Intercoolers

[Boyko]

Intercoolers are they needed are not? It is true that at some point with a lot of boost you need to control pre-ignition and intercoolers can help. If you are not at that higher boost level then you don't need an intercooler. It is also true that a cooler air charge will help with power. In the winter you already have cool air. If you are going to drive around at 65 like a diesel truck then an intercooler is just the thing. But most of us do something else, we race, and there are some issues with intercoolers.
1. Intercoolers add to the system so there weight but most of all they have more area that the turbo must fill with air, you will always have some turbo lag with an intercooler. Some intercoolers are better than others but all will have turbo lag. Take a look at the top drag racing cars (NO intercoolers). F1 and indy cars no intercoolers. There are many other examples of engines without intercoolers, because there are other and better ways to get the job done than with an intercooler. Some of the ways are really cheap and some are not, but for racing they are better.
2 To reduce turbo lag the intercooler size and piping size must be reduced and this makes the turbo and intercooler less efficient.
3. The effectiveness of an intercooler is dependant on air flow. The better the air ducting (in and out of the intercooler). and the faster you are moving makes the intercooler more or less efficient. In a short bast of acceleration your intercooler does zilch but give you trubo lag. In a longer run your intercooler only gets to working at the end of the run.
3. Out side air temp. is always changing so the effecency of the inntercooler is never the same.
4. I have a hard time thinking that an intercooler stuffed under an RX1 hood with really poor aid flow management works very well.

One thing about racing if you can get extra speed sooner and quicker, like out of the hole, then you can carry that speed all the way to the end. I have not heard of anyone with the Lightinpro Turbo (no intercooler) having problems.

Nealsracing

Thanks Neil lots of good info here, I total agree that you need lots of air moving across the intercooler for it to work properly and the placement in the yamahas does not look to be affective, but in the cooler air they are defiantly helping. sorry I do have to argue a few points

The major cause of turbo lag is not caused by having to fill your intercooler full of air, a 1L engine spinning at 10000 rpm at 80% volumetric efficacy (the r1 engine is well over 90%) is moving 66L of air per second naturally aspirating. Trying to pull air through a smaller intercooler and piping before your boost is up will cause it. Mainly you have to get your turbo spooled up by building heat on the turbine side. F1 cars are naturally aspirating, Indy cars run 100% methyl alcohol, you do not need a intercooler with alcohol even when you mix it with nitro. Pro 5 cars run huge air to water coolers. Intercoolers help make more power and push the limtations of your fuel. Jeffs dyno sheet he has posted on his site claims a 75 degree drop in intake temp through his intercooler, so did he have air moving across the cooler on the dyno? I like my intercooler it is shiny and looks cool I would like a bigger one sticking out of the hood, Maybe next year.


Just my opinion

Boyko

 

[dirkdiggler]

If you have an intercooler you think you need it if you run an Lightning pro Turbo you know you don't need it based on the performance of the RX-1 motor with the LP kit.

There is noting wrong with running an intercooler or not running one. It just kills me that the guys that run tehm have to bag on the LP kit because the kit they use runs a cooler. I can tell you I've watched the LP Turbo beat the sht out of every kit out there that runs a cooler at many local races. The only guy that can beat them is Neon Phil.

 

[Neal Stanley]

Boyko, very good reply, I agree with you, and your post is just an extension of information from my post, very good. I do feel that the basic RX1 intercooler installed in most sleds needs a lot of improvement. The intercooler in most kits works something like this. With you driving your car and the windows cracked a couple of inches, put your right hand straight up in the air then fell the heat exchange. Now put your hand out the window, and fell how it should work. I said that there are better ways to get the job done, and in your post you listed a few, air to water cooler and alcohol. I use water/menthol mix sprayed under high pressure into a mist, just aft of the turbo. It will cool at 5 time the rate of an intercoller and the effectiveness is constant. Tunes very easy and is adjustable when it comes on and how much volume. When I picked the turbo, I went with the Lightning Pro for many reasons. The turbo location is great, it spools very quick and no real lag. The turbo uses carbon seals so there is no problem with oil in the intake. It can easyly do 18 to 20 pounds of boost. It is controlled with an external waste gate. It is a simple system with no issues with the carburetors. oil boots, jetting and so on. Some modifications can easily be amde, such as just bolt on a bigger turbo or carburetor. I know that each system has its good and bad points, but everything you choose is a give and take, gain here lose there. We all just try to make the right choices, but additional understanding really helps when we do make our pick.
Nealsracing

 

[Boyko]

Sounds like a well thought out setup you a running Neil, The problem with the rx-1s is there is just not enough room for a intercooler that will cool big boost. The kits that are around do work but a bigger cooler will have a lot less preasure drop. A Serpico core that is 12 X 8 X 3 will flow 450cmf and is rated for around 320 hp and will be sticking out of your hood. I would like to cut up mine up and anything else in the way to accomadate a larger cooler, I hope it is not one of the projects I daydream about the just does not happen. Does anyone know the preshure drop at 20# of boost I bet it"s going to be big. Well any way I do not claim to be any expert on boost and of corse this is just my opinion.

Boyko

 

[rxrider]

Great info guys, thanks

 

[dirkdiggler]

Until someone messures intake temps on the intake side of the carbs on a Intercooled sled and compairs those temps to the LP kit the arguments are moot.

The benifits of the Lp kit for outweight the benifit of the intercooler.

 

[RunninRX1]

I agree.
Anytime I am tuning a blown (turbo or blower) car, I put thermocouples after the blower/turbo and after the cooler (if it has one). From there, I know what I have to do with fuel and spark and what I can do with boost on a given octane fuel.
If a customer wants to run 20 PSI on pump gas without a cooler.. I'm going to suggest a cooler as I will have to retard his timing so much it's not worth running 20 PSI non-intercooled. 14 PSI non-intercooled might make the same power on his car.
As for the LP kit benefits.. you WILL get to a point where an intercooled setup WILL make more power. I don't know where that point is since I don't have that kit (or any kit for that matter). It's just plain physics.

 

[dirkdiggler]

I agree.
Anytime I am tuning a blown (turbo or blower) car, I put thermocouples after the blower/turbo and after the cooler (if it has one). From there, I know what I have to do with fuel and spark and what I can do with boost on a given octane fuel.
If a customer wants to run 20 PSI on pump gas without a cooler.. I'm going to suggest a cooler as I will have to retard his timing so much it's not worth running 20 PSI non-intercooled. 14 PSI non-intercooled might make the same power on his car.
As for the LP kit benefits.. you WILL get to a point where an intercooled setup WILL make more power. I don't know where that point is since I don't have that kit (or any kit for that matter). It's just plain physics.

the intercooled sled will only make more power if the cooler is working. Most air-to-air intercoolers are only 50-65% efficient. That means for example, that with 11psi boost and its 120°f air charge temperature increase, an intercooler reduces the air charge temperature only 60 degress.

I can tell you the intercoolers on the RX-1 and Apex sleds do not cool at that high of a rate. Most intercooled sleds make the cooler hot to the tocuh whcih tells me they are not being properly cooled!!!!

So your better off using water injection or NOS as a natrual intercooler which can cool the charge.

 

[RunninRX1]

You'd be amazed at how much of a difference 60 deg drop can be and what you can do to the tune to take advantage of it. Even a 10 deg drop in temp is something good.

Don't get me wrong, I'm not saying every kit needs a cooler. All depends on what your doing.

Also be on the lookout for a twin turbo Apex GT

 

[dirkdiggler]

I've seen the beifits of water injection on the dyno. I've also seen the LP turbo on a bad motor make 225hp 5 times in a row on a heat soaked motor. Not sure how many guys have driven a 225hp sled but it's scary fast for trail riding. To much power as a matter of fact!!!

In race form the LP has made as much as 325hp on Freddie Klies dyno. With the small trail turbo.

 

[Neal Stanley]

OK it is just plain physics. The frist law of thermodynamics states that two things put together will seek the same temperature. Then Fourier's Law basically states that the rate of heat flow equals the thermal conductivity, times the area, times the temperature gradient. Looking at Fourier's Law, the nearer the temperature of two things then the less the heat exchange. (hot intercooler, not much heat exchange, and a cold intercooler lots of heat exchange). In a intercooler there are two heat exchange cycles. Heat from the hot gases out of the turbo to the aluminum and then from the aluminum to the out side air. How much heat that is taken out is absolutety determined buy the thermal conductivity of the materials being used (thats why plastic is not used) the area of the intercooler (that why bigger is cooler) and the temperature gradient (that's why intercoolers should be out in front of the vehicle).
On my sled there is about 20 sq inches of vents (on the top) over where let us say an 150 sq. inch intercooler would be. Also when running these vents will be in a low pressure area. (Bernoulli's Law). Get the picture.
You should put some thermocouples on and prove that winters cold temp. is all that is needed, but at the end of the day I think you will be in for a shock. I think you guys already know, because your intercoolers get hot.
Nealsracing

 

[Boyko]

Ok, so your intercooler is hot and some think it is not working because of this. Now your flying down a lake with your buddies way behind ya and you happy because your fast and you know it, your boost gauge is pulling some good numbers that only you can brag about after you wait for your unboosted friends to catch up. Let say your comperessed air comming out or you turbo is 275 degrees and say your intercooler is pulling 75 degrees of heat out of you intake charge, your intake temp at the carbs is 200. So the intercooler is hotter than boiling water but it is still helping you. Of corse as stated earler you have to get some probes into the system to measure it. My concer would be having a preasure drop were air coming out of the turbo is at 30# and only making 22# of boost. This is bad because now your compressor side of your turbo is at 30psi and your turbine side is going to be higher than 30psi. And your poor exhaust is paying the price weather it is a header or your stock yamaha manifoilds on a rearmount, its getting realy hot. This is where you are stealing power from the motor to spin the turbo kind or like a belt on a suppercharger there is no such thing as free power on a boosted motor. At this point you are making lots of uneeded heat. I am not saying that this is happening to the systems out there but untill someone can post some numbers on tempature drop and preasure drop at a given boost on a speciffic system it is hard to say how effetive that intercooler is. Im pretty certain for this application that running 12 of boost on the systems out there it is worth having.

This is just my opinion of corse please correct me if I'm wrong.

Boyko

 

[dirkdiggler]

Ok, so your itercooler is hot and some think it is not working because of this. Let say your comperessed air comming out or you turbo is 275 degrees, now your flying down a lake with your buddies way behind ya and you happy because your fast and you know ,your boost gauge is pulling some good numbers that only you can brag about after you wait for your unboosted friends to catch up. Lets say your intercooler is pulling 75 degrees of heat out of you intake charge and your intake temp at the carbs is 200. So the intercooler is hotter than boiling water but it is still helping you. Of corse as stated earler you have to get some probes into the system to measure it. My concer would be having a preasure drop were air coming out of the turbo is at 30# and only making 22# of boost. This is bad because now your compressor side of your turbo is at 30psi and your turbine side is going to be higher than 30psi. And your poor exhaust is paying the price wether it is a header or your stock yamaha manifoilds on a rearmount. This is where you are stealing power from the motor ot spin the turbo kind or like a belt on a suppercharger there is no such thing as free power on a boosted motor. At this point you are making some uneeded heat. I am not saying that this is happening but untill someone can post some numbers on tempature drop and preasure drop at a given boost on a speciffic system it is hard to say how effetive that intercooler is. Im pretty certain for this application that running 12 of boost it is worth having.

Just my opinion

Who's kit do you have?

 

[Simons CPR]

you should get some testing equiptment and end this insanity. opinionated discussions like this just tend to muddy the water and confuse people who are trying to learn. we have done our own testing and i will tell you this....most of the people in the snowmobile performance business are all talk and no facts, reguardless of how smart they may sound, they know little more than whats been posted on this site from another source, they take that knowledge and consider themselves "experts" spewing their interpetation of that knowledge as facts....some are smarter than others, but as a general word of caution, buyer beware... so far i have just talked like many do...the fact is we ran a 7.97 sec 1/4 mile at 170 mph. here is a link to that run, http://media.putfile.com/cpr797 it is a full race turbo rx-1 we set that record with, we used nos to spool the turbo for a quicker holeshot. the nos is not used the rest of the run, it is not needed, the engine produces 550 hp without it. to get to where we are it took years of testing, and over 100,000.00 dollars in development costs. there are some of the facts you may need, to determine my credibility. my full time job is turbo development. for those who are saying the intercooler gets hot during run time and is no longer useful, you should rethink your position...lets reveiw this... intake charge is close to 300 degrees, outside air is 30 degress, if the intercooler is in the middle transfering heat from one to the other, just how "cool" do you think it would be???? if its cool its not doing anything and is not needed in the system, its hot because heat is continually passing through it. if its hot its working. its hot because its transfering the heat from the presurized air to the outside air... understand now. the human hand can withstand around 140 degree surface temp without major discomfort. so if you can keep your hand on the intercooler i would say its working better than not having one. here is an experiment you can do at home with your car....engine water temp is 200 degrees, outside air is 70 degrees, go drive your can for 5 minutes, get out and grab your radiator, "holy #*$&@ thats hot" you'll say. i guess its not working. now pull it out and drive home, the results will not be good. lol. others are entitled to their opinions, if you don't want an intercooler don,t run one. just make sure you are working with proven facts, not sales fiction. jeff

 

[dirkdiggler]

you should get some testing equiptment and end this insanity. opinionated discussions like this just tend to muddy the water and confuse people who are trying to learn. we have done our own testing and i will tell you this....most of the people in the snowmobile performance business are all talk and no facts, reguardless of how smart they may sound, they know little more than whats been posted on this site from another source, they take that knowledge and consider themselves "experts" spewing their interpetation of that knowledge as facts....some are smarter than others, but as a general word of caution, buyer beware... so far i have just talked like many do...the fact is we ran a 7.97 sec 1/4 mile at 170 mph. here is a link to that run, http://media.putfile.com/cpr797 it is a full race turbo rx-1 we set that record with, we used nos to spool the turbo for a quicker holeshot. the nos is not used the rest of the run, it is not needed, the engine produces 550 hp without it. to get to where we are it took years of testing, and over 100,000.00 dollars in development costs. there are some of the facts you may need, to determine my credibility. my full time job is turbo development. for those who are saying the intercooler gets hot during run time and is no longer useful, you should rethink your position...lets reveiw this... intake charge is close to 300 degrees, outside air is 30 degress, if the intercooler is in the middle transfering heat from one to the other, just how "cool" do you think it would be???? if its cool its not doing anything and is not needed in the system, its hot because heat is continually passing through it. if its hot its working. its hot because its transfering the heat from the presurized air to the outside air... understand now. the human hand can withstand around 140 degree surface temp without major discomfort. so if you can keep your hand on the intercooler i would say its working better than not having one. here is an experiment you can do at home with your car....engine water temp is 200 degrees, outside air is 70 degrees, go drive your can for 5 minutes, get out and grab your radiator, "holy poop thats hot" you'll say. i guess its not working. now pull it out and drive home, the results will not be good. lol. others are entitled to their opinions, if you don't want an intercooler don,t run one. just make sure you are working with proven facts, not sales fiction. jeff

With all this vast Turbo Knowledge you have You'd think that you'd provide the data yourslef and end "this insanity" as you say. I don't think anyone here is saying Intercoolers are bad. I think they are saying nonitercooled isn't as bad as some would like to pretend it is.