Intake Temps

[SmbFD3S]

sounds good, some decent monitoring will only help inform
 
I need to monitor intake temps, cos my engine bay is a bit crowded and I\'m sure the air going into the filters is hotter than it should be...
 
The guys above quoting air temps, where are you measuring from?

I assume they are getting their temps from the Apexi mate so standard sensor location under the UIM... Thats where mine are taken from at the moment

[Warthog]

What you need is an independant stand alone sensor in the intake airflow with a rubber seal so it\'s not affected by heat soak so you can see exactly what the temperature of the air is.  I\'m currently looking for one that will do the job so i\'ll let you know

My temps are from a SPA twin read Intake and Water temp gauge and independant sensors. HTH.

[RedRummy]

I assume they are getting their temps from the Apexi mate so standard sensor location under the UIM... Thats where mine are taken from at the moment

cool, thanks

[SmbFD3S]

Quick update, i\'ll post a better one and some pics or something once a bit more testing has gone on.
 
Fitted the sensor into the plastic elbow as near to the throttle body as i could without the TB actually affecting the sensor.  Also did some airflow test in the elbow pipe to see how the air flowed through it so i could position the sensor to get the best flow across it.
 
So after fitting everthing back together i left it for a couple of hours to settle down.
 
Turned the ignition on to read the Commanders temp readin (not started the car yet) and it read the same to within 0.5 degrees as the new sensor so that was nice
 
Took the car out for a couple of hours and monitored everything.  Now the new sensor changes every 1 second while i think the Factory sensor actually changes every 10 or so so much better monitoring can be achieved with the new sensor.
 
Everything going fine, water temps up to 84 as normal, doing 70, little boost used at this point and the commander is reading 26 the same as the new sensor.  Now for a little play, come to a roundabout and floored it through 2 to 4th.  It really is amazing you know how much compressed air heats up!!!  Sensor went from 26 ish to 42 pretty damn quick, the Commander read 35 at this point, let off and cruised a bit at 70, new sensor reducing quickly to around 32, commander still reading 35.
 
Got home and left it to have dinner.  Went back out and to no suprise due to heat soak, Commander was reading 74 degrees, the new sensor reading 54.6...
 
The next bit is the suprise.  Started the engine and the new sensor started to fall very quickly, commander still on 74, drove off with the commander on 74 and the new sensor on 46.  5 mins up the road the commander has dropped temps reading to 57, new sensor on 38.  After about 10 mins of driving on open roads, the commander was saying 43 and the new sensor back down to around 27 so guessing the heat soak never really goes once the UIM has got warm.
 
Also it\'s quite suprising just how fast the intake temp rises when sat in traffic, and the heat soak effects on the Intercooler, guess this dont matter what IC you have. Spray Bar/Water injection/Fan is bound to help this tho...
 
Just thought i\'d share my experiment/experiences with you guys.

[lockwood77]

Nice, good write-up mate. Sounds like what we expected is the case - heat-soak takes much longer to get rid of than it actually takes to cool the air in the system down, and there is a lag between what\'s really going on and the PFC reading (in both directions, e.g. your new sensor reading higher than the PFC after boosting).

[Ricco_04]

Thanks for posting up the results :cheers

[lockwood77]

Well, on track at Silverstone last night (GP circuit) I managed to see 65C at one point! That was going round the track, not heat-soak...

Didn\'t take long to get it back down, but I have to say I was boosting into the 50s a lot of the time as keeping it below 50 would have meant about one lap at a time! :rolleyes:

Car didn\'t seem to mind, it\'s conservatively mapped as far as I know, although whether that makes any difference to likely det due to intake temps I don\'t know. :?

So, something needs to be done, cos it wasn\'t even a hot day yesterday - water injection here I come I think, got to be the cheapest/least hassle method and I don\'t feel the need for any more power at the moment (although I do have a C-West nose, so front/V-mount is perfectly possible...)

[Spartacus]

Just to give some insight to what I have learnt from similar experiences with my LS1 FD.
I have the oem intake temp sensor built into the intake elbow just before the throttle body and have been suffering what I would describe as heat soak. The problem with the LS1 ecu is that should the sensor report too high a temperature the ecu cuts timing (not good). From some research it seems that the sensor can give false readings for a couple of reasons.
1) The standard thermistor is slow to react to temperature changes.
2) It suffers from heat soak due to it\'s mounting which retains the heat of it\'s surroundings.

Both of these factors make the ecu believe and adjust for a hot air charge when there may not be.

From what I have read on other forums it seems there are a couple of thing you can do to alleviate this problem.
You can swap the original thermistor for a faster reacting one (I have one on order) although in the case of a rotary fd you would need to find one compatible. (Just to give you an idea I got mine from here: http://www.omega.co.uk/ppt/pptsc.asp?ref=44000_THERMIS_ELEMENTS&Nav=)

Also you can insulate/isolate the surroundings of the thermistor with normal foil/foam etc as you would do anything else.

The guys in the US who have done this type of thing are reporting a much more stable and actuate readings and a much better place to start before trying to gain more performance with cold air feeds etc.

[nikp]

...I have the oem intake temp sensor built into the intake elbow just before the throttle body and have been suffering what I would describe as heat soak. The problem with the LS1 ecu is that should the sensor report too high a temperature the ecu cuts timing (not good)...

Actually, it is good to retard the timing when temps get too hot. It\'s for safety (To help preserve the egnine). But it\'s not good for power. So that\'s another reason why we want cool temps: to stop the ignition from being retarded (Same for any type of engine)

[Spartacus]

Actually, it is good to retard the timing when temps get too hot. It\'s for safety (To help preserve the egnine). But it\'s not good for power. So that\'s another reason why we want cool temps: to stop the ignition from being retarded (Same for any type of engine)

I agree but the point I was making is that the temperature readings from the thermistor are not the readings of the air temperature, which is not good.
You need accurate reporting of intake temps before you can start to look into a colder feed.

[nikp]

I agree but the point I was making is that the temperature readings from the thermistor are not the readings of the air temperature, which is not good.
You need accurate reporting of intake temps before you can start to look into a colder feed.

Very true. Agreed.

[SmbFD3S]

I agree but the point I was making is that the temperature readings from the thermistor are not the readings of the air temperature, which is not good.
You need accurate reporting of intake temps before you can start to look into a colder feed.

As i proved also with my little experiment
 
I am currently looking for replacement thermistor also with faster reacting times and i know there was a guy on here using a Triumph one so i am going down the bike route also, as these will inevitably need to be faster reacting due to higher rev\'s....

[Warthog]

So which is a direct replacement???

[SmbFD3S]

See this thread:-
 
http://www.mazdarotaryclub.com/forums/showthread.php?t=26579

[gmogle]

Whilst on the subject of intake temps, my mrs and I went to Thorpe Park yesterday in her Polo. We got stuck inevitably on the m25 and we did 7 miles in 40 mins !!! It got me thinking about the Rex, if I was stuck in this traffic jam I dread to imagine what the intake temps would be, I went out today in Norwich and got stuck and saw 45 degrees after 10 mins.

But more importantly I was thinking about what would fare better....a v-mount or a FMIC in traffic ?

Also I found an old article in Banzai with a Dragon Performance pink FD in it, the car had a custom v-mount with a radiator that was 30% smaller than standard. What would happen to water temps being stuck in traffic with one of these ?