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Bitten by the
Modding Bug

by Christi
May 2004

There’s no such thing as enough horsepower. Only enough to thrill temporarily, but the hunger for more always returns. There’s no sense in me trying to hide from the modding bug, it was time to tear into my 350Z. Headers, mild cams, and a new intake plenum should help me get my fix, right? After all, it’s about shaving every possible second off a lap time. My goal was to reach the 300 rear wheel horsepower mark, and have a smooth, strong power band kick in no later than 3000 RPMs and just keep going.

Now before I get into the nitty gritty of the installs and product reviews, I have to give a HUGE “thank you” to Aaron Bunch and his group at ATS Racing (www.atsracing.net). Being primarily an MR2 shop, they bravely took on the task of the headers and cams – both of which I wouldn’t dare pursue in my 2 car garage. Aaron provided a baseline dyno and interval dynos after each modification was complete to provide me with the most accurate results possible. He called to keep me informed of the progress, and didn’t mind my visits to see how my “baby” was doing. ATS is on of the few shops I’ve dealt with that I completely trusted and felt assured my car was receiving royal treatment. So thanks again, Aaron, for all your work!

HEADERS:

For the headers, I decided on the XERD long tubes. I liked the less radical bends and the fact that they were the only long tubes on the market (blame that on the V8 mentality I’ve had for years). For added finesse, I had them coasted with an aluminized ceramic coating, inside and out. Added protection and better air flow certainly helps. The power was right in line with XERD’s claims of 17 hp. After the dyno, I had an extra 16 hp and 14 foot pounds of torque at the wheels. Now that’s a good start!

As far as the sound goes, well, this is one VERY loud 350Z! The mild rasp I had before with the B&B exhaust now seems 10 times louder, and above 3000 RPMs, the car screams like a banshee. So much so that I’m now looking to replace the B&B with a true dual system that includes at least two resonators. I might even go with something custom to ensure I get exactly what I want.

CAMSHAFTS:

This was a tricky decision, because I wanted something fairly mild and something that would work well with a supercharger later on (just in case), but also wasn’t going to require major retainer, lifter, shim, etc. changes. The only plausible solution for me when I was shopping was the NISMO cams. I ordered from Performance Nissan (Thanks for all your help, Jenny!), and these cams advertise 13 more hp at the wheels. From what Aaron told me and from what I saw, the install is NOT for the weekend mechanic. Different torque specs for each cam and major engine disassembly made it a very involved job.

When all was said and done, the dyno results were a little disappointing. A gain of 8.5 hp and less than 1 foot pound of torque were added on the upper end of my now smoother power band. Initially, the car had some idling issues; however, I did not get my idle raised, as suggested by Nissan. For only 8 ponies, I wanted to at least keep the sound of a cammed car. After a month of driving, the ECU seems to have adjusted well, and any idle problems are virtually gone, but when they do creep back up, a quick turn on of the air conditioner bumps up the idle perfectly.

CRAWFORD PLENUM:

I ordered the new Version 5 plenum from Doug Crawford, powder coated in silver. Upon arrival and inspection, the exterior looked amazing, but some of the interior welds and the warp in the plenum itself worried me. I wanted to ensure the smoothest possible airflow into the engine, so Brinks Race Craft re-welded and flattened it perfectly for me. Now don’t get me wrong, I’d still choose Doug’s plenum over the current competition – something just doesn’t sit right with me about a plastic piece flexing repeatedly over time, especially since forced induction isn’t out of my head. Install was straight forward, although a shop manual is a good tool to have, since there is a sequence to removing and replacing the many bolts.

The advertised gains say 9 hp throughout and up to 17-20 more ponies at peak power. My results will be updated as soon as I get back on the dyno, but there are several independent dynos that back up Crawford’s advertised numbers.

CRAWFORD STRUT TOWER BRACE:

The stock brace will not clear the new plenum, and for a month and one autocross, I simply ran without one. The difference in handling has not been noticeable; however, having the new bar can’t hurt. I’ll be running my car with it, but with my other suspension upgrades, it seems like it’s more a personal preference.

CONCLUSIONS:

The pursuit of a naturally aspirated 300 rear wheel hp car is not a short one. After my cams and headers, I went from a spiky 241 rwhp to a much smoother 263.8 and 246.0 foot pounds of torque. Assuming the plenum provides the advertised power, I’m sitting right around the 280 mark. Not quite my goal, but still 40 more ponies than I started out with, and now my power band is surprisingly smooth and keeps on climbing right on through redline. If I had it to do over again, I would have researched a bit longer and waited for a few more options in cam choices to come out. It’s still a BLAST to drive, and I keep thinking to myself, “It’s not supposed to be this easy to break loose a set of 19x9.5 inch tires, is it?”


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© 2003 Z Chickz
Last updated: Sunday, January 14, 2007 8:45 AM