I am turboed so i know lowering compression is a way to run more boost and be safer...i know i will need more fuel and a PB. but are the benifit of running lower compresson there??

I am mainly looking for benifits for lowering compresson on our motors.....and to anyone whose is a math/engeering guy....if i were to get .08" thick gaskets what would that make my CR?

Give me suggesions, warnings, ideas etc.

here is a link to the RPW gaskets. http://www.visionimports.com/lancer_headgasket.html

 

Lowering compression will make your low end really crappy but when turbo will spool they you're on the go. That's the disadvantage, for the advantages, decompression gasket will give you more room to play with timing. Your motor will not need all the octanes to not detonate.
Also their gasket is stronger than the stock one. Over some time it should seal the motor better than the stock one, less chance for blown head gasket.

 

but if i were able to tune the timing the low end wouldt be that bad....just make it so the turbo spools faster.....so really there are no serious disadvantages??

 

i BELEIVE that the RPW stage I drops the compression from 9.5:1 down to 9.0:1 while the stage II drops the CR to 8.6:1 that is what i read somewhere. the RPW site is a little unclear about it but mentions it in the engine build section.

mark

 

cost is an issue. tboth of the gaskets lower the CR enough that it retards the timing enough to require a stage I verneir cam gear. if you've got the cash flow than it shouldn't be much of a problem. should talk to some of the FI guys and see if they have ever done it.

 

Think of it this way, before that turbo will spool your engine will run like a 80whp engine. It's just an assumption tough.

Seriously, I think decompression gaskets are awesome, as long as your turbo will spool you're good.

 

^ thats one of the main reason im reconsidering the gasket method i might leave it alone and just run lower boost

 

john you do make a good point. although i am not sure if i would go the same route. yes, you do lose a large amount of low end power but as soon at you start to spool up you'll be making a lot more i guess it all depends on your preference and what your intentions are for the car. i can fully understand both choices though.

mark

 

For maximum power I can see running the headgaskets, but if all you're doing is making a street car, I wouldn't bother personally. I wouldn't see the trade off of sub 3500 RPM power being worth the gains above say 4500 RPM.

 

very valid and educated opinion the reason i considered it is because one day (yeah years from now) i hope to get one of the fastest lancers. there will be a large trade off though to make that power. will it be worth it? i honestly am not sure.

 

Just figure out what you will be using your car for. Is it going to be driven in heavy traffic? Or mostly as a race car?

I know I would just stay with a stock headgasket because I do get stock in the traffic sometimes. And let's face it, lower the low end torque more power you need to get yourself going, the more stress you will put out on the engine and your clutch.

 

for now it is a street car. it will be staying a street car for atleast one more year. i should have the turbo in by summer time. once that is all worked out i am starting to save up for a 2nd block + head to stroke, port/polish, build up, etc. at that time i will be buying a beater civic or something to get around in while i go out of comission to build a monster

 

all make vaild points.....but for the low end im thinking just retard the timing a lot down to make up for power....my friend done this on his 2.5RS-T....his CR is like 8.2:1....low end feels fine plus u can get faster turbo spool...ill have to think about this one....also having a stonger headgasket wouldt be that bad of an idea...

 

8.1 is pretty damn nice! what year is the car? you need too keep in mind though that the 2.5 RS in AWD. my brother sold his in november. it was a cool car....but yeah, the AWD will accelerate much quicker. IMO you wouldn't really notice the power loss as much. between the AWD and a 2.5L engine that boasts around 166hp stock...they should maintain a larger amount of power then the lancer.

this is all just what i have been able to fathom in the last couple minutes. i could be dead wrong. it's just a point i thought might raise good discussion topic.

 

I remember Omar's car had lower compression and it wasn't really that bad. You almost couldn't notice it but he had EMS.