I am planning an engine build for my Tiburon and like the idea of using the pistons and rods from a 1.8 to drop the compression. I don't have gobs of money to spend on forged pistons and rods. My question is, the common consensus that this setup will hold 400 hp, is that due to piston material or design? ie: will the piston strength differ if i use aftermarket stock replacement pistons? I will need to bore the block so getting a set from the junkyard is out.

 

My 2.0l G4GF beta is in the shop now getting a rebuild and i'm opting for a decompression plate rather than going for forged pistons & rods so i guess ill soon find out how it handles the 9.5 psi from the supercharger....

 

A stock 2.0 Beta will hold up under 300HP pretty much forever, 350HP for maybe several years and 400HP for possibly as little as a few pulls on the dyno. Lowering the static pressure in the chambers seems like a silly thing to do in general to me, especially using 1.8 pistons AND rods. The 1.8 pistons are taller, the rods are shorter. Use your 2.0 pistons and the 1.8 rods if you want to use OEM rods to lower compression. A far better idea would be to get a turbo setup properly tuned in the 300-320HP range, and if that isn't enough power then save up for stronger rods and pistons. The block, transmission, and axles will hold up with more power than you can drive comfortably on the street.

 

Whats the old saying?

 

Got into the motor, spun a bearing on #1 rod. not really sure if I want to see what else is wrong. The turbo is a T3 out of my daytona, I doubt it would take me past 300hp. There is a motor on car-part with 124k miles that claims good compression for 300$. Maybe I'll just throw that one in and call it a day.

 

Whoa whoa, if you use the 2.0 pistons and 1.8 rods you are going to kill compression, the 1.8 pistons are raised compared to the 2.0 and offer a 7.7:1 ratio on their mating rods. If you drop the 2.0 pistons on the 1.8 rods you will be very low 7:1 compression.



I've been boosting for 6 years and have used a decompression plate, 1.8 rods and pistons, 2.0 rods and pistons, and now forged internals. I've been around the block a few times and suggest that you leave the block the way it is, get a good tuner and boost away. If you decide in the future or mid build that this is no longer the route for you then at least you aren't switching internals again.

 

7.7:1 or 7.1:1, it's too low for a street engine. My idea of lowering compression on your daily driver is: it's dumb, don't. If you are going to go for low compression, go for it all the way. Then (unless you are making a race-only engine in which case you are asking a different set of questions!) you will realize the HARD way that you aren't boosting all the time and want high static compression again, and you'll have to open the motor and you've wasted the effort.



Both those paragraphs you posted are worthy of a + so I'm off to find another post you made and + it as well because I can only + 1x per posting. I'm also going to try to remember that second paragraph for the next time the same question comes up.





Leave the block alone people!

 

" I don't have gobs of money" just buy a decom plate,slap it together.



fyi my old compression=8.5.1 on tigerlilly and stock rods

present compression = 9.1 on wiseco and pauter rods.