you know, for quite a while now I've had a flat spot or two on WOT acceleration. Didn't matter too much on the starting speed, the acceleration just bogged down. It was baffling.

Of course I checked and rechecked for air leaks in the convoluted air tube, nothing showed up.

Yes, I changed the fuel filter, seemed like maybe an improvement, but nah just the good old placebo effect. (At least it didn't hurt anything)

Then by chance I looked at the area I'm pointing to in the photo. The factory bolt was missing! It must have worked itself loose over time.

Well a quick trip to the auto parts store and $1.35 later she was secured. Its a 6mm bolt with a 10mm head on it fyi. A black flange bolt would have been better, the plastic has an oversized screw hole, but for now the silver bolt with a washer works fine.

I looks like the motion of the engine block under torque creates an air leak here.

I immediately saw a difference, nice smooth acceleration. FYI, performance seemes to have even improved after a few drive cycles! Big smile driving around today.

Guess I'm all excited about such a super cheap fix with such huge impact, we don't get to see this too often.

Maybe someone else will run into this someday.

John

 

Well done....

 

Have to remember that one

 

ooh, is that black duct tape on that plenum? I had to do that on my 560SL but I taped it from the inside making the tube look OEM. If that shiny new bolt bugs you a black sharpie will make it disappear.

 

Yes you got me on the duct tape! Darn thing cracked last time I had to take her off. Coincidentally, thats where I was "certain" I'd find the darn air leak ;-).
love the idea about a black sharpie - thanks.

John

 

Replace the cracked plastic air duct tube with the Mina Gallery aluminum air duct tube kit. I did so in April 2019 after having installed an OEM plastic replacement tube in October 2012 and it eventually cracked as expected. One more lousy plastic problem solved on this car....

 

Thanks Jon89!

 

Interesting and I will check that on my car. My 2002 XKR has a flat spot. If I moderately punch the gas from a stop, it takes off, then flattens out, but then takes off again once the supercharger winds up. But if I just punch it at any speed, it pretty much takes off.