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Engine Specific Info and Questions => IDI Engine => Topic started by: docadillac on June 23, 2009, 02:12:00 pm
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I've read a number of different threads in which intercoolers are installed on turbo diesels. At what horsepower does adding an intercooler become necessary? If let's say using a 1.9 head with an ALH intake and a K24/26 hybrid turbo on a 1.6 block or is this even the right question??
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An intercooler is always a good idea as far as I'm concerned. They give your engine cooler, denser, more consistent charge air to work with. The result is more power, usually better economy and less wear on your engine through lower exhaust temps. The only real drawbacks could be seen in cost and turbo lag (depending on the setup).
That being said: At stock boost levels (8-10psi) it's probably not all that important. However, every time you push the boost higher, it will become more important.
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Cooler air will result in more torque specifically as well.
Cooler = denser = more O2 present = more lovely Diesel get's burnt per stroke.
NO2 will also yield a similar effect ::)
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I agree. Hot air is not the friend of your engine. The cooler the charge, the more thermodynamic efficiency you will get. Aircraft have take-off limits that are affected by the air temp (and pressure) at the airfield they want to leave. IMHO, turbo lag is only an issue if you want to race someone / something...
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Thanks everyone for the replies. I was hoping to avoid using an intercooler but I guess I'll have to figure out what size is needed and where to mount it.
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An intercooler with no other mods will not increase power. Its primarily to reduce combustion temperatures, allowing for more fuel to be injected safely and for longer.
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i have to agree that with stock boost levels the intercooler isn't too important, but it can make a difference. on a real hot day electronically controlled diesels can limit the fuel to decrease smoke, but for the mechanical crowd, we need to find other ways to achieve the same thing.
at first i didn't think an intercooler would help much, but i drove a 1.6TD with 20 psi boost and upped fueling.. it was a hoot! the car had so much more power than my similar setup, and what got me was when i popped the hood and felt it. i nearly burnt my hand!!! thats how you know these things work. they can get so hot that an auxiliary cooling fan would be a great idea when you come to a stop light, to reduce heat soak. that is why i'm partial to an air/water intercooler setup.
the perfect air/water intercooler setup IMO is to have a thermostatically controlled cooling pump, controlled by the air exiting the intercooler (30-40C should be a good trigger). the coolant is then sent to a radiator up front with either its own fan or somehow rigged up instead of the a/c condensor or however someone can rig it up (very creative people out there). then the radiator would work like the engine coolant radiator and have a thermoswitch to control the fan. as an added bonus, the air water intercooler will give less turbo lag and pressure drop in addition to the large amounts of heat it can dissipate.
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Someone here mentioned turbo lag from and intercooler, i seem to have quite a bit of turbo lag on my gtd which has a stock intercooler what can i do to remedy this or is it just something i will need to get used to,
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I too agree that an IC is not a good choice for bolt on performance without already having some modification.
I have a ported/polished AAZ (a 1.9 litre head) head on my 1.6. My turbo (garett T3) is set to limitless psi but i have the fueling set to not go above 25 psi except for on really long pulls. I have did a govenor mod and the LDA (the space ship thing on the injection pump) is set to the max fueling setting.
I still don't have an IC (intercooler).... but when you're boosting above 10 psi it's nice to keep the EGT's (exhaust gas temp.) below 1,200 which is NOT what's happening with me. I see 1,200 frequently at WOT(wide open throttle) even with 2.5 inch straight pipe exhaust from the turbo back.
The only time turbo lag (in my honest opinion) is an issue is if you're running a turbo way too large to be on your engine OR if you want that fast of a response perhaps you shouldn't have started with a 1600cc diesel :P
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Someone here mentioned turbo lag from and intercooler, i seem to have quite a bit of turbo lag on my gtd which has a stock intercooler what can i do to remedy this or is it just something i will need to get used to,
water/methanol injection. NOS. Two turbos. 1 small turbo to spool 1 very large turbo.
If you really don't care about the engine - Propane.
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smaller intercooler piping might help spool up aswell...?
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the perfect air/water intercooler setup IMO is to have a thermostatically controlled cooling pump, controlled by the air exiting the intercooler (30-40C should be a good trigger). the coolant is then sent to a radiator up front with either its own fan or somehow rigged up instead of the a/c condensor or however someone can rig it up (very creative people out there). then the radiator would work like the engine coolant radiator and have a thermoswitch to control the fan. as an added bonus, the air water intercooler will give less turbo lag and pressure drop in addition to the large amounts of heat it can dissipate.
It would be better to have it running all the time the engine is. Engine bay heat will continue radiate into the intercooler water even with no boost. The closer the water is to ambient the more effective it will be. A water pump drawing 1-2 amps continuous power isn't worth having to switch on/off frequently.
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the perfect air/water intercooler setup IMO is to have a thermostatically controlled cooling pump, controlled by the air exiting the intercooler (30-40C should be a good trigger). the coolant is then sent to a radiator up front with either its own fan or somehow rigged up instead of the a/c condensor or however someone can rig it up (very creative people out there). then the radiator would work like the engine coolant radiator and have a thermoswitch to control the fan. as an added bonus, the air water intercooler will give less turbo lag and pressure drop in addition to the large amounts of heat it can dissipate.
It would be better to have it running all the time the engine is. Engine bay heat will continue radiate into the intercooler water even with no boost. The closer the water is to ambient the more effective it will be. A water pump drawing 1-2 amps continuous power isn't worth having to switch on/off frequently.
forgot to add that i would use a very high flow pump. those shurflo pumps draw quite a bit don't they? i was thinking like 10 amps. that thing would super cool the intercooler :) it might also be good to insulate the cooler lines coming from the rad, and the intercooler unit itself.
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That's a lot of info guys. Thanks much. I am trying to picture what it is and how it would plumb into the stock cooling system. Thanks for the 10lb.+ tip on temperatures. If I've got this thinking right it would be to mount the intercooler in front of the radiator. It already has a dual fan set-up that kicks in with the temp. switch at around 87 degrees c. I am trying to imagine the plumbing route for the lines to and from the intercooler ie under and around the engine or?? Then what size intercooler and how do you calculate it properly. Does anyone have pics on this set-up?? Great replies so far thanks again all.
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INTERCOOLERS ARE SO IMPORTANT.
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An air/water intercooler should be completely separate from the engine's cooling system.
This is how Toyota did it.
(http://opc.mr2oc.com/online_parts_catalog/st165_intercooler.gif)
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An air/water intercooler should be completely separate from the engine's cooling system.
very true! but i do recall some large trucks using the engine coolant to cool the intercooler... would probably help a lot in colder climates though!
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ive got an aaz and i put a mk3 tdi intercooler on and it made quite a difference. car is a lot more rev-able if that is even a word and im only boosting at about 12psi with no fuel mods other than a new lda pin. whilst the small cores may not be as efficient when ur stuck in traffic, they still do something when ur actually moving and for me it was well worth the money spent :)
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A bit off the subject of water cooled intercoolers but here is my set up on a 81 Rabbit with a Saab Blackstone ic. It works great nice cool charge back to the intake.
(http://i637.photobucket.com/albums/uu91/DieselDean113/000_1436.jpg)
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It doesn't help that you're sucking in hot air though.
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Nope no hot air it gets plenty of flow from the front of the car. I move the radiator over to make room for the ic.
(http://i637.photobucket.com/albums/uu91/DieselDean113/000_1427.jpg)
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You do have the timing belt covered now right? Scares me, but I live all around dirt roads and stones. Earlier this year I took out my grill with a dove. It ended up on the spark plugs of the 83 GTI with its head dangling right about where the belt would meet the IP :o
Back to intercooling...
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Ahh yes the filter... I have thought about running it into the rain tray. Yes the timing cover is on now the pics a bit old.
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I plan to use the washer nozzle tank as the IC sprayer tank, the line now has a nozzle on it that will spray water on the intercooler when I want to, plus you could always put a small rad fan on the I/C that is pressure activated?
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I plan to use the washer nozzle tank as the IC sprayer tank, the line now has a nozzle on it that will spray water on the intercooler when I want to, plus you could always put a small rad fan on the I/C that is pressure activated?
yea just buy one of those hobbs pressure switches off ebay. totally adjustable too :) thing is at speed you don't really need it, so a temperature one is better, but more $$$. rainbow electronics sells one that reads from 0c-120c, but i can't find their website anymore :(
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All good info !!
What is your opinion on the cheap eBay intercooler kits ?
I dont see myself spending 750 for a brand name intercooler.
Woulsdlike to stay away from plastic end tank types if at all possible.
Also what is the relevence of single or dual core?
It's for mounting on a MKII chassis, the longer ones would fit great inside
the big bumper 90-92 style but I wonder about getting the piping back up to the
turbo with as little bends as possible.
Can fab up all my own stuff, no worries there.
Just need education from you guys,
Much thanks,
Hugh
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Found this over on the French side by Moise,
great install !!
Just what I was searching for :
http://www.vwdiesel.net/forum/index.php?topic=17736.15
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Ahh yes the filter... I have thought about running it into the rain tray. Yes the timing cover is on now the pics a bit old.
I like how you have it set up, looks like it came like that. I think it will really make a big difference though once it gets cooler air to begin with. I had given the rain tray some thought too about putting the I/C in there to eliminate some tubing and supposedly less lag. I'm sure somebody has done it on one of these Rabbits before. That's where the old Ram-Air muscle cars got their air from if it made any difference. I'm sure something could be made to fit in there.