b_dupy

So this may have been already done, I did a quick search and didn't see anything. But this is always a pretty interesting topic, so let's see what you all think. What's the better method, all things considered, for the VQ37 engines when it comes to forced induction -- supercharging or turbocharging?

Black Betty

iTrader: (60)

Waste86

From what I have read supercharging is the least expensive option but also with the least potential for growth. If you are looking for 400 WHP on a budget, it is probably the way to go.

If you are still semi-budget minded, you could get a single turbo from Boosted Performance and have great hp exceeding 600 WHP with the right fuel and supporting modes. Someone may correct me, but I do not believe you have to drop the engine to install the BP kit.

If you want twins, it will cost a bit more than the single kit. Someone may have to chime in here, but I am guessing there is a little bit more ceiling with the twin turbos for power.

Other limiting factors may be your transmission type. Also, if you have a 7AT then you either should upgrade it or keep the power low. I haven't gotten my car back yet (I am going twin turbo), but in hindsight I think I would have gone single turbo for the power and cost effectiveness.

PongSanity

iTrader: (5)

http://specialtyz.com/blog/?p=2887

Worthy of a read. SC power band is linear where peak boost is achieved at the top of the power band and turbo is not. Stillen and gamma motors are the providers for such. Avg 6k per kit

Single turbo is one large turbo that's good for mid range and top end. Boosted performance and vsr/vortex/rjm motorsports produce such kits with a precision 6266 turbo. The bp kit can be done in your back yard and the other kit requires your car to be shipped to Tampa. Avg 8k per kit

Twin turbo is two smaller turbos that is excellent for low and mid range power. Fast intentions (Garrett turbos) is the best twin turbo kit on the market followed by aam (borg warner turbos) and then gtm (Garrett turbos). Avg 10k per kit.

Waste86

Also as a note, there are probably 3 mods that you SHOULD do if you want to make the power as safe as possible. That would be a CJ return fuel system, step colder spark plugs, and an oil cooler to control temps. The return fuel system and the spark plugs will help decrease the likelihood of running lean which will cause detonation. From reading this forum and the 370z forum, it seems leaning the engine out is the most common form of failure.


I would also install an oil pressure gauge.

takeapieandrun

iTrader: (2)

I've heard that supercharging is easier on the engine because boost builds gradually, rather than "hitting" boost or it kicking in quick in the case of a turbo spooling. Also, your torque down low will be better. But turbos are more efficient and can make more power.

Waste86

If you were to just run no boost controller then that would be a semi-accurate statement. With a good boost controller you can ramp the boost in gradually. I am not sure how the Gamma SC kit is designed, but if it is anything like the Stillen design I would argue that it is rougher on the engine than a non-boost controlled turbo.

RadioFlyer

iTrader: (1)

Lotsa hate for the Stillen kit.

The Stillen kit used a Voretech V3 supercharger. That's a centrifugal supercharger that builds boost based on RPM. Spin it faster, and you get more boost. When you're daily driving, and shifting at 4K rpm, you only see ~1.5-2psi. That's super easy on the motor. So you aren't taxing the motor at those rpm's the way a most turbo setups would. Most turbo setups are set to reach full boost as early as possible, so they see ~9psi at 3-3.5K rpm. I don't know why anyone would want to tune a turbo setup to 'lag' until high rpm - you'd be leaving a lot of power/torque on the table. But you're right, you COULD tune a turbo setup to build boost the same way. But I usually see that with dyno queens. Otherwise, just stick a huge turbo on there, and just lag through the whole powerband until you finally build boost from 6.5 - 7K rpm. You could hit real hard at the top and have a huge hp number to brag about. Done.

Positive displacement superchargers are a different story. Those are the kinds that come to mind when you think of a blower. They make boost pretty much as soon as they turn, so you get full boost throughout the whole rpm range. Those are hard on a motor.

booster

The amount of boost applied in a turbo configuration is based on load not RPM.
If you don't hammer it you don't build boost regardless of RPM.
That's the reason why turbos are considered easier on the engine. The difference is that on the turbo car, you have the possibility of boosting the car in the low RPM range, and that can be very destructive to the engine. This is of course relative to the engine displacement and turbo size.

RadioFlyer

iTrader: (1)

Right, but as long as load is minimal on any engine, turbo or supercharged, you're not hurting anything. I thought we were talking about the stress on the motor when it's under load. You can coast on any motor, and you're not going to blow it. I don't think that was the concern of the OP.

micafd3s

iTrader: (2)

anyone know if the boosted performance kit for the g is the one that places the turbo underneath the car..

PongSanity

iTrader: (5)

Yes. That kit is mid mounted off of the factory headers...

Ape Factory

iTrader: (3)

I've done aftermarket supercharger kits and turbo kits (albeit on different cars and none were a G).

Turbo kits have a distinct power advantage across the rev range and generally speaking, there's so much engineering being put into compressor wheels/turbine housings that they're far, far more efficient than anything Vortech is using. They'll come on stronger and pound of boost vs. pound of boost, will produce more power with lower air temps and faster spool up. The lower air temps are actually a big benefit when it comes to longevity and avoiding knock under boost.

Yes, turbos will ramp up cylinder pressures very low in the rev range and good tuning is essential. Most folks don't blow engines at redline, they blow it "lugging" the engine or somewhere in the midrange where torque peaks and cylinder pressure is actually at its highest. As a result, a good turbo kit, single or dual, is far more flexible and more fun on the street. Just more usable overall.

The SC has more parasitic loss but produces almost zero additional heat other than possibly increasing oil temps via combustion chamber temps/increased hp and cooling the SC. I'd run a cooler with either without question.

As far as turbos being load based and avoiding boost by staying in vacuum, sure that's true but what fun is that?