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Forged Pistons...need some "more" advice!


Starwolf
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I am sure this has been brought up a lot in the past...but here goes.

 

I cant help but ask because its $500 we are talking about here...

 

If i plan on getting a super 16g turbo (i figure its better than the 17c?) and do not plan on making more than 300whp..

 

Should i get forged pistons or not? ive heard several different answers...and the reason i do not plan on making more hp is because i dont plan on going MPI (YET!)

 

 

So just some advice would be VERY GREATLY APPRECIATED!

 

Thanks in advance!

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the primary purpose to get forged over other options for sub 300 HP builds is that many change their minds later. If you try on 250 HP and decide you want more (boost is addictive) then what will you do with your $$$$ motor that was built with weaker pistons.

 

It costs far more to upgrade later, or to replace a damaged bottom end than it costs to get forged up front.

 

If you are CERTAIN you will never pass 300, then forged pistos are just more $$$ that could be better spent elsewhere. However, if you think there is a chance to upgrade beyond your current goals, why not upgrade now?

 

BTW, a forged piston is not a waste on a low power build, they take a lot mroe abuse so if you have tuning issues or have problems, they will hold up to a lot more abuse. It's really just a $$$ thing, can you afford to get them now, or is it better to upgrade later?

 

For me, I'd either keep the stock pistos or go forged, why spend $$$ on the middle of the road when the stockers are fine with the lower power levels you plan to run.

 

Only you can make this decision, we can only give you the details and some real world experiance.

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BTW, a forged piston is not a waste on a low power build, they take a lot mroe abuse so if you have tuning issues or have problems, they will hold up to a lot more abuse. It's really just a $$$ thing, can you afford to get them now, or is it better to upgrade later?

 

If you can't afford them now, Put your engine rebuild on hold intil you can. You won't be sorry!!!

 

CALIBER 308

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Yeah thanks with the replies guys...

 

Im definitely goes forged now...might as well eh?

 

also just to jack my own thread....for a quick street car i planned on using the big 16g...

 

if i send my 12a into forced performance...does that sound like the best bet...or a completely different turbo?

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Yeah thanks with the replies guys...

for a quick street car i planned on using the big 16g...

 

if i send my 12a into forced performance...does that sound like the best bet...or a completely different turbo?

 

Do some research into PSI efficiency ranges and Spool times on different turbos for a Street car. If it was me, I'd buy one outright. In other words, all ready built.

 

CALIBER 308

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A big16g is a good choice, another thing that forged pistons will get you that wasn't mentioned in this thread was you will have, depending on which choice you make, an increase in your compression ratio. You may not think about that much as you hand over 500-600 dollars and wonder what you'll get from it. For a stock bottom end you can do allot of other things with 600.00. Whether it will get you 300hp I can't say but don't bet on it. Not all are going to be able to get actual 300hp with forged pistons even when they try. Having a higher CR gets you more power from the same turbo at the same boost with less fuel. What you must watch are your EGTs
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A big16g is a good choice

 

I will have to disagree on this choice. I myself, would rather the boost came on sooner with a street car at (10 psi instead of 15). Like I said, Do some research into Efficiency ranges.

 

CALIBER 308

Edited by Caliber308
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Good stuff going on...i like the read.

 

And thanks for the explanation of the better compression from the forged pistons indiana...

 

well i could name the setup i was plannning on getting...but how will i know how much boost is too much boost? i want to be able to outrun some people top end too...if thats at all possible :P

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Good stuff going on...i like the read.

 

 

well i could name the setup i was plannning on getting.

 

Well, tell us so we can better help you out in your choice of turbos. Engine mods (planned) Head work (planned) and anything else.

 

CALIBER 308

Edited by Caliber308
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Okay i will try to get everything on one try here...but i bet i wont ;)

 

Forged pistons from dad

 

new marnal head from dad (ported and polished)

 

2.5 or 3" exhaust catless

 

lc1 Wideband?

 

255 walbro fuel pump

 

the $80-$90 top gasket set from dad...and bottom end gasket set

 

maf-t + GM AFM?

 

lighten flywheel to 22 pounds?

 

stage II clutch

 

BSE kit

 

TB rebuilt kit

 

 

dunno if that lists it all...but any idea of the turbo i should have with that...and what psi i could run with it?

 

thanks in advance!!

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Lower boost wtih a bigger turbo will typicaly be more resistant to detonation. Higher boost with smaller tubos often leads to high intake temps which will detonate on poor timming or bad/cheap gas. I made more power with a T-4 at 12 PSI that I did with the stock 12A at 23+ Either setup will require more fuel (bigger pump and perhaps some electronics/EFI upgrades).

 

Choose the turbo for the type of driving it will most often see if you paln on streeting it.

 

If you plan on racing it occasionsly and will tolerate lesser performance during normal use, then it's OK to get one that is best suited to high boost so you can maximize topend.

 

When you look at compressor maps, the ones that reach higher in the scale (high boost pressure ratios) often make more HP. those with shorter maps typicaly perform better at lower pressures, they make less HP but are more drivable.

 

At a given boost pressure, the shorter map can often beat the taller map if it's more efficent at that given boost. the bottom of the map of the tall turbos ususaly suffers to accomidate the high boost limits. this is why they performe worse at street pressures. There is no magic turbo that fits every need. Running a short map turbo beyond the upper boost limits increases the chance of detonation and shortens it's life greatly.

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I will have to read what you said SEVERAL times chad....love your knowledge about these things though...

 

about the only thing i can respond to that is saying that i will probably drive VERY slow and not under any boost most of the time i drive (people hate me when i drive my fast truck 10mph under the speed limit but hey...gas is crazy right now)

 

But i already have a lot of people lined up because they dont believe my car will be fast because its a four cylinder..i live in a hick town....3k people and our freakin school mascott is a hillbilly :\

 

anyways...so i want to be able to perform really well when i do hit boost...but i have no idea what would be best for what i plan...since i have never been in a turbo car? :'(

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If you plan on short runs TDO5H 17C: 10 to 20 psi. If you plan on more open highway runs TDO5H Big 16G:15 to 25 psi. C compressor wheels spool faster than Gs. Same CFMs: 550.

 

CALIBER 308

Edited by Caliber308
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Think about a TD06-17C, it's verry versitle at street pressures, and still pulls very hard at higher boost due to it's larger turbine wheel (which is a TD05).

 

The 16G is similar, just a tad smaller. The S16G is better for high boost and probalby makes more power on most setups, but will be less resopnsive from a cruise to full throttle situation. the 18G is a little bigger than all of them, and most say it streets very well, but the bigger you go, the less responsive they become. They will all require simiar fuel system mods to run safely long term (to allow occasional racing pressures) so there is no cost factor there.

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well which of these are a bolt on to the stock exhaust manifold?

 

can you not just rev the car the same to get the boost you need from a takeoff?

would the bigger turbo's always give a better 1/4 time?

 

 

im just not a fan of going realllllly fast from 0-80

 

i would rather go fast from 40-120

 

if that makes any sense?

 

i would feel more powerful :P

 

*edit also what is with the TD06 ...are they always going to be better turbo's?

 

and thanks for the info guys...im SOO writing this stuff down..

Edited by Starwolf
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Yah, the TD05H wheel is also a good choice, it's in between the TD05 and TD06 in size. The 06 will have more topend and probalby won't lag much more, but the 05H may be easeir/cheaper to setup.
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sounds like i will be going TD06 then...

 

any downsides to that?

 

and chad would you suggest me sending in the 12a i have to forced performance to get a new one back?

 

or buy a brand new turbo?

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they are all bolt-ons, which is why they are so popular. We can start listing non-bolt on's like T-3's too, but then you will be overwhelemed with choices (which will require a more dedicated and educated appraoch), and the conversion to a T-3 platforms also adds cost and complexity.
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If you use a core, it has to be a good core. A new assembly is always nice to start with, but that is a $$$ decision for most. Dont' be affraid of a core turbo if you have it done at a reputable shop, like forced performance is. If your core parts are junk, they will tell you, not just use it anyway. Keeping the 05 wheel you have now is cheapest. If you are upgrading your turbine too (to an 05H or 06) then none of the moving parts get reused anyway so most any quality core can be used.

 

The TD05 housing you have now may not be able to be machined to a TD06. It can be machined to an 05H with ease. That is up to your turbo builder to decide so it's best to askt that upfront.

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well i think the 12a i have has some shaft play...so it might not be good ...

 

there are no turbo builders around here i am almost positive... (and if there were i wouldnt trust them)

 

i guess i would want the TD06 since it seems to be the best bet...

 

any idea what it would cost for a new TD06 17c turbo?

 

(i love jacking my own thread?)

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the 05h is bigger than the stock 05. the TD06 is bigger than both. the bigger your turbine, the more flow it will accomidate. You dont' want to goo to big or you'll suffer lag from lower shaft speeds. Turbine wheels that are too small choke the motor as it tries to push all that exhaust though the small wheel. Turbines that are too big take longer to spinup to speed from a lower RPM.

 

It's all about balance, you can't tripple the flow on the compressor side while keeping the turbine stock sized and still have a well balanced efficent assembly.

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I know this is impossible to answer...but from the mods i stated earlier....what would you suggest? your about the best person to talk to about this imo anyways...

 

(as far as you being trustworthy...still have those studs :)

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I'd try to get TD06-17C, but the probabl lower cost of the TD05H-17C may be a big factor. Mitsu did make a TD06 housng for our manifolds, but It's not common and I don't belive it was even US spec. If your builder can't/won't use your housing for the larger wheel, you can see where it will cost you more...

 

I'd used forced performance personly, they have a good reputation and very reaonable prices. there are a few others with similar good reputations, just none come to mind.

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