GazJenno

Hi all, Thought I'd let you know my findings on intake temp on MY93 WRX with standard slanty intercooler running 16.5psi, full de-cat with heat wrap and OE turbo heatshield modified to fit over the bellmouth.

I recently installed a temperature probe in the pipe between the intercooler(IC)and throttle body(TB). Today where I am has been quite cold and foggy as well as damp in the air I would say air temp was about 8-10°C max and the IC reading when cruising was between 12-15°C depending on my speed which I thought was quite good. 1) Opinions if that is good or not?

Under hard acceleration from about 30mph to 70mph through 2nd and 3rd gears the temps increased rapidly about 3-5°C per second which resulted in the temp reaching 22-25°C just as I hit 70mph and dropped it into 5th. This clearly shows how quickly the temps can rise under boost. However they soon went back down to 12-15°C once cruising at 70mph for a few more seconds. 2) does that seem quite a good cooling down time?

This obviously shows the theory of prolonged WOT causing engine faliure on early Impreza's. Note that I reached a max of 22-25°C on a very short period of acceleration which is quite a low temp reading but yesterday the air temp started at 20°C but I didnt driver the car but I imagine intake temps would have been up to 30-40°C doing the same thing.

I also found that when I got back and let the car cool down for its 2mins that the temps increased to 30°C from 12°C which clearly shows heat soak problems. Even when the engine was off the temp increased to over 40°C within 10mins.

I will fit an IC air splitter and possibly an STi 8 scoop, if a can bring my self to fit the big ugly thing, and see what that does.

Any way just thought I'd share my findings, I thought it was quite shocking and am eager to see what happens on a hot day.

3) any other info you have on this then post it

cheers,

Gaz

robf

Interesting data. Some questions;

Which turbo?
Standard filter box, or cone in the engine bay?
No IC splitter at all?
Any way to log data and put in a graph?
Any way to also measure pre-IC temps?

-Rob

GazJenno

Hi Rob,

Its got the OE turbo, TD05 90° entry
OE airbox
No IC splitter... will be getting one to see if it helps any
Havent got a way to log data which is a shame
and I have already got plans to fit another monitor in the air box for pre-turbo temps

I dunno if these findings are of any intrest at all but I always wanted to know and couldnt find anything on it so thought I'd find out for myself.

any advice on other things to try is welcome.

Gaz

lightwave693

been waiting for some one to do this type of test. been wanting to do it my self but never got around to it etc. where did you get your monitor from? im changing my 98standard intercooler for a uk300 one once i sort out this lean problem and would like to see if it makes a difference. got sti8 scoop already and looks nice, well i like it anyway.

GazJenno

I got the temperature monitor from Maplins, think it was about £10 for the screen and £2 for the probe which needs to be solderd to the screen. I need to make surround to fit it in to make it look good and add some LED's to light it up but I enjoy doing stuff like that... To fit the probe I just drilled a hole in the rubber hose joining the IC to the TB and pushed it in then sealed it with some glue and silicon.

Got the idea off other people Harvey being one as I found his findings quite scary so thought it would be a good idea to monitor mine for myself.

Gaz

robf

I think they are very interesting, cheers for the data.

My gut feeling without looking at other models to compare, is that, #1 and #2 look great considering it's a smallish IC and you don't have proper air ducting. For #3, the heatsoak doesn't look that bad at all compared to other top mounts ICs I have had experience with (GT4 and MR2SC). The real question is how fast the 40C came back down after driving.

Might I suggest fitting a pre-IC probe (and a hood scoop temp probe if you are feeling adventurous), get a mate with a digital video recording camera or cell phone, and do a few runs. From the video you can go back through in slow-mo and manually plot the data (a stopwatch on the side will help with time axis). That would give a real good indication of IC efficiency. The slanty IC gets kicked around a lot, so would be nice to see exactly how bad it really is.

-Rob

GazJenno

Cheers for that, I will try all of the above. The thing is today was quite cold and damp so probably cooled the IC better than normal so will see how bad it is on a hot day. Wasnt sure if anyone would find this intresting but will post more findings when I can.

Thanks again for the feedback and ideas,
Gaz

The Rig

iTrader: (13)

Any pics or links to the kit u used, would be good to fit this to my MY95 as i have just fitted an STI8 scoop and wonder if this has reduced intake temps at all.

GazJenno

Probe Fr Temp Module

The screen is on its own, the probe and a facia can also be bought

also Harvey suggested

Detail Page

which is in a proper gauge format. 3 reasons I didnt go with this is because it didnt have a red backlight, it was more money and you had to drill a hole in the IC, I think, and then screw it in. I maybe wrong about the drilling bit tho.

Gaz

silent running

I've done similar tests on my MY98 WRX with a standard TMIC, with similar results. If you do a longer WOT run you'll see 50-70 C depending on ambient temperature to start with and at that point I let off. As far as your questions go, 1 and 2 are good results considering the equipment you're working with. In more general terms, when you think about what intercooling is supposed to achieve, the results are crap. But it's the limitation of top mounting an intercooler instead of front mounting and there's not a lot you can do about it. You can do all kinds of tuppenny-ha'penny mods but at the end of the day you're pissing in the wind, to coin a phrase.

Unless your intercooling is keeping charge temps stable under very long WOT runs, it's not sufficient. If you're having to let off because your intercooler can't reject heat fast enough, just changing the scoop or adding tilts and splitters will only delay the inevitable - it won't cure the problem.

The Rig

iTrader: (13)

This the lot you got then ?

Temperature Module

"A very versatile digital thermometer module with the LCD display and circuitry on a small pcb with a16-way solder edge connection. The PCB is fixed to a small plastic bracket that includes an AA battery holder. At its simplest, simply insert an AA battery and the module will display the ambient temperature via the onboard sensor. An external waterproof sensor is also available (Order Code FE34M). However, it is capable of much more than that. The edge connector has connections that allow you to set the time, set the high and low temperature alarm points, select Celcius or Farenheit, etc. It also has outputs that go high when these points are reached and connections for an external buzzer. A comprehensive operations manual is supplied with the module. It shows how to connect relays to the temperature set point outputs, how to connect a buzzer to the alarm output and full details are also given on the 13-bit BCD serial data output and how to read it. A plastic bezel is also available for a neat finished look (Order Code FE35Q). The LCD display itself will only operate in the temperature range +5°ree;C to +50°ree;C; so for temperatures outside this range, the external probe will be required"

what temps are getting into the dangerous area then at WOT ?

p1mark

It depends a bit on how the car is mapped obviously but 50 degrees is where mine started to det whith a version 8 TMIC on.

dynamix

iTrader: (3)

my 2.5 2006 STI with top mount and charge temp gauge situated in the same place sees cruise charge temps at Ambient to Ambient + 1C

WOT runs through the gears up to silly speeds will see this rise to Ambient + 20

Track Use sees it go to Ambient plus 25-30 ish.

An STI top mount and cold air feed rather than induction kit sucking hot air in will help massively i think.

The Rig

iTrader: (13)

Well,Gazjenno,got the kit u bought, it takes a bit of getting used to with all the switching needed etc,but i just set up the 1 second responce and have it set to celcius.
to install the probe i removed the onboard temp sensor and soldered the probe on, is this how u dd it ?

GazJenno

yep, exactly how I did it. I trick I did to stop the probe being blown out under high boost was to get some wide cable ties, drill a hole in on and feed the wire through then tighten them up around the IC hose so its constantly pushing the probe in. Obviously to avoid the probe being sucked in make the hole smaller as the probe is tapered.

Also make sure the probe is in enough to get into the sir steam but not to far to get sucked in. I fitted it then looked down the IC pipe with the IC off to see how far in it was.

Gaz

The Rig

iTrader: (13)

Cheers Gaz, i havent fitted it to the car yet, sounds like a plan,any pics

GazJenno

Sorry I havent got any pics but will try and get some next time I have the IC off. Let us know how you get on.

Gaz

The Rig

iTrader: (13)

i didnt mean a pic down the throttle body,just a pic of the engine with the probe attached

i will post one up tomorrow, i have just mounted the unit inside the car in a piece of trim under my stereo,how did u mount urs

The Rig

iTrader: (13)

With a decent AA Battery in im hoping for 1 yr at least if use from it

GazJenno

I mounted mine in the little cubby hole under where the cigerette lighter would be but I no longer have the cigerette lighter or ash tray as I made a plate to fit gauges, I am now going to remove the cubby hole and fit another plate two house to of the temp displays, with LED's to illuminate them and wire the LEDs and temp displays up to the cars power supply using resistors.

Thats my plan anyway...

You cant actually see the probe on mine as I turned the IC pipe so the probe was at the bottom out of site, this may affect the Temp readings somewhat but I havent seen anything obscure from the display so all is well I think.

Gaz

silent running

I've tried the sorts of temp modules mentioned above before - a cheapo Maplins one, the more expensive modular one where you solder on the separate probe, and an ebay special which had the bonus of being backlit. They all did the job OK but looked like a bodge.

I got hold of an STi3 air temperature sensor and I've hooked it up directly to my Power FC, which then gives me a pretty accurate air temp reading. The only problem is I don't know the sample rate or ability to track fast changing temps as in an intake tract. We'll soon see though, because I've got it screwed into the side of one of the boost pipe going into the throttle body from my FMIC. Soon as the FMIC is fitted, I should have a pretty good idea of charge temps on my FC Commander.

The Rig

iTrader: (13)

Gazjenno,im still not sure on how u connected the probe intot he rubber join from intercooler to throttle housing, did u insert all the probe,or just the silver tip ?

cant seem to favom out in my head ur cable tie job

ive got it all plumbed in except the probe into the IC chamber now....

My engine temp went from (while hot) 25 to 49 in about 1 minute in traffic LOL !! (as the probe is still just waiting to go in properly)

GazJenno

I actually drilled a hole in the IC pipe and pushed the metal tip in and pushed it abit further so some of the rubber/plastic bit went in which means the tip is in the air stream more. I drilled the hole in the centre of the pipe so the probe would fit in between the IC and TB, hasnt got much room between them but this can be looked as as and advantage as it means the probe cant be sucked in as the other end with the wire coming out is too fat to fit through, but the hole shouldnt be made big enough for the hole thing to fit through easily anyway.

As for the cable tie thing... I drilled a small hole in a wide cable tie and pushed the wire through, this means that the wire goes through the small hole and the rest of the probe cant. I then used another two cable ties and stringed them together to make one big one which would fit around the IC pipe, tightend them up just enough to hole the probe in place then finally sealed the probe with some glue then some silicon. Obviously to thread the wire through the cable tie you need to de-solder it which. It was an after thought so I ended up soldering it twice...works quite well though

As Silent said this is a pretty ugly way to do things, abit of a bodge, done on the cheap...I havent got a large budget so it was perfect for me, and I'm determined to make it look the part too. It really does work though the probe is sampling every second and reads quite accuratly to one decimal place.

Hope this help you, Rig.

Gaz

silent running

Yes they definitely do work as long as you set it for the once-per-second sample rate.

The Rig

iTrader: (13)

well,i just installed the probe into the rubber joiner pipe,i used a washer to stop it going thru too far,so i have the metal tip plus about 3mm or so of the white plastic in as well,dont know if the araldite will hold it tho,but it at least cant get sucked in,but blown out !

the temp im getting while engine is cold and hasnt ben run as im waiting for it all to dry etc is 16.9,now, its quite warm here so will the temp display read the outside temp before the car is run,as i thought it would read alot lower due to it being confined

cheers

The Rig

iTrader: (13)

Well,heres my readings.

Once car is warm and upto temp the cruise temp (55-60mph) seems to be 14.2c, fluctuating slightly lower if i go to about 40mph.

i gave it a spirited drive thru the lanes and it rose to 18.4c and didnt go any higher, this wasnt full throttle but 3/4ish and to about 80 mph.

its hard to do WOT in the morning !!

when the car is shut off the temp gauge slowlyrises to about 38c,whereas when i had the probe loose in the eengine bay before total fitment it rose to 68.

cheers

harvey

iTrader: (48)

Interesting results.
If you do a search you will see various results I have posted over a period of time on numerous cars including 95 WRX, STi 3 Wagon, STi 6, STi 7 and STi 8.
On the STi 3 for instance, even on a cold day, ACT is off the clock at 70C between 120 and 140 mph in a standing start WOT run.
1)Fitting an STi 8 scoop on the STi 3 from DRMotorsport is an improvement but only an interim measure in advance of fitting a proper FMIC (like Hybrid)
2)Do NOT buy a temp guage and probe from e-bay from a guy in the leeds Bradford conurbation area.
3)The TMIC on the STi 8 works best but in all other cases it is a compromise and when you start tuning an 8 you still need an FMIC.
4)Monitoring ACTs on cars with TMICs will most likely preserve a few engines.

The Rig

iTrader: (13)

Hi Guys,reserect an old thread.

the maplins one served me well,i replaced my TMIC and the inlet hose the probe was in and i think i may of damaged the probe as now my display LCD modulejust shows - - - C as its reading,bugger.
no problems,get a new one, seems maplins dont do them anymore ???

they do have one which is very similiar but has a refresh of 10 seconds only.pah !

all i can really find is Hong kong stuff

Digital Thermometer Temperature Auto Car Meter Gauge on eBay, also Indoor Outdoor Thermometers, Weather Devices, Gadgets, Electronics (end time 09-Jun-09 05:17:25 BST)

i know the maplins one is prob made there too,but any others out there i cant seem to find ???

cheers

The Rig

iTrader: (13)

well,i just found this so will order it,not too bad, £25

Mugen spoilers, splitters, grills and wind deflectors / Civic EP3 type r specialists / Contact 07984 573301 or HQ 0845 8382517

joz8968

iTrader: (13)

Hi Silent.

I have a PFC Commander monitoring my 93 WRX. I too would like to add a later STi temp probe so that the Commander can monitor my replacement STi 2 TMIC's ACTs...

1) Where did you obtain your STi 3 air temp sensor? How much was it?
2) Is it okay to mount it in the IC to TB short pipe (as mentioned by the others)?
3) How do you wire it up to the ECU wiring loom?

Cheers.