A number of you expressed an interest in how the fitting went with the HFCs and my Stillen CBE. Some members were thinking of adding the HFCs to get that lovely noise but knew i was having fitment issues.
For those that havent seen it here's an example of the impact it had on my car. Putting it simply it was awesome
Unfortunately I've now had to have them removed and i'm back to stock cats. Two very respectable garages, both with prior experience of zeds and mods, were unable to get the Stillen and HFCs to fit properly.
The issue appears to be the Stillen exhaust as it hangs very low. With stock cats that is ok as it still clears the cross member. The trouble is that the flanges on the HFCs end up a good inch lower than the stock cats. As a result the HFCS pull the Stillen exhaust even lower so it ends up resting on the crossmember, causing rather unpleasant vibrations through the car.
Research on the US forums shows this is not an uncommon problem. General resolutions seem to range from:
- inserting rubber bungs between the exhaust and cross member
- lowering the cross member with washers
- bending / cutting the exhaust
Tarmac was kind enough to send along some Stillen HFCs to compare to the Berks. The Stillen HFCS were a good inch shorter but did not fix the problem.
Here are some photos to illustrate the issue
Berks and Stillen HFCs from one side lined up
And the other - Stillen are a good inch shorter
Heres the clearance above the berks HFCS
And heres the clearance with the stillen HFCS
And heres the clearance with the stock cats
Now i know the stock cats have a lot of extra bits around the pipe but a comparison of the flange clearance shows they are much lower, a good inch to a an inch and a half lower
vs
or even clearer
vs
Net effect is that they keep pulling the exhaust too low.
Heres a picture of the clearance my exhaust (temporarily wrapped for protection) was getting with the HFCS added :
It just wasnt going to work so they had to come off.
In all honesty though the sound of the standard stillen CBE is lovely and im more than happy with it. When i had the HFCs on it was fun blasting around with that lovely race car noise but in all honesty it was too loud for me. I did cringe a little in traffic and pulling away from home and work. As a weekend fun car maybe but as its my daily drive i think the noise would have been too much. I guess it was meant to be that way.
So in summary my recommendation:
If you have a Stillen CBE and want to add HFC's it should be fine BUT check the clearance you have above the cross member before the fit. If its close i would not recommend trying the HFCs as you will have the same issue i had. However if you have lots of clearance and want your 370z to sound like a thoroughbred race car go for it and enjoy it sounds amazing
Hope this is informative and help avoid others having the problems i had. But its all sorted now and im very happy, just a little quieter
I have to end with a huge thanks to Tarmac. Hes been brilliant throughout this whole process chasing Stillen and Berks and providing feedback and advice. You have been a star and sorry for all the hassle its caused. Thanks mate