Lower Compression???? Better or worster???

[tommyg2b]

hey, guys, I was just wondering....I am planning on lowering my compression by swapping my stock pistons out and putting aftermarkets in....You guys think I can gain more power by doing that and how much PSI will be safe for me to run on....Planning on going atlease 8 for compression.

[Jeph]

Going with an 8:1 compresion will make your car feel more sluggish off the line, and cause you to lose low end torque. BUT you can safely run more boost with lower compression pistons.
You won't gain any more power by swapping pistons, and staying at the same boost level. You may want to think about a complete engine build since the weak link in our motors isn't the pistons, its the rods...

[orng1]

^^^what he said, it's the rods that are the problem, and you won't gain any power with swapping pistons unless of course you raise the compression but then you'd risk detonation under boost. The thing with lower compression is that its easier to tune under boost add a little more boost maybe some timing and you can make more power. It's just easier than having to retard timing for adding boost, but there are sacrifices down low and when not boosting. Look into rods and pistons, there has to be a deal on both somewhere.

[tommyg2b]

so, should I stay with stock pistons and just boost my turbo to somewhere 10 PSI?

[low_psi]

it sounds like you should stay at stock boost and take the time to learn about these engines and turbocharging first. then make an informed decision.

[orng1]

so, should I stay with stock pistons and just boost my turbo to somewhere 10 PSI?
NO, please list your mods and then we can help you make a decision on what steps you should take. 10psi+stock=BOOM. (I don't care to hear anyones stories about how you boosted 10 or moer stock for the time being thats just understood here.)

[ChopstickHero]

it sounds like you should stay at stock boost and take the time to learn about these engines and turbocharging first. then make an informed decision.

good suggestion. (first)

[orng1]

wow everyone jumped on that one quick, good catch to all of you LOL. Listen to everyone, these cars don't last long at 10 psi stock.

[tommyg2b]

okay, all I got so far are Denso IK20 plugs, FMIC, Injen intake, Greddy Type S BOV, and stock exhaust, cuz the pigs always get us here.

[tommyg2b]

Oh yeah, how PSI should I run. Since My msp is my daily driver.... (safe for it)

[jeffmsp]

wow everyone jumped on that one quick, good catch to all of you LOL. Listen to everyone, these cars don't last long at 10 psi stock.

there has yet to be a properly setup car fail. Stop spreading this nonsense. Give me a link to one person that has blown a motor at 10psi and had fuel control and IC/exhaust. just cheap asses or people that didnt know what they were doing and now the MSP has a bad wrap.

[tommyg2b]

hey, jeffmsp....what do you think i should do? huh......Tell me...Thanks

[low_psi]

Leave it at stock boost if you've got the stock exhaust. Or get an exhaust and deal with the "pigs" :rolleyes:

[tommyg2b]

yeah right......I got busted so many times.....dealing with those pigs in the past......Well anyone else have any ideas for me....What PSI should Run at if I get a FMIC????

[dominoy2k1]

damn pigs!!

[jeffmsp]

are you serious about building the motor or do you want power now? If you are building the motor right now talk to MAM or HiBoost. Both are great and can help you plan out your goals for the car. If your like me and just want good power on the stock motor, a afc, intercooler and exhaust should get you going low 14s on street tires and 91 octane @ 10psi, thats pretty much where I am. With good gas,more boost and a methenol injection kit you are laughing and still on the stock motor and are in the 13s on street tires. Pretty much the max the stock clutch and rods can take at that point,traction also starts becoming a bigger problen. then you give HiBoost or MAM a call for a built motor and look for a used Quiffe(or reweld your stock LSD) and really good tires.

[69RMSP]

The number one mod before you up the boost should be your exhasut(thats if your only going to about 10psi). Go get something custom and keep the stock Axel back. That shouldn't be much louder then stock. I aslo suggest 1step colder plugs and a DSMAFC

[tommyg2b]

that's right dominoy2k1. Damn pigs......hahhahaa.....Okay guys about my question......At what PSI should I run with a FMIC......

[dominoy2k1]

32.68

[Fede_italiano]

that's right dominoy2k1. Damn pigs......hahhahaa.....Okay guys about my question......At what PSI should I run with a FMIC......

What don't you get a 2.5 exhaust? It is not loud. It will cost you 500 for exhast and midpipe.
You have all the bolt on and you could probably go to 8 10 psi safely with the AFC and sparkplugs.
Maybe 8 psi with no AFC.

[low_psi]

do you have a FMIC yet or not? you said you did, then in your next post you say you don't... I still suggest you stay at stock boost until you learn some things.

also, disrepecting the police won't get you too far here... 1st impressions...

[DiscreetSpeed]

hey, guys, I was just wondering....I am planning on lowering my compression by swapping my stock pistons out and putting aftermarkets in....You guys think I can gain more power by doing that and how much PSI will be safe for me to run on....Planning on going atlease 8 for compression.
neither worse nor better. 9:1 or 8:1. all in your set-up and tune. want a quicker spool with an 8:1 compression get a set-up that suit it.

[DiscreetSpeed]

do you have a FMIC yet or not? you said you did, then in your next post you say you don't... I still suggest you stay at stock boost until you learn some things.

also, disrepecting the police won't get you too far here... 1st impressions...
wrd...start with the basics and learn. (thumb)

[Rawyzf]

yeah right......I got busted so many times.....dealing with those pigs in the past......

You must do something to piss the police off then. Don't redline near them if you don't want to make too much noise. (boom07)

Or you can do this, and get out of it. (blowjob)

[jeffmsp]

stay at stock boost until you get an exhaust on there.

[jsahyoun]

I have to say that my 2.5 Apex DP and Greddy SP-2 catback is not loud at all! i dont even think it is any louder than my stock MP3 exhaust. I cant see the cops giving you a hard time for an exhaust like that.

I am catless btw.

[tommyg2b]

are you sure your exhuast system is not loud???? Cuz anything just louder than the stock exhuast and those dam pigs are after me already......Just about everyone over here in Wisconsin gets that....

[tommyg2b]

oh yeah, by the way, I do have the fmic coming in....I just bought it from ebay.... It was a pretty good deal....Now I just need the pipings....

[Nino Uvita]

The higher the compression the more efficient runs the engine. Turbo vehicles has lower compression ratio than normally aspirated vehicles in order to withstand the aditional pressure of the turbo. This is done to increase the durablity of the engine. If you are looking to get more performance you may want to try to increase one or more of the following: spark (i.e. spark plugs that spread better the spark [splitfire]), fuel (change fuel injectors [bigger ones] and air intake [increasing turbo size, etc.]. Just keep in mind that you will trade off engine durability by doing this.


QUOTE=tommyg2b]hey, guys, I was just wondering....I am planning on lowering my compression by swapping my stock pistons out and putting aftermarkets in....You guys think I can gain more power by doing that and how much PSI will be safe for me to run on....Planning on going atlease 8 for compression.[/QUOTE]

[low_psi]

WTF, you just repeated some of the most general info regarding cars EVAR. You sound like you just read an issue of MotorTrend. Higher compression/= higher efficiency. There are lots of other variables that must be optimized to make that statement work. Hmm, my MSP is a "turbo car" but it has the same compression as any other NA Protege.... As for the rest, garbage aswell.

Please don't clutter helpful threads with this crap.

[tommyg2b]

okay, okay, i guess i'll stay with stock boost for now....I'll just do my exhaust system including downpipe and then better plugs then fmic and then for sure a afc because of the hesitation it's giving...

[dominoy2k1]

fuck it just boost 32psi and let the good times roll.(drive2)

[mazdaspeed75]

there has yet to be a properly setup car fail. Stop spreading this nonsense. Give me a link to one person that has blown a motor at 10psi and had fuel control and IC/exhaust. just cheap asses or people that didnt know what they were doing and now the MSP has a bad wrap. I blew mine up at the track , I had mpi with extra njectors and lots of timming pulled . Load killed my motor , I was trapping 103.88 too. I was making good power but the track killed my car , should ahve kept in the streets . But hey it will be back strong as hell. Iam testing soem things out first .