Suzuki Alto Works – More Intercooler Fun

Many months ago, back in January, I upgraded the small stock intercooler to a big Greddy one. I’m changing this again.

The Greddy intercooler was good. It has a massive core and low restriction

After changing from the tiny standard intercooler I could almost immediately feel an increase in low-end power, particularly when climbing hills. Clearly the Greddy IC flows more air than the stock IC.

On the track in Jan, it did its best to keep intake temps down. 25c+ ambient temps meant that I was seeing 50-60c IAT on 8psi and over 70c on 15psi boost. The temps would drop quickly off boost as the Greddy IC could shed that heat easily, but it seemed to struggle a bit to keep the temps in check when on boost. I suspect this is because I’m working the little turbo quite hard and since the IC flows so well it doesn’t have time to grab that heat from the air. I believe either running stock boost, or a higher flow turbo that’s making less heat would work better with this IC. The other thing that could help would be reinstalling the IC water spray the previous owner had in Japan…

So that’s where I decided to move the Greddy IC onto a new owner, who is running a stock setup that would benefit more from how well it flows, and get a particular new IC that is a different design.

In the meantime, I decided to remove the Greddy IC and swap back to the stock one for now, and start to reinstall the water spray. I didn’t want to install the water spray on the Greddy IC because I would have to drill into the shroud to install jets, which I wasn’t going to do, and the stock shroud had jets fitted already.

The Greddy core is a monster, with huge tubes

In contrast, the stock IC is a tiny wee thing

You’ll note there that I had temporarily installed a catch can too. I wanted to see how the blowby was, so threw this in. I was pleasantly surprised to note that the hoses and catch can were completely dry of any oil after a couple of hundred ks, so ended up removing it and reverting to stock.

This gave me a little more room to play with in terms of the IC water spray hoses. I tidied up the hoses that came with the car and reinstalled them.

The black hose currently runs through the firewall grommet and is looped in the glovebox. This will eventually be run to the boot of the car, where a 5l tank and washer pump are located. This bottle fits almost perfectly, except the cap was a few mm too tall, so I used some heat to squish the top of the bottle down and lower the cap. It’ll lower the capacity too, but there should be plenty still, and I can top up between sessions.

It was interesting to note that as soon as I refit the stock IC again the car felt slower, so it wasn’t a placebo, the Greddy IC is good.

After a few weeks of running the stock intercooler, my nice new one arrived. Meet the Suzuki Works Kurume Sports Intercooler.

It’s a really nice bit of kit. The Greddy IC was all welded sheets of Alu, which was nicely made, but this SWK is next level with cast aluminium end tanks.

Compared to the stock IC the overall dimensions are basically the same, except the core is slightly taller

The difference is the thickness. This thing is a thicc boi.

Alto for scale

The protective cardboard shows how much taller the SWK core is

Being legit JDM gear, it bolted right in with no fitment issues.

Now I just needed a shroud.

The SWK intercooler comes with adhesive foam strips to stick to the shroud and close up the stock gaps

And with the shroud fitted

You can barely tell from the top, just the little silver end tank gives it away. From the side though, it is a beast

The main thing here for me is that it means I can run the stock shroud, including the water spray jets. It should also drop temps over the stock IC due to the taller and thicker core.

I haven’t really logged temps since fitting it, and the big test will be the next track day which will hopefully be next month. I want to be running 15psi all day and keeping temps under control.

It’s hard at this point to say if it’s had the same boost in power that the Greddy IC did since I’ve done some tweaking to the boost controller at the same time. I’ve had an “issue” where when on 15psi the turbo just makes boost too easily, and it can lead to some surging when driving as it comes on and off boost at the slightest twitch of my foot.

To counter this, I finally set up the RPM and TPS settings on the HKS EVC

This allowed me to set an offset map. It may need tweaking as I drive it more, but at the moment this is what I have (this is page 1 of 4, the other pages are 60-100% TPS, and 5000rpm-9000rpm).

Long story short, the vertical axis is the throttle position, and the horizontal is the engine RPM. At low throttle position or low RPM, it makes less boost, increasing as the RPM and/or throttle position increases. This is a percentage of the total target boost, so at 0%/2000rpm it makes 35% of the 15psi target.

The hope is that when I’m cruising at high rpm (ie 4000rpm on the open road) but have a lower throttle position, it won’t be so eager to make 15psi with a twitch of the throttle now. It should also be a bit nicer on my engine at low RPM, where it probably doesn’t love life having 15psi shoved into it when it’s barely spinning.

So far my testing shows it’s pretty effective. The car feels a bit less frantic to drive but is far more manageable to drive smoothly when you aren’t trying to beat everything from the lights.

I’ve only set this up for the 15psi setting, as it’s not been an issue on 8psi. 18psi may get a map, but I don’t tend to use that as 15psi is plenty fast.

This car is pretty much where it needs to be now. I need to finish the IC spray, but otherwise it’s ready to hit the track again and see if I can demolish my previous times now that it can go around corners.