does anybody know what the compression ratio no.'s are for the 1986 1.8t and 1.8 non turbo?
also, are the bottom end parts (crank, rods, piston type) for both the turbo and non T motors the same?
I'm thinking about having the heads on my n/a 1.8 decked to raise the compression. i figure if both motors have the same bottom end parts, then raising the compression on my n/a motor will maby have a similar effect as if it were turbo charged. it's just an idea, and i know these 1.8's don't have alot of bang, but i'd like to see what i can do with it without forced induction of a motorswap.

The numbers for a 1986 engine code O with a 1.8 tbi are 84hp @ 5200 rpm net torq 102 @2800 bore/stroke 3.50x3.15 at 8.8:1 . Next is the same yr engine code J 1.8 MFI turbo 150@5600 rpm net torq 150 @ 2800 bore/stroke 3.34x3.13 at 8.0.1 compression. I am not engine fluent enuff to answer ur other ?s about but sure someone else with motor knowledge about the differences or similarities can help u in that area.I hope the above helps minus the similarities and if they are similar or interchangable or possible upgrades as u descibed with what u want to consider.

the bottom end of the motor is very different. the turbo version uses different pistons, aswell as other htings.

upping the compression is a proven way to get more power. however, decking the head only takes you so far, as you still need enough piston to valve clearance, and you usualy cant up the compression a significat amount without getting to close. typicaly, the best way to up compression is to get different pistons.

honestly, if you are wanting more power, ditch the 1.8l ohc and throw in a v6 or a 2.0l turbo. it is a bit of work and money, but it realy isnt worth it to modd a 1.8l n/a.

thanks guys, all that makes me look at what i was considering in a much diffrent light.
sharkey, i actualy hadint even taken valve clearance into consideration, that realy could turn into a problem. I have been considering a swap, but just hapened to have the idea of raising the compression instead. but with the shortcomings u pointed out it just wouldint be worth the trouble of trying.
Guess all this means that i will be looking for a v6 realy soon!

thanks again

DEFINETLY not worth the time trying to make power out of a 1.8 N/A. It would ONLY be worth it if you had a 2.0 , and did the 16 valve DOHC swap... trying to squeeze power out of an 80's 1.8 liter sohc motor is pointless/futile.

Would HIGHLY reccomend doing a swap to a 2.0 turbo, as it would nearly bolt in. You would want the better/later HM282 5 speed trans which is bulletproof, and the wiring harness and ECM from a 2.0 turbo, which you should be able to get if you find a 2.0 turbo donor car. Other then that it would bolt right in basically.

Could also do a 3.1 v6 swap but, fi you're going to do that, do a 3400 swap.