5 Mods in 5 Hours - CAT, Plenum, CAI, Ztube, Exhaust

On Saturday morning my brother an I installed the Crawford Plenum and High-Flow CATs, the Nismo Exhaust, ZTube, and JWT Pop-Charger. Here are my impressions on each:

JWT Pop Charger:
Very easy to install. Not a perfect fit for the FX (and maybe for other cars too). The heat shield just kind of sits in the car and is only really attached in one location. We installed a felt pad where the filter touches the heat shield. The filter too is only attached in one location, which is why it rests on the heat-shield. Even so, I have no doubt that this is an effective mod, but if you want the "polished" look, go for the Stillen instead.

Install Notes: When you cut and reuse the original rubber accordian piece, make it as long as you want. The place where you cut is smaller diameter, and this part goes INSIDE the Ztube. This is just rubber inside rubbery plastic, so you can't make the clamp too tight or you'll be squeezing the accordian piece out of the ztube. this is why it's nice to make the overlap as long as you can. The original larger opening goes OUTSIDE the MAF.

Z Tube:
Pretty straightforward.

Crawford Plenum:
The Crawford plenum is slightly bowed from when it cooled after welding. This is not a big deal, just use 2 gaskets and some liquid gasket if you want to be extra sure. The engine cover will not fit back on without flexing over the plenum.

Install Notes:
The engine coolant circulates through the plenum to pass federal emissions startup test. Basically, this requires that a car warm-up in two minutes. My brother recommended leaving this off the plenum to keep the intake air cooler. You will have to connect the two hoses to each other somehow.

Crawford CATs:
High flow cats have less than half the resistance of the stock cats. Instead of 2 cats (one dense and one "sparse"), there is just 1 "sparse". Also, they weigh about 10 pounds less each. With the stock exhaust, this mod barely changes the exhaust volume at all. I highly recommend this MOD compared to a cat-back exhaust. You can sell the palladium from your stock cats for about $100 if you know the right people :roll:.

Install Notes:
Surprisingly it is not too hard to remove the cats. On the Y-pipe side there are 2 bolts on each which are easy to remove. At the headers, there are 3 nuts. One of the nuts can be removed easily from under the car with about a 12-inch extension. The other 2 can be remove from above the engine by using all of your socket extensions and then some. And, a universal joint makes things easier. You will definitely need 2 people. Installing the high-flow cats you must use a bolt&nut combination, so you will need a short 14mm wrench to hold the bolt in confined areas while the other person tightens the nuts. If you are also installing the z-tube, do the cats while the intake is off.

The heat shield on the left CAT was much closer to the car than on the right side. I'm not sure why. When the engine is under load, the CAT was hitting my car and vibrating. We ended up chiseling off the heat shield on the left side. We tried a torque-strap on the motor but it didn't help. It is probably also possible just to bang on the heat shield with a hammer to make it clear, but we didn't have time to try this and have it fail.

NISMO Cat-back:
The installation for the cat-back is really simple. It takes about 30 minutes to change the exhaust. But my wife and even myself did not care for the louder exhaust note. I have no idea what this would sound like with the original CATs. But with the high-flow, it is a bit too loud for this type of car. I removed the exhaust on Sunday. If I had left it on, I would have needed another hanger to hold it up over the cross brace under the car. Also, the tips should be extended 7 inches for the FX35, or 2 inches for the G35. Extending the tips would probably make it quieter inside the car too.

FOR SALE: G35 Nismo CAT-BACK EXHAUST. I paid $950 + 80 shipping. Make me an offer (@nc.rr.com, e-mail buchu). I can deliver in the Raleigh or Richmond area personally.