Do your Coolant temps and AIT's a favor

[TitaniumTT]

Plug the exhaust port passages in your housings. I know there are a few 2nd gen owners in the middle of rebuilds now so I thought I'd post this here as well.

Recently I rebuilt a motor and the ONLY thing that I changed, aside from the seals and the housings, was to plug the exhaust port passages in the housings. In my case, they were RE housings and have a HUGE port with an insert in them. I first tried tapping the insert for 1/4" NPT but the insert started spinning. So I drove that out and tried for 3/8" NPT. No dice as the housing would have to be machined. Instead what I ended up doing was taking my plate of 3/8" 5052 aluminum and cutting out something that resembled a circle of about .6". Then I spent a fair amount of time hand fitting it to .550" with a slight taper in it. I then drove that mother into the passage blocking all the exhaust gas from making it's way through the housing, into the LIM which, obviously, has the ACV & EGR passages blocked. I was quite proud of those little pieces. Here they lay

http://rotarycarclub.com/rotary_forum/attachment.php?attachmentid=5749&stc=1&d=1245729971

So, what was the result? Sadly I cannot speak intelligently on the AIT's as I'm measuring them pre-TB. Coolant temps however......... mine are retarded to begin with, generally they were around 174-175* on the highway and never getting above 187*. They are consistantly ~4* colder and the ambient temp has risen about 10* on average. All that from blocking the little f'n port underneath the exhaust sleeves. I will NEVER build another motor with these things left open.

[need RX7]

Good stuff :icon_tup:. Thanks for sharing, I'll definitely keep it in mind when I do my monster motor build (assuming we're still driving cars by that time)

[Justen]

i'm sorry i don't think i'm completely understanding this from the image shown. Did you block the COOLANT passages around the exhaust port? ...cuz i'm currently in the middle of a rebuild. and always interesed in lowering coolant temps lol

[Justen]

wait, okay that was a stupid question lol. i think i see what you did there. Is it possible to post another pic to clarify? i'll have to take a look at my housings i guess

[Flooder]

Im not getting it. Could you elaborate on this a little more?

[TitaniumTT]

wait, okay that was a stupid question lol. i think i see what you did there. Is it possible to post another pic to clarify? i'll have to take a look at my housings i guess

Sorry, no more pics. I thought that one would explain everything that needs to be explained.

Im not getting it. Could you elaborate on this a little more?

If you dissassemble an engine and look at the irons and the housings you will see a few passageways that allow extremely hot exhaust gasses to move to other places of the motor besides the exhaust/turbo mani. The passageways lead to the LIM where they enter the LIM enroute to the ACV. Most people have long since removed thier ACV so sending hot exhaust gasses to it does nothing beneficial. All it does is heat the LIM and the charge air as well.

While getting to the LIM the exhaust gas is confined in the housings and irons and transfering exhaust gas heat to these pieces which is being absorbed into the material and also heating the coolant more.

By plugging that little passageway you are preventing the exhaust gas from going anywhere but out the exhaust sleeve where it belongs.

Make sense?

[N.RotaryTech]

I just took some pics of what your talking about.
The rotor housing here is from an s5 na.
I took out the sleeve.

http://i184.photobucket.com/albums/x70/RotaryTech/DSC02956.jpg
The sleeve has two small holes, one of them hidden in the picture but on the other side of that one hole.
And the exhaust port has a hole that leads to a chamber in the housing, this hole is hidden under the sleeve, also notice the two small holes under the exhaust port.
Picture of the "chamber":
http://i184.photobucket.com/albums/x70/RotaryTech/DSC02958.jpg

I guess that "chamber" leads to a passage way in the irons which end up in the avc / lim.
Basically you have hot exhaust gases running through your engine along side the coolant passageways.

Thats not cool.

[EJayCe996]

pun intended?:)

[vex]

An added benefit that is not mentioned yet is that isolating the exhaust gases to be away from coolant passages such as these you actually allow more exhaust gas energy to transfer out of the engine completely. What this means is that your turbo will then benefit and decrease the amount of temperatures your metal sees at all operating conditions. Combine this with the knowledge that the 13B is already able to transfer more energy to a turbo charger than most other engines are able to dream of, we are able to raise the bar just a little bit.

Summary: Coolant Temps go down, AIT's go down, Spool time goes down, More heat rejected through efficient means and further able to be used down the exhaust stream (another turbo if you wanted).

[RETed]

Summary: Coolant Temps go down, AIT's go down, Spool time goes down, More heat rejected through efficient means and further able to be used down the exhaust stream (another turbo if you wanted).

I doubt this makes a significant difference.
I'd be surprised you get 1hp out of the whole ordeal.


-Ted

[vex]

I doubt this makes a significant difference.
I'd be surprised you get 1hp out of the whole ordeal.


-Ted

I wouldn't imagine HP would be measurable at all, but allowing the exhaust gases to travel to the turbine directly and not get rejected through the cooling system will increase spool response, also increasing the temperature and pressure differential of the turbine. Though as you said I doubt it would be significant if at all.

[Phoenix7]

I just took some pics of what your talking about.
The rotor housing here is from an s5 na.
I took out the sleeve.

I guess that "chamber" leads to a passage way in the irons which end up in the avc / lim.
Basically you have hot exhaust gases running through your engine along side the coolant passageways.

Thats not cool.I see now.

[Flooder]

Makes a lot more sense now, thanks!

[TitaniumTT]

I doubt this makes a significant difference.
I'd be surprised you get 1hp out of the whole ordeal.


-Ted

I wouldn't imagine HP would be measurable at all, but allowing the exhaust gases to travel to the turbine directly and not get rejected through the cooling system will increase spool response, also increasing the temperature and pressure differential of the turbine. Though as you said I doubt it would be significant if at all.

It's a shame teddy put me on his ignore list for disagreeing with him. He might have learned something. Such as my logged 4* DECREASE in coolant temps..... which, btw, were down to 168* this morning on the cold drive out to PA

[RETed]

Yeah, and if you cannot comprehend what I just said...
I claimed that HORSEPOWER GAIN (or loss) is going to be insignificant.
Your minor change in temperature can be also due to other factors...hell, I bet the sensor deviation is within those ranges.

Besides, you just plugged up ONE way the exhaust gets through to the intake manifold.
You do realize that the exhaust gases still get around the exhaust sleeve by the leading edge, right?
Mazda designed the EGR system to be like that.

You're might be onto something significant, but don't pat yourself in the back too much yet...


-Ted

[N.RotaryTech]

Horsepower, ted is the only one that mentioned this.
We dont care if there is more or less horsepower.
This is a reliability mod, And for the ppl that remove the emissions system, an don't care about egr.
Yeah this might be something significant, possibly new, an I thank Titanium for posting it up.
He is contributing to the community a little helpful piece of info here.
Lets give it a try here an there and post up results, before bashing it and claiming that this wont make a significant difference.

About significant difference.
Some of the things we do with our rotaries probably don't make a significant difference. Ive heard of lots of little things to do, weather it comes with rebuilding an engine, removing stuff from the engine(emissions removal), turbocharging, tuning, etc, That help in a little way with performance, reliability, etc.
Its not all about a significant difference.

[RETed]

Hmmmm, I didn't realize critical thinking got thrown out the door just because you think someone is an authority (mind you, I'm using this pretty loosely)...
I didn't realize that just because I'm the only one objecting to these conclusions, it's called "bashing" now...
Apologies if I tend to be suspicious of claims from any tom, dick, or harry...

Nor I guess you think it's rather normal for someone to call me "teddy"...
Funny, cause no one else calls me that.
Just for the record, my legal name is "Ted", not "teddy", nor does anyone else call me "teddy".
I guess you find it appropriate that someone that I don't care for is allowed to call me that?

Oh, if you want to drop your temps and increase spool up on your turbo, might I suggest a turbo (turbine) blanket?
These have been used for years and have been proven (and produce more significant results over these posted in this thread).
Oh, wait, but you already knew about that, right...?

Hey, sorry for raining on your parade.
I'll let you get back to your normal scheduled programming, and excuse the blip on your TV screen.


-Ted

[kuromi7]

:lol: Ted's softening up, he went easy on you guys...he must like you. This, plus teh other mods to drop intake temps eventually add up.
- Phoenix7 (logged in as Brooke apparently.)

[classicauto]

One thing I also did to reduce turbulence was to weld/smooth the two little EGR ports in the exhaust sleeve itself.

Obviously, its doing dick all by itself, but its another item that may just help keep that side of the engine cooler, and thus, take some load off the radiator.

But yes gas will still go around the sleeve, but there's yet to be a real solution to that problem being that the housing is AL and the sleeve is ferrous.

[N.RotaryTech]

Ok, "bashing" probably wasn't the word to use.

Critical thinking? Sure.

I tend to reply to "critical thinking."

[vex]

...
Oh, if you want to drop your temps and increase spool up on your turbo, might I suggest a turbo (turbine) blanket?
These have been used for years and have been proven (and produce more significant results over these posted in this thread).
Oh, wait, but you already knew about that, right...?

Hey, sorry for raining on your parade.
I'll let you get back to your normal scheduled programming, and excuse the blip on your TV screen.


-TedCan I imagine you laughing while typing that?

The same principle still applies with the turbo blanket. The turbo will only spool as fast as the temp/pressure differential is available (Which I know you know but for everyone elses benefit), so the more heat you keep within the turbine the faster it will spool. Of consequence plugging the hole will give more exhaust gas temperature to the turbine than a blanket alone. This modification would be to isolate the exhaust gases from exchanging heat through contact and heat soak directly to the coolant passages. I imagine one could theoretically further increase the heat rejection benefit of the coolant passages by filling the egr void and plug area with an insulator material (silca comes to mind as an example) and then blocking off the locations themselves. Though I'm personally not familiar with the passages and so can not say it would be a good thing or not and may be more of a hassle than is really worth.

More to the point blocking off these passages may at the most provide a good 50-100F (I pulled these numbers out my ass though) temperature difference which to a turbo isn't a whole lot and wouldn't really be noticable when the EGT's reached normal operating temperature. Basically it's something that, by itself, is not worth it to pull your engine and take apart to do.

You could however decrease spool time by increasing the temp/pressure differential. There's (more than) two ways to do this. One is to allow a majority of the exhaust gas to go directly to the turbine, or cool down the exhaust gases as quickly as possible after the turbo. One can let their imagination run from there I figure.

[classicauto]

FWIW, I noticed zero actual increase or decrease in preturbo EGT's before and after this.

Coolant temps - mine vary because of the way my fan is setup (meaning hits traget temp, fan comes on, temp goes down, fan goes of...) but there was no appreciable difference in my setup regarding water temps before or after.

As for my AIT - I'd have to have had a sensor right in the LIM to quantifiably say one way or the other - but I do not.

One thing I can tell you with 100% certainty - it was fun to do and made me feel better :lol:

[vex]

FWIW, I noticed zero actual increase or decrease in preturbo EGT's before and after this.My thought is that the increase in temperature would actually be registered as a dT/dt (change in temperature with respect to time). Meaning you'd come up to temp quicker, but that probably comes out in the wash with the thermocouples. Dunno though.

I know i've been trying to explain what I mean for a few posts now but it's hard to make sense and keep it simple without writing a huge article on it.

[TitaniumTT]

:lol: Ted's softening up, he went easy on you guys...he must like you. This, plus teh other mods to drop intake temps eventually add up.
- Phoenix7 (logged in as Brooke apparently.)

I was crowned the evil forums Epic N00b Powerhouser so I wouldn't consider that the slightest bit insulting or demeaning in comparision to some of the things that I've said to people soooooooooo, whatever.

On to more important things. I never once claimed anything about horsepower becuase I never had a chance to dyno anything nor would it make a shit of difference because the engine was rebuilt with better housings and different seals so any claim would be completely bullshit.

I didn't mention any numbers about the AIT's because the proper place to measure those to make the comparision would be in the LIM which I'm not.

I mentioned the coolant temps that saw a difference that were logged.

And someone explain to me how exhaust gases can get past the PLUG IN THE PORT that I built?

[RETed]

I imagine one could theoretically further increase the heat rejection benefit of the coolant passages by filling the egr void and plug area with an insulator material (silca comes to mind as an example) and then blocking off the locations themselves.

You're right, but here's the problem...

How do you get (the silica - "silca"[sic?]) to stick to the metal housings?
RTV'ing the passages (on rotor housing, side irons, and intake manifolds) has been done before, but RTV only has a claimed 700F intermittent temperature resistance.
Almost anything else will either:
1) burn due to temps?
or, 2) come loose due to heat expansion / contraction from the engine.

The good thing is that once everything is plugged up, it's a dead end.
So, the plugs that are closest to the engine (i.e. rotor housings and side irons) are getting the hottest.
The plugs at the intake manifold should hold up fine?


-Ted

[vex]

You're right, but here's the problem...

How do you get (the silica - "silca"[sic?]) to stick to the metal housings?
RTV'ing the passages (on rotor housing, side irons, and intake manifolds) has been done before, but RTV only has a claimed 700F intermittent temperature resistance.
Almost anything else will either:
1) burn due to temps?
or, 2) come loose due to heat expansion / contraction from the engine.

The good thing is that once everything is plugged up, it's a dead end.
So, the plugs that are closest to the engine (i.e. rotor housings and side irons) are getting the hottest.
The plugs at the intake manifold should hold up fine?



-Ted
Edit: Sorry didn't realize I had missed an 'i'
Silica is glass (or more commonly known as: sand or silicon dioxide). I chose that media as the insulation because it can be small and remove about 99% of the air that would be in the chamber (since the silica particulate is so small). Thermal expansion shouldn't matter much if at all because the particulate itself is so small. When the chamber volume expands the silica will move to compensate, when the chamber volume decreases the silica *should* be able to move to compensate.

http://en.wikipedia.org/wiki/Silica

Another alternative would be Aerogel. It is mostly composed of air which makes it tremendously light. It also has an increased strength compared to other similar materials of equal dimensions. The real benefit is that they are wonderful insulators. This is the stuff that astronauts have in their suits to protect them from solar radiation (the heat, not the gamma). The trouble is I do not know the thermal expansion rate nor any of it's physical properties.

http://en.wikipedia.org/wiki/Aerogel

What I would find interesting and I think a little beyond anyone's skill on this forum would be to use thermoelectric coolers to cool the chamber wall and dissipate the heat directly into the insulation that holds them there. Granted you'd need to run wires and find a way to protect them from being melted/fried (probably have to encase them in the insulating material itself). Beyond that you should see a decrease in temperatures without increase in coolant temps (though this is not something for nothing). The trouble is as the heat increases and the thermoelectric device attempts to cool it, the more current will be drawn until either the wires burn up or the ceramic breaks apart. But it's interesting to consider.

http://en.wikipedia.org/wiki/Thermoelectric_cooling
http://www.fujitaka.com/pub/peltier/english/index.html?gclid=CNS6z72ZqJsCFRJM5Qodnjbf9A

[RETed]

I am not going to mess with stuff that is basically very small tiny bits of glass.

I've messed with aerogel, but only with speakers...I'll leave that stuff with transducers.

Peltier devices are notoriously inefficient devices.
By the time you create enough cold to counteract the heat, you've produced enough (or not enough?) current on the order of significant horsepower.
So all that did was load the engine down or blow your alternator?


-Ted

[vex]

I am not going to mess with stuff that is basically very small tiny bits of glass.

I've messed with aerogel, but only with speakers...I'll leave that stuff with transducers.

Peltier devices are notoriously inefficient devices.
By the time you create enough cold to counteract the heat, you've produced enough (or not enough?) current on the order of significant horsepower.
So all that did was load the engine down or blow your alternator?


-Ted
Hence why I didn't think it efficient at all but a nifty science experiment (thermoelectric). How's the Aerogel? I've never had a chance to work with it, does it compress and expand agreeably with metals?

As for the silica, I don't think it would cause any problems unless the metal deteriorated enough to cause them direct access to the combustion chamber or leak into the oil reserves (which I don't think they would at all unless there was a catastrophic failure). Combining the silica with a metal based epoxy or resin would eliminate any fear that a rouge silica particulate would find its way into a place it shouldn't be.

The only other option would be to fill the chamber with insulation material (fiber glass) and some aluminum.

[classicauto]

And someone explain to me how exhaust gases can get past the PLUG IN THE PORT that I built?

I don't think it can.

Rather, that exhaust is still getting around the sleeve itself and thereby heating that entire aluminum portion surrounding it (which is cooled by the jackets). Despite the fact that it can't get out of that chamber now since you plugged it - that portion of the AL on the housing is being blasted with exhaust.

:)

I tried to minimize it by welding shut those holes in the sleeve, but the leading edge of the sleeve still doesn't seal against the housing and until it can, gas will still go around (a bit...)

[RETed]

Rather, that exhaust is still getting around the sleeve itself and thereby heating that entire aluminum portion surrounding it (which is cooled by the jackets). Despite the fact that it can't get out of that chamber now since you plugged it - that portion of the AL on the housing is being blasted with exhaust.

:)

I tried to minimize it by welding shut those holes in the sleeve, but the leading edge of the sleeve still doesn't seal against the housing and until it can, gas will still go around (a bit...)

Yep, despite his limited intelligence, he still can't quite grasp the idea of exhaust gases getting around the exhaust sleeve...literally.
Mazda designed the exhaust sleeve so that exhaust gases can get around it, hence, my statement about that particular fact earlier.
I bet there's more exhaust gas entering the leading edge of the exhaust sleeve versus the two holes on the "ceiling" of the exhaust sleeve itself.
The exhaust gas vector is more apt to enter that way.
Keep in mind that in most set-up's, there's also a scavaging effect downstream (from the other rotor) causing a negative pressure area that makes it even harder for the exhaust gases to enter those two holes.

If he's bitching about how much exhaust gases are getting past even with his plugged holes inside the exhaust sleeve, why bother plugging the two holes in the first place?


-Ted

[TitaniumTT]

Yep, despite his limited intelligence, he still can't quite grasp the idea of exhaust gases getting around the exhaust sleeve...literally.
Mazda designed the exhaust sleeve so that exhaust gases can get around it, hence, my statement about that particular fact earlier.
I bet there's more exhaust gas entering the leading edge of the exhaust sleeve versus the two holes on the "ceiling" of the exhaust sleeve itself.
The exhaust gas vector is more apt to enter that way.
Keep in mind that in most set-up's, there's also a scavaging effect downstream (from the other rotor) causing a negative pressure area that makes it even harder for the exhaust gases to enter those two holes.

If he's bitching about how much exhaust gases are getting past even with his plugged holes inside the exhaust sleeve, why bother plugging the two holes in the first place?


-Ted

Are you blind or retarded? And that's a serious question. Look at the pic I posted after you take your head out of your ass and then ask yourself how exhaust can get past that. Yeah yeah radiant heat etc etc but now its contained and not spreading up to the LIM heating the AITs and passing the exhaust heat into the coolant and the rest of the engine. NOT through the LIM as that sounds. Ever weld aluminum? Notice how far and FAST that heat travels?