The Iso Thermal system does do its job of lowering plenum temperatures by about 30-60 'F.
See this page for a more technical discussion on the subject.
https://my350z.com/forum/intake-exha...dy-heater.html

In your case, when you were at the track and you noticed that your plenum was hot, there are a few ways that can happen.

1) Iso Thermal reduces the heat transfer rate significantly, but it doesn't stop it completely. So even if the Iso Thermal is doing its job of lowering the heat transfer rate and making your plenum run cooler while you are driving or racing, once you stop the car and shut off the engine, the plenum temperature starts to rise.

The engine compartment heat soak temperature shortly after shut down goes to about 170-180 'F. Its been a while since I did all the plenum temperature measurements but the stock plenum temperature will rise from about 150'F to the equilibrium temperature 170-180'F in about 3-5 minutes.
With Iso Thermal the plenum temperature will rise from about 90-110 'F to the equilibrium temperature 170-180'F in about 6-8 minutes.

Iso Thermal reduces the plenum temperature considerably while driving.
When the car is shut down the plenum temperature will still go up to a frying hot 170-180'F but it takes a little longer.

So what it does is reduce the heat transfer rate. It doesn't eliminate it when the car is shut down.

If you were at the track and did a pass and then immediately shut down the car and felt the stock plenum, it would still be hot.
If you had Iso Thermal installed and did that same pass then immediately shut down the car and felt the plenum again, you would feel a big difference in plenum temperature. It would be a lot cooler.

If you do the feel test to compare pre/post plenum temperatures to get an idea of how the Iso Thermal works, it is best to do it immediately after shutting down the engine. If you wait too long, the plenum will become heat soaked again.

When I did all my testing of the Iso Thermal I had an array of thermocouples all over the plenum and data logged all of it. I also made sure to do all of the pre and post measurements under the same driving conditions.


2) There is also one other really important factor. If you use just about any kind of short ram CAI it negates any insulating effect from the Iso Thermal. This is because CAI's like the pop-charger draw in a lot of hot air from the engine compartment. The short ram intakes can draw in a lot of hot 150'F engine compartment air where if flow through the plenum and heating up the entire air intake tract.

The plenum assembly can never be cooler than the air flowing through it. So that is another thing to look for (or consider) when testing the plenum temperature.

In my experience, the stock air box is by far the best cold air intake available for Z.
It completely seals out hot engine compartment air and allow Iso Thermal to do its job.

A while back I made posts on all of the thermocouple measurements I did but I can't remember the exact location of them. I'm sure they can be found with a search in the 2005 time frame but they do go into a lot of detail on the data and how it works.

Tony

 

Thanks Tony!

I haven't had anything to officially "test" my temperatures which is why i asked Z1 what he used for his logging. I figured the rise in temp would be due to lack of airflow once the car was off.

I appreciate the in depth and very prompt answer. I'm still using it because i don't have a reason not to use it. I was just curious how much of an advantage i was getting.

 

You know, one day it just hit me that there is an extremely easy way to test the dyno advantage of Iso Thermal.

Rather than all the thermal analysis to back out a number, its much simpler than that. Direct measurement is easy.


1) Measuring pre/post plenum temperatures with thermocouples is easy enough. (30-60 'F)
2) Just throw the car on the dyno and do the full dyno procedure as you normally do with the hood open. This will give you a baseline with the plenum at approximately ambient temperature. This is the way dynos are nearly always done.

3) After you get the baseline, shut off the engine while still on the dyno, then quickly cover the plenum with a blanket of fiberglass or some other heat resistant insulation. And within a few minutes the plenum temperature will rise quite a bit. Once the plenum temperature goes about 45'F above the baseline temperature, start the engine and quickly do another set of dynos with the hot plenum.

You will see the power curve moves down with the hot plenum and with each successive pull the plenum will get cooler and the power will increase once again the the baseline value.

So this is an easy way to measure the effect of Iso Thermal on the dyno.

I've done this test procedure myself and it works quite well. In fact, it works quite a bit better than I expected. I could post my results, but I'll leave that one to an independent test. Hopefully it could be organized some day soon.

Tony

 

still in the process of getting my before and after dynos posted... but here are some pics to feed the masses.

 

Awesome work!

 

Been a while since I posted in this thread. I have kinda taken it to an extreme with my manifold. Polished inside, lowered the top of the front and middle runners a bit and eliminated all the bolts that are in the center. Also welded in the PCV area and then welded the entire manifold shut. Large NPT plugs (which sit perfectly flush on the inside) provide access to the six main bolts that bolt the manifold to the collector.


All powder coated and ready to install:


On the car:


The center has a plate welded on top in order to add rigidity for high boost and provide better thread contact for the plugs.

 

hey sexyrob, what tools/equipment did u use? looks really nice

 

Hey guys, just starting the game here. I recently bought a 2005 lower collector so I'm gonna start working on polishing down the inside and smoothing everything out. This is going on my 2006 Revup engine so I'm hoping to gain a bit of torque back with the swap. I'm also working on an upper plenum right now. Trying to polish the upper inside and out as well. And eliminate all the excess casting lines and make the surface as smooth and dent/bump free as possible.

I have a question though as well. The inside of my lower collector says M R2 and M L2 rather than M R1 and M L1. What are the differences? I bought the lower collector from a 2005 350z, so unless it was an AT, which would be a Revup motor I believe, why would the number be different. :/ I'm scared to hear the answer.

I'll post up pictures of my progress tonight as soon as I get some time to load pix.

-Paul

 

its possible if it was a track model. but if it looks like the ones in any of the pics its not a rev up collector.

 

Here we go, this is the lower collector I bought, and the about 1 hour or so that I've spent so far on getting it polished:

edit: pics got lost...

 

From what I could find, it came off a 2005 Enthusiast Roadster, 6MT.

 

Ok, just did some google image searching and looks like I'm ok. Found and saw the differences between the rev up and non rev up lower collectors, and I am positive the one I bought is a non rev up collector so I'm good!

Now I wonder why some are number M R1, M R2, and I have now also seen M R3!....

 

u got the right one. and ur deff on the right path keep up the good work.

 

Thanks man! I appreciate someone responding to somewhat of a dead thread hahaha I'll post some finished pictures and comparisons for sure when I finally get it finished!

 

I know this is somewhat of a dead thread, but what did you guys use on the inside of the intake runners to clean it up? I was thinking of starting with sanding discs on my Dremel tool and then using some port and polish buffs. I have read through the entire post, but do not recall anyone saying what they used...maybe I just missed it. Im getting pumped to see the difference it makes in my 06 rev-up with a spacer when I'm all done.

Also, anyone else have dyno results other than Aceman?

 

^Sorry man. I've been slacking in this thread also! But what I've been using for the inside of the runners is a dremel tool with a flap sander bit on an extension. The extension allows me to kinda get farther down into the runner without botching up all the metal on the outside. Then after I used the dremel, I've just been doing most of it by hand with some 90 grit sandpaper. And then once you get all the scratches out left behind by the dremel, I'm using 150 grit, then 220 grit. Haven't decided yet whether I should go all the way up to 320 too....

I have the underside of the upper plenum completely finished. All blemishes removed, excess casting flashed, and polished up. I'm almost finished with the lower plenum; I'm using 150 grit paper on it right now. And then my intake manifold/lower runners just came in the mail yesterday. So I'm going to start working on flashing and polishing the insides of that too after I finish the lower plenum. Just ordered my Cosworth Thermal Intake Plenum Gasket, and I'm about to place an order for the P2R Phenolic Intake Manifold Gaskets (which are actually cheaper than the OEM gaskets btw). And call it a day! All in all, here is what I have about to get installed on the car:

Stock Flashed/polished Upper Plenum
Powerlab 3/8" Plenum Spacer
Stock Flashed/polished Lower Plenum w/ Lowered Front Runners (MREV2)
Stock Flashed/polished Intake Runers/intake manifold
Cosworth Thermal Intake Plenum Gasket kit
P2R Phenolic Intake Manifold Gasket kit

^With all those, installed on my 2006 Rev-up engine (which was just recently replaced under the Oil TSB through Nissan Warranty), I hope to gain about 15hp. I'm not expecting too much I don't think, and in my opinion, that number sounds about right. I can't wait to finally get it all on though! I'm excited to feel/hear/notice the difference.

I'm also thinking about painting the outside of the lower plenum and lower runners, like what SexyRob did, with high-heat paint. I will have the upper plenum polished on the outside, so I'm leaving that polished, but I think it'd be nice and clean to have the lower parts painted. I don't know what color to go with, but it will probably end up being plain black to just make it all look clean, or white to match the car.

 

working on getting a big dyno session to test a bunch of intakes/plenums, check out my thread

http://g35driver.com/forums/dfw-g35-...take-mods.html

wonder how well mine will do?


pfregeolle: you dont need high temp paint if you have the thermal gaskets, my plenum never gets hot to the touch so paint will be fine.

 

Really? Hmmmmm good to know! I'm almost finished with all my chit. The upper plenum is finally completely done. Outside is mirror polished, and inside is totally smooth. Just still finishing the intake manifold and the lower plenum. Got both my gaskets, except now I think I need to order a throttle body gasket also before I do the install. I will upload some new pictures soon!

 

Any updates from anyone? News? Thoughts? Newdz?

 

Here's where I'm at right now. Pretty close to being done!!