Sucky Sucky

Update on car work. I spent last weekend working on the intake of the FX. If you remember, I’d complained about the gutless low end during the SCCA Test&Tune, so I figured I’d check out the intake system. My guess was something was wrong with the TVIS system. TVIS stand for Toyota Variable Induction System. Each cylinder has a pair of intake runners and the TVIS is a set of butterflies that close off one set at low rpms. What this is doing is tuning the intake size. At low rpms,  since the pistons are moving slower and sucking slower, closing half the runners you get a narrower intake tube, increasing the air velocity getting better mixing and charging of the cylinder. Once the rpms get high, the piston speeds are high and sucking in faster, the narrow intake becomes a restriction so opening up the second set lets in more air. When you’ve got it floored and the throttle wide open, you can actually hear when this happens. Toyota put this into the GE performance engine cars during the 80’s, and then it went away in the 90’s. It’s come back in a different form in Lexus’ with ACIS, kind of similar concept, but it varies the length of the intake. So I removed the intake and TVIS from the spare 16 valve engine from the original FX, and then the same from the new FX. As I suspected, the new FX intake is crusty. Hooking up the sucky thing, the vaccum diaphragm works, but it doesn’t shut the butterflies all the way. Rather than monkey with this, I decide to install the original FX intake, which I had previous done some port matching and smoothing work on. The intake casting is actually rather poorly matched to the gasket and TVIS plates so I decide to grind more to get them to match better. It may seem like a lot of work for something so little, but little things count here. I next spend a whole heck of a lot of time cutting off vaccuum hard lines that are now unneeded since I removed the EGR. I’m sure the neighbors were getting tired of hearing the Dremel cutting away at all the brazes on these little pipes. This may have been a bit frivalous, but it’s cleaner, and if you’re being weight weenie about it, lighter. I’m happy to report that after all this work, I can perceive a difference. Though not a torque monster by any means, the little engine now has regained some bwop in the low end, and I can once again hear the TVIS opening up. It’s amazing what a difference this actually made!

Saturday March 1

The next major thing I need to take care of that’s been driving me batty is the exhaust system. With only the big shiny 5Zigen muffler on the end, it gets the harsh fart can sound I hate. And worse yet, the pipe isn’t routed high enough and rests on the rear sway bar so sounds totally ghetto when I hit any kind of bump and clank away. I just ordered a small cylinder glass pack type muffler to act as a resonator, and a new cat. This is the setup I had on the first FX. Hopefully it’ll work as well here. I also steal the tubular steel headers from the 20 valve of the one previous FX. I plan to replace the cast iron 16 valve ones with it. The cast ones are actually regarded to be designed quite well, as you can see the designs are very similar. But the tubular ones look cooler, and are quite a bit lighter. The only problem is the 20 valve has different bolt positions on the end. That’s nothing a little drilling and grinding won’t take care of.

Got it dryfitted and looks like it’ll work good! I need the down pipe too so I pull that out and fit the old style O2 sensor. Once all the parts come in, I can take this all to Exhaust Systems and tell them to put it in. Can’t wait to be clunk free!