mt_goat

You can take care of height with a bodylift.

maxigaz

Well i have a 2nd gen 4runner amd want to upgrade.My problem is similar too 3.4 with supercharger or 4.0. Both has the similar power.Only thing i am not sure which would perform better at higher altitude?I heard super/turbo charged engines are better...
Any idea?

Texas_Ace

Yes, as a whole a forced injection engine will fair better at higher altitudes.

mt_goat

I'd agree with that, I've run my SCed 3.4 all over the continental divide and was very happy.

mastacox

Technically speaking, a supercharged engine is affected by altitude just as much as a naturally aspirated engine, unless you put on a smaller overdrive pulley at altitude. The supercharged engine just has more power to start with.

Only turbocharged engines are able to dynamically increase their boost to make up for changes in air density due to altitude.

Texas_Ace

True, and if he live higher up he could run a smaller pulley and he would be fine. Seeing as for our trucks there is not an easy turbo option that is about his best bet without something really custom.

mastacox

In theory, he might be ok as long as the ambient temperature is low enough. But you'd have to keep an eye on EGT's and ping because even at high altitudes if it's 80 degrees outside a 2.0" pulley might push your CDT to high and cause ping, high EGT's, and other trouble. That, and a smaller pulley spins the supercharger a lot faster, compromising the overall life of the rotor bearings.

hross14

there are some reasons why people PING in some areas and in others they do not...

1. Higher altitudes means you can run lower octane
2. Texas (Ace and Myself) are in the greatest country--err I mean we are close to sea level so we need higher octane
3. The 1uz is a torque motor (as used in the LS400..etc..)
4. An LS1 is small and compact and light and efficient

But if you want to stay with the 3.4--think about cams, Manely high flow valves with polished and down sized stems, Headers, properly designed exhaust system, balancing the rotating assembly and intake matching---and if you are not worried about Gas prices/octane--bump the ratio up--

Per 1 point increase in Comp Ratio you get 4% HP return....i.e.. 9:1 CR @ 100 hp and then bump to 10:1 =104 hp.

But in the long run all the little things add up and the reason i didnt go with the SC is because i like simplicity and want to take it on expedition type runs....

OK sorry for the long post

Texas_Ace

I was thinking more like a 2.1 pulley, should give him about the same power as the 2.2 but it will still be safe if he comes down the sea level.

And even the 2.0 is still below the SC RPM limit.

mt_goat

Where did you get that info? I've heard different

Texas_Ace

Don't remember exactly where, i just remember when i was reserching everything for my SC that i heard the RPM limit on the m-62 supercharger is XXX which is a 1.X pulley. And if you get special bearings it cuts that almost in half.

mastacox

It's not known if you're really safe or not unless you have an EGT gauge. AFAIK a 2.1" pulley (and definitely a 2.0" pulley) are probably not safe without properly tuned W/MI because EGT's get into the red zone.

Not according to URD's website.

Belize Off Road Team

Good to know