I posted this info in another thread and thought it might be more useful as a stand alone thread. It's not all of the detail, but it's definitely a good starting point. There is countless detailed information on other forums such as www.b15sentra.net or www.thevboard.com, but just trying to add some more info here so that this section of the site can start building a little bit. Anyone feel free to add anything that I may have missed. Enjoy!
But to answer your question (The question was "What mods should I do first?"), it all depends on what you're looking for. Do you want more power, or do you want the handles? I went with CAI and exhaust first, then header, motor mount inserts (a must to reduce wheel hop, and they're cheap!), pulley, short shifter, and those are my GO mods. But this was my first modifiable car and I was uneasy in dealing with the suspension because it felt better than anything I had driven. But when I did the suspension, it was WAY more fun to go faster around the corners then to go faster in a straight line. If I were doing it all over again, I would kind of intermingle the go fast and handle mods. Here's my list in order:
- $200-$225 (AEM, Injen, Nismo, Hotshot) - Cause you want to go a little faster, it looks nice in the engine bay, and sounds good.
2. Motor Mount Inserts
- $50 (Energy Suspension) - Trust me, you need these. And they're cheap. They help reduce wheel hop tremendously, as well as improve the shift quality since the engine is not shaking around as much and pulling on the shift cables. Another addition to improve shift quality is to replace the tranny fluid with either Royal Purple or Redline tranny oil. You'll need 3 quarts.
3. Coilovers or Springs
- $200-$250 for springs and $700-$1,200 for coilovers dependent on brand and desired adjustability (Springs - Eibach, Tein, Sprint, B&G, Progress / Coilovers - Tein, JIC, K Sport, Nismo)
-Your needs and budget will determine what you get here. If you just want a little drop for cheap, the Eibach Pro Kit is the normal first choice. Only $200+ for the springs with a decent drop and higher spring rates. If you get just springs though, be prepared to buy new struts in a year or a little more than that. Most people then replace with adjustable Koni Yellow inserts, but they're a PITA to install.
-If you save and spend a little more on a coilover setup, you will be happily rewarded for your patience I promise. The Nismo's ($600 or so) are good if you want a slight drop (about an inch), better performance, and just a plug and play. The Nismos are a direct bolt-on affair. With all the other suspensions, you have to take off the upper mount for re-use. These are really good for the driver looking for a nicer suspension, but doesn't really want to race the car. The Tein Basics ($750-$800) are very good if you want only height adjustability only. They provide a stiffer ride and allow for lowering to your preference. Very good for the beginning racer, but also very good for everyday use. The Tein SS ($1100-$1200) are exactly like the Tein Basics, but provide adjustability of the dampers. These are definitely a greater investment, but you are rewarded with the additional adjustability. Very good for being able to fine tune that suspension to your particular liking and use at the time. You can make them softer for everday driving, and stiffer for racing, as well as being able to control the difference between the front and rear stiffness. The Tein SS can also be made even better with the addition of an EDFC (Electronic Dampening Force Controller - $400) which is like a little servo that sits atop the damper and can turn the dampers stiffer or softer from a controller inside the car. The next major investment are the JIC FLT-A2's, which have all the benefits of the Teins, but also include adjustable camber plates for the front. The only problem is, the camber plate lies on top of the strut, but below the strut tower. You have to take off the upper part of the suspension to adjust it. There is also only so much adjustability to the camber that can be allowed, due to the smaller opening of the hole in the strut tower.
- $300-$750 (Greddy, Magnaflow, Stromung, Apexi, Stillen, Megan Racing, Nismo, many others) - This all depends on how much money you want to spend and what kind of sound you want. You can get an axle-back for cheaper from either Stillen or Megan Racing, or go all out with one of the many catback exhausts which range in piping from 2.25"-2.5", although it is believed by many that the 2.25" piping is the best for overall performance. Also, now you have that great exhaust sound that everyone can hear from miles away!
- $200-$500 (Hotshot, AEBS, Megan Racing, Nismo, OBX, Stillen, a few others) - This mod is a MUST! If you want to have the most power bang for your buck, this is it. Now that you have the CAI and exhaust, this just helps complete the package for some really good performance gains. You will also notice a louder exhaust tone. Not only that, but if your 2002-2003 Spec V has not had the pre-cat recall done, this will keep you from damaging the engine, but that was mostly a 2002 problem. All of the headers above will give you a nice power increase, it just depends on how much money you want to spend and what kind of quality you want. The Hotshot is one of the most popular and a very quality piece for not alot of money. The OBX is a Hotshot knockoff giving pretty much the same power, but not as quality. The Nismo is really nice, but really pricey. The Stillen also comes with a replacement mid-pipe as well so that there will now be no-cats. Also, most of these headers require you to extend the wires for the secondary O2 sensor and weld in another plug behind the cat to keep from getting a CEL light. Even after relocating, you may still get a light which can easily be fixed by using an O2 simulator from Casper Electronics ($40). If you want to complete the header/exhaust combo, hpautoworks.com sells a midpipe to replace the second cat, as does Megan Racing. Also remember, if you get the header before the exhaust, prepare for the worst sounding exhaust EVAR! Trust me, it's that bad.
6. Rear Sway Bar ($175), Lower Tie Bar ($125), and Front Sway Bar ($175)
- (Nismo, Stillen, and Progress) - Now it's back to the suspension! Of these three companies, the best bars to get in my opinion are the Nismos. These bars will completely change how the car handles...again.
-Now that you have the coilovers (preferably), it's now time to get rid of some of that nasty understeer. This is where the RSB comes into play. The Nismo RSB is adjustable so that you can change the stiffness depending on your preference, driver skill level, and general driving style. This should not be set too stiff initially, as you will need to get adjusted to how the car handles. Under mid-turn throttle lift, you could easily experience some slight snap oversteer if you're not careful. The RSB connects the trailing arms of the rear suspension to stiffen things up and has sliding mounting points to control the stiffness.
-Next is the LTB. This is an excellent suspension modification as well. The LTB connects the lower pickup points of the suspension to hold things tight up front. This has an excellent effect on initial turn in, as the car now seems to go exactly where you want it when you turn the wheel. It also helps keep the suspension from getting more positive camber while in the middle of the turn. The LTB also lowers the ground clearance of the car by about a little over an inch as an FYI.
-FSB is also a nice addition. It once again helps to stiffen up the front and control some of that body roll. This is a nice additional mod to kind of bring everything completely together. It's not a necessary suspension mod, but it does help stabilize the car a bit better.
-I didn't mention the Nismo Front Strut Tower Bar, simply because we already have a FSTB stock, and personally I can't see the Nismo really helping out much handling wise. But it will look nice in the engine bay!
- $175 (Unorthodox Racing, Southwest Autoworks) - The pulleys provided by both companies is NOT an underdrive pulley, but a lightweight pulley of the same diameter. No changes in the belt are required. The pulley is another nice addition to the performance, since the stock pulley weighs a ton. It has been proven to add horsepower to the car, but it's biggest benefit is the increase in acceleration from the quicker revs, now that the crankshaft has less mass to turn.
Now this is where the mods start getting a little more hardcore, involving actual internal engine modification.
8. Balance Shaft Removal Kit
- $100 (Jim Wolf Technology) - The QR25DE was built with a balance shaft to help smooth out and stabilize the crankshaft to reduce vibrations. Some have said that due to this balance shaft counteracting with the crankshaft, that there could be negative long term effects and is not needed. This has been proven due to the fact that the QR25DE for the X-Trail in Canada, does not have a balance shaft. The BSR Kit calls for removal of the balance shaft assembly, and replaces it with a couple of oil trays (I forget exactly what they're called and what they do, but it's good for your engine). This mod has been known to add up to 8 whp, due to the fact that there are no longer these counteracting forces working on the crankshaft. This mod requires taking off the lower oil pan, and taking it out from inside the engine. This will no doubt completely void any warranty and is not able to be returned to stock. Cheap cost and nice hp gains, but make sure it's worth the commitment. Also, removal of the balance shaft assembly allows for a total of 6 quarts of oil I believe, instead of the normal 4 1/2 quarts.
9. Clutch and Flywheel
- $750 (Jim Wolf Technology) - Probably the best and most used clutch/flywheel combo on the market. While you're doing one, you might as well do the other. They can be purchased separately, but why would you do that? The lightened flywheel weighs in I believe at 11 pounds, once again reducing the mass that the engine now has to turn, thus improving acceleration and quicker revs. The clutch is a very streetable clutch as well. I've driven on it and it's not that much more stiff and provides excellent grab. Definitely a mod worth the money, if you're ready and willing to do the work or pay someone good money to do it for you. This is one of the more difficult DIY mods.
- $650-$750 (Nismo and Jim Wolf Technology) - I'm not extremely knowledgable on the cams, so I'll try not to pretend to be. I believe that the two sets of cams are fairly similar (JWT vs Nismo), and the general results have been an increase in power, not a huge increase overall, but most of the increase coming at the top of the powerband, where the engine tends to want to die out. Now with the cams, the power feels strong all the way to redline. Once again, a much more difficult DIY mod.
11. Apexi SAFC II
(Super Air Fuel Controller?) $250 - The SAFC II is a controller that allows you to fine tune your air/fuel ratios throughout the powerband and allow for smoother and additional power. Some people have seen up to around 8 whp, depending on mods. It is a great way to really keep everything running smoothly. It will also show throttle position, RPMs and other little gagdets. You may be wondering though why I have this mod so late in the install list, and here is my reasoning. To accurately tune your a/f ratios, you need to get it tuned on a dyno. An hour of tuning on the dyno runs somewhere around $150 per hour, and that's also if you can find one in your area. And each time you add another mod, your SAFC II "should" be retuned for the new changes. If I were getting one, I would make it my last planned mod so that I could only go to the dyno once to fine tune everything and leave it alone. Now there are a lot of others who just street tune their SAFC II and things seem to be okay, but it's not an exact science. Also, many people will do this mod after intake, header, and exhaust.
12. Turbo Kit
- around $4,000 (Powertech Imports) - If you want the ultimate power, you can always just opt for the PTI turbo kit. It is a kit that is proven to turn out on average around 275 whp. Now if you plan on doing this, don't waste your money on an intake, header, or exhaust as these pieces will be replaced with other goodies. An exhaust may be okay though, provided you are getting a 2.5" catback exhaust, but 3" would be optimum for a turbo setup.
Good places to purchase these parts:
I have purchased parts from each one of these places and have had a positive experience. Just search around and see which site has the best prices on the part you want. Another good way to find these parts for cheaper is to get involved in group buys on other forums, as well as the classifieds section. Great deals on good items.
And I'm finished with it, for now. Hopefully this information will help give others an idea of what they want to do. It's not all of the detailed information, but hopefully enough to get people looking for the exact details on other forums. Remember too, there are a lot of things in here that are my opinion, and I am by no means an expert, nor do I claim to be. If I missed anything feel free to let me know. Once again, I hope this gives you an idea of what's out there and what you want to do. Good luck and happy modding!