Let the tinkering continue.....

[gregozedobe]

All very interesting. Have you thought about allowing the heat to escape more easily?? (Via the rear of the bonnet perhaps).

It's to some extent unavoidable that you will get heat sink, but you have to remove air to let more in, so the way i see it, if you allow more hot air to escape out the top at the back, you will allow more cool air in at the bottom in the front..

I'd be a bit careful doing this, as while this idea may work great when you are stopped at the lights, I have a vague idea that when you are driving along the highway (ie at speed), the bottom of the windscreen is a high air pressure zone, so you could end up with some air trying to go backwards from the rear of the bonnet back out through the grille - not good for cooling at all

Of course I could be totally wrong (again), so it might be worthwhile doing some pressure testing at various speeds to see where the air will want to flow easily (or not). As always, empirical, in-situ evidence from a well designed experiment will prevail over nice-sounding theories every time

[Greg Roles]

I tried removing the rear bonnet seal, and it worked nicely at the lights, but Greggo is right, at speed I was getting more stagnent air and the underbonnet temps increased. What I am aiming for is flow over the engine, over the turbo and out the transmission tunnel. Easy to achieve at speed, and the reason I want a "at idle" temp fan, that dumps down over the engine pointing at the turbo.

I can easy get some figures with the manometer, but the temps tell me enough. Plus just how many dials and meters do I want on the front seat anyhow!

[Preen59]

Hmm furry muff. I didn't think about that fact.

Good point. I'll get back in my box now.. haha.

[Greg Roles]

Well I got my "worlds best intercooler spray" happening over the weekend, and I must say, the pump is both rather quiet, and amazingly powerful, it does indeed produce a very fine mist out the front of the radiator area. You'd expect that with over 200psi ! The scary 240 v inverter is sitting in behind m drivers headlight washer garnish, did a little more hacksaw work that would scare most people ( except Polar? ), but you can't see it with the cover in place. Nice safe, DRY spot. Still it's only on momentarily when the box decides the real time temps, and load warrant turning it on. It's why I have it open on the dash, with a bulb hooked up so I can mess with the settings.

I aimed it forward, so that you "drive into" the spray, and you get the best spread according to Autospeed.

I've set it to go off at 40 degrees, so once I isolate the load wire from the MAF, I'll start running it with the box perched up on the dash, alongside my digital therm which is pushed into the intercooler nearby the spray thermistor.



Be interesting to see how it slows temp spikes, as I expect it will.

Going to be a few weeks of Autospeed and Jaycar kits, as I need a temp switch for my air blower at idle, a turbo timer to run the radiator fans for a few mins after shutdown ( and my forthcoming shut down throttle flap ), and a water level kit for my now plumbed in windscreen washer intercooler spray.

I so love Autospeed!

[POLARBEAR666]

Well I got my "worlds best intercooler spray" happening over the weekend, and I must say, the pump is both rather quiet, and amazingly powerful, it does indeed produce a very fine mist out the front of the radiator area. You'd expect that with over 200psi ! The scary 240 v inverter is sitting in behind m drivers headlight washer garnish, did a little more hacksaw work that would scare most people ( except Polar? )You would need to get out an angle grinder before I even became slightly nervous hehe, but you can't see it with the cover in place. Nice safe, DRY spot. Still it's only on momentarily when the box decides the real time temps, and load warrant turning it on. It's why I have it open on the dash, with a bulb hooked up so I can mess with the settings.

I aimed it forward, so that you "drive into" the spray, and you get the best spread according to Autospeed.

I've set it to go off at 40 degrees, so once I isolate the load wire from the MAF, I'll start running it with the box perched up on the dash, alongside my digital therm which is pushed into the intercooler nearby the spray thermistor.

Be interesting to see how it slows temp spikes, as I expect it will.

Going to be a few weeks of Autospeed and Jaycar kits, as I need a temp switch for my air blower at idle, a turbo timer to run the radiator fans for a few mins after shutdown ( and my forthcoming shut down throttle flap ), and a water level kit for my now plumbed in windscreen washer intercooler spray.

I so love Autospeed!

I have tried running my spray manually when sitting at lights or under boost / just after boost.. various variations of that. I have not seen anything that was like 40' 5 seconds 35'. It basically just stops it going up and then very very slowly comes down. So if you are sitting on 30' intake air temp... and you just paste the cooler.. I mean run it flat tack for 2 mins straight... you slowly slowly come down in temperature.

I think you won't have enough water for this system to run for very long. On my subaru I had a 10L boot mounted alloy water tank for a water spray and even with intelligent spraying - run by the ECU on load and temp - it was mowing 10L in about 15 mins of hard driving.

Good luck though, will be interesting to see if your much higher water pressure and smaller water droplets achieves a better outcome than a basic spray running flat out.

[Greg Roles]

That's the beauty of the latest Autospeed system I'm running. By using a stupidly high pressure above 200psi, it produces an incredibly fine spray that supposedly enters the intercooler better ( especially by getting larger coverage and getting through the AC core ), and owing to small size evaporates far more rapidly. Remember the endothermic or heat "taking" part of the equation is the phase change from water to vapour, and a layer of water actually hinders that in a way. I'm also taking their advice and spraying it forward, so the car ( or fan ) "drives into an already cooling mist of water.

It all seems to be about the most optimal water system design to me!

This week I've been monitoring core and underbonnet temps, and I've found some interesting things. Also got to measure a regeneration cycle, and compare EGT's, intercooler core and underbonnet temps in traffic.

SCARY!

The intercooler core, from the fins where my probe is stuck usually runs only a few degrees above "ambient" and if you drive quietly, it's roughly the same.

Turn on the air conditioner, and understandably, as the AC radiator is out the front, the temps rise 5-10 degrees. If you run the AC, expect the intercooler to be less effective.

On a "hotter" 27 degree arvo in traffic this week, I watched the intercooler temp rise over 30 whilst idling at the lights for a second time ( I didn't get through the first green ). So basically for a two minute idle, the "fin" temps don't rise dramatically, although my previous internal measurements show the actual air temps do. After about 4 minutes of idle, the fins themselves start getting hot, and the intercooler itself is starting to heat up ( as it should ).

The underbonnet temps are downright scary. My second probe is sitting on top of the MAF sensor, hanging out into space a bit, and it routinely sees 50's on idle at the lights. Also, once you/ve done an idle, everything stays hot for some time. Heatsoak is still the major issue.

My TDI did a regeneration cycle, and the EGT's were a minimum of 350 degrees up to a max of 500 degrees. remember this is a probe just outside the turbo outlet, and not in the DPF itself, where the extra fuel is actualy supposed to be combusting, so I'd expect it to get hotter.

Underbonnet temps hit 70 plus degrees on idle on a 25 degree day, and the intercooler core ran at least ten degrees hotter on idle during this time. I can only imagine what the actual air temps post intercooler were.

Bottom line I am convinced a fan to blow air to minimise heatsoak at idle, coupled with a water spray for core temp rises is the way to go. It's all about the start stop problem, that you'll never encounter on the highway.

Oddly enough I've noticed normal boost levels on regen, where the tech bulletin says turbo pressures are altered so the drivability is the same during regen. Well I can say there's a lot of heat involved, and the sooner mine can become a wall ornament, the better. ESPECIALLY with what I'm reading about the ultra fine soot particles that DPF's are producing in Europe. Seems the old smokey 4x4 is actually safer than my new fangled DPF car. Looks bad, but doesn't enter your bloodstream like these new particles appear to!

[Transporter]

Good work there Greg.
I also found the business website in CZ. where they offer to remove inside of the DPF than put it back, do the software mod and they say that the car would pass the emission test and there would be no more smoke from the tail pipe as well. So it should be undetectable as well.

Amazing!

[Greg Roles]

JBS in the UK offer the same options over there, an emptied DPF canister put back on to look stock, or the larger 2.75 inch downpipe in my signature I have in a container as we speak. I figure at this point my engine etc warranty is kaput, and if I do get pulled over, the inlet plumbing and stuff under the bonnet will be a dead give away that it's modded. Might as well go the bigger, simpler pipe, and it's less mass to heat up under the bonnet as well. It's why I haven't been putting exterior "look at me officer" bling to my car, I need to keep what I'm up to somewhat under the radar!

Clever idea all the same though!

[gregozedobe]

I also found the business website in CZ. where they offer to remove inside of the DPF than put it back, do the software mod and they say that the car would pass the emission test and there would be no more smoke from the tail pipe as well. So it should be undetectable as well.

Amazing!

Hmm, I must admit to a tiny bit of skepticism re "no more smoke". Given that the whole point of a DPF is to capture (and later burn) visible soot, I have trouble understanding how removing it wouldn't result in more soot (smoke). Maybe if they increased the air going in and reduced fuel that would work, but I would expect that would also give less power at full tilt.

However, it may be that a DPF isn't actually a legal requirement for diesels manufactured before a certain date. VW were selling a variety of TDIs over the last few years, some with and some without a DPF, and presumably they were all legal. So it may depend on when the regulation that requires a DPF to meet the emission standards was actually enacted (effective date) as to whether your particular car is actually required to have a DPF or not.

Might be worth investigating if you are interested in a legal DPF delete ?

[Greg Roles]

There won't be any real long term DPF delete legallity, as the current governmet focus is on heavy vehicles, and how to introduce the retrofit of DPF's. It's already happening in the USA. The plan from there is to roll this out to the small vehicle fleet, so it's only a matter of time till it will be law for all diesels to have a DPF. If you read the gov websites it shows they are discussing how to best test particulates, so once they manage it effectively on trucks ( bay far the greatest pollution source obviously ) the rest of "us" will be next. I'd say we have a few years at best.

The problem is whilst a DPF does lower particulate matter, which is great, so too does it "create" ultra fine particles with a much larger surface area, which is the main problem. One large soot particle can have the same mass as millions of ultra fine ones, but obviously the reactive surface area is infinitley larger with numerous particles. These go deeper into your lungs, and are much harder for your body to expel.

It seems there is no perfect answer, except for more efficient engines, which VW is obviously aiming at.