Project help plz

[BZR4AGE]

Hi there all, i just need some help and confirmation on some tech issues, as i want to get my project underway for my car.

i am planning to put a superchager into a 4AGE blacktop 20V. My friends been telling me supercharger has less less lag than turbo, and also it works better at higher revs. Is this true?

also, if i use my factory pistons, i can only run low boost. now, does tht mean i can only run low boost because the piston will not allow high boost, or does it mean that i "NEED" to run low boost or else i will blow my engine? must i change to low compression pistons? is so, anyone know where i could source some?

another question is it easy to fit a supercharger into a black top, i am planning on putting at SC-14 supercharger, which is bigger than the 4AGZE SC-12.

here is wht i am planning to do.
1) recon my engine and use forged pistons, and change to brand new heavy duty valve springs and valves.
2) acid dip the block: anyone know how much it will cost???
3) in the process of recon, i will do port polish too
4) fit supercharger

people may ask why i dun fit a turbo instead. well, thts just because i want to keep most of the car's characteristics. which is "high revs" unless my frds been telling me the wrong thing. then i probably won't even bother with the supercharger.

Cheers all for any advice.

[Adamal]

Your friend is talking out of his behind.
I'm more of a S/C fan than I am a turbo fan, but turbo's will always be able to produce more top end power in any application.
That is especially so when compared with the SC12/SC14.
It's a roots type S/C, which will provide pleanty of torque down low in the RPM range, but once you get to the high end, it can't keep up with the air requirements of the engine and acts as a restriction.

As far as superchargers and lag are concerned, there isn't lag, because you don't have to wait for anything to spool up. However, there is a greater parasitic loss than a turbo.

There are actually 3 types of S/C. Roots type, which will help a lot with torque in lower RPM. Centrifugal type, which is pretty much the compressor side of a turbo that is belt driven instead of using exhaust gasses. And then the Twin Screw. These ones use two 'screws' that turn into each other to compress air in a very efficient manner. They provide the flattest torque curve out of all charging methods and can provide compression at low RPM through to the redline. However, they are by no means cheap!

[Lloyd]

i want to keep most of the car's characteristics. which is "high revs" unless my frds been telling me the wrong thing. then i probably won't even bother with the supercharger.

Well with the 4AGZEs they start to lose power over about 5500 (MAP sensored versions anyway) and over that you're pretty much just making heat. The superchargers aren't made for high revs, they are for low down torque and instant throttle repsonse. You put your foot down and you have boost, no waiting for it like turbo.

You will need lower compression pistons unless you want to run very low boost. You'll need a computer that can handle the positive manifold pressure and injectors that can keep up with the extra fuel requirements of running boost.

SC14 would be nice but it will be a little more mucking around to mount it than the SC12 (depending on your engineering experience of course). Turbo will probably give you better bang for your buck. You'll have bugger all lag with a small turbo and you'll still be able to rev it out quite nicely if you're only running low boost. A T25 would do it, bit small if you're planning on going with low comp pistons and reasonable boost.

My advice would be to go turbo, T28 kinda size with aftermarket computer, 3S-GTE or bigger injectors, 4AGZE pistons (there are 8.0:1 and 8.9:1 versions). It depends how much you're willing to spend and what sort of power figures you are after. Oh, and if its to be a track or strip or road car