limited) design that forces intake air to wrap nearly 180 degrees from the airbox to the plenum. straight lines are more efficient when moving anything, including air. did anyone think (or is it even possible?) to move the throttlebody to the abosolute right of the plenum and lessen the angle that restricts air flow? granted, it will change the problem of starvation from the front two cylinders to the left bank, but that can be addressed with a lower plenum runner design to match and/or increasing the volume of the plenum's left side. above all else, it will increase intake air velocity over the OEM "gooseneck" design.

 

does the aam offer different sizes...or is this slant type one size fits all and how much is this going for?

 

now we are getting somewhere - this is a MAJOR limitation of the stock design, however there is lots that can be done to address this as well There are several other areas as well

Road Warrior - nothing is going to reduce temperatures with this piece as its still an all aluminum affair. Best thing to do is cool the incoming charge as much as possible and have the air move as quickly as possibly to eliminate heatsoak through the metal parts. Once you really start playing with the intake side of things, there is lots you can do to address these issues

 

Wow, I have been in another thread trying to say pretty much the same thing, hehe. I couldn't agree more. Total volume is crucial to maintain velocity in the intake, especially at low rpms. I just posted in another thread that I would like to see a plenum with a lower total volume but a larger inlet for a larger TB. This would preserve vacuum and allow intake velocity to be controlled more by the TB. This could also be acheived by adding more TBs, but would be more difficult to control and more expensive. I would think one could cast a plenum with lower volume, bigger and better inlet placement, then use a larger Nissan TB Not sure what would be needed to control the Larger TB but I am sure someone could figure it out.

 

Moved.