forged pistons/compression?

[mazda2002]

I have read that many of you have upgraded to forged pistons. I heard that the compression was lowered, is this right, does changing internals give you a good power difference?(without tubo)

 

[azian6er]

ok, forged pistons, just like forged anything else will be stronger than stock, yet still not invinsible. People upgrade to forged parts because in many instances, for example, those running FI applications, the material the pistons are made of can hold up to some of the regular detonation that their stock counterparts couldnt.

All in all people upgrade to forged pistons/rods as a safety measure.

Just replacing forged rods/pistons without over boring, increasing compression will not yield any significant gains unless your motor was taking a s*** before you swapped them.

Basically if one is going Naturally aspirated (no turbo supercharger ) then one wants higher compression ratio pistons, where as turbo engines opt for lower compression ratios because air is already being forced into the engine which in turn raises compression ratios.

For a goos mix of daily driving pep and weekend road racing, a compression ratio of about stock, or 9.1:1 is thought to be good. If you are building a strictly race car then i would say lower compression pistons, ie 8:1 or 8.5:1 would be better because with the lower comp. ratio people are able to boost more safely.

get it now?

--B

 

[zmepro]

also, keep in mind the cost, rods alone can run you $700 and then there is the labor which is going to be at least $1000 and you don't wanna have it done by some retard, you need a reputable shop and there is the downtime because it doesn't just slide on, there is alot of work

in sum, there are lots of things to do before forged internals, especially with an lx (like all the NA 2.0s) there are much more importent things to do with the money

 

[twilightprotege]

see zmepro's comment. much more to do before forged parts

 

[mazda2002]

I have a very limited budget, I was planning on saving money over the summer,(student budget), and getting forged internals, I would't be able to put NOS or turbo for a while after that, due to budget. Is it much easier to change pistons without complexe tubo set-ups?

Will I loose power with that sort of setup. I plan on running turbo or NOS in the future.

Arn't forged internals lighter than stock, in addition to being stronger due to the forging process.

The blned engines on this page scare me, I am pretty hard on my car.

 

[igdrasil]

depends...

some forged pistons are heavier for turbo apps.

others are lighter, meant for N/A apps which takes advantage of lighter internals to develop HP.

dont look for forged stuff if you are not going over 200hp, stock pistons are VERY strong. They will hold if tuned correctly.

you want power...you need $$$

 

[zmepro]

well heres the deal, if you are thinking about turbo or nos, go with a turbo, all the turbos out there on the market (hiboost, flyinprotege, wagner) are designed to work with your stock internals (at 6-8 psi) you don't have anything to worry about at that boost level and as long as you don't increase the boost you are ok. The MSP owners that are blowing there engines are doing things like underdrive pulleys (a bad idea in my opinon) and increasing the boost to unsafe levels with poor quality components (at least this is my understanding) The MSP has the same internals as all other proteges and works fine at stock boost levels. a turbo will cost you about $3000-4000 and will give you between 70-100 horsepower at the wheels (significantly more then the msp) and forged internals will cost you about 700 for the rods, maybe 500 for the pistons and at least 1000 for labor, counting all the other parts its gonna end up costing nearly $2500. (USD)
Your best bet is to get a turbo, keep the boost at a safe level, then when you have the time and money throw in the forged internals then crank up the boost.

 

[mazda2002]

how much would that cost me in total, according to you?

The way I count it:

JE Pistons with rings: 500-600$
Pauter rods(do they fit together?):700$
Head gasket:???
Installation:10hrs@60$CAN:600$CAN

Please feel free to correct these number and pardon my ignorance

 

[zmepro]

$60 an hour candian is really cheap for shop work, around here it is at least $90 USD an hour, i would question the credibility of the shop

you are looking at around $3000 CAD for the installation

 

[zmepro]

and after you spend that $3000 cad you are not going to notice any difference, while you could be 3/4 of the way to 100 hp from a turbo, just something to keep in mind

 

[mazda2002]

Would you get that done to a special shop, can't a garage do that, what machining is there to do?

Do you know how it is done?

 

[PeaB0dy]

Average here in Toront is around $80-$85 per hour..

I can get $75 from my mechanic..

 

[zmepro]

some garages may be able to, they need to have engine building capabilities and there are a few specific rod tools, engine mount things, other various big and expensive tools they need, so the shop at the gas station prolly couldn't but you wouldn't want them to anyway, a performance shop or something along those lines, speciality shops, would be where to look, the best possibility is if there is a mazda specilty shop (not dealership) but engine building is engine building and most of the basics are the same. theoretically with the right tools, space and enough patience you could do it yourself, but i would only do it if you really trusted your mechanical ability because there is a high margin for error and things need to be lined up and the tolerances are very tight and if you **** them up, say goodbye to your engine.

 

[zmepro]

$75 cad? thats not bad at all

 

[mazda2002]

From what I understood,they take off the head and anything under the block that stops you from getting to the crankshaft and pass the pistons and connecting rods from the top.

They also bore out or polish or something to get rid or marks left from the old pistons.Then they pass the new stuff through and close it up.

 

[zmepro]

i belive it requires you remove the engine so you can get at the crankshaft

 

[mazda2002]

At the dealership, the price is at 72$/hrs if I am not mistaking.(Montreal Qubec), An other place I got my car looked at was 52$/hrs if I remember correctly

 

[mazda2002]

has anyone on this board done it themeselves?

 

[PeaB0dy]

Best thing right now is leave the engine, and when you have another car to drive around, then rebuild the engine in this one..

What you are looking at doing is a BIG job, and needs a lot devoted to it..

Doing the research here is only part of it, read up on rebuilding engines, and look what goes into it..

No shop likes to raise and lower cars very many times, they would take off the hood, and remove the engine..

 

[igdrasil]

Changing pistons/conrods assembly is a very serious task. You need to unbolt the head, transmission, crank case, etc.

You need torque specs.

Check pictures:
/members/igdrasil/proyect/000_2216.jpg

/members/igdrasil/proyect/000_2219.jpg

/members/igdrasil/proyect/block_bay.jpg

/members/igdrasil/proyect/block_top.jpg

/members/igdrasil/setup/new_piston_set.jpg

/members/igdrasil/enginerip.jpg