Intake Manifold Isulator

[pollyp]

Hi
I was reading an article about replacing the standard intake manifold gasket with a thicker insulating type so that it keeps the manifold cooler therefore cooler intake air.

does anyone know if they exist for the k11?

 

[frank]

the throttlebody is water heated anyway fwn (you,re best to bypass that first )

 

[pollyp]

yep mine's bypassed.

seems odd that nissan used two methods of cold idle control together when the IACV works fine on it's own, so i bypassed the coolant, keeps the TB cooler.

 

[frank]

yep mine's bypassed.

seems odd that nissan used two methods of cold idle control together when the IACV works fine on it's own, so i bypassed the coolant, keeps the TB cooler.

the waxstat is a coldstart fast idle really tho eh (extra to the idle control)

 

[pollyp]

aye, prob a failsafe incase the IACV sticks.

on my 98 1.3 slx loom the IACV alone works fine without the waxstat (fast cold idle then normal warm idle)

but my other 93 1.3 slx loom the IACV isn't workin properly (slow cold idle then fast warm idle symptom). swapping over the 2 TB's gives the same outsome for that loom so i think either the older ecu isn't controlling the IACV properly or the IACV loom is faulty.

 

[topau]

I know this is an old thread, but just being curious... does anyone have any measured data to see how much these mods lower the intake air temperature?

As I am living in Finland I wouldn't take out the TB heating due to low temperature (down to -30'C) engine starts here during winter. But for a summer only car I think it would work perfect also here.

 

[pollyp]

hey forgot to update this thread cos wrote it on my blog instead page 50 post 2487

http://micra.org.uk/threads/pollymobiles-rebuild.35251/page-50

made the insulator out of ptfe

previously with a normal inlet gasket and bypassed TB coolant lines, the manifold would be very hot to touch (est > 40C)

but now with the ptfe insulator its barely warm to touch (est < 30C)

 

[topau]

Ok. Nice to see that someone is documenting their work.

Yes, I know that the intake runners will be cooler using spacers, but how about the air inside. Has anyone made an intake air temperature measurement close to the injector to see that there is really a difference?

Here is one commercial data from intake runner temp:
http://www.hondata.com/heatshieldgasket.html#Details

I have to plan to make a custom intake some day, so I could make spacers also at the same time, if that is seen to have some real results.

 

[pollyp]

not taken actual air measurements inside, only what i could feel on the outside of the mani which is definately cooler and so the airflow is now only exposed to hotter surfaces for very short period (ie cylinder head) during its path from the air filter to the cylinders. originally the airflow would be exposed to a heated TB and hot inlet manifold which will certainly have heated the air afew degC.

the improvement of inlet insulators are well proven as you've shown

 

[topau]

The link was only showing decrease in the intake runner temp, not the air. I think the air inside the intake travelling at a speed of 50 meters per second is not getting much energy from the intake, so I am a little sceptic on this. But I would make an insulator, If someone could show some proof in a form of dynosheet or other measurement.

There are also some "studies" like this below,, but this is not Micra related and there are too many loop holes to say anything conclusive.
http://www.myaudis4.com/images/mods/phenolic/pst.htm

Any pointers to measurements?

 

[pollyp]

check this article

http://autospeed.com/A_110474/cms/article.html

 

[topau]

Thanks, that was interesting! Anyone in the forum with similar results?

And of course the question after reading the article is that does anyone have a CAD-file from CG13DE intake ports? ;-)

 

[frank]

i run with 3 gaskets, it probably drops the heat transfer a tad and cost me nowt
the undermani and pipe lagging probably has more effect

 

[reflexuk]

Just because I don't know, why did nissan chose to run coolant through the tb anyway?
While I think about it what is the exact spec of the pipe needed to get coolant to bypass the tb? A thin metal tube of abut 160mm long and 8mm od I would guess.