BATMAN

If ur running stock IC, SMIC, FMIC (please state make/model of aftermarket IC)

Also, if ur running stock intake, cold air intake or "hot" air intake from the engine bay.

I have Greddy SMIC (made my own SMIC duct that gives 100% of cooling fins coverage as opposed to using the stock ducting for the Greddy SMIC https://www.rx7club.com/forum/showth...ight=smic+duct ) with stock intake box pulling hot air from the engine bay. I haven't done the cold air intake mod yet.

Intake temps at cruising and freeway speeds in 75 degree weather is right around 38C~.

Stop and go is 45C~.

93BlackFD

my intake temp in 4th gear, 95F day outside, is about 140F

after a full 4th gear pull, it was 103F

this was with greddy fmic, no underbelly, aquamist 50/50 isopropyl alcohol/water mix

BATMAN

Looks lke the FMIC cools around the same as the SMIC.......

93BlackFD

@ 16psi, i think that affects it a bit

spoolin93r1

i have an apex'i fmic and my air temp sensor mounted in my intake elbow. tonight i passed a temperate sign at a bank. it read 24*C and my power fc was showing 26*C. keep in mind that that's just cruising. the most it will go over ambient temp during a hard run is maybe 6-8*C. althought it seems to take forever for heat soak to go away if it's been sitting for a while

RX7WEEE

iTrader: (16)

M2 large SMIC 25C just cruzin, "hot air intake"

Snook

iTrader: (12)

Bullshit

Me: Greddy 3 Row FMIC lowest I've seen is 31 on highway with light rain.
normally in the mid to upper 30s in traffic...seen in 40s highest
air intake thermosensor is in greddy elbow and I have water/alcohol injection but rarely use it

Without turbo or intercooler Ive seen 68 highest

single turbo just a k&n on it

Yanni

7racer

M2 medium, RX7fashion CAI....

on highway mid 40's no boost in 95 degree ambient....

stop and go...60's....

BATMAN

Well he does live in WA.

If those are numbers in the winter that might be believable.........

BATMAN

I wonder how much does the CAI help?

7racer

zero!!


I really think that there is little benefit due to the area that its getting the air...but its so hard to tell and measure....

and wasn't there an old thread where someone noticed a postive difference with the top of the box off?

wReX

iTrader: (6)

Batman, I've been wanting to start a thread with these numbers...thanks.

Pretty much the same readings for me except I am running the Greddy SMIC and Apexi Twin Power intakes.

Can anyone tell me why my car stalls/dies when it hits 63C-64C though? Reading off the Power FC. Not sure where the air intake temp senor is located(stock location I'm guess). Any help is greatly appreciated.

BATMAN

No problemo wReX, BATMAN is always here to serve the community

speeddemon7

so based on these hard numbers it seems like either a front mount of a smic will do the job about the same.But the front mounts impact the radiators cooling capability by reduced air flow.Seems to me like the best setup is a smic.

Tom93R1

iTrader: (2)

I have stock IC, Pettit "cold" air intake, and home made water injection spraying straight into the elbow.
On a 95F day I was able to get the PFC to read 26C which works out to 79F. That was 50/50 water and alcohol but way too big of a nozzle. Normally on my summer cruising the temps will be about 55C on the highway or 65C in traffic, 105F day. When I boost for anything over a couple seconds the temps will drop to about 40C with the current mister.

BATMAN

It's a sore topic that has been much debated.

These are my initial impression about FMIC & SMIC:

FMIC probably cools a little better since it's bigger and outside. However the large volume may increase lag.

FMIC tax the radiator and subsequently the rest of the engine with greater heat.

A good SMIC like Greddy bolts right in in a matter of minutes.

BATMAN

i like to see some v-mount numbers..........

Mark'sMazda

I know it's not an FD, but for what it's worth my t2's intake temps w/the stock top mount are usually in the mid low 30C's driving normal on an 80F day. The temps shoot up @12 psi though.

a v-mount system is highly dependant on good ducting. A friend of mine (fd) has the rotary extreme kit w/a cold air intake, stock hood, no duct work, he see's temps as high as 70C sitting in traffic on a hot day.

wReX

iTrader: (6)

So is boost really that big of a variable when it comes to intake temps? Whenever I see temps above 50C on the Power FC I try to avoid boosting all together. Figured it wasn't good. Still no explination why the car cuts out at ~65C though.

FD_Newb_1974

I have the Pettit Cool charge II, Pettit CAI, Aquamist 2d water injection. I'm running about 15lbs of boost.

In 90F Ambient, I see temps in the low to mid 50C's while cruising. Stop and go traffic I see temps creep as high as 70C pending the length of time I sit. When I am able to boost repeatedly for prolonged peariods, temps drop to mid-high 40's. this is with the stock AIT and stock location.

BATMAN

Does hot air contribute to detonation or does it merely hurt HP?

I understand that if the air is too cold there is a lieklyhood of kaboom (i.e. - car not being armed up properly)

Tom93R1

iTrader: (2)

My theory is that there should be an optimum temp to keep from detonating. Too low of a temp and you get too much oxygen which can lead to detonation. Too hot and your intake temps start to get up lcose to the point where the fuel can spontaneously combust. Mostly though I think too cold is more dangerous than too hot for your engine. That is why an intercooler upgrade means you need to add more fuel to your mixture, more O2 because of cooler intake charge and not so much because of more air flow. Higher temps are mostly just limiting power IMO.

BATMAN

My gut instinct tells me to concur with u on that notion.

rallimike

iTrader: (1)

My setup is a SMIC (custom Bell) with 2 radiators located in front of the wheels, and 2 oil coolers relocated to the front. Normal road driving (light boost to 12 psi now and then) my intake temps are ambient. They never rise above where they were when I started the car. If i drive it hard, lots of 2nd and 3rd gear accelleration @ 15-16psi, I get to +5C over ambient and light cruising for a few miles doesn't change it. If I stop and park it, when I start it up again I'll be in the 45-48C range. 4 miles of highway driving will get it back to +5C of ambient. I have never seen 50C since I installed this setup. BTW, I have an Aquamist 2D, which probably helps lower the high boost temps noted above.

spurvo

Stock IC, stock intake, battery relocated and hole left open, BUT cooling duct diversion to inadequately cool the battery sealed off with shiney tape

Cruising on freeway fully warmed up I see mid 30's C. Get on it and the temp will pop up to 45 to 50C, then come back down nicely. Turn on fans and temp starts to climb steadily, topping about 55C while cruising 60-70 mph with fans on low.

Sit in traffic and all goes to hell. Basically, once the fans go on and there is no flow, the temp goes to 65C or so and sits. Goes back down once the car is moving over 40 mph, and will drop to the above mentioned 50C or so until fans are turned off. Then will drop to 30's if continue to drive.

If I sit in traffic with no fans on, the intake temps climb slowly, likely due to radiator heating up IC. But eventually, got to turn on fans to keep water temp down. Damn traffic...

Lastly, if I pop the hood with the fans on, either just to the latched position or fully open, the intake temps drop slowly, from say 65C to ~48C, then stop dropping. Vented hood would likely mimic this behavior.

This is the temps measured at the AWS intake on the backside of the elbow with a thermocouple plugged into a Fluke voltmeter set up for temp measurements. So it's reasonably accurate. Interestingly, the first 15 minutes of driving have the temps below 30C, but of course no boosting until oil bees warm.

Probably the thing to be most paranoid about with respect to intercooler performance is the ability to absorb more heat from the intake charge when already at a given temp. I'm sure the calculations exist somewhere, but it would involve calculating the amount of air running through the IC at a given rpm at a given psi, and determine the temp before and after the IC. The differential is roughly the thermal efficiency of the IC. Then check the differential when the IC is at 30C, 40C, 50C, 60C and 70C. I would of course expect the differential to be reduced as the IC temp goes up, which allows us to know the "headroom" for intake temp reduction for a given IC temp. This then relates to horsepower and detonation, and is what we would want to tune for if we could, or at least limit boost under these heated conditions.

I'm experimenting with adamc's intake to see if any difference exists. As I'm pushing more air through the IC, I would expect faster rise and drop times for intake temps, but cannot yet confirm this.

I kinda want a better SMIC, but I agree that for stock twins at 10 psi and stock ports, it probably won't make THAT much difference, and certainly I would suspect an FMIC under the same conditions to be basically bling factor. But what the hell do I know?