can intercoolers be too big? FMIC 1HZ td0516g

[crunk81us]

Well as the title says can you go too big with an intercooler?

Application. 100 series 1HZ TD05 Mitsubishi turbo @ 10-14 psi

[GUtripper]

Logic would suggest that the bigger the intercooler, the more the potential for lag.............. and perhaps after a certain size point the heat exchanging / thermal efficiency limit would be reached....

hence why HP hero cars (Summernats, HP Nats etc) go with dry ice intercoolers instead of humungous traditional intercoolers.

[dumbdunce]

on a diesel without a throttle butterfly, a large intercooler tends to increase lag only in first gear/starting out, but under constant, through the gears acceleration, acts as an accumulator, actually improving response.

bigger = less restriction + more heat rejection. put the biggest you can fit.

[the gun]

on a diesel without a throttle butterfly, a large intercooler tends to increase lag only in first gear/starting out, but under constant, through the gears acceleration, acts as an accumulator, actually improving response.

bigger = less restriction + more heat rejection. put the biggest you can fit.

Think of blowing up a balloon, the smaller the balloon the quicker u will reach that balloons capacity. Therefore the larger the intercooler the more time it takes for the turbo to make max boost. I dont know that its makes any difference whether there is a butterefly or not. How can u store boost in an intercooler? Like storing a fart in a bottle with no lid.

[3 cyl]

Maybe the turbo's pressurizing the fart in the bottle?

[dumbdunce]

on a diesel without a throttle butterfly, a large intercooler tends to increase lag only in first gear/starting out, but under constant, through the gears acceleration, acts as an accumulator, actually improving response.

bigger = less restriction + more heat rejection. put the biggest you can fit.

Think of blowing up a balloon, the smaller the balloon the quicker u will reach that balloons capacity. Therefore the larger the intercooler the more time it takes for the turbo to make max boost. I dont know that its makes any difference whether there is a butterefly or not. How can u store boost in an intercooler? Like storing a fart in a bottle with no lid.

yes, it takes longer to blow up a bigger balloon, which is why it takes a little bit longer to get to full boost off idle. once the balloon is blown up, it stays blown up for longer - a small balloon will empty much more quickly than a large one - the compressor continues to pressurise the intercooler volume for a short time after throttle release, and the engine continues to receive boosted air. not having a throttle butterfly means you don't get a boost spike due to the inertia of the turbo - the boost stays high but does not go too high.

This is not just theorizing - it is based on observation of the performance of diesels before and after intercooler installation. the bigger the intercooler, the smoother the boost curve between gear changes. with no intercooler you might drop to 2 - 3 psi, with a big intercooler it might only drop to 6 - 8 for a 13psi peak system. this means more instant response as soon as the fuel is back into the equation.

all that aside, the two main requirements of an intercooler are heat rejection and pressure loss, and you get the best heat rejection and lowest pressure drop from a bigger cooler.

[crunk81us]

ok thanks.. I will go for a large ( but not ginormous) cooler

[the gun]

on a diesel without a throttle butterfly, a large intercooler tends to increase lag only in first gear/starting out, but under constant, through the gears acceleration, acts as an accumulator, actually improving response.

bigger = less restriction + more heat rejection. put the biggest you can fit.

Think of blowing up a balloon, the smaller the balloon the quicker u will reach that balloons capacity. Therefore the larger the intercooler the more time it takes for the turbo to make max boost. I dont know that its makes any difference whether there is a butterefly or not. How can u store boost in an intercooler? Like storing a fart in a bottle with no lid.

yes, it takes longer to blow up a bigger balloon, which is why it takes a little bit longer to get to full boost off idle. once the balloon is blown up, it stays blown up for longer - a small balloon will empty much more quickly than a large one - the compressor continues to pressurise the intercooler volume for a short time after throttle release, and the engine continues to receive boosted air. not having a throttle butterfly means you don't get a boost spike due to the inertia of the turbo - the boost stays high but does not go too high.

This is not just theorizing - it is based on observation of the performance of diesels before and after intercooler installation. the bigger the intercooler, the smoother the boost curve between gear changes. with no intercooler you might drop to 2 - 3 psi, with a big intercooler it might only drop to 6 - 8 for a 13psi peak system. this means more instant response as soon as the fuel is back into the equation.

all that aside, the two main requirements of an intercooler are heat rejection and pressure loss, and you get the best heat rejection and lowest pressure drop from a bigger cooler.

So u have answered the question, yes an intercooler increses turbo lag, the bigger the intercooler the more lag thats created and every time there is a decrese in boost (gearchange.ie throttle off) it takes longer to recover that max boost. Of couse a fast gear change wouldn,t lose as much boost as a slow change.

[the gun]

ok thanks.. I will go for a large ( but not ginormous) cooler

spot on. Bigger isnt always best.

[KiwiBacon]

So u have answered the question, yes an intercooler increses turbo lag, the bigger the intercooler the more lag thats created and every time there is a decrese in boost (gearchange.ie throttle off) it takes longer to recover that max boost. Of couse a fast gear change wouldn,t lose as much boost as a slow change.

You do know how fast pressure waves travel through air? It depends on the temperature, but 330 m/s is pretty quick.
The intercooler is already full of air (it's not a balloon), the only problem is how long it takes for the pressurised air wave to get to the intake.
This isn't significantly different to a non turbo engine.

But, the pressure drop across the intercooler and piping can be. If you've got 2psi drop, then your turbo has to get to 4psi before the inlet see's 2psi. But this isn't due to the volume of the intercooler, this is due to flow restriction.

IMO, put the biggest intercooler you can. However, how much boost can a 1HZ take anyway? I wouldn't expect it to like the amounts of boost at which intercoolers become necessary. At 10-14psi, why bother?

[muzza85]

x2 with what the gun said

bigger isnt always better

IMO id go 300 x 400

[the gun]

So u have answered the question, yes an intercooler increses turbo lag, the bigger the intercooler the more lag thats created and every time there is a decrese in boost (gearchange.ie throttle off) it takes longer to recover that max boost. Of couse a fast gear change wouldn,t lose as much boost as a slow change.

You do know how fast pressure waves travel through air? It depends on the temperature, but 330 m/s is pretty quick.
The intercooler is already full of air (it's not a balloon), the only problem is how long it takes for the pressurised air wave to get to the intake.
This isn't significantly different to a non turbo engine.

But, the pressure drop across the intercooler and piping can be. If you've got 2psi drop, then your turbo has to get to 4psi before the inlet see's 2psi. But this isn't due to the volume of the intercooler, this is due to flow restriction.

IMO, put the biggest intercooler you can. However, how much boost can a 1HZ take anyway? I wouldn't expect it to like the amounts of boost at which intercoolers become necessary. At 10-14psi, why bother?

You can quote all the figures from a book until the cows come home but logic says the more volume required, the longer it takes to fill it i.e. the longer it takes to reach the max boost, either governed by the waste gate or the turbo it self. If it aint on maxium boost it aint going.

[80's_delirious]

on a diesel without a throttle butterfly, a large intercooler tends to increase lag only in first gear/starting out, but under constant, through the gears acceleration, acts as an accumulator, actually improving response.

bigger = less restriction + more heat rejection. put the biggest you can fit.

Think of blowing up a balloon, the smaller the balloon the quicker u will reach that balloons capacity. Therefore the larger the intercooler the more time it takes for the turbo to make max boost. I dont know that its makes any difference whether there is a butterefly or not. How can u store boost in an intercooler? Like storing a fart in a bottle with no lid.

yes, it takes longer to blow up a bigger balloon, which is why it takes a little bit longer to get to full boost off idle. once the balloon is blown up, it stays blown up for longer - a small balloon will empty much more quickly than a large one - the compressor continues to pressurise the intercooler volume for a short time after throttle release, and the engine continues to receive boosted air. not having a throttle butterfly means you don't get a boost spike due to the inertia of the turbo - the boost stays high but does not go too high.

This is not just theorizing - it is based on observation of the performance of diesels before and after intercooler installation. the bigger the intercooler, the smoother the boost curve between gear changes. with no intercooler you might drop to 2 - 3 psi, with a big intercooler it might only drop to 6 - 8 for a 13psi peak system. this means more instant response as soon as the fuel is back into the equation.

all that aside, the two main requirements of an intercooler are heat rejection and pressure loss, and you get the best heat rejection and lowest pressure drop from a bigger cooler.

So u have answered the question, yes an intercooler increses turbo lag, the bigger the intercooler the more lag thats created and every time there is a decrese in boost (gearchange.ie throttle off) it takes longer to recover that max boost. Of couse a fast gear change wouldn,t lose as much boost as a slow change.

nice info DD. I have read similar from some of the diesel tuners in the US. It makes sense to me.
A turbo diesel is different from a turboed ricer that blows off all boost at every gear change. If you watch the boost gauge on mine it doesnt drop to zero boost at gear shifts and that is without intercooler. Lots of factory perfromance cars incorperate a plenumm or reservior in the intake tract to give basically the same effect DD describes.

[dumbdunce]

...logic says the more volume required, the longer it takes to fill it i.e. the longer it takes to reach the max boost, either governed by the waste gate or the turbo it self....

you can make up all the logic you want, too, if you don't have a complete and thorough understanding of the subject at hand. the facts are that a big intercooler does not significantly (in many cases even noticeably) increase lag. turbo lag is far more likely to be caused by a turbo mismatched to its application. the facts are that an intercooler is an inlet restriction. for that reason you want it big, to minimise that restriction. the fact is that intercoolers are for dumping heat from the inlet charge air. the bigger the intercooler, the better it does that.

having played with different intercoolers on the same engine, I have the experience to say what difference it makes. Kiwi is a nerdlinger and loves the theory of these things, as well as putting it into practice - if he says bigger is better, I'd be inclined to listen. Are you just having a stab in the dark with alleged "logic" or are you prepared to accept that you might not have it 100% correct on this one?

[the gun]

...logic says the more volume required, the longer it takes to fill it i.e. the longer it takes to reach the max boost, either governed by the waste gate or the turbo it self....

you can make up all the logic you want, too, if you don't have a complete and thorough understanding of the subject at hand. the facts are that a big intercooler does not significantly (in many cases even noticeably) increase lag. turbo lag is far more likely to be caused by a turbo mismatched to its application. the facts are that an intercooler is an inlet restriction. for that reason you want it big, to minimise that restriction. the fact is that intercoolers are for dumping heat from the inlet charge air. the bigger the intercooler, the better it does that.

having played with different intercoolers on the same engine, I have the experience to say what difference it makes. Kiwi is a nerdlinger and loves the theory of these things, as well as putting it into practice - if he says bigger is better, I'd be inclined to listen. Are you just having a stab in the dark with alleged "logic" or are you prepared to accept that you might not have it 100% correct on this one?

While I've had experiance with turbos on both petrol and diesels I wont claim to be an expert, however until someone can come up with some first hand evidence my view wont change.

having played with different intercoolers on the same engine, I have the experience to say what difference it makes.

What did u find?

[color=yellow]This is not just theorizing - it is based on observation of the performance of diesels before and after intercooler installation. the bigger the intercooler, the smoother the boost curve between gear changes. with no intercooler you might drop to 2 - 3 psi, with a big intercooler it might only drop to 6 - 8 for a 13psi peak system. this means more instant response as soon as the fuel is back into the equation. [/color]

Is the "smoother boost curve" more noticeable now because of the extra volume of the intake (intercooler acts as a shock absober)?

Taking into account of the above statement what happens when the intercooler used is double in size or tripoled? Dose the drop in
boost also drop more than "6-8"?

Lag?

[brad-chevlux]

whats the biggest intercooler you are going to fit in the front of an 100 anyway?

300/600/75? 300/600/100? its pretty much the standard size every one fits to anything these days. I doubt you'd be able to fit a big enough intercooler to increase pressure lag to a point that it becomes annoying.

[Quadcamshorty]

Thats what I was thinking,
Unless you wanted your 100 looking like a drag rotary?

[1MadEngineer]

...logic says the more volume required, the longer it takes to fill it i.e. the longer it takes to reach the max boost, either governed by the waste gate or the turbo it self....

you can make up all the logic you want, too, if you don't have a complete and thorough understanding of the subject at hand. the facts are that a big intercooler does not significantly (in many cases even noticeably) increase lag. turbo lag is far more likely to be caused by a turbo mismatched to its application. the facts are that an intercooler is an inlet restriction. for that reason you want it big, to minimise that restriction. the fact is that intercoolers are for dumping heat from the inlet charge air. the bigger the intercooler, the better it does that.

having played with different intercoolers on the same engine, I have the experience to say what difference it makes. Kiwi is a nerdlinger and loves the theory of these things, as well as putting it into practice - if he says bigger is better, I'd be inclined to listen. Are you just having a stab in the dark with alleged "logic" or are you prepared to accept that you might not have it 100% correct on this one?

i love it!
BUT
i have to DISAGREE
Smallest you can get away with BUT with enough heat rejection to acheive the required result...

I spent 14months doing engineering consultancy and development work on hybrid CAC systems for http://www.titanresearch.com.au , my last project was for the toyota V8 D4D's.

this is the CAC fitted to a new 70series





flow test and heat calcs, would theoritically rate this in the 800-1000hp range as compared to other manufacturers. It was built as pure overkill, but fits into a std group31 battery location. Max pressure drop across core was <0.51 psi, boost command was outstanding. This setup / unit was tested at the Ford/ACART test lab in geelong and performed amazingly well. Just a shame no-one in the motoring industry has any money anymore .

[GreyPower]

The following graph is a Datalog of a 4.2L Patrol driving over a hill & back. Total time is 1min 37 secs. It is an extramely accurate race car logger.
You can see, everthing changes as you change gear, pressures, temperaures etc.
I also have to say that you can go too big with an ic & loose power & response in relation too an optimum size. There is also a difference between a short - high & a wide - low ic,. which has the highest pressure drop ratio. The bigger the 'intake window' (tank height - width), the lower the pressure drop due to lower air speed, BUT, if the core is too long, the drag from all the extra internal surface area will increase pressure drop for very little cooling drop. In very general terms, 1/2 the cooling is done in the first 1/4 of
the core, so the length of the core has an exponential decrease in cooling effeciency.
In my opinion. Regards Richard

[KiwiBacon]

flow test and heat calcs, would theoritically rate this in the 800-1000hp range as compared to other manufacturers.

I thought dodgy ebay sellers were the only ones to rate intercoolers in hp.

[the gun]

...logic says the more volume required, the longer it takes to fill it i.e. the longer it takes to reach the max boost, either governed by the waste gate or the turbo it self....

you can make up all the logic you want, too, if you don't have a complete and thorough understanding of the subject at hand. the facts are that a big intercooler does not significantly (in many cases even noticeably) increase lag. turbo lag is far more likely to be caused by a turbo mismatched to its application. the facts are that an intercooler is an inlet restriction. for that reason you want it big, to minimise that restriction. the fact is that intercoolers are for dumping heat from the inlet charge air. the bigger the intercooler, the better it does that.

having played with different intercoolers on the same engine, I have the experience to say what difference it makes. Kiwi is a nerdlinger and loves the theory of these things, as well as putting it into practice - if he says bigger is better, I'd be inclined to listen. Are you just having a stab in the dark with alleged "logic" or are you prepared to accept that you might not have it 100% correct on this one?

Smallest you can get away with BUT with enough heat rejection to acheive the required result...

[dumbdunce]

...logic says the more volume required, the longer it takes to fill it i.e. the longer it takes to reach the max boost, either governed by the waste gate or the turbo it self....

you can make up all the logic you want, too, if you don't have a complete and thorough understanding of the subject at hand. the facts are that a big intercooler does not significantly (in many cases even noticeably) increase lag. turbo lag is far more likely to be caused by a turbo mismatched to its application. the facts are that an intercooler is an inlet restriction. for that reason you want it big, to minimise that restriction. the fact is that intercoolers are for dumping heat from the inlet charge air. the bigger the intercooler, the better it does that.

having played with different intercoolers on the same engine, I have the experience to say what difference it makes. Kiwi is a nerdlinger and loves the theory of these things, as well as putting it into practice - if he says bigger is better, I'd be inclined to listen. Are you just having a stab in the dark with alleged "logic" or are you prepared to accept that you might not have it 100% correct on this one?

i love it!
BUT
i have to DISAGREE
Smallest you can get away with BUT with enough heat rejection to acheive the required result...

I spent 14months doing engineering consultancy and development work on hybrid CAC systems for http://www.titanresearch.com.au , my last project was for the toyota V8 D4D's.

this is the CAC fitted to a new 70series





flow test and heat calcs, would theoritically rate this in the 800-1000hp range as compared to other manufacturers. It was built as pure overkill, but fits into a std group31 battery location. Max pressure drop across core was <0.51 psi, boost command was outstanding. This setup / unit was tested at the Ford/ACART test lab in geelong and performed amazingly well. Just a shame no-one in the motoring industry has any money anymore .

with a water/air cooler I'd have to agree, however the original question I believe involved a front mount air/air cooler. water/air virtually eliminates charge air flow restriction from the equation, making adequate heat rejection the critical criterion.

[crunk81us]

Why intercool a 100 series @ 14psi?
...
Because they dont like heat, because I will probably want MORE (I suffer from mentally induced power loss)

I love the look of that water to air setup, but I will be doing this myself and therefore want it to be simpler, and without pumps that might fail.

Thanks everybody for all the posts

[KiwiBacon]

The following graph is a Datalog of a 4.2L Patrol driving over a hill & back. Total time is 1min 37 secs. It is an extramely accurate race car logger.
You can see, everthing changes as you change gear, pressures, temperaures etc.
I also have to say that you can go too big with an ic & loose power & response in relation too an optimum size. There is also a difference between a short - high & a wide - low ic,. which has the highest pressure drop ratio. The bigger the 'intake window' (tank height - width), the lower the pressure drop due to lower air speed, BUT, if the core is too long, the drag from all the extra internal surface area will increase pressure drop for very little cooling drop. In very general terms, 1/2 the cooling is done in the first 1/4 of
the core, so the length of the core has an exponential decrease in cooling effeciency.
In my opinion. Regards Richard

Is the boost-in and boost-out on that plot mislabeled? At all the points I checked the boost out is higher than boost in.

[tweak'e]

The following graph is a Datalog of a 4.2L Patrol driving over a hill & back. Total time is 1min 37 secs. It is an extramely accurate race car logger.
You can see, everthing changes as you change gear, pressures, temperaures etc.
I also have to say that you can go too big with an ic & loose power & response in relation too an optimum size. There is also a difference between a short - high & a wide - low ic,. which has the highest pressure drop ratio. The bigger the 'intake window' (tank height - width), the lower the pressure drop due to lower air speed, BUT, if the core is too long, the drag from all the extra internal surface area will increase pressure drop for very little cooling drop. In very general terms, 1/2 the cooling is done in the first 1/4 of
the core, so the length of the core has an exponential decrease in cooling effeciency.
In my opinion. Regards Richard

nice graph.

interesting point about heat soak tho. you can see where the intercooler turns into an interheater. i would assume not a big problem on a petrol motor due to minimal air going through on the back throttle but diesels still flow lot of air though even at part throttle.

so one down side of big IC is the IC acts like a heat storage and puts the heat back into the intake air.
i wonder if a THINNER (but wider) intercooler would be better, bigger frontal aera for the amount of mass of the IC.

[KiwiBacon]

nice graph.

interesting point about heat soak tho. you can see where the intercooler turns into an interheater. i would assume not a big problem on a petrol motor due to minimal air going through on the back throttle but diesels still flow lot of air though even at part throttle.

so one down side of big IC is the IC acts like a heat storage and puts the heat back into the intake air.
i wonder if a THINNER (but wider) intercooler would be better, bigger frontal aera for the amount of mass of the IC.

The file location for that graph says it's a top-mount intercooler. Which accounts for why the heat soak levels out at just below the engine bay temperature at the start of the graph.

[GreyPower]

G/day Guys
I'm amazed some body's taken the time to study the graph, I nearly wasn't going to bother posting.
Two points - Because it's a high end race car data logger, the boost starts at atmospheric which is 1 bar, so it's only maxing at .8 bar or 11.8 psi.
- the terminolgy used is ambiguous. It can be turbo out - plennum in, or intercooler in - intercooler out, which is the opposite.
There are a number of graphs on our website.
http://www.are.com.au/Inter/4x4%20Products.htm
Regards Richard

[Z()LTAN]

i wonder if a THINNER (but wider) intercooler would be better, bigger frontal aera for the amount of mass of the IC.

Thats the way im going with my 1HZ water air cooler

[GUtripper]

i wonder if a THINNER (but wider) intercooler would be better, bigger frontal aera for the amount of mass of the IC.

Thats the way im going with my 1HZ water air cooler

NICE work on the battery clamp there.........

[zagan]

on a diesel without a throttle butterfly, a large intercooler tends to increase lag only in first gear/starting out, but under constant, through the gears acceleration, acts as an accumulator, actually improving response.

bigger = less restriction + more heat rejection. put the biggest you can fit.

But you don't want to be so large that the air doesn't get a chance to drop in temp, maybe the size of intercooler isn't the factor but the size of the piping.