How I fitted a HUGE intercooler to Evonne the Turbodiesel!
It took a couple tries, but I got it to fit.
Why a new intercooler?
As you’ll see early in the video, the intercooler I installed in Evonne the Turbodiesel is MUCH larger than the stock one that I removed. It’s actually narrower, but it’s substantially taller and thicker. I changed to this intercooler because:
The stock intercooler’s plastic endcaps won’t stand up to increased boost pressures.
The stock intercooler’s size limits flow.
Increasing boost pressures leads to increased temperatures at the intake manifold, which can cause increased exhaust gas temperatures (EGTs).
How it was done.
Here’s the video showing the process I used to mount the intercooler and then to modify how it’s mounted:
Early in this project I had heard that a Mishimoto J-line intercooler would fit under the bumper in my E320 CDI. In retrospect, some photos I saw showed the intercooler’s leading edge actually behind the bumper’s front edge. When I installed my intercooler, I found out that I couldn’t recess it this way at all, because the cylindrical accumulator / filter for the air conditioning winds up right behind it.
The recessed intercoolers I saw must have either been another, thinner line of intercoolers or those cars must not have had air conditioning installed (this could be the case in some foreign locations where Mercedes isn’t automatically seen as a luxury brand).
When installed as close to the bottom of the bumper as I could get it, the intercooler was still too low, pushing out and causing bulges in the bumper cover while exposing the cracks that were already present in the original, Florida-baked, brittle cover that was on the car when I bought it. I drove the car around a little bit like this and the intercooler’s paint did get scuffed in the corners where it was making contact. I have to believe that substantial damage could occur to the bumper cover and the intercooler over the course of tens of thousands of miles. I didn’t want to see the intercooler or my new bumper cover damaged this way, so it had to be relocated.
How I fixed it.
By marking some lines on the aluminum bumper 1 1/2” above the intercooler, I was able to cut into the aluminum and make room to pull the intercooler up about 1 1/4”. I then supported the intercooler in its new position using a floor jack and redrilled the brackets that support it. When I installed my new, freshly-painted bumper cover, the move have given me a gap of at least 1/4” at the corners where contact had previously been made.
The Results?
Honestly, I can’t say, yet!
I’ve recently installed a boost / EGT gauge and I now know why the car doesn’t seem to be as quick as expected. Boost is very low except at high rpms. Some driving with the SDconnect monitoring the system reveals that the turbo actuator that controls the VNT (variable nozzle turbine) vanes isn’t moving. The vanes are remaining in a wide-open configuration that won’t spool up the turbo until high engine rpms are reached. So, the performance behaviors match what would be expected in this situation.
The whole point of a VNT system is to angle and accelerate the exhaust gasses at low engine rpms such that the turbo spools sooner, giving great acceleration response before the engine spools. As the rpms increase, and/or less boost is demanded, the vanes open. This reduces exhaust backpressure, reduces the acceleration of the exhaust flow, and allows the exhaust gasses to move toward the center of the turbine radially. The point is to avoid overspooling and damaging the turbo, while allowing the engine to rev with fewer restrictions.
Because my engine is receiving low-rpm fueling that anticipates boost at those speeds, the exhaust gas temperatures (EGTs) rise fast at low rpms if I go heavy on the accelerator pedal. It starts feeling better as the rpms increase, but I can see the EGTs rise to unacceptable levels on the gauge by the time I get there. Many don’t realize this, but boost is super-important (in addition to a good intercooler) to keep the air/fuel ratio in check and avoid high combustion temperatures that can damage the engine and the turbo.
Soon I’ll sort out what’s happening with the VNT system and then I’ll be able to share the performance figures that result. When I have this information, I won’t really know exactly how much the intercooler contributed, because my modifications were all done in one step, including the hybrid turbo, the cleanup of the intake, the larger intercooler, the cleanup of the exhaust, and the turbo mufflers. I expect to feel a car with a strong pull when I’m on the accelerator, while my gauge shows EGTs that are under control. The intercooler will be an important part of the system delivering the combination of performance and efficiency that Evonne the Turbodiesel is all about.
Please come back soon for more! Please comment, as I’d like to hear from readers and viewers of my materials. I learn a lot from comments, too!
Thanks for reading!
—Mark-A-Billy
I'd like to thank Mark for this video . I used this to install the same IC in one of my cars.
Will note that I had to cut off the bumper cover mounting tabs that attach to the underside of the crash bar as that section where the bolts would go gets cut out and the tabs need to be removed as they'd otherwise hit into the IC. ALSO, there's a clip-like, plastic piece (like two fingers) behind the upper part of the grill pieces that will also need neutering.
Nice work Mark. Don’t you have a die grinder?