If this hasn't caught your attention, then you must be a petrol head with no knowledge of diesel engines. To put it into perspective, with the same big chunky 36" tyres & the same diff., he has gone from 75.3kw. with the top mount air-air, to 81.0kw ( 7.6%increase) with our air-water, to 193kw (138%increase) with our prototype air-water intercooler-plennum unit !!! Obviously, there is allot more than our intercooler involved here. He went to a tubular exhaust, ball bearing Garrett turbo, tidied inlet ports & a very special big $$$ fuel pump. All the work was performed by Heath & Ian with product from businesses in south east Qld.

These three pics are what I used to convince the guys to go with an untried idea I've had for years, & spend much more than they wanted too. I had shown them the six pages of our computer modelling programme with a few different scenarios, & they knew that was very accurate from past experience, BUT, there was two stumbling blocks. The plennum was untried & I'm not that big into diesels so didn't give any guarantees, & Ian said that he could do a Chev V8 conversion for similar money - valid. Heath pointed out that while a V8 could have more power, it would never have the low end Grunt & engine breaking of these diesels. I'd given them a bloody good price as they were the 'guinea pigs',& it would be two at the same time, so it was crunch time. I clearly remember the guys talking it over out at their car for over an hour, before coming in & laying a deposit down.
The carbon build up is a give away to the poor factory design when the boost is raised. The blacker the area, the slower the air speed &/or turbulence, meaning those cylinders are not getting the same amount of air. Three & four are clearly the lean cylinders & will burn the pistons up early (or at least dramatically shorten head gasket - valve - ring life at best) at the tune levels these guys wanted to go to. We also considered welding the single entrie & making two entries into the oe log, which would've been heaps cheaper, but I bet they're bloody glad we didn't take that shortcut.

It's not the sort of job you get a mate to do for a couple cartons. There's my thirty years of air flow bench & 20 years of TIG welding experience in this. I had to pad weld this part of the inlet to get a very smooth transition with the best transition angles. In fact, I picked up a little flow on the second plennum, so cut the first one off & did the same mod to it, at no charge. Not many shops are that conciencious - or maybe I'm a dickhead?

This is tricky welding, 3mm plate butted onto 4mm plate of cladded alloy, 4 mm from 0.03mm fins & it has to be a full penetration weld as it has the full weight of the cooling matrix hanging off it.

Trial fit up during fabrication to make sure everything lined up. The engine is swallowing over 900 cfm now, & with the chunky tyres throwing rocks, dirt & dust everywhere, filtering is paramount. I just can't stress this enough. That's why we fitted such a big K&N pod filter & our own easily replaceable foam pre filter that slides in the mesh near the entry.In a sense the inlet track is 20mm long as that's the total of length between the turbo outlet & tank inlet. How much lag? Compared to a front mount it's almost unmeasurable.
Even though our plennum is 478% larger than oe., lag is heaps less than a front mount instal
                                                 850rpm,        2500rpm,        4500rpm
- front mount & pipeing -            0.691 sec        0.235sec        0.131sec
- our air water/plennum assy.-    0.499 sec       0.169 sec        0.094sec
the above figures are from are computer modelling Lag programme. They are how long it takes a molecule of charge air to travel from the compressor housing outlet to the valve head, at the rev. stated & if the pipes are straight. There are far too many variables to be able to calculate accelerating lag as you can see it is exponentially quicker as revs rise.

This is the end result on Heaths truck. He kept the same radiator( which will struggle on a long straight on a hot day), & of course, the Davies Craig EWP will handle the flow easily.
Apart from cost, the only other problem could be longetivity, with so much weight swinging off the top of a vibrating engine & then being pounded be such rough use these guys throw their trucks at! We have done everything possible with both materials used & fabrication skill & tricks for the longest life possible. The air speed in the short 63mm pipe connecting the compressor housing to the the ic. inlet tank is 254kph! We're now pulling 63kw (3583 BTU/m)of heat out of the intake charge, allowing their other engine mods. to achieve the impressive power output. They're good turbo petrol engine specifications, but then I'd love to see this engine in a 1400 kg VL Commodore beside allot of imports at the lights! It would have similar power to a HSV 300 kw Monaro, less weight, & don't even think of how much more torque !! What a burn out weapon - mega grunt at any revs.

The air speed in the 4" snorkel is 92kph! so you can see why I talked them into such an elaborate air box - it's necessary at this level believe me.