Intercooler -------------

[--alpina--]

Hi, as i have turbo fitted on my car, not yet been on rollers, but soon will be!! the turbo itself is a Garrett T3 (big turbo) do i really need an intercooler for it?, the turbo is up front so airflow does hit it as well as water pipes circulate the turbo housing i.e. water cooled..

Any suggestions would be great to hear!

J

 

[MicraPRO]

Hi, as i have turbo fitted on my car, not yet been on rollers, but soon will be!! the turbo itself is a Garrett T3 (big turbo) do i really need an intercooler for it?, the turbo is up front so airflow does hit it as well as water pipes circulate the turbo housing i.e. water cooled..

Any suggestions would be great to hear!

J

A turbo like that will make some serious heat surely an intercooler would be a positive thing..?

 

[--alpina--]

A turbo like that will make some serious heat surely an intercooler would be a positive thing..?

Id thought it be the otherway round as a smaller turbo will struggle more generating heat wouldn't it?

J

 

[MicraPRO]

Im thinking about air pressure making heat bigger turbo surely makes more heat?
A little turbo gives quick snappy blips... and doesn't need intercooler im sure @frank removes his in winter...
A large turbo suffers from lag compression turns the inlet air hot from heat transfer and pressure???

 

[--alpina--]

Im thinking about air pressure making heat bigger turbo surely makes more heat?
A little turbo gives quick snappy blips... and doesn't need intercooler im sure @frank removes his in winter...
A large turbo suffers from lag compression turns the inlet air hot from heat transfer and pressure???

I see what you mean! so keeping the intercooler is a must on this kind of turbo unit? i thought maybe free up some space in front of the radiator and have direct pipe from turbo to throttle body ans shield the piping away from any source of heat etc all thou there will be under bonnet temperatures etc!!!


J

 

[frank]

i would say a smaller tubby creates more heat personally, the air is being compressed inside a smaller compressor turbine running at higher speed
i just run a heatsink during summer

 

[MicraPRO]

i would say a smaller tubby creates more heat personally, the air is being compressed inside a smaller compressor turbine running at higher speed
i just run a heatsink during summer

View attachment 30724

You run an intercooler in summer tho frank right? I was under the impression you had a little diesel turbo? If not I apologise profusely...

 

[--alpina--]

i would say a smaller tubby creates more heat personally, the air is being compressed inside a smaller compressor turbine running at higher speed
i just run a heatsink during summer

View attachment 30724

Creating more heat is what i thought, not only that i was told by a few people but need an opinion and someones thoughts on the micra forum, is that i have an Audi TT intercooler and its jammed right against the radiator and if having the chance id rather have it off and run the turbo without an intercooler if possible BUT if/when summer comes will the car suffer with loss of power due to weather no being dense enough for solid power combustion!..

J

 

[frank]

You run an intercooler in summer tho frank right? I was under the impression you had a little diesel turbo? If not I apologise profusely...

mine,s a TD04 tom (the smaller 9b one from a mitsubishi 3.0 v6) and i tried a diesel intercooler last year, but felt it was pointless tbh and removed it

 

[jk9194]

Frank, have you try out on any petrol intercooler?


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[frank]

Frank, have you try out on any petrol intercooler?


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intercoolers are intercoolers really jk, the base model k12 dci has no intercooler and runs about 1 bar of boost, my half a bar wont be creating a lot of heat
i did some testing last year by ragging the car then testing the compressor temps etc, and came to the conclusion that as long as the car is moving you can easily keep it cool with a heatsink (but when you stop the engine the heat travels from the mani/exh turbine, along the turbo core, and then the compressor housing gets mega hot !)

 

[jk9194]

Alpina, have you put your turbo kit in your micra?


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[pollyp]

all depends on amount of boost, how long it's on boost and how hot things get.

compressing air will increase it's temperature.
more pressure = more heat.
running a centrifugal compressor beyond it's optimum efficiency range will make it heat the air faster rather than provide pressure.
the longer the turbo is running at high boost with insufficient cooling = more heat generated overall and transferred to the compressor housing, piping & air.

this all means that the resultant intake air will be hotter and increases the probability of pre-detonation, gambling with the engines life.

on modern ecus with knock sensors and mapping, this just means upon detecting knock it'll pull back n timing n other maps and reduce performance as a protective precaution.

on an old micra ecu that don't support knock sensor or knock maps and even with a tuned daughterboard, this either means:
- the tuner would have to be very conservative n safe with the mapping and rob performance if/when his additional external sensors keep detecting knock
- or if it wasn't tuned properly or ran too hard/long n raised inlet temp and it knocks, there's no way the ecu will know or take action in protecting the engine from damage, then its game over.

fitting an intercooler is a preventative measure to reduce the chances of failure.

 

[h701micra]

A turbo like that will make some serious heat surely an intercooler would be a positive thing..?

A small turbo creating higher boost will generate more heat as its working harder
A big turbo won't have to put in half the effort to generate the same boost. Less heat

But colder air is always better

 

[--alpina--]

Alpina, have you put your turbo kit in your micra?

Yeah its been in since last year, its running at 3psi and havent been on the rollers yet as i have been busy and to be honest ive been lazy about it althou i have the modified injector rail and injectors and the NIStune ECU oh and the fuel pump.. just been driving around as is... pulls good..

J

 

[mas12555]

considering a small charge cooler?

 

[Low Rider]

At 3psi, you'll be <50degC* inlet temps based on fag packet maths.

People running 0.5bar are going to be around 80degC* non intercooled. Those at 1bar are going to be more like 110degC*.

*Assuming ambient air temperature of 20degC.

 

[--alpina--]

So running the micra at 7-8 psi, with a garrett T3 turbo would you say an intercooler is definetly needed or can i get away with removing it and have a straight pipe from turbo to the TB?

J

 

[h701micra]

A T3 isn't putting much effort in to achieve 7psi so your inlet temps will be lower as opposed to say a t15. You'd get away without but for maximum use of the boosted it needs cooling

 

[--alpina--]

A T3 isn't putting much effort in to achieve 7psi so your inlet temps will be lower as opposed to say a t15. You'd get away without but for maximum use of the boosted it needs cooling

Thanks h701, its that if i dont really need it id rather do away with the intercooler and have more space in the front of the radiator cos everything is really tight there and too many bendy pipes to avoid parts of the engine, id rather have one straight pipe from the TB to the turbo simple and easy!

J

 

[Enuo]

I think that Low Rider was giving the temp increase that arises simply as a result of compressing the air, and not taking into account the extra heat caused by the inefficiency of the compressor or any heatsink from the turbine side.

 

[Noddie]

The difficult thing is knowing the compressor efficiency at different pressure ratios and air flow rates. This is why you need a compressor map for your turbo you may find that the T3 has poor efficiency at low air flow rates at pressure ratios.

EDIT: error in my drawing: 0.5 bar of boost on top of atmospheric pressure is 150000 Pa (I was getting mixed up with silly psi).

 

[Low Rider]

I think that Low Rider was giving the temp increase that arises simply as a result of compressing the air, and not taking into account the extra heat caused by the inefficiency of the compressor or any heatsink from the turbine side.

I'd taken a typical efficiency of 70% on those figures. 65% for the 3psi calculation due to poor efficiency at lower boost/flow levels. I'd also taken a quick glance at a T3 50trim compressor map as a rough guide.

 

[--alpina--]

hahahaha, ok so what now? whats recommended and what you lot recommend/?

J

 

[Noddie]

As LowRider says, at 0.5 bar you will be running about 80degree inlet temperature. This will basically negate any advantage due to the loss in air density. (based on temps out of turbo, they will be lower at the engine entry due to some heat loss in the inlet system but I cant say how much this would be).

You also have to retard the ignition with raised inlet temps to avoid knock.

I would run an intercooler. one that can shed around 4kW of heat at 40mph wind (I have absolutely no idea about specking an intercooler based on desired heat release )

 

[frank]

Thanks h701, its that if i dont really need it id rather do away with the intercooler and have more space in the front of the radiator cos everything is really tight there and too many bendy pipes to avoid parts of the engine, id rather have one straight pipe from the TB to the turbo simple and easy!

J

thats the option that i took J, you have to bear in mind that an intercooler needs a good flow of air through it, and that it will cause a pressure drop and a slight drop in throttle response.
if you are going to rag the car around a track then an intercooler will have a large effect, but on an urban daily where you just point and squirt away from the lights, or when you exit a roundabout, then its just willy waving bling
i,ll do some proper temp sensor testing when i get a chance

 

[--alpina--]

Cheers frank and noddie, probably have to do some temp tests and see how i get on and feel the charecteristics of the engine whilst driving with and without an intercooler!!!

J

 

[pollyp]

I think one day I'll try to fit some of those tiny thin temp sensors throughout the inlet plumbing such as between :
filter - turbo, turbo - IC, IC - MAF, MAF - inlet ports
and see what happens under various loads, application, duration and conditions

wish I knew how to make my own datalogger

 

[Noddie]

My friend at uni is developing a customisable data logger, should be done in a couple of months. I'll keep you updated

 

[frank]

i did some testing on my 30 mile each way commute to redditch today with this probe taped to the steel chargepipe (aluminium tape, and some lagging/insulation ontop), next to where i fitted a coolant temp sensor last year, (arrowed)
last years sensor did,nt move the needle at all, but this one recorded 7deg c this morning, rising to 19deg on a long hill climb on the M5.
then when i arrived at work and turned the engine off it rose to 30 deg 10 mins later (and topped out at 32deg after half an hour)

 

[Low Rider]

 

[frank]

thats interesting eh dave ^ so was that a 20deg C ish rise in temp ?

 

[pollyp]

I've always wanted to buy/hire a FLIR camera

 

[Noddie]

Good info! Would be nice to do the same for a longer period so that I/C has less chance to act as a heat sink.

 

[frank]

Good info! Would be nice to do the same for a longer period so that I/C has less chance to act as a heat sink.

the i/c is showing some colour difference across it off boost, but does,nt appear to be having any effect on boost ? was it fan cooled at the time ?

 

[Noddie]

the i/c is showing some colour difference across it off boost, but does,nt appear to be having any effect on boost ? was it fan cooled at the time ?

Is the IC not what rhe cross thing is on? That looks be rising all the time

 

[frank]

Is the IC not what rhe cross thing is on? That looks be rising all the time

yeh, but for the i/c to be effective i would expect a colour/temp difference from left to right ed ?

 

[Low Rider]

The only way to semi-accurately measure the charge temps is to place proper fast acting thermocouples within the air stream. Anything else isn't going to show what's actually going on at the time. Even a good air inlet temperature sensors will have some delay due to the poor thermal conductivity of air and steady stating is dangerous on the road.

For those who cannot log air inlet temperatures the below link offers good insight into theoretical charge temperatures. If you have a relevant compressor map you can get an idea on what the intake temperatures are likely to be.

Intercooler efficiency becomes a little complex in reality, as the assumption will be that the intercooler is sufficiently sized and there is therefore no thermal runaway.

http://www.stealth316.com/2-turbotemp.htm

If your inlet temperatures are significantly below the calculated values, then it's one of those eBay specials that defies the laws of thermodynamics

But anyway, back to the original question. If you're only going to run 3psi, I don't see the need for an intercooler at all and you'll save on the complexity and cost it would bring to the build.

 

[frank]

The only way to semi-accurately measure the charge temps is to place proper fast acting thermocouples within the air stream. Anything else isn't going to show what's actually going on at the time. Even a good air inlet temperature sensors will have some delay due to the poor thermal conductivity of air and steady stating is dangerous on the road.

For those who cannot log air inlet temperatures the below link offers good insight into theoretical charge temperatures. If you have a relevant compressor map you can get an idea on what the intake temperatures are likely to be.

Intercooler efficiency becomes a little complex in reality, as the assumption will be that the intercooler is sufficiently sized and there is therefore no thermal runaway.

http://www.stealth316.com/2-turbotemp.htm

If your inlet temperatures are significantly below the calculated values, then it's one of those eBay specials that defies the laws of thermodynamics

But anyway, back to the original question. If you're only going to run 3psi, I don't see the need for an intercooler at all and you'll save on the complexity and cost it would bring to the build.

yes my testing is akin to monitoring the temperature of the downpipe to assess the exhaust gas temps, not ideal but its all i have atm
the probe is currently cabletied to the inlet mani, to compare those temps on tomorrows commute

 

[frank]

on a 10 mile shopping trip the inlet mani averaged 40 deg c, and rose to 49 deg soon after parking up.
and that,s with 3 mani-to-head gaskets fitted ^, and t/b waterheated delete

 

[Low Rider]

I did a datalog to see what was going on in my case.

In traffic inlet temps are <35C. Where I live there's little opportunity or need to get into boost in start stop 20mph / 30mph zones to further add to this, so it's almost all certainly related to under bonnet temperatures. 35C was peak worst case based on 18C ambient temperature.

Upon getting onto a 50mph road the inlet temps dropped off and stabilised at 22C. This takes a few minutes due to heat soak. A few sprints at 14psi saw those increase up to a peak of 27C, which then settled back down to 22C baseline within 20seconds. There's not much opportunity to test further unless on a track due to safety/legal reasons.

I am sure actual charge temperatures are higher momentarily but it's down to what the temperature sensor can detect, which is installed in the charge piping just before the throttlebody.

 

[frank]

inlet mani temps averaged 35deg C on my commute (30+ while cruising on the motorways, and 40 in traffic)
and that rose to 45deg one hour after parking up !
gonna look into fitting a plastic inlet mani, and then i,ll try testing an intercooler

 

[h701micra]

The way I see it. Manufacturers saw fit to fit intercoolers on their petrol turbo production cars with standard boost between 7-10psi...
Diesels are different as they require heat to function so overcooling them is counter-productive
I'll take the word of subaru, nissan, toyota, volkswagen etc etc any day of the week.
They've alot more money than me to test these things
Still... a larger turbo running sub 5 psi shouldn't need an intercooler

 

[frank]

scoured the yards for a suitable plastic inlet mani to mod and fit, because the stock alloy one is reaching 55 reg C (20 deg ambient temp), but nothing caught my eye.
so we,ve lagged the stock one with cloth tape, layers of silicon sealer, and aluminium sticky tape
intercooler testing is next on the list now

 

[Noddie]

Surely you want heat radiation from the inlet system with the turbo? You thinking its heating up the inlet air?

 

[frank]

Surely you want heat radiation from the inlet system with the turbo? You thinking its heating up the inlet air?

there,s a lot of heatsoak from the back of the engine ed (mainly in traffic, off boost) , so i need to get the mani temps down to about 10 deg above ambient.
else i,ll be removing some heat with an intercooler then putting heat back in as it passes through the mani

 

[pollyp]

also needs this to guarantee a cool manifold

http://micra.org.uk/threads/pollymobiles-rebuild.35251/page-50#post-510149

 

[frank]

also needs this to guarantee a cool manifold


http://micra.org.uk/threads/pollymobiles-rebuild.35251/page-50#post-510149

i,m using 4 gaskets instead paul

 

[h701micra]

Or raise the rear of the bonnet to draw the heat out?
Much more effective, cheaper and guaranteed to work

 

[skymera]

Or raise the rear of the bonnet to draw the heat out?
Much more effective, cheaper and guaranteed to work

I read raised bonnets are trash since the base of the windscreen is high pressure