7. Drive train/Engine modifications: I listed this category towards the end for good reason. The first reason you should be getting use to your car in stock form and learning its limits before adding hp. I felt I need to add hp to my Z the very first day I drove it off the dealer lot. Not until I took it to a track did I realize the full capabilities of my 350Z. I found that while I was driving it, the main performance modification needed to be modified was me, being the driver learning how to drive it to its full potential. Honestly, if you care anything about performance, you should take your Z to the track. No matter how aggressive you drive on the street, driving it on a track allows you to push it much harder and in a safe environment. Besides that, it is a blast to do.
There are new options in this group being released almost daily. Just in this month alone (November 2003), the Vortec SC is being released; the Greddy TT is now taking new orders. Several other SC and TT kits are scheduled to be released within 1-2 months. Waiting a little bit to add other modifications is not a bad idea. Let’s go over the options:
NOS: Do you want cheap HP and your desire is to beat that Mustang next to you? NOS is an option you should consider. Some people dislike it but no one can disagree that it adds hp for short bursts and does it cheaply.
NA: Some people think real engines are Naturally Aspired (NA). For those people, NOS is just flat cheating and SC and TT cars are better but have limitations. Every one of these options has pros and cons or there would only be one option. Here are the pros/cons of NA: SC and TT may have a tendency to run hotter. There is a question of reliability when you FI a motor. The 350Z VQ motor was designed as a high compression motor yet FI motors run optimally as low compression. With a NA motor, you do not have the “turbo lag” often found on TT. This turbo lag can be an enemy on the track. Most people that decide to add hp by NA often state it as being more dependable and predictable on a track. The negative is cost. Expect to spend approximately $5000 to add 50-60 hp. In addition, as soon you you add cams, your motor warranty is void, even if it is a NISMO cam because the NISMO cams are type R which is for racing thus no warranty as compared to type S which are for street and maintain the factory warranty. Typical NA mods include exhaust and headers, cams, pulleys, air intakes, and plenum. Remember, don’t add a plenum and then decide to get a Dream Workes or Stillen supercharger because you will simply be taking off the plenum you just purchased. You got to make up your mind if you are going NA, SC, or TT before you begin modifying your motor unless you like wasting money.
Superchargers: There are two types of FI, Superchargers (SC) and turbos which are most often twin turbos (TT) on 350Z’s. A lot of debate is covered on various threads concerning advantages and disadvantages of SC vs. TT. Some people tend to be very pro – supercharger and others are pro TT. I will try to be as objective as possible but I am sure my opinion will differ from others.
Supercharger kits typically run about $4800-$6000 + installation takes anywhere from 8-20 hours labor depending on the kit thus figure at least another $1000 in labor to install. All of the kits either come with an intercooler (IC) or can be added as an option to the base kit. I strongly suggest you get the IC since it keeps the motor running cooler and cooling is a major issue for any FI motor.
The two most common types of SC used on the Z are the centrifugal SC and the Root type SC.
The ATI Procharger and Vortec SC are the most popular centrifugal SC available currently. Both of these kits put out approximately 350-370 rear wheel hp (RWHP) at 7 psi of boost. Adding the approximate 17% loss from the crank to the wheels, that would equal about 409 to 432 rwhp. This is a significant jump over the 287 crank hp (approximately 230-245 rwhp found on a stock 350Z). Both of these kits void the engine warranty by Nissan unless you can find a dealer that will sell you them installed on the car when it is new. The significant difference between the centrifugal SC and the root is the centrifugal SC does not have full boost until you reach higher rpm’s. To be simplistic, a centrifugal SC has 1 psi of boost per 1000rpm being the peak boost is 7 psi. Boost increases hp thus a centrifugal SC really kicks in when it is above 4500 rpm since it is then approaching full boost/ peak hp.
The other type of SC is the root. The only current root SC available is made by Stillen. Dream Workes (DW) is scheduled to release a root type SC in January of 2004. The root blower is position on top of the motor as compared to the centrifugal SC that is located off to the side of the motor. The Stillen SC sets so high on top of the motor that to install it, the strut brace has to be removed reducing handling and the hood has to be cut out and a scoop added or an entire hood has to be installed. The soon to be released DW SC is designed to use the stock hood and maintain the strut. Both of these root type SC have full boost at low to high rpm thus more low end grunt. These SC kits tend to put out less peak hp by approximately 20-30hp but advocates of the root type blower will say that the root SC provides you with more power where you need it rather than a little more hp right before you shift. The Stillen SC will provide you with an engine warranty if you do not boost it over 5.5 psi but then you will be putting out approximately the same hp as a built NA motor. DW plans on offering their SC with 400 crank hp (approximately 330 rwhp) with a full drive train warranty and be the first to offer CARB legal installation which means that owners in California can pass smog with their SC Z’s. In addition, they plan on having upgrades to further increase hp but the warranty will be voided. Stillen has just released an IC for their Sc kit which creates more hp. the warranty would be void with this set up so it comes down to hp vs risk level. that is a choice you must make based on your needs and comfort level.
With all of these FI kits, tuning and boost seem to be critical issues related to reliability. I cannot stress enough that you should get an experienced tuner to install these kits. Before doing that, you should read hours and hours of posts and anything else you can get your hands on before selecting a kit and an installer. Do your research and ask a lot of questions before you decide on a kit. If you raise the boost, most of these SC kits have the capability to exceed 500hp. The other side of the coin is if you raise the boost, are you keeping within the specifications of the kit your purchased? Even adding a simple addtional modification might cause problems with a FI kit. Be sure to talk in detail to the manufacture and installer before doing anything. Something you might think is ok to do might not be ok and cost you thousands of dollars to repair. As with turbos, I strong suggest that if you exceed 7psi of boost, you consider modifying your pistons, rods etc to maintain durability.
Twin Turbos: for the person that wishes to build the ultimate hp capable in the VQ, the TT is their most likely choice. Boost can be modified on a SC by changing the pulley but it is simpler and quicker in the TT. You simply dial it in sitting in the driver seat. The two most commonly discussed TT kits currently are the Greddy TT and Power Enterprise TT (PE). Both of these kits cost approximately $7-8000 and then installation needs to be added to that cost. The TT has the potential to exceed 800hp. Before you dream of just turning up the boost to get those numbers, strongly consider building the internal portion of your motor to accommodate that power output. You better know what you are doing if you are putting out this much hp. An improperly tuned motor putting out this much hp is a time bomb waiting to explode.
Since all of these SC and TT kits have either been just out a couple of months or not even out yet, the reliability of these kits are not proven to MY personal satisfaction. Large debates over how much boost can be given to each kit goes on daily. To be blunt, everyone has their opinion but the fact is no one knows what is a safe level of boost yet. Motors will be blown up defining those limits. Some argue the VQ is extremely limited in the amount of boost it can take, others feel it is a question of proper tuning and once tuners get a better handle on the ECU (car computer) and can control the fuel management, they will be able to safely increase boost to higher levels.
Because of the introduction of new kits monthly and the issues of safe boost and tuning, I again caution you to modify your wheels, tires, stereo, and suspension first until these issues are resolved. If you know more than me and feel comfortable doing it now, then that is fine as long as you know enough to make an educated choice with your money. A lot of people will tell you to go for it, that is easy to do when it is you taking the risk with your money. In my opinion, if you want only 400 – 435 crank hp and you are on a budget, the SC kit might be a wise choice. If you are desiring the ability to exceed 500hp with unlimited options in tuning, the TT kit may be a better choice for you assuming you can afford it.