Nissan 370Z Tech Forums banner

1 - 9 of 9 Posts

·
Registered
Joined
·
3,089 Posts
Discussion Starter #1
Hi guys

Ive decided next purchase will be the plenum spacer along with the KJR pulley

I did some online browsing and found two spacers, the AAM and the Motordyne

My question is, since the '05 has a larger lower plenum, would the AAM angled spacer work incorrectly? I think i read that the 206kw plenum is angled at the front restricting air to front cylinders, hence why the AAM is angled at the front

Would i just be better off with the Motordyne?

Also, for those that have fitted the spacer, how does the car feel. Is it simply smoother at high rpm, or is there noticeably more pull?
 

·
Registered
Joined
·
587 Posts
Well a Friend of mine is flow bench testing the AAM angled spacer today. We are testing it on the 03 lower intake as well as with the 05 lower intake.

I was going to add the 05 lower intake to my Z but the people that have done this mod are losing HP and torque down low and only gaining hp above 5500 RPMS. so we are testing to find out which setup has the best air flow. after we figure that out we will dyno test the best setup.
 

·
Registered
Joined
·
3,089 Posts
Discussion Starter #3
sounds good, could u post ur findings in this thread, id really appreciate it

re the 05 plenum on the 03, yeah im not suprised theyre losing power. The lower torque and higher top end is the 05 norm, plus the 05 has other changes like the cams for eg that would take better advantage of it

im thinking motordyne is the best bet, itd be a constant volume increase throughout the plenum

it may have clearance issues though with the brace, im pretty sure the 05 plenum sits slightly higher at the front (from what i can make out from pics that is)
 

·
Registered
Joined
·
87 Posts
Originally posted by TPIACE@Jun 12 2005, 10:06 AM
sounds good, could u post ur findings in this thread, id really appreciate it

re the 05 plenum on the 03, yeah im not suprised theyre losing power. The lower torque  and higher top end is the 05 norm, plus the 05 has other changes like the cams for eg that would take better advantage of it

im thinking motordyne is the best bet, itd be a constant volume increase throughout the plenum

it may have clearance issues though with the brace, im pretty sure the 05 plenum sits slightly higher at the front (from what i can make out from pics that is)
[snapback]113062[/snapback]​

I have now flow tested my original 2003 lower plenum. One note is I did polish the inside to remove major casting roughness, but did no porting. So the total airflow is probably up 10 to 15 CFM. I wanted to test the AAM spacer so could not justify the expensive of doing three more runs.
2003 polished lower plenum
The front flowed 232 CFM @ 28" H2O
The back flowed 255 CFM @ 28" H2O

Bottom line is you can take a 2003 lower plenum and polish it and the upper and get just about the same airflow as a stock 2005 lower plenum.

Now for the spacer results.
2003 polished lower plenum with AAM angled spacer
The front flowed 250 CFM @ 28" H2O
The back flowed 255 CFM @ 28" H2O

AS you can see it does a great job of balancing the front to rear airflow. The interesting thing is it did nothing for the back airflow even though it raises the back a little also. Makes me wonder if having it angled is important or not.

If you get the AAM I recommend you buy some extra bolts. They only supply new bolts for the front of the plenum where it is raised the most and do nothing with the studs (they say to leave the nuts off since they don't reach and not to worry about it). The bolts in the back have very little bite and are really too short IMHO. Buy 11 stainless or grade 8 M6 x 35mm bolts and you will be better off. I would also remove the two studs and put the 35mm bolts in their place (need 11 if you do this).

I put my 2003 lower plenum back on the car and can really tell a difference. The 2005 just kills the torque. My Stillen upgraded valve body had not turned out as well as I expected, but I put it in at the same time that I switched out the lower plenum. Now that I have my 2003 lower plenum back in I can really tell a difference. The valve body upgrade was well worth the money.

If you have forced induction, the 2005 lower plenum may be a good fit. It flows more air, but without dyno testing and forced induction I just am not sure.

I'm going to order a spacer from http://www.motordyneengineering.com to see if having an angled spacer is really necessary. Chazz's AAM spacer that I tested showed no increase in rear airflow, so the angle may not be needed.

I guess more testing will be coming.
 

·
Registered
Joined
·
3,089 Posts
Discussion Starter #6
wow thanks for the info :clap:

admittedly i am more interested in the motordyne because it comes with all the bolts and is cheaper as well. Looking forward to those results

re the loss of torque on the 05, is that because of the plenum? I would have thought that was because of the different cam profile

u also gotta let me in on the secrets of how to polish the plenum :cheers:
 

·
Registered
Joined
·
87 Posts
Originally posted by TPIACE@Jun 25 2005, 08:03 PM
wow thanks for the info  :clap:

admittedly i am more interested in the motordyne because it comes with all the bolts and is cheaper as well. Looking forward to those results

re the loss of torque on the 05, is that because of the plenum? I would have thought that was because of the different cam profile

u also gotta let me in on the secrets of how to polish the plenum  :cheers:
[snapback]121971[/snapback]​


The loss in torque is the 2005 plenum design.

I use a 1 inch velcro sanding rubber drill attachment. The sanding discs and drill attachment are available at www.woodworkingshop.com
hook and loop pad FP25100
discs are KD40005 (150 grit)
you will need to go all the way to 1000 grit for the exterior of the upper plenum if you want to get that mirror polished look.
 

·
Registered
Joined
·
87 Posts
Originally posted by TPIACE@Jul 1 2005, 09:46 PM
i still dont follow  :helpsmilie:

would love a DIY when u have some spare time  :cheers:
[snapback]125638[/snapback]​


I think Chazz wants to polish his when he installs his spacer. Maybe we can take pictures then.
 
1 - 9 of 9 Posts
Top