Red Devil

Are you claiming 100% intercooler efficiency with just an air to air setup?

Or 100% with meth injection also incorporated?

Bastage

iTrader: (1)

MM's got an Air/Blood Intercooler. He just hooks it up directly to his mechanical heart so his cold blood can circulate through it efficiently.

paulmasoner

iTrader: (1)

you can take meth out of the picture altogether... rather i think he's alluding to the compressor efficiency which the SC guy dont have. it's made up for in other areas i suppose, but then the argument about soaking your A/W interheater will start....

IIRC, i think i saw somewhere way back, that with that turbo you could hammer it all day long and keep charge temps ~10 degrees above ambient. that was just on air-air intercooler........ efficiency ftmfw

MazdaManiac

iTrader: (3)

I get below ambient with just washer fluid.
You guys are over-thinking it a bit.

Red Devil

You're off a little...compressor efficiency has nothing to do with an assertion that an air to air unit is 100% efficient. There is no such thing as a 100% efficient air to air ic - standalone - you must have water spray, meth, ice, etc...something auxiliary to gain 100% efficiency and return charge temps to ambient.

As for the second paragraph, not really related at all.

So in other words it's not just from air to air alone. If Pettit owners are returning their temps to ambient with auxiliary injection also, where's the issue? Seems to me both sides are able to achieve ~100% return in cooling...sounds like a wash to me. Only thing that comes to mind is the threshold before the air to water system heat soaks.

paulmasoner

iTrader: (1)

i wasnt trying to even consider intercooler efficiency... of course its not 100%... i was just pointing out that even with an efficient intercooler it takes an efficient compressor to keep charge temps that low w/o injection....

the second statement was really all i was trying to say.

again, my second statement... he gets just below ambient with washer fluid. with NO injection he was seeing only ~10 degrees above ambient(iirc)

what do the other guys see for charge temps w/o injection of any kind? and how long does that last before heat-soak of the A/W heater.

i think i actually agree with what you're saying, i just didnt present my thoughts well and they were slightly misunderstood for it

MazdaManiac

iTrader: (3)

Price!

Red Devil

Come on, you always do better than that ...everyone's wallet and perspectives are completely different...while we're at it, though, we should all agree from this point forward that the sunrise is always more beautiful on Tuesdays than any other day of the week...

Who's with me...Tuesday's sunrises???

MazdaManiac

iTrader: (3)

My point is that all of these expensive mixes do nothing that a jug of water and a bit more fuel in the tune can't accomplish in this application.

Rote8

/Popcorn FTW

MazdaManiac

iTrader: (3)

That's not popcorn - its detonation.

Bastage

iTrader: (1)

I saw 106-108F temps today just cruising at 40-55mph, with temps going up to the 130's after parking the car to go into a store and pick up some lunch. It got back down to normal cruising temps after cruising about 5 miles. Ambient temps were 95F, and I had the meth off. With the meth on and on a day like today, I can get the AITs down to the 80's. AITs are not much of a problem down here unless you're stuck in traffic on a hot day, but I would think that there's no practical way to avoid that. With the meth though it would be pretty easy to get them back down below ambient given the opportunity. I think the humidity down here makes the hot temps a little more bearable, since it eases the transfer of heat from the radiators to the air.

Phil's 8

iTrader: (3)

the cool temps you have with the water saturation, it has got to cooling- It's only 115 here today with 6% humidity. If you take that up percentages you would be over heating also.

MazdaManiac

iTrader: (3)

Its a chilly 107°F here today.
I got in the car ans started it cold. The sCANalyzer said my IATs were 121°F and my coolant was 150°F by the time the starter motor stopped spinning!
Once I got moving, the IATs dropped to just above ambient and stayed there.
I drove 8 miles. The coolant got to 221°F and the IATs averaged 117°.
My intercooler inlet was 170° and the outlet was 107°F (ambient) after a 3-gear boosted run before stopping at the car wash.

My water/meth nozzle is after the IAT sensor.

Phil's 8

iTrader: (3)

My god you must be haveing the monsoons to get the temp that low. You can leave your jacket when you come here next week.

Moon Assad

221F, holly crap batman

MazdaManiac

iTrader: (3)

That's average. Most RX-8s around here will hit that under certain conditions.
I used to hit 230°F pretty regularly (before the aux rad).
Do a search. There are quite a few RX-8s out here that see 240°+ daily this time of year.
The highest freeze-frame I've hear of was just shy of 300°F, right before she blew.

Remember, we have no water in our air, so the rad does very little. Its all auto-regulation by the motor itself.
Typically, the coolant temp is the ambient times 2 plus 2° for each degree over 100°F ambient.

Bastage

iTrader: (1)

So your IATs are still averaging about 10 degrese above ambient when you're running hard? That's what I'm seeing down here too (with no meth). I've never had a problem with my intercooler heating up the charge, I ALWAYS get cooler temps at the AIT sensor than I get at the MAF, and even with this heat they're anywhere from 20-40 degrees cooler, and this includes driving in bad traffic (stop-and-go) etc.

Rote8

Sounds like MM (and Arizona in general) needs a misting water spray nozzle in front of the radiator.....
Another product for Black Hills Racing?

MazdaManiac

iTrader: (3)

As stated several times here and elsewhere, that doesn't work.

I've misted as much as a full gallon of water (all at once!) through the rad with no effect whatsoever.

Don't underestimate the volume of water that goes through a rad at speed in a place with 30% humidity.
You guys in FL (with your 75% - 100% humidity) pass dozens of gallons through your rad at speed.

Rote8

Evap will cool; the question is how much water can you carry to spray your radiator. (the RX8 tow along tanker?)
On the plus side, if it catches on, the desert will turn green along the roads from all the water sprayed on radiators....

MazdaManiac

iTrader: (3)

Well, a gllon (at 7 pounds) did nothing.
I suspect that you could probably get that one-time effect with about 4 gallons of water (almost 30 pounds).
So, the question becomes - does it make sense to lug around 30 pounds of water to lower the coolant temperatures a single time?

Once again, scale, economics and physics render another suggestion moot.

olddragger

iTrader: (3)

special needs in mm's environment that is true. its damn harsh. most pro guys on track shut it down(cooling laps) if coolant gets to 235. even recips dont like those temps for long. ask the off road guys.
Jeff my iat is measured at the upper intake junction. the highest i have ever seen on the street is in the 130's without meth. course power that you can feel does go down some after about 120f or so.
the meth does bring more octane into the picture dont forget that.
yall ever measure the lower intake temps? wonder about front versus back rotor? it may surprise you.
currently i am looking into supplementing my cooling system. it is my 1st summer with fi. i am too close to the edge for me at 205 street(highest) to 225 on track at 90 ambient. stay tuned.
jeff and them may end up having to do some pretty significant work to get the temps under control,since the heat and low humidity is about as harsh as of an environment has you can dump on a rotory
you are going to need at least 3 cubic inches per hp cooling AND you are going to have to increase oil cooling capacity. look to the diesels for help?
olddrgger

MazdaManiac

iTrader: (3)

Actually, no. Since the stoichiometric ratio for meth is double that of gasoline, its octane doesn't really contribute - especially at the ratios achieved by just injecting it with water at the rates that the injection system delivers.
The effective octane changes, but the water does that.
Remember - the meth (what little of it there is) is trying to speed up combustion. Its the water that is slowing it down.
Its the cooling effect that does much of the work, but the quench of water slowing the flame front is what prevents autoignition.

Yes. The lower intake will get damn hot in the OE configuration - on the outside.
A thermocouple lowered into the airstream (through the service port) shows little difference in the temp of the air going through there once it gets up to operating mass (above 80 g/sec or so). The heat of the LIM is only an issue at low-speed operation.
It is a pretty dense piece of aluminum and it acts like a heatsink for the engine block.
The rear rotor gets much warmer, but that is mostly due to the way coolant and oil flow through the motor.
That said, it still pays to sheild it (like everything else).

olddragger

iTrader: (3)

yes that lower intake is about 1/4 inch thick---everywhere. low speed is what will heat soak for sure. once the air velocity increases it doesnt have a chance to heat up. phenolic spacer is on the way i hear.
while it is true that water does boost octane--so does methanol. at a 50/50 blend we are injecting as much meth as water. On this i will have to disagree with you, thank God we are not tuning for max water meth gains.
oldragger