Ok after heavily looking into superchargers and whatnot, I have a final question..

should I build a low compression engine and supercharge it or should I build a high compression engine (about 12:1) and not supercharge it? which will get more power? I assume w/o the supercharger method would be cheaper?

 

is this car going to be driven on the street/pump gas?

 

after the complete engine build, it will be street driven until I can afford a new car, but this one does have to pass cali smog and I want it to run the highest compression for 93 octane pump gas. which I believe 12:1 was the highest you could go for 93octane, correct?

 

I wouldn't go 12:1 on California 93 octane. I'd go 11:1 to be safe.
Thats just me. Supercharging an 8:1 engine would be more expensive, but you'll have more power potential in the 'smog legal' catagory.

 

Thats pushing it, even with aluminum heads, which are a must with high compression. Is this FI or Carb, and what carb or FI setup?

 

atm it is TBI

If i supercharge, I will prolly go carb, otherwise I will be going TPI.

 

if i supercharged an 8:1 with about 6psi, i would get 11.3:1 compression ratio. are you saying this way would be better for passing smog then if i just had a straight engine pushing the same comp ratio (11.3:1)

 

Not necessarily, but you will make much more power with the same emmissions.

 

you mean I will make more power with a supercharger with less worry about emissions? even at the same compression ratio?

 

if you're right at the limit of cali emmissions on a properly tuned engine, you will make more power with the supercharger

 

will the power to money ratio be worth it though?

 

thats for you to decide. for me the answer was no. do you plan of doing all the work yourself? a supercharger will cost more than $2000. You can buy a lot of parts for $2000. I also like the appeal of a standard engine. A standard engine will probally last longer. Also remember if you are going for serious power you will soon blow your tranny and rear, and the stock suspension will have problems hooking up. So figure on at least a few thousand you upgrade those parts. If you can afford it, cool, you should have a nice car. I'm not trying to rain on your parade but i'm just trying to prevent you from making the mistakes me and many other members on this board have made already.
JP

 

ya no problem, i appreciate all the input i can recieve. Im trying to learn all I can as well as choose how I am gonna build my first engine before i start buying parts. The more I am reading about supercharging though, the less I like it. it sure sounds cool to say you are supercharged, but it seems much better to run a 'natural' engine with high compression.

so 11:1 sounds good for 93 octane? will I have harder trouble with emmissions with higher the compression? thanks!

 

11.1:1 is REALLY pushing it on 93 octane. even with aluminum heads.

it might run alright at first, but 15,000 thousand miles down the road

go with something more like 10:1 maybe 10.3 or so.

as for emissions, assuming you have a good ignition that can properly burn the mixture, the more compression you run, the more efficent the engine is at using fuel it gets, then less emissions and more power.

i would say go N/A as for the engine, pass up the supercharger, and spend the extra money on good heads, and a roller cam.

 

any second opinions on choice of compression ratio? thanks!

 

I'd like to bump my saftey margin down to 10:1... You can still make plenty of power without a high compression engine, dude. High compression is just one trick in a huge bag of go fast goodies...

 

ok thanks, i will aim for 10-11 to 1 ratio

Now my next question is!

how do you determine the ratio with the combination of heads and pistons?

 

compression ratio calculator
http://www3.sympatico.ca/peter.matte...ompression.htm

 

You can't put a carb on it and pass inspection. End of story. Move on.

It's going to have to be an induction system that comes from the same year or newer, with all emissions-related parts installed and operating; and all non-factory parts blessed by CARB. You can slide a few non-obvious things like cams through that don't have a CARB EO #, but carbs (now that looks stupid doesn't it!!) won't go through on a 89 model car.

But, there's always the issue of huge gangly things sticking off the motor that didn't come there, and getting an inspector to say OK. They get paid the same whether you pass or fail. Don't ever forget that. There's little video cameras in every Smog Check station that Big Brother can watch any time he wants to, and the people who work there know it. If there's any question, any doubt at all about whether your car is legal or not, especially if it's obviously modified to the point that the video camera can see it, guess which side the answer is going to come down on.

On CA gas, which is basically watered-down cat pee, I wouldn't try to go past about 10:1 with iron heads N/A, and about 10.7:1 with aluminum heads. With a blower, it will need to be in the low-mid 8s for best results.

 

The problem you have is that you can't run a cam large enough to bleed off cylinder pressure at low RPM and pass emmisions. This is key to preventing detenation and limits you greatly on power potential also. I am running 10.2 to 1 in an iron headed 350 with a Hotcam but I am pushing it.
Good luck,
Charlie