Another area where I’ve got some fun ideas to carry out on this project.
It’s been a while since the last update, and that is because I’m currently 71 hours in on this exhaust project (I told you this swap would have some very different requirements than a typical one!). I’ll have it finished up by the end of this weekend, so I can finally start posting about it and will have finished pics in a couple days.
Before we get started, there’s a BIG difference between the LFX and just about every other motor out there when it comes to the exhaust. The LFX collects the exhaust gasses from all three cylinders on each bank before they exit the head, so it all comes out in one single outlet on each side of the motor. People come by the shop to take a look at the car and ask “what are your plans for the headers” and the answer is… there aren’t any headers! They are much more appropriately called Downpipes – as they are just a single tube on either side of the motor which drop down to the underside of the car much like a turbo system.
Now, there’s an EASY route for doing your LFX exhaust… V8Roadsters makes a tidy pair of downpipes that get you from the engine down to beside the bellhousing. Then it’s a simple matter of taking the car to a good exhaust fab shop and get something made up to get things out to the back of the car with whichever combo of cats, resonators, and mufflers you want.
For this project, we’re going a different route. Always thinking towards maximizing the competitive advantage where possible, this exhaust is going to go out to the sides of the car. Benefits should be three-fold; it will be overall lighter, there will be less heat by the transmission and differential, and it will allow for several aerodynamic ideas that I want to implement on this car.
Fun idea, but this presents plenty of challenges – the biggest one is there’s no space for a side exhaust on an NA chassis; there isn’t room for a big wide wheel and race tire to turn with an exhaust tube trying to share the wheel well space, and there is nowhere to put resonators or mufflers along the side of the car without them hanging WAY off the car – which would not be good for drag or ground clearance.
Some drastic surgery will be required.
Started with drilling holes and using the scope to figure out the internal layout of the rockers, then with a rough idea of how I want things to end up I began cutting, taking a little bit out at a time then investigating, adjusting, cutting more, etc.
Nearly all the cutting is done in the pic above, but the pinch weld is still there. After a lot of test fitting, I decided to get the fitment I wanted with everything I was going to have to take that out too. This meant more work – this is a critical area of the car in terms of chassis rigidity so anything I remove I have to rebuild a replacement for.
Below pic has the pinch weld cut out as well, and weve got the resonator mocked up roughly in position:
Now for the fun part. Need to rebuild the rocker in its new shape that accommodates the exhaust, and ideally we want the end result to be even stronger than the stock rocker.
The sections that will make up the main sides of the rockers:
The idea is to make the rocker concave instead of convex so there is room to nest the exhaust about half way up within the chassis. Something like this:
Holding that main piece up to the car it all looks pretty straightforward… I wish it was.
Creating the new rocker and the new lower section of the front wheel well took several pieces including a rather complicated 90° bend to transition between the two, plus a dozen or so additional pieces to rebuild the pinch weld inside the rocker so that all the chassis loads that normally transfer through that area can continue to do so, plus some additional gussets to make it all stronger than what was there before, To top it off it needed to be able to go together in a sequence that allowed me to weld each rocker piece to the ribs and gussets on their back side.
To put this all together took 5 yards of welding per side:
Cleaned up and primered:
Naturally, I weighed everything that got cut out and put in on this project. Thanks to a lot of careful figuring out, the new rocker matches the weight of what was removed within one pound.
At this point, I was lamenting the fact that this is a V engine and it was time to do this all over again on the driver’s side.
Both sides are done now and mirror each other, and you can see why this car took 40 hours of work on the exhaust… before I actually began making the exhaust.
Exhaust is in progress now and will be done by the end of the weekend, part 2 coming soon!