Water/air Intercooler Installation

[Ionos]

Having owned 2 RB25DETs now for over 4 years, both with the dime a dozen 600x300x76 FMIC's, I've always missed the crispness of the factory intercooler. My first R33 was almost factory standard when I got it - I did the usual Stage 1 mods without really that much knowledge except that I wanted 'moar powa'. After installing the 3" exhaust with decent 'seat of the pants' dyno results, I purchased a FMIC kit back when $500 for a new kit was a bargain. I remember the disappointment after spending a whole day installing it (bolt on kit my arse!!) with the lag that came with changing from the standard induction path to that of a cross body FMIC. Later I realised that you could get the Blitz style kits which reduced this slightly, but I always thought it was going to be a trade off for a car that was strictly used on the street.

Now, I know of course that FMIC's are the only way to go for the track due to their unparalleled efficiency. Having said that, I never go on the track and most of my driving is partial boost, partial throttle. My second R33 (after the first was stolen) was purchased already modified with about 240rwkw and mods to suit including a GT2535 and PowerFC, and of course a FMIC. The GT2535 is still quite a responsible turbo, but the feeling was still there that I had to pressurise this massive intake tract before that precious boost was getting into my engine. No more! The solution – a compact, Water/Air intercooler with a shorter intake tract then even the factory SMIC. Mounted on top of the pod filter (no air box) it would be a simple matter of two 90 degree silicone bends to take boost off the turbo, into the WAIC and back into the engine cross pipe.

Some concerns – the WAIC is very small. What if it wasn’t big enough to cool the intake charge with 17 PSI? What if I couldn’t make it fit? What if I ended up losing power? What if I was wrong, and it made little difference to the turbo lag despite all the effort (after all, everyone seems to swear by those FMIC’s).

After researching for a very long time and being unable to find someone who has actually gone down the road of installing a Water/Air Intercooler on their Skyline, I decided to take the plunge and give it a go myself. I bought a ’600 hp’ kit off Frozen Boost along with the required accessories to install it – Heat Exchanger, Pump, Hosing and Clamps as well as a Thermo fan which is currently unfitted. All up the gear cost about $600 including delivery, thanks to a great US Dollar.

I’d already measured up and was confident I could make everything fit. Off came the front bar, FMIC and piping and I set to work looking to fit the new hardware. The most difficult part was making the Heat Exchanger fit – while the core was the same width and height as the FMIC (600x300) the top tanks made it sit too low. The solution was to fabricate some custom brackets to sit it on a slight angle. The pump was a cinch, fitted behind the left fender, with plumbing going into the engine bay via the now unused standard intercooler holes.

Finally the actual intercooler core fitted onto of the AFM and Pod with more custom brackets fabricated to hold everything in place. Last step was to fill her up with a little coolant (anti corrosion), make sure there are no leaks and everything is tight both on the water and the air plumbing and fire her up.

A cautious off-boost test drive revealed little difference compared to with the FMIC. Once she was up to temperature though, the first pedal mash resulted in a whole different car! My boost jumped straight to 20PSI (up from 17) due to the almost non-existent pressure drop with the new Intercooler (WAIC’s have very, very low pressure drop <1psi). I quickly retuned the duty cycle on my AVCR to go back to 17 PSI. I was now achieving the same boost as before but my turbo didn’t have to work anywhere near as hard – less heat and less wear. A few more runs showed a remarkable difference, power came on smooth and progressive, almost like a V8, instead of the nothing then big surge that I was used to. It was especially evident on partial throttle/partial boost, the whole car felt significantly snappier.

The WAIC has been fitted for a few weeks now and absolutely no regrets. I’ve done several full boost runs in a row and noticed no difference in ‘seat of the pants dyno’ power, although without actually putting it on a proper dyno it’s difficult to tell if there is a slight power drop. Even so the huge increase in response is well worth a slight top end power drop, if there even is one.

Hope you enjoyed the read and that this inspires another Skyline owner to enter the world of Water Intercooling!

[Rowdy]

impressive! its a shame you couldnt get some air temp figures for before and after. i do like the idea though buuut i miss the look of the fmic lol

[r33canada]

i really like the idea, especially for being someone like me who would rather have a more sleeper appearance.

[r33canada]

Are you going to run a water temperature probe with it? im curious to know what your temps are in boost and during regular driving. Iv been meaning to fit a fmic but if this ends up being cheaper and more efficient then i may go for one of these.

what lengh of pipe did you use for leading to the turbo? what i mean is did have to make any custom cuts to the IC piping or just find pieces that fit?

[Ionos]

Are you going to run a water temperature probe with it? im curious to know what your temps are in boost and during regular driving. Iv been meaning to fit a fmic but if this ends up being cheaper and more efficient then i may go for one of these.

what lengh of pipe did you use for leading to the turbo? what i mean is did have to make any custom cuts to the IC piping or just find pieces that fit?

No water temp probe, although i've put my hand on the jacket to feel the water temp after several full boost runs and it still feels cold. There is about 2 litres of water in the system so it will soak up a fair bit of heat - ideal for street use but again you wouldn't use this sort of system on the track. More worthwhile would be an air temp system and ideally I could have tested the intake temps with the FMIC to compare to the new system, but I didn't have the hardware for this and am reluctant to spend more money on something that is just a 'nice to know'.

The pipe between the turbo elbow and intercooler is simply a 20cm straight piece of 2.5" Aluminium pipe. Apart from that, 2x 2.5" to 3" 90 degree silcone bends is all you need to fit up to the WAIC with this location.

I would note as well that the system is not cheaper then an off the shelf FMIC kit - they can be had for around $300-$400 I believe these days. You are looking at $600 minimum for all the gear to install a water kit like this, and that assumes that you can fabricate the mounting hardware yourself. It is however much more efficient with a lower pressure drop due shorter intake piping, less bends, and less restrictive internals inside the core - the inner passages of water intercoolers are much bigger then bar&plate air coolers. This means that you can squeeze more boost (perhaps up to 2psi more) out of your turbo for the same effort. For someone running a factory turbo this would be ideal.

Edited July 30, 2011 by Ionos

[kungpow]

a friend of mine had one of these on his blown 6.4L and he swears by them as the best thing for street use all ways had good intake air temps and that was pushing decent figures as well.

[Geeteeeeessssstttt]

Ionos, you inspired me to do a mod like yours, and install a WAIC my self in my rb25det, i would like to know if you can provide me some photos of your setup, how you runned the lines to the heat exchanger and pump, i would be really greatfull if you can pass me those photos. Thanks