spirilis

iTrader: (2)

I notice people are pretty enthusiastic about boosting these VQ-series engines.

I have a few questions. I know when boosting via turbo it's required to lower the compression ratio so it won't ping like a mother!@#$er, especially when pushing high amounts of boost, using either a copper head gasket or special pistons...
Is this not necessary for supercharging as well? i.e. if I considered supercharging my '00 Maxima (VQ30DE), would I be considering major engine work first on TOP of the $4-5K supercharger kit/parts required?
If anyone's supercharged WITHOUT lowering compression ratio, what's the catch? Must use premium gas all the time (which I do with the stock setup anyhow)? Can't go beyond a certain amount of boost? Would installing a copper head gasket to lower the compression ratio be advised for someone who wants the engine to last a long time?
(sorry if this is a common post; I searched on the test site for "compression ratio" and couldn't find squat...)

Stephen Max

iTrader: (59)

Judging from the experience of people on this board, lowering compression ratio is not necessary for the amounts of boost supercharged people are running, i.e. 10 psi and below. There are some above 10 psi who are using some form of charge air cooling or electronics (e.g. J&S Safeguard) to protect against detonation. Some are using JWT programmed ecus that provide a pretty healthy safety margin against detonation by timing adjustments and a 11.5:1 afr under boost.

I like having the stock compression ratio because that is what provides good low end power. Lowering the compression ratio in order to run higher boost pushes the power curve into the high rpm range.

The best way to lower compression ratio is with new pistons. Thickening a head gasket also makes it weaker.

turbomax97

iTrader: (6)

lowering compression isn't necessary even up to 14 or 15 lbs boost as long as you're getting enough fuel.

spirilis

iTrader: (2)

Wow, that's amazing. I'd imagine this has been discussed and beaten with a dead horse 10 times over, but what kind of reliability might I expect with a Stillen supercharger kit at whatever stock boost it gives? Might the car last to 200,000+ miles like I'd hope? (it's a '00 with 31K mi, switched everything to synthetic) Or have people blown engines with a stock-configured supercharger? I'm wondering if it's worth investigating, or if I should forget about it and be content with the power I have

Do superchargers help out low-end torque a lot? I wouldn't mind having some more kick during day-to-day driving (I don't wind my engine out much...)

JAY25

iTrader: (38)

I am on all stock internals, 10PSI, the only two things I have to cool the air is the Custom CAI, and the SAFC to tune the air fuel ratio. Nothing else has been done to the engine, is not like we have many options to go with.

BlackCat

iTrader: (6)

If you don't hammer your boosted Max all the time then the reliablity should be good for a few years. Lasting 200,000 miles? I doubt that many here have driven for that many miles boosted.

The most common problem has been drive belt overtightening which leads to blower bearing wear and failure. I've had mine since Oct.2000 and had bearing wear back in Nov.2002 due to overtightening. I was trying to fix belt squealing during the winter months and I've learned my lesson.

The blower kicks in around 3000 rpm so no it doesn't help low-end torque.

spirilis

iTrader: (2)

ah k. In that case I suppose F.I. isn't for me... I'll just keep my motor stock (and tuned up all the time like I typically do, cleaning plugs every couple months/switch to copper plugs) and make her last 'till 200+K if I can

Craig Mack

The VQ engine itself won't fail any sooner with S/C FI as long as you maintain it properly and treat it right.

And the supercharger for our cars is a centrifugel type blower, which means nothing under 3000rpm unless your running a small pulley.

turbomax97

iTrader: (6)

well, to an extent, you're obviously still going to have quicker wear on your motor, but as v8 lover said, do your maintenance religiously and you'll be fine.

Craig Mack

V8 lover also knows that the VQ is an extremely well designed engine that can take high levels of abuse on stock internals. V8 lover would nut his pants if the Maxima came with a VQ57DE.