Project Evo X MR is Back!



The ARC intercooler (minus the threaded hanger) weighed in at a svelte 9.2 lbs.  We were surprised that it was actually lighter than the stock intercooler!.

Overall the welds on the ARC intercooler were fantastic and the entire unit is very well made.  Clearly you can tell the folks at Abbey Road Company International were very good at Q.C.  Since the purchase of the intercooler, ARC International has declared bankruptcy in Japan and worked their way out of financial protection, but the parts are still hard to get.  The good folks at Mackin Industries can still bring in what you need.  However, the long lead times are somewhat prohibitive. 

3.  Cosworth Upper and Lower Intercooler Pipes

Now that I had the fancy pants ARC intercooler, I wanted to be able to feed air to it as efficiently as possible.  The stock upper intercooler pipe is basically a thermally protected rubber hose, and the major downside to that is that it tends to expand under high boost conditions. 

The factory lower pipe is a nicely made hard pipe, however I felt that since I was going to change one side, I might as well change both.  Enter the Cosworth aluminum upper and lower intercooler pipe kit (p/n: 20014525).  These mandrel bent aluminum pipes are extremely well made (powder coated a metallic silver) and are attached together via high strength silicone couplers.  The upper intercooler pipes (hot side) are 2.5″ in diameter, while the lower intercooler pipe (cold side) is 2.75″ in diameter.  (Now wait here a second, I had said “as efficiently as possible” just a few lines up. Why get intercooler pipes of different sizes when the intercooler is a different size, didn't I measure before I purchased? Simple answer: nope. I was too excited to get parts and that was one thing I overlooked.  Turns out if I had gotten a Cosworth intercooler, there wouldn't be any fitment issues, but that's not what happened, so….)

We went to Cosworth for their intercooler hard pipe set.  In our experience with our other EVO projects we have found that there is quite a bit of power to be found in this.  The Cosworth pipes have smoother bends and the hard tubing does not expand under boost unlike the stock rubber parts which actually produces a feelable reduction in lag.  Charge pipes do not expand and thus do not increase the amount of work that the compressor must do.  Less compressor work, less backpressure the turbine makes.  Eric Hsu explained that one to me and all I know is that time and time again, hard pipes have made more power on MotoIQ's Evo Projects.

The upper intercooler pipes consist of two pieces to accommodate for engine movement, and the lower piece allows for the relocation of the factory blow off valve from an area by the rear firewall to an area closer to the throttle body to reduce turbo lag. 

Also included is a section of 90 degree bent tubing to allow for reconnection of the stock recirculation valve tubes.

The factory pipes with all the rubber hoses and clamps weighed in at 7.1 lbs.


The Cosworth pipes weighed in at 6.9 lbs.  The upper intercooler pipe bolts straight in where the factory pipe resides on the upper radiator frame rail and reuses the factory rubber isolators and hardware.

As I alluded to earlier, the ARC intercooler inlet/outlet pipes were designed for the factory intercooler piping size of 60mm (2.36″) but since the Cosworth pipes and supplied silicone hoses were 2.5″ and 2.75″, I needed to find new silicone transitional hoses.  Luckily for me, FRSport was just down the street from Cobb Tuning SoCal and had some in stock.  I ended up using a 2.25″ to 2.5″ for the upper pipe, and a 2.25″ to 2.75″ for the lower pipe.  (Thank you Mike@FRSport!)

4.  AMS Widemouth Downpipe

Just as in the MotoIQ Project Evo X GSR, I also went with the excellently designed AMS Widemouth downpipe.  The cast stainless steel monster could fit almost your entire forearm (or at least my forearm) inside the large cavity that bolts right up to the rear of the factory turbo. 

There is a large flex portion that allows for exhaust movement during driving.  I won't go too much into detail of what was already written in our Project GSR write up.


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