Intercooler theory and sizing debate

[rchalmers3]

According to several posts all over the web real world observation on EGT's show that an intercooler reduce EGT's by 1-200 degrees fahrenheit.

Christian, what is the relationship of EGT to engine coolant temp? And what happens to turbo effectiveness by lowering the EGT's?
I thought having the turbo receive hot, expanded gasses was a benefit???

Most people I have seen here are considering a intercooler not for lowering EGT's, but more for lowering the charged air temperature. Maybe you can explain this to me and help me understand your point of view.

However while the front of the truck may seem very compact, the tunnel where the radiator sits is almost 3 feet deep, before you reach the engine. So there is a lot of room actually.

That's great! Your intercooler and radiator will be well protected. I recommend installing your intercooler with an electric fan with temperature operated or constant fan, for those times when you are crawling overland and not pushing so much air!!!

We are actually planning to use the internals of the R150F paired with a 5th gear from a R452 thus geatting a 0.7:1 fifth gear. With Michelin XZL 11/16 tires we will be doing 37 km/h at 1000 revs in fifth.!

Christian, are you including the differential and portal gear ratios? What will your kmph be at 2200rpm? This is an important number, as the motor makes maximum torque here.

Looks really good! Who will make your fibreglass house?

Rick

 

[Stone]

I was told that water cooled intercoolers were only effective in short runs because the coolant circulating starts to warm up after a while and cooling efficiency significantly decreases. Over long runs, the air to air intercooler is supposedly still the way to go. Case in point...dragsters have water cooled intercoolers, but obviously they run for only short bursts. Is there validity to this? Seems to make sense to me...

I'm a bit hesitant to come up with an intercooler solution myself...I don't think the "going with the biggest one you can fit" method is a good way to go. If turbo lag becomes an issue with a poorly planned intercooler setup (or negligible cooling in the case of a cooler too small), then not having an intercooler and just having the factory setup would be better.

 

[R2HKS]

I was told that water cooled intercoolers were only effective in short runs because the coolant circulating starts to warm up after a while and cooling efficiency significantly decreases. Over long runs, the air to air intercooler is supposedly still the way to go. Case in point...dragsters have water cooled intercoolers, but obviously they run for only short bursts. Is there validity to this? Seems to make sense to me...

The reason that drag cars use water to air is because they use dry ice to get the charge air temp below ambient.

A small radiator is all that is needed to keep the water cool ie not much above ambient. a 4 cyl radiator is overkill.

To the OP what don't you like about water to air? Are you worried about it leaking into the engine or possibly damaging the water to air rad? If you say you have that much space up front then a small radiator out front and running the coolant lines to the water to air cooler will be so much easier than having to plumb in and air to air. Intake temps will be lower and you won't have to do be doing 70km+ to get any kind of benefit out of an air to air.

 

[Christian]

Christian, what is the relationship of EGT to engine coolant temp? And what happens to turbo effectiveness by lowering the EGT's?
I thought having the turbo receive hot, expanded gasses was a benefit???

Most people I have seen here are considering a intercooler not for lowering EGT's, but more for lowering the charged air temperature. Maybe you can explain this to me and help me understand your point of view.

I cannot give you a good explanation. That's why I started this thread. I am only reffering to other threads listing other peoples observations. But you are right, the main reason for adding an intercooler is to lower the charged air temp. But in doing so logic suggests that you remove some heat from the engine bay.

That's great! Your intercooler and radiator will be well protected. I recommend installing your intercooler with an electric fan with temperature operated or constant fan, for those times when you are crawling overland and not pushing so much air!!!

I am planning on fitting the biggest electric fan possible. Another reason for doing so is that the original fan on the Volvo is driven by a driveshaft from the waterpump to the mechanical fan. The original design called for this because of the distance between the enigine and the radiator. Eventhough the system works it is a notorious source of noise.

Christian, are you including the differential and portal gear ratios? What will your kmph be at 2200rpm? This is an important number, as the motor makes maximum torque here.

Looks really good! Who will make your fibreglass house?

Rick

Jep! The speed at 2200rpm will be between 70 and 82km/h or 43 and 51 mph depending on tyre size. We will be building the camperbox ourselves using NidaCore panels.

I was told that water cooled intercoolers were only effective in short runs because the coolant circulating starts to warm up after a while and cooling efficiency significantly decreases. Over long runs, the air to air intercooler is supposedly still the way to go. Case in point...dragsters have water cooled intercoolers, but obviously they run for only short bursts. Is there validity to this? Seems to make sense to me...

That is exactly what I've heard and read. The article mentioned in top supports this when stating that a diesel intercooler works harder and more of the time than a gas one. This relates to the "heat-sink" argument.

I'm a bit hesitant to come up with an intercooler solution myself...I don't think the "going with the biggest one you can fit" method is a good way to go. If turbo lag becomes an issue with a poorly planned intercooler setup (or negligible cooling in the case of a cooler too small), then not having an intercooler and just having the factory setup would be better.

That could be true. However I have consulted a good friend and excelent mechanic i know. And the advise I got was to stop speculating, pick one and fit it - of course when picking it consider the size of the ones originally fitted by Toyota to these engines.

The reason that drag cars use water to air is because they use dry ice to get the charge air temp below ambient.

A small radiator is all that is needed to keep the water cool ie not much above ambient. a 4 cyl radiator is overkill.

To the OP what don't you like about water to air? Are you worried about it leaking into the engine or possibly damaging the water to air rad? If you say you have that much space up front then a small radiator out front and running the coolant lines to the water to air cooler will be so much easier than having to plumb in and air to air. Intake temps will be lower and you won't have to do be doing 70km+ to get any kind of benefit out of an air to air.

Your last point is absolutely true. And I am considering that option now. But my main points of reluctance towards water to air is;

1. I haven't seen it used by that many factories. So it seems a bit "exotic"
2. It adds complexity and weight
3. It is much more expensive. I can get a really desent air/air for 1 - 200$. The water/air systems i have seen have been above 1,000$

An in my mind a well executed setup with an air/air with an electric fan seems to be at least just as efficient all in all.

To all of you, I am very grateful for your input. Having to question my ideas and reconsider many of them is a great excercise. I hope I don't come over as overly protective of "the original design" and not willing to take your inputs in to consideration.

 

[rchalmers3]

I cannot give you a good explanation. That's why I started this thread. I am only reffering to other threads listing other peoples observations. But you are right, the main reason for adding an intercooler is to lower the charged air temp. But in doing so logic suggests that you remove some heat from the engine bay.

Hi Christian, if you have only nebulous ideas, I advise you to save your $200 and time. If you have no specific parameters you are trying to achieve with engine power output, then adding an intercooler will be only an exercise in "cool factor". (of the social type)

If you are planning to increase engine performance for specific power gains, then you will be able to tell us the boost levels of the charged air required and the calculated temperature rise.

Only with this information we can discuss the need for an intercooler and it's shape and size. Otherwise, you may as well pick a pretty one and make it stick out the front where everybody can see it!!!


Dougal has already offered the opinion you will not need an intercooler at stock boost levels. I agree with him and wonder why he encourages a retro fit of one regardless. Dougal?

Jep! The speed at 2200rpm will be between 70 and 82km/h or 43 and 51 mph depending on tyre size. We will be building the camperbox ourselves using NidaCore panels.

Perfect! You will have power and accelleration to run 100 kmph if you want without over-revving. The original designers of the Volvo will be jealous! I look forward to your project details and success!

To all of you, I am very grateful for your input. Having to question my ideas and reconsider many of them is a great excercise. I hope I don't come over as overly protective of "the original design" and not willing to take your inputs in to consideration.

Christian, thank you for sharing your fun and adventure! Participating in this forum has let me see you making new things out of your 60 series, move in with your girlfriend (I was peeking) and purchase the Volvo for this wonderful project. I am glad to complete my day and get on the computer to look at what you are working on.

Best wishes to you in your life and on your projects.

Rick

 

[lshobie]

I agree with Dougal, if you are running factory boost then don't bother with an intercooler, if you think an intercooler is going to prolong the life of the engine then I also think you are wrong because if you run an intercooler then you will need to up the boost in order to make it efficient - thus you put more strain on the engine. Also, putting a fan in front of your intercooler is a waste of time and could actually degeat what you are trying to accomplish. The intercooler needs air flowing over the whole surface in order to make it runner better, stic a fan in front of it and you are going to block off parts of it so it will be less efficient at highway speeds.

Also, not sure if it has been mentioned but when you use air/air piping you can add 10 feet of theoretical piping for every 90 degree bend - so work out the bends and restrictions before you just work out how "efficient" the intercooler would be. If you run water/air then it should be more efficient for that reason alone.

I have an air/air intercooler in my HZJ79 right now, I am swapping a new PWR 4X10 barrel type water/air intercooler in its place shortly. The air/air works great with ram air at faster speeds but no good for slower climbs and pulling. I also need the space under my hood for dual batteries, dual arb air compressors, new albright winch solenoid etc etc - the air/air piping take up too much room.

REgards,

Louis

 

[Stone]

Hmm...some excellent points. I think at this time, I'm going to leave the Intercooler idea alone and run my 12H-T factory. With my freshly rebuilt (oversized bearings) and ceramic coated CT26, I don't have any plans of increasing the boost significantly over factory.

 

[Dougal]

I cannot give you a good explanation. That's why I started this thread. I am only reffering to other threads listing other peoples observations. But you are right, the main reason for adding an intercooler is to lower the charged air temp. But in doing so logic suggests that you remove some heat from the engine bay.

In addition to cooling and increasing the density of the charge air, the heat removed by an intercooler is heat the engine doesn't have to shed by any other means.

With 10psi on a 3 litre engine at 3000rpm you're only going to lose about 3kw worth of heat through an intercooler (inlet 87C, exit 47C). If that 3kw went into the engine maybe 30-40% of it would exit through the cooling system.
If you cooling system is within 1kw of the capacity that things start to overheat then you've got bigger problems.

 

[Christian]

Christian, thank you for sharing your fun and adventure! Participating in this forum has let me see you making new things out of your 60 series, move in with your girlfriend (I was peeking) and purchase the Volvo for this wonderful project. I am glad to complete my day and get on the computer to look at what you are working on.

Best wishes to you in your life and on your projects.

Rick

Thanks for the very kind and flattering words! I am truly grateful and humbled that what I do is of interest to others! (it might not be the best formulation but I hope you understand what I mean)

Ishobie:
I would place the electric fan behind the radiator, thus having the air drawn through the intercooler first, then through the radiator. Hence the fan would only influence airflow when needed the most; when there is no ram air effect.

So, What I think I can sum up from all of you is:

1. If the rest of the engine is kept stock, an intercooler will not yield any benefits. Actually the increase in resistance and the inherent drop in boost level reaching the intake side may actually impede performance.
2. An intercooler will not prolong engine life. If placed so it restricts cooling in any way, it will decrease engine life.
3. Water to air might, in spite the added complexity, be the best way to go.

In my original post I stated three goals I wanted to gain from adding an intercooler:

1. The 1KZ-T has a reputation for cracking heads. This is usually because the engine runs too hot, adding an intercooler might help.
2. Keeping engine bay temps down. the Volvo being a cab forward design, there's a possible heat build-up under the cab where the engine sits. adding an intercooler might help that.
3. Getting a few more ponys...

The conclusion from your input must be that the only goal an intercooler can fulfil is 3: Getting a few more ponys, but only with additional tweaking boost-pressure etc.

After having read, an in some cases re-read, on several other forums I have seen that those who experience gains in adding intercooler on these engine have also added a more free-flowing exhaust, including the elbow on the turbo. Some have increased boost-pressure too.

I will make a more free-flowing exhaust, and have removed the exhaust elbow weeks ago because i thought it looked like a bottleneck. And it is! The diameter is 44mm or 1.7". According to a rule of thumb I have heard, the downpipe should have the same volume as the engine contained in the first 50cm or 20". That means that the diameter should be around 88mm or 3.4". Doubling the diameter makes the area, and thereby the flowcapacity 4 times bigger.

Maybe I should go for number three, more ponys...? The engine we got it the 1KZ-T with the lowest power/torque ratio, so there's a opossibility to gain some, eventhough this is the non-ecu version. But it might be at the expense of the head. So it might be worthwhile to change the head before such alterations.

What does the panel think?

I know some of you have questioned the cooling ability of the Volvo. Having re-read the thread and looked at the pics I have included I can understand why. The tiny grille makes it look like there's no room for a radiator at all.
So here's a more clear picture of the front:

As I have indicated there's free airflow from beneath the bumper too.
The original radiator is 52 x 57 cm or 20.5" x 22.5"

 

[syche]

Hi Christian

I owned for 6 years and up to 250 000km a KZJ73 fitted with this engine. Early 1994 version like mine had the injection pump gear issue due to poor bolts quality and too low torque, Fixed from 95.
Also in 95, upgrade in the head. The biggest reason for head cracking is, or was, that the hole through the head for the stud bolts where too narrow, and when it heated up, the alu expended and touch the studs, creating froce and finally cracking the head.

But over everything, the difference is the driving. The KZT engine is a very powerfull and extremelly torquy engine. A fantastic base for offroaders, but at the time it came out, it was also the only one that was pulling like a GTI car, and peoples were driving it wrong.
One this this engine hate...highway with more than 3000RPM rev. This for 5 or 600km, will give you a head. Max permanent rev for this engine 3000 3100 rpm and you are out of troubles.

Mine was seriously upgraded, turbo pump timing, got about 150/160hp out and a big torque. I used the low gear only to pull my friends out when we are in african trips. all dunes in 1 and 2 long, and easy.
Never any over heat problems.

Loaded for 1 month trip, 16 000km in a month, only thing not working 100% perfect...the water spray switch due to dust..

I had the same idea to fit this engine a volvo like you, but they are extremely hard to find now, so i went for a lc 80.

For the cooling, air outlet is more important than air intakes. you need more surface for the air to escape than to go into your cooler to ensure a good flow.

Intercooler, i would go for a water to air, one guy in france did with a PWR 4x6 prety good result. But frozenboost do some good stuff for much cheaper.
If you can, get a factory cooler from a kzj 7 series, you can't go wrong.

Again, very good engine, just take care of it and do not hesitate to tune it up a little. But get this done by a good guy. Mine, timing advanced 4 degrees, turbo 900gr (no intercooler, with it, 1kg or 1.1kg) and change the LDA in the injection pump, in europe you can get ADONIS kit, pricey, but Huge, without cooler, 160HP mini, up to 210. Keep about 160 with intercooler you will be fine.

I have a frind in DK with a runner KZT engine, he is even before upgrades.

Have fun

 

[syche]

I forgot 2 things.
-On your truck i would add an extra oil cooler witha sandwich plate on the filter block.
-for the down pipe and exaust piping, don't look too far in size, the factory one is ok. Just keep in mind a turbo need back pressure in the exaust to really give you the best. Freeflow is far to be good a mid rev and heavy pull. You can find some glaspack exaust system. they are really efficient, you keep the low rev fast response and increase the mid and high rev torque and hp.
We have try a lot of things on this kzt engine, and all did not work

 

[R2HKS]

Just keep in mind a turbo need back pressure in the exhaust to really give you the best.

Back pressure in the exhaust for a turbo, you have to be kidding? Normally aspirated engines need back pressure in the exhaust system but for a turbo you want 0 back pressure. All it will do in a turbo engine is slow the turbo spool up.

You want a free flowing exhaust system with as little back pressure as possible and a free flowing turbo muffler (or none at all). A regular NA type muffler will create back pressure.

Back pressure for turbo's is not good.

 

[Christian]

Hi Syche

That sounds good!

You wrote that you put an 80 in to a Volvo, I would really like to know more about that.

And what you have done to your KZJ. And pictures please!

I found the Adonis technologies website, but I don't understand french, so I'm lost and don't know what they offer?

Where are you from and who do you know here in Denmark?

 

[Christian]

Back pressure in the exhaust for a turbo, you have to be kidding? Normally aspirated engines need back pressure in the exhaust system but for a turbo you want 0 back pressure. All it will do in a turbo engine is slow the turbo spool up.

You want a free flowing exhaust system with as little back pressure as possible and a free flowing turbo muffler (or none at all). A regular NA type muffler will create back pressure.

Back pressure for turbo's is not good.

Exactly what I have heard and read everywhere..?

 

[Dougal]

Hi Christian

I owned for 6 years and up to 250 000km a KZJ73 fitted with this engine. Early 1994 version like mine had the injection pump gear issue due to poor bolts quality and too low torque, Fixed from 95.
Also in 95, upgrade in the head. The biggest reason for head cracking is, or was, that the hole through the head for the stud bolts where too narrow, and when it heated up, the alu expended and touch the studs, creating froce and finally cracking the head.

If they did update the head in 95, it wasn't the final fix. Late 90's 1KZ's still crack heads.

Here's a forum full of them, worth a read.
3.0 Turbo Diesel - Hilux Surf Forum

I would replace the head before fitting the engine. Seriously.

 

[syche]

Hi all,

Yes in 95 the head has been improved. Some peoples still had issue, but for most of them it is due to bad use, or cheap head replacement, a lot of cheap head are ont he market and they are crap..
Mine and many others i know, have over 250 000km without problems. highway with high rev kill it.

Regarding the back pressure, i knew you would react this way as i rode a lot here and in australia.
I tryed 3 type of exaust and a lot of test has been done here in france arround that too.

Factory, not that bad but very restricting.

Short side exaust freeflow: Very noisy, very good response from 800 to 1200rpm, but going up slope on road or sand you have...80HP.

Long free flow with a rally none turbo 60cm muffler ( inner tube 63mm, outer 100, the 63 tube is driller all the way and special fiber inserted between the 2 tubes). Little less noise, but still very much. Idem short side free flow for the turbo, a little better on sand and up hill, but far to be good.

And the final set up, was a short counter pressure muffler on the right side. Gain huge, tubo response perfect, and high power all the time.

Since some of ours guys from the forums tryed and test them, we all run thoses now, they are cheap and exellent. the inertube of this special muffler got small scoop to catch a part of the flow and and creat the back pressure. You keep at low rev the turbo response, and at higher rev you keep your power.

I did not believe in it at the first time. One of my friend is engine designer, he worked for some french company devlopping combustion, injection and turbo set upf for 1.9 and 2 liters new generation engine. He told me with out the right back pressure i won't get the best of my turbo as it will not have any torque on the wheel. The turbo work with the airflow, but also and we forget it, the air pressure in exaust.
I know you are going to laught of it, but , jut try it.

Christian, no i did not go for the C303 or 306 as i could not find any of them. Have to go to DK or Sweeden for that and i have no adress there to find a good one.
So i went for an old but in a good shape HDJ80 GX witch i am upgradin now.
My first work will be on the engine. even it as the 4.2L turbo, it is very far to be as fun and torquy as my KZT engine was.
I need to work on the turbo (hybrid T3/T4) intercooler (small air air or water to air) injection pump and replace the muffler for a glaspack (it already has a stainless steel well made piping).

For exaust an other very good adress in france is "Techinox", they have a website and speak english. You would be surprise of the piping diameter...why is it so small...keep some pressure in it.

For the moment i mis my KZT engine. I look forward to finish my HDT upgrade to find again a nice torquy and quick response engine.

Christian send me a PM, so we can change mail i will find some pics for you, and help you for some translations if you need.

Regards to all

 

[rchalmers3]

I am swapping a new PWR 4X10 barrel type water/air intercooler in its place shortly.

Louis, it's show time. We need pics of your cooling set up. Best to do so on a new thread.

Rick

 

[rchalmers3]

I tryed 3 type of exaust and a lot of test has been done here in france arround that too.

Hi syche, Did you receive test results for us to review? I would like to see a demonstration of how exhaust restriction increases turbo efficiency. Thank you for speaking to us about your experiences, I look forward to more technical information.

Bon jour

Rick

 

[syche]

Result is value as experience. i don't know for you in US or Ausi but in France we don't have much dino tester, and acces are very restrited.

So i cannot give you a dino test. But i had some high way slope that where tough enough to get me down from 120km/h to 80 with a freeflow, and with the right exaust, i kept the 120 and had more to come, but i never drive over 3100rpm, so i kept them spare

You can just look at all the race toyota 4wd used on Dakar race, they don't use big exaust, have a small muffler and get hell of power and torque even with the race regulation restrictor on it (to mount on intakes after turbo).

To charge your intakes, the cold wheel from your turbo need speed for the flow, but need torque for the charge. And the torque is a result of pressure on the hot wheel.
It is a big compromise to find. As amateur we are not having the best result, but we are getting closer with the exaust i mentioned. It is working a little like P=UxI in electricity. P power, I curent is the picture of torque for an electric motor.

Also one funny thing, i have been told several time, that the NA engines need free flow exaust to flush the gaz faster. Rally NA cars exaust are actually design this way.

Now this is my experience and the one of many others down here using KZT engine.

Regarding overheat..i have no experience of it on Runner (surf for you i think) but on 7 series, no problems at all. Even in mauritania, full loaded, no IC, 950gr boost in soft sand.

I can even add a point, the last african trip was with 2 kdj 9 seie, so the same engine but D4D new generation and 2 KDJ 120, same engine again. Factory spec is about 165 HP and much more torque than my upgraded KZT.
In practice, they could not use long gear as the torque is placed much higher than the old design engine, due to polution management preventing extra fuel a at mid and low rev.
They were 2nd, 3rd low, 2 to 4000rpm, i was 1,2, 3 long, 800 to 2000rpm.
They used for the 1000km sand and rock loop off tracks (no fuel station) 30 to 40% extra fuel compare to me and a mate with his 80. They got my extra jerrycans. An other trip wit an auto gearbox was getting carsy on fuel, +50%, and he did not plan it, so, we had to seriously shorten the trip

Same thing happen between an old HDT 80 12v with 345 000km and a recent HDJ 100. Also had to transfer fuel.

On the paper the torque on the new engine are very interesting, but in the field, or, on the track it is an other story.

But back on road....they drive 30 to 40km/h faster for the same fuel as we do with our old burner.

Now i let you guess witch car pull the other out of sand all the time.....the old toys are unbeatable for that.
Hj61/ KZJ 7 serie/ HZJ and HDJ 80 (kings of africa). followed by HDJ 100 then KZJ 9 serie, KDJ 9 serie and then KDJ 12 serie.

You reverce the list and you have the top 8 on road

 

[Dougal]

Yes in 95 the head has been improved. Some peoples still had issue, but for most of them it is due to bad use, or cheap head replacement, a lot of cheap head are ont he market and they are ****..
Mine and many others i know, have over 250 000km without problems. highway with high rev kill it.

The vehicles I know of were original toyota, not cheap head replacements.
Why do you keep saying that high revs will kill it? High revs certainly accelerate wear, but something is badly wrong if an engine will die from that alone.

As for bad use, well a heavy 6x6 vehicle will give it exactly that. Overheating doesn't seem to be the cause of these head issues.

So i cannot give you a dino test. But i had some high way slope that where tough enough to get me down from 120km/h to 80 with a freeflow, and with the right exaust, i kept the 120 and had more to come, but i never drive over 3100rpm, so i kept them spare

That is a huge power difference you are talking about there. To run at 120km/h up what was an 80 km/h hill takes more than 50% more power.
An exhaust would have to be virtually plugged to cause that much difference.

To charge your intakes, the cold wheel from your turbo need speed for the flow, but need torque for the charge. And the torque is a result of pressure on the hot wheel.

The torque on the turbine is the result of the pressure difference, heat and mass flow.
Without exception, more pressure downstream of the turbo will hinder it's operation.
The only time a manufacturer would spec a minimum backpressure is to avoid overspeeding a very small turbo. This isn't a performance issue, but a reliability issue.

I can even add a point, the last african trip was with 2 kdj 9 seie, so the same engine but D4D new generation and 2 KDJ 120, same engine again. Factory spec is about 165 HP and much more torque than my upgraded KZT.
In practice, they could not use long gear as the torque is placed much higher than the old design engine, due to polution management preventing extra fuel a at mid and low rev.
They were 2nd, 3rd low, 2 to 4000rpm, i was 1,2, 3 long, 800 to 2000rpm.

I have found the opposite. The 1KD engines with their variable vane turbos have far superior low and midrange torque to the 1KZ. The reason they use more fuel offroad is simple, they have more power and the drivers use it.

Same deal with the 100 vs 80. The 100 can burn a lot more diesel if you want it to. Despite being in a bigger and heavier body, the 100 burns similar amounts of fuel to an 80 driven at the same speed.