Can you do one please Sasha?
OK. Because Bing is a lazy girl and can’t do the research himself, here is a quick VQ35 Power Upgrade Walk through. It’s MUCH more complicated than the SR20 because of all of the engine variants, and of course the different routes you can go with NA/Super/Turbo etc.
VQ35DE Non Revup - This is the motor that spins to ~6600rpm and has variable cam timing on the intake cams only. It tends to baseline on our dyno from 200-210whp. This engine is generally the least responsive to bolt ons.
VQ35DE Revup - This motor spins to 7000rpm and has variable cam timing on both intake and exhaust. It has a different intake manifold with shorter, larger runners that make more top end power but less mid-range. The cams are larger, rods stronger and tends to make far more power with bolt-ons than the non-revup. We usually see revups baseline between 215-220whp.
VQ35HR - This engine comes in the 2007+ Z’s and G’s or around that time. The engine has been totally re-designed and the HR features DLC coated valve buckets, larger cams, a taller block with a longer rod, and a 7500rpm rev limit. The intake manifold has dual throttle bodies and the exhaust manifold is much better than the previous years. HR’s tend to baseline anywhere from 260-270whp, so it’s a substantial difference.
First Note - Buy an HR if you can afford it. I won’t discuss HR’s anymore in this thread, as most aftermarket parts are not compatible with the HR.
VQ35DE Power Upgrade Walk through - Keeping it NA
At SG we suggest flashing your ECU, as that tends to make 7-12whp out of the box and further tuning with bolt-ons will optimize the power you can get out of the motor. With simple bolt-ons we have realized that you will NOT make more than 255-260whp with a non-revup and 270whp with a revup. The simple modifications that make the most power are:
#1 - SGM longtube headers, or Nismo / Tomei short headers. I suggest stock cats with short headers because ALL aftermarket cats and even test pipes can make the car sound like a bag of shit. Our headers sound amazing and I suggest them with Nismo’s exhaust and Y-pipe as it is quiet and sounds choice. Video:
#2 - a GOOD y-pipe and exhaust. It doesn’t particularly matter what you get, but single exit will make the most power and be the lightest. A true merge collector at the y-pipe is critical for maximum power.
#3 - Intake. Many believe the stock intake (specifically on the revup engines) makes more power than any aftermarket intake. While it is pretty good, I usually suggest the Injen intake because it sucks cold air from in front of the bumper, and makes great power on our racecar.
#4 - Intake manifold spacer - Adding volume to the intake manifold tends to make 4-6whp. I recommend the Skunk2 spacer as it is the biggest and makes the most power. Your strut tower bar will most likely no longer work, but they aren’t really that useful.
That’s really about it for bolt-ons. Intake, spacer, headers and an exhaust NA you’re looking at around 235-240whp non-revup or 240-250whp revup on average. Spark plugs, ignition systems, grounding kits, etc. are all bullshit. Don’t waste your time. Under driven pullies can make a little bit more power but not more than 5-6whp.
Further N/A work:
The stock injectors are OK for up to 300whp, so you really don’t need to worry about the fuel system. What you need to be concerned with is airflow across the heads, and that can only happen with RPM and volumetric efficiency. The main bottleneck in the system after the exhaust system are the cams, followed by the intake manifold. Currently there are no replacement upper intake manifolds that make any real power, as the throttle body and elbow on the plenum are the main issues. When it comes to cams, the labour to swap cams is VERY intensive, so if you’re going to do it once it makes sense to get a big cam. Otherwise it’s really not worth doing. Jim Wolf make the best cams for these motors and there is no real other company to consider. I would suggest the C8/C8R (revup) for pretty much any application other than a full boring street car. They are a competition cam that require valve springs but will make 280whp with headers, 300 on a really well setup vehicle. Larger cams are available for guys that have full out track cars.
Beyond cams the only way to make more power with these motors is custom intake work with a standalone ECU, and high compression pistons help. The stock oil pump in the non-revup is good for about 7000rpm, the revup oil pump seems to be ok to over 8000. Stock rods on the non-revup won’t handle more than 7000rpm continuously, the revup can deal with 7300-7400 all day long with upgraded valve springs.
Typically we don’t see NA builds over 300whp, my racecar is currently about 350whp, but is not streetable.
The first thing I must say about forced induction is that I hate turbos on this engine and car. The engine bay is already very tight, and V engines aren’t setup best for turbos. There are a few single turbo kits on the market that use the stock exhaust manifolds, and they run exhaust pipes everywhere and they scare the shit out of me. We have successfully installed a few kits that are still running around to this day, but none of them are lapped or raced hard enough to know if they would fail or not. Twin turbo kits are better but are very expensive, and I will only install them by first removing the engine and doing everything PROPERLY. There isn’t enough space to do a good job with the engine in the car, in my opinion. Superchargers will never make as much power, but they are cheaper, easier, and more responsive and don’t create nearly as much heat. For 99% of people modifying the VQ, supercharging is the way to go.
The best kits out there for single are Momentum Performance, and twin would be APS, Greddy or Jim Wolf. The stock non-revup engine can handle 350whp all day long, any more and it’s only a matter of time until you throw a rod. Revup’s can handle more, but exactly how much is hard to know for sure. Maybe 400whp. Turbocharging really only makes sense if you want to spend 25k on the powertrain and you’re looking to build the engine and shoot for over 500whp. Otherwise supercharging and making 350-425whp is the best compromise.
I am currently recommending the HKS supercharger kit to all of my customers, as the vortech makes a shit ton of noise and the fuel system that comes with the Vortech is a complete joke. Rising rate fuel pressure regulators and in-line pumps that you’re supposed to self tapper to your front cross member is a disgrace. Both kits are setup for around 6-8psi and tend to make 350whp after a tune on our dyno on most cars with the usual bolt-ons. To do the installation properly the best thing to do is to get a tuner kit and do your own fuel system. As 350whp is the upper limit for the non-revup engine, you can see how a supercharger kit fits perfectly into the plans for anyone that doesn’t want to spend another 6-10,000 building an engine. Don’t forget there are NO guarantees when it comes to engine building.
The Vortech is known for problems with belt slippage. There are a few companies that make aftermarket additional idler pullies to add tension to the supercharger pulley. These are recommended at the same time as the supercharger installation. You can also buy smaller pullies to spin the super faster and make more boost, and thus more power.
Boost with a supercharger is linear to RPM. Double the RPM, you will double the boost. For that reason you will never have the mid-range torque of a turbo, (on a VQ it’s not un common to see turbo setups that make the same torque as horsepower). Because the engine already has healthy displacement, a supercharger to help build more top end horsepower is really all that’s needed.
Fueling and Engine Control:
There are currently TWO real solutions to engine control. UpRev ECU flashing, and Haltech standalone. I recommend the Haltech for ALL turbocharged applications, and any supercharged application running more than 400whp. In my experience the Haltech doesn’t run the car AS well as the stock ecu / uprev at lower rpm/throttle positions, most likely because a MAF is just that much more accurate at low engine speeds, but that may be more my fault than the ECU’s fault. There may be some tricks still to be learnt. The UpRev is the total opposite. You don’t have 100% control of what the engine is doing simply because you’re manipulating tables in an ECU designed without forced induction in mind. That being said, UpRev runs forced induction cars very well and I have a few customers with UpRev tuned supercharged cars making 350-390whp. The UpRev is cheaper by far than the haltech of course.
Fuel injectors, if you’re going with a Haltech the only injector choice is Injector Dynamics. Because they only make a 725cc injector, if going for a 350whp supercharged setup those are a little on the big side, so a 500-550cc injector is best to use with the UpRev. There are a few aftermarket companies that drill stock injectors for that size, but they will NEVER run as well (specifically at low rpm/throttle) as a properly made injector. Most of my cars running drilled injectors still run very well though, so it may not be THAT big of a deal. With the UpRev you also need to upgrade the mass air flow meter, as the factory one will not read airflow levels beyond 310whp. We sell these mass airflow meters, along with injectors and UpRev flashes of course.
There are instructions online on how to retrofit a Walbro fuel pump into the 350z pump and regulator system. Because it’s returnless you can’t just throw a pump in it. A fair bit of work is required to keep the fuel pressure the same and consistent, but you can still have the pump installed in a few hours and the cost of the pump is very cheap. A single Walbro on the returnless system will work until about 425-450whp. Beyond this point you need a return fuel system with either a single or dual pump. They are expensive.
Bolt-Ons for Forced Induction
Like N/A stuff, cams make big power. Superchargers running a smaller pulley and cams / header will easily make over 400whp. Turbo cars out of the box will be maxing out the power the short block can handle, but with a built engine and fuel system we’ve done 550whp pump fuel 350’s with relative ease. On small small turbos. Head porting and intake manifold work doesn’t do much, but a good valve job is worth doing if you’re building the engine.
Under $5000 - N/A with boltons. 250-260whp max.
Under $10,000 - N/A - big cams, valve springs, good headers, 280-290whp
Under $10,000 - HKS base supercharger kit - 320-350whp
Under $15,000 - HKS supercharger, smaller pulley, fuel system and uprev custom tune - 350-375whp
Under $15,000 - N/A - high comp motor build, big cams, valve job, headers, exh, custom intake - 300-310whp
Under $20,000 - Twin turbo kit, cams - 375-400whp
Under $25,000 - N/A - high comp motor, ITB’s or custom intake plenum, big cams, valve job, headers, standalone - 315-330whp
Under $30,000 - Twin turbo kit, lower compression motor, return fuel system, cams etc. - 450-600whp
Under $40,000 - Twin turbo kit, built motor with cams, sleeves, return fuel system dual pumps, external gates, bigger turbos - 600+ whp
Revup motor will always make more power (until you put big cams), but they are known for burning oil.
Stock block is good for 400whp that’s it.
Returnless fuel system is good for about 450whp.
UpRev will reliably run the car up to about 375whp, at which point I’d rather switch to Haltech
Superchargers can be setup to run up to 400-425whp, above that you want turbos.
N/A is best! But expensive and won’t make a ton of power. Will be the most reliable, sound the best and be the most awesome though. My suggestion for lapping / trackday cars.
awesome info for those new to vq’s! seems really hard / expensive to make big power on these motors, never knew that
what would you recommend for incremental modding?
i guess you would recommned the basics: injen intake, plenum spacer, some exhuast stuff as a first go around. then cams, valve springs, long tubes, UpRev…