Engine Bay Mods


Photo Credit: Rene Saran, Jose Vargas, Rabbit Hole Motorsports

Push-In -8AN fittings to accommodate the 5/8″ PCV tube found on VQ engines valve covers to clean up your Oil Catch Can setup. These are AN fittings designed to be pushed in your engine valve cover plastic tube outlet, they do not replace the threaded PCV Valve. Made with precision machined 6061-T6 Aluminium, hard-anodized finish and laser-etched RHM logo.

You can order on their website or contact on Facebook.


Credit: Ballistic Autowerks

I get asked about this frequently. These vehicles are extremely sensitive when it comes to adding accessories to the battery, even with a factory alternator that ranges from 130 to 160 amps depending on the brand. Upgrading the “Big 3” components of the electrical system is crucial for accommodating additional add-ons such as air suspension, stereo systems, underglow, interior lights, and more.

We offer pre-made Big 3 kits specifically designed for these cars, including the dealer for JS Alternators. Today, we completed one of these installations (with unlimited color options available) using the customer’s existing setup and enhancing it with a Big 3 upgrade to prevent power drops. This upgrade is beneficial not only for aftermarket setups but also for maintaining the health of the battery and alternator in factory configurations.


Member Credit: Aaron92SE

Ever since the 2009 Maxima came out, I knew that an NWP Engineering VIAS Block Plate Kit could possibly be a great modification to offer to the community. And for the past year or so, I have been working on this project for the 7th gen 2009+ Maxima. I realize that a block off plate kit is currently being sold by someone else. But, I do not feel it’s necessary to abort a project simply because a different kit came out before we had a chance to finish our testing.

Here are some pictures of the NWP Engineering prototypes:

Several hours have been spent on the dyno testing these prototypes. The stock 7th gen Maxima only comes with a CVT (Continuously Variable Transmission). This means that the gear ratios are always changing during the dyno pull. Since this is the case, you are unable to accurately use the dyno charts to determine HP gains and losses in various parts of the powerband. Simply put, running a CVT on a dyno can possibly provide some ballpark numbers to look at, but they will not be accurate in determining low end, midrange, and top end HP results and comparing before and after dyno runs. The only way to properly dyno test a vehicle with a CVT transmission is to lock it into a 1:1 gear ratio and currently, this has never been done on a 7th gen Maxima

Here is a before and after dyno comparison of a stock intake manifold with stock operating VIAS actuators versus the VIAS actuators being removed and block plates installed:

As you can see, there is a huge 19 ft-lbs of torque loss in low end power and roughly only a 2HP increase on top end. But, this is only comparing two dyno runs. If you know how NWP Engineering does dyno testing, you know that we are way more accurate than this! We always like to take an average of all the dyno runs.

We did 4 dyno runs before and 3 dyno runs after the NWP Block Plates were installed. Then, we exported the runfile data to an Excel spreadsheet so that the numbers can be analyzed more thoroughly. Horsepower and torque data was taken at every 100rpm and used for this comparison. At every 100rpm increment for every dyno run, an average was calculated and then plotted on the dyno chart shown below.

Since the 2009 engine was running so consistent, our average dyno comparison chart looks almost identical to the two dyno runs shown above. But, these average results are even more accurate than simply comparing two dyno runs with one another.

As you can see from this dyno chart, that by eliminating the VIAS actuators, there is a low end torque loss of 18.9 ft-lbs at 3600rpm with an average loss of 14.6 ft-lbs between 3200-3900 rpm. And there is a gain of 1.4HP at 6200rpm with an average gain of 1.3HP between 6000-6400 rpm where the 09 Maxima CVT holds the revs at during a wide open throttle run.

In order for your Maxima to accelerate at the same rate or faster from 0-60mph or in the 1/4 mile, you will need a much greater top end HP gain to compensate for the big low end power loss even with the efficiency of a CVT. So in other words, your car will accelerate slower from 0-60mph and in the 1/4 mile with the VIAS actuators removed.

I am really surprised with the efficiency of the stock 09 Maxima Upper Intake Manifold (UIM) with the stock variable induction air system (VIAS).

Unfortunately, the results are not what we had hoped for. I knew there would be a low end power loss, but I didn’t know it would be this large of a loss. And I really thought there would be a noticeable top end HP gain to make it worth it overall like the 02-08 Maxima VIAS removal does. But, what seems to work for the 02-08 VQ35DE Maxima does not necessarily work on the 2009 and newer VQ35DE Maxima.

Due to what was proven in our testing, I do not see a need to produce the VIAS Block Plate Kit for the 2009 and newer Maxima. But, I feel compelled to share this information to the Nissan community to let you know what kind of projects NWP Engineering has been working on lately.

As you can see, we thoroughly test all our products before they are released. I won’t release a product unless it has been proven to benefit your car’s performance. This is not the first time we’ve tested an NWP prototype and had to abort it due to low performance gains.


Every engine swap requires tuning. Why? Without proper tuning, the engine control unit (ECU) will operate on a low timing map up until around 5000 RPM. After that, it starts to add more timing, and you’ll notice the vehicle suddenly accelerate. However, performance will be suboptimal—expect lower power and reduced fuel efficiency.

For those driving engine swaps without a tune, your perception of the car’s power is likely inaccurate. However, if you’re satisfied with an untuned swap, just imagine the significant improvement a tune can make. In the past, enthusiasts would install new engine swaps without tuning them and then compete against first-generation cars, often losing by significant margins.


Credit: Victor Dragos

  • If you are very proficient at wiring.. like you’ll need to rewire the whole car in order to run 02+ ECU, add electric gas pedal, a different cluster, different fuel pump module + a lot of other small things.
  • Or You’re good at mechanically to swapping to 3.0 timing and only need to wire up/change 6 injector plugs and iacv plug.
  • I’ve done way too many 3.5L motors on 3.0 timing and only 1 full 3.5L wiring swap.
  • If you consider that +15hp difference.. I’d rather do 3.0 timing everytime. If boost is involved forget the 3.5l wiring.. too many issues too many things to tune.
  • 2020 motor 3.0timing 5spd vlsd gearbox below. (Mijo Too Wavy build)

Credit: Rick Eggers

  • Simple, no replacement for displacement. Variable time is usually not for added HP, is for low end torque, emissions and fuel economy. If you’re looking for HP getting rib of variable times is usually a good thing. Plus, when you do a VQ30 to VQ35 swap and reuse the VQ30 timing you can reuse the VQ30 wring harnesses, sensors and ECU with slight modifications. If you keep the VQ35s timing it’s a totally different ball game!

Credit: Rob Tilley

  • This is a 99 vq30 timing vq35 with cams/pistons. Stock rods. 6spd. @11# on a jwt ecu maxing out a z32 maf.



Credit: Weimar Ben

This guide assumes you will be using the 3.0 wiring harness with a 95-01 ECU.

Acronyms used during write-up:

  • 4G- 1995-99 Maxima
  • IACV – Idle Air Control Valve
  • ECU- Engine Control Unit
  • FSM – Factory Service Manual
  • TB – Throttle Body
  • TPS – Throttle Position Sensor
  • FPR – Fuel Pressure Regulator
  • UDP – Underdrive Pulley

Tools needed:

  • Cherry picker (engine hoist)
  • Metric socket set
  • Torque wrench
  • Gasket scraper
  • Breaker bar (for the crank pulley only)
  • Air tools are a great time saver
  • Floor jack
  • Jack stands
  • Common sense
  • A buddy to help you mount the engine and lock the flywheel in place when taking off the crank pulley.
  • 95-99 FSM
  • When you receive the engine, do a leak down test to verify the health of the engine. You do not want to go through the work of putting in the engine only to find out that there is a problem with it.

To use the 3.0 ECU, you must use the 3.0 inner and outer timing cases, chain, and sprockets. You can use the 3.5 cams you will need to enlarge this hole in order to use the VQ30 timing cases. You need to enlarge the corresponding hole on the left side of the timing chain case as well.

(Credit: Nismo3112)

Drill the intake cams in order to reposition the dowel hole or you may purchase an spacer piece by StephenMax for $75.

To use the 3.5 cams, you must use cam spacers. (Credit: japmaxSE)

You will need to modify the TB to be cable driven or use the 01-02 Pathfinder TB. The cable plate from the 4G maxima bolts onto the 3.5TB butterfly rod PERFECTLY, you just need to add a small washer for it to clear. This is much easier than finding a Pathfinder TB, and cheaper. It saves $100-200 from having to buy a Pathfinder TB for the swap.
(Credit: Nismo3112)

Things to make it work:

1. The TB is flipped upside-down
2. You need to dremel a little off of that gold piece that goes with the TPS, and make a bracket for it to work. The gold piece to the left of the TPS you see in the pic, will go on the rod before the nut.
3. A stopping nub is shaved off, the other stopping nub was shaved some.

Getting the TPS to turn nicely with the throttle rod is the hard part.

Completed Fabrication of TB/TPS: When mounting in the vehicle, do not mount it on the firewall, your car will jerk like there is no tomorrow!

NOTE: This isn’t the only way to do it, be creative. (credit: Nismo3112)

If you want to use the 3.5 injectors and fuel rail (and you should), you will need to convert your fuel system to returnless or you will need to add a FPR in place of one of the 5.5gen dampers.
(Credit: Nismo3112)

All you would need to do is put a tee in the fuel line between the fuel filter and the fuel rail. One leg of the tee goes to the (unmodified) fuel rail, the other leg goes to the FPR and from there to the return line to the tank. Voila, a returnless system, as far as the fuel rail is concerned.
(Credit: Stephen Max)

The FPR needs to be around 51PSI or be adjustable for this to work properly. There is a NISMO adjustable one at CourtesyParts for $127. A generic one with a dial on it from of Ebay for $45 will work just fine.

(Credit: JClaw)
“You can keep the VQ35 oil pan and all the accessories will still bolt on. You can use the 3.0 oil pans and still retain the 3.5 oil cooler. The oil cooler bolts right on to the 3.0 oil pan. This way, you don’t have to remove any material to have the 3.0 CPS sit at the right distance from the signal plate and you don’t have to plug the coolant hole. If you use the 3.5 oil pans, you have to shave about 1/4 inch off where the CPS at trans goes, If not the sensor is too far away to read the flywheel. I would rather not remove the lower and upper 3.5 oil pans. That’s more work than just shaving 1/4 of an inch off.”

Replace all injector harness connectors with VQ30DE-K(2000-01) or VQ35 connectors.

Make a mounting plate for the 4G IACV and route the idle air hose to somewhere into the intake manifold.

Remove all of the ignition coil harness over wrap in order to be able to connect the ignition coil harness connectors to the coils. Rewrap with electrical tape once you have them rerouted. While in the motions you should replace the hoses, belts, and fuel filter just to be safe.

Completed Setups:

(Credit: Dubbya)

(Credit: Nismo3112)


What does it cost?

  • $700-$1200 for a used, low mileage engine. Check Car-part.com(link is external)
  • $250-$400 for an upgraded clutch
  • $80 – RPM switch
  • $50 – drilling of the 3.5 intake cams
  • $80 – JWT cam spacers
  • $50-125 – FPR
  • $50-$100 – misc. tools and supplies you will need – couple of tubes of RTV sealant, belts, fuel filter, hoses, etc.

Where can I get an engine?
A local junkyard would be best. If you can’t find something locally that is suitable try Car-part.com(link is external). Tilleys99 sells prepped 3.5’s that are ready to drop in for either $1500 or $2000?

Can I use the 02-06 ECU?
Yes, but it’s a pain in the rear end and you basically have to rewire the car. If you choose this route, you’d better have a wrecked 02-06 that you can cannibalize parts from.

What are the pros of using a 02-06 ECU?
Better timing, E-gas, variable cam timing, 5-10whp more.

What are the cons of using a 02-06 ECU?
Wiring, higher cost, shitty fuel maps above 6000rpm, 100% throttle at 6000rpm really means only 80%. The fuel maps and E-gas problems are fixed by ECU upgrades.

What are the pros of using the 95-99 ECU?
Easy wiring, lower cost.

What are the cons of using the 95-99 ECU?
Crappy timing, fuel maps, lack of variable cam timing.

How hard could the wiring for the 02-06 ECU really be?
Here’s what JCLAW had to say about that…..

“The thing that really f*cks everything up is drive by wire. Sure, you can simply swap in the main harness and not worry about anything else, but then oh no, the drive by wire harness is part of the body/electrical harness, a bunch of taped-together wires the size of your d*ck, pick and choose, find the good one, then you have to buy the steering column from a 02 Altima or Maxima, rip both apart, and try to fit the ignition equipment from the newer car in the older column, which leads to another problem.

Oops, the airbags are on the same harness, so won’t work. Then oops, you’re trying to fit the 02 Altima drive-by-wire gas pedal and it wont fit, it should be on the floor right where the steering column base is. No problem, just try to shape/weld some complex bracket there so the gas pedal is where it should be.

Then you have to drill 2 1-1.5″ holes in your firewall, because the 02 Altima has more electrical hardware in the front than your 4th gen does, and those harnesses are essential because, remember, the drive by wire (10-12 wires I believe) is part of it, so you have to use it, that means you have to rip apart your entire interior, and hope to hell that the 02 Altima you got it from has a sunroof if you have one, if not, no more sunroof.

Then, you have to hope as hell the wires will plug into your electric door motors, and oops, they don’t, so you have to buy the 02 Altima door motors for your electrical windows to work, that’s in addition to the engine (1 grand), and another grand’s worth of ECU, 3 complete wiring harnesses and an electronic gas pedal whose signal no one can crack. So you hope like sh*t that the electrical door motors from the Altima will fit in your 4th gen, but the f*ckers won’t! So now you gotta weld complicated brackets into your doors (!!), thus adding weight to your car, just to make the f*cking window motors work!

Then you have to rewire all connectors for every single light in the car, and hope to hell the gauge cluster from the 02 Altima works in your dash… oops, it doesn’t. No problem, right? Just cut the dash apart. Then you have to fit all the electrical hardware in the engine bay, in a platform that wasn’t made for it.

Fans? Radiator? AC? Forget it. And the transmission? Nope, not the same sensor, plug is different, aw sh*t car won’t start, you need the immobilizer. Big black box.

No problem, go back to a junkyard, if you can find one that’ll sell it to you. Oops, sold. Get the immobilizer from another car, right? Sh*t, the ECU, ignition key, and immobilizer ALL MUST come from the same car, so if the immobilizer doesn’t match the ECU and ignition key of the very same car, it won’t start, ever, and since you don’t have the same exact immobilizer, means you’re quite completely f*cked now, doesn’t it?”

But, but, I’d really like to have the better timing, better fuel maps…….
Get a Technosquare or JWT ECU and have them advance the hell out of the timing. Alternatively, you could get a E-manage Ultimate and do the same thing and be able to alter the A/F ratio.

Where can I get the 4G FSM?

What comes with a junkyard engine?
Full wiring harness, coil packs, exhaust manifolds, IM, TB, water pump, all sensors. They usually do not come with any of the accessories-starter, alternator, PS pump, A/C compressor.

How much power will I get?
Stock: 200whp/220wtq
Some mods: 230-240whp; 230-240wtq

How fast will it be?
With mods, low to mid 13’s in the ¼ and 5’s 0-60. No mods, high 13’s. low 6’s for 0-60.

Is it a direct drop in?
Yes, and no. Externally the 3.5 and the 3.0 blocks are pretty much the same and everything bolts right up. The sensors, fuel rail, and fuel injectors are not the same.

Can I use my 5 speed?
Yes, it bolts right up.

Can I use the 6 speed?
Yes, it bolts right up, but it’s a lot of work. The consensus is that it’s not worth it unless your 5 speed has assumed room temperature.

The 5 speed is rod-driven and the 6 speed is cable driven. In addition, the flywheel is different. The 4th gen ECU will not be able to read the 6 speed flywheel. You need to hack a 6 speed flywheel to have the 5speed CPS ring to use it with the 4th gen ECU. You will also need to get different axles (CV joints). You will need to get the 6 speed tranny mount and bolt it to the frame. You will also need to get the 6speed shifter assembly.

Do I need to upgrade my clutch?
YES, at least a stage 1 clutch, stock 5.5gen, or Altima 3.5SE clutch. The stock 4th gen clutch will not hold the TQ the 3.5 puts out.

Can I use my autotragic?
Yes, but they’re some debate whether the 4G auto can handle the power. Some say the 95-03 4spd autos are all the same and some say the 02-03’s are beefed up. Autos in general usually take more TQ well and I think that a 4G auto should work fine, assuming it’s in good mechanical condition.

What mods are recommended for the swap?
Headers or the 4th gen exhaust manifold with a y-pipe are highly recommended. This frees up around 20-25whp. Intake is maybe 5whp. UDP is also a good mod. I recommend the Motostorm UDP. The UDP for the 3.0L is the same except the 3.5L UDP doesn’t have the timing ring.

Do the 3.0L headers (exhaust manifolds) fit on the 3.5 block?
Yes, everything matches up perfectly. If you’re not using aftermarket headers, I highly recommend that the 3.0L headers be used since they don’t have any precats in them.

3.5L stock headers with the 3.0L stock Y-pipe would be VERY restrictive. Don’t do this unless you want to have potentially less power than your 3.0L had.

Can I use other 3.5 engines other than the maxima 3.5?
You can use the 3.5 from the Maxima, Altima, Murano, Quest, and I35. You CANNOT use the G35, 350Z, Frontier, or Pathfinder engines because they are RWD.

Does the Altima SE-R and the 04-06 Maxima engines really have more power? What are the differences?
The consensus is that they have a little more power due to ECU tuning and a slightly different IM. The difference is probably 5hp or less. The 04-06 Maxima engine has an external EGR valve, so it would be easier to pass emissions in most states with an external EGR than trying to convince them that the exhaust cams do it in the 02-03.

Can I use the TB (E-gas) that comes with the engine?
If you use the 02-06 ECU, you can use the E-Gas TB. If you use the 95-01 ECU, you will need to mod it to be cable-driven or use the 01-02 Pathfinder TB.

If you want a better 5th gear for highway cruising or want a more aggressive final gear, you can do what jclaw did and swap out the final gear and 5th gear from other transmissions. I’ll have to find jclaw’s thread for that.

Can I use the 3.0 heads on the 3.5 block?
Yes, but this is not what you want to do. The 3.5 heads flow better and get better HP and TQ.

Can I use the 00VI on 3.5 heads/block.
Yes, but the ports don’t match up. Many think the 00VI flows better, but no one’s done a dyno yet. If you want to go this route, you should get pathfinder heads that have ports that line up with the 00VI IM. Putting the 00VI on the maxima 3.5 heads may lose you some power. I recommend using the 3.5 maxima heads and waiting for a decent IM from Kinetix.

Can I use the 350z/G35 IM?
NO, it won’t have the TB in the right place and it won’t fit under the hood. In addition, the mounting holes don’t line up and the ports don’t match up. Thank you Nissan!!! The 350z IM may line up with 04/05 maxima engines, but you would still have to find a way to get it to fit under the hood and make a mount for the TB.

Will I still have cruise control?
You can keep cruise control no matter what TB you use, as long as your TB has the CC throttle cable attachment.
Credit: Weimar Ben



Credit: Shawn G. / EddyMaxx

For those looking at boosted setups and want an intercooler, below is one that fit good. It needs to be same-side because trying to route piping on the passenger side will be very rough. Plus with this setup, you can retain your fog lights. It just requires modifying the crash bar for it.

Manufacturer: EMUSA
Price: $119.00 + Tax ($130.00)
Amazon Link: https://www.amazon.com/gp/product/B077QH74JC/ref=ox_sc_act_title_1?smid=A1K0UU5ZLPKT3U&psc=1

Intercooler Specs:

  • Oversize: Oversize 27″X11″X3″
  • Core size 22″X11″X3″
  • 2.5″ Inlet and Outlet
  • 5 – 50 P.S.I. RATING
  • 600-700 HP MAX

Intercooler Photos:

Installed Photos: