Can cast pistons work?

[Dragon_284]

My brother owns a talon tsi (awd turbo) and was telling me the other day that dsm's (eclipse, talo, and laser) had cast pistons. Now I know most turbo from the factory cars come with forged internals, but he told me that he looked it up and that his car came with cast pistons. So here is my question. Is it possible to build the bottom end (forged rods, new bearings, etc...) and then get cast pistons instead of forged? Now this question applies to a ka24e. So is it possible only on an engine with oil squiters? Can I do this ka24e? If so how much could the pistons take? Lastly would I want to do this even if its possible? Thanks again.

[TurboKA37]

remember that the DSM pistons have a much lower CR than the KA and alot of the reason that stock KA pistons tend to fail under moderate boost is because their design around the rings. the same thing that destroys cast pistons will destroy forged pistons (poor tuning). it just might take longer for the forged to fail. is it possible to run cast pistons with higher boost on the KA? sure, if you can find a set that has lower compression and is designed better than the stock ones. but finding those pistons will be the hard part.

[Nismo_Freak]

remember that the DSM pistons have a much lower CR than the KA and alot of the reason that stock KA pistons tend to fail under moderate boost is because their design around the rings. the same thing that destroys cast pistons will destroy forged pistons (poor tuning). it just might take longer for the forged to fail. is it possible to run cast pistons with higher boost on the KA? sure, if you can find a set that has lower compression and is designed better than the stock ones. but finding those pistons will be the hard part.

Ahhhh finally I get to unveil my ghettotastic idea.

Put KA24DE pistons into a KA24E... voila instant low compression.

It's an exact reversal of the cheapie hi-comp setup people run on DE's.

[WDRacing]

Yeah but the pistons still suck Alan. The first ring land is made out of chocolate cookie dough...lol.

[WDRacing]

One of the good things about cast or Hypertectic(SP) pistons is that they don't expand under heat like the forged ones do. So you can have alot closer clearences. So if you get a piston that had thick ring lands you'll be good till atleast 400whp easy. Since the stock one will go that far themselves.

By the way, the stock rods are forged and shottpeened from the factory, no need to replace them, maybe just the bolts and the bearings.

[TrunkMonkey]

Put KA24DE pistons into a KA24E... voila instant low compression.

yeah and at a 7.something:1 compression ratio, even miss daisy would be telling you to hurry up.

-demetrius

[TurboKA37]

what is the stock CR for the KAE? 8.5 or 9:1 i think? i also heard that the piston design was much different than the KADE's so the CR would change when installed on the DE. i think thats what demetrius is refering to tho.

[TrunkMonkey]

what is the stock CR for the KAE? 8.5 or 9:1 i think?

9.1:1 early 89. 8.6:1 late 89 thru 90.

Quote »i also heard that the piston design was much different than the KADE's so the CR would change when installed on the DE.[/quote]the only difference between the E and DE pistons is dish volume. other than that, they're exactly the same.

-demetrius

[nissanfanatic]

yeah and at a 7.something:1 compression ratio, even miss daisy would be telling you to hurry up.

-demetrius

hahahahahaha. If you are going for a low budget build-up, just replace pistons. They take most of the abuse, so its the last place you want to skimp.

[Dragon_284]

So the rods on ka24e are forged and shotied up (as I call it) from the factory. I read about that in another post but I thought that was just on the ka24de's. I just recently found out about the CR differences between the DE and the E. I was looking at the those supertech pistons they sell on ka24de.com but I found out that they are made for the DE and if installed in my E it would lower my CR to 8:1. (I was going for a 9:1 turbo setup) So I have a couple more questoions. First since the stock rods are forged and shotpeened then would some nismo stock replacments be the same way? Last is where can I find some forged pistons for the E? 8.5:1 or 9:1 either would be fine. Thanks again.

[Nismo_Freak]

Yeah but the pistons still suck Alan. The first ring land is made out of chocolate cookie dough...lol.

You getting elitist on me chump? I thought you KA-T kiddies loved the ghettorigging hahah.

Either way you can't argue that it wouldn't be a cheap way of getting another 20-30whp out of the cast piston.

I was more or less aiming at it being a joke, although a forged DE piston into an E motor would give you something Cosworth-esque.

[Nismo_Freak]

yeah and at a 7.something:1 compression ratio, even miss daisy would be telling you to hurry up.

-demetrius

It'd still be faster than a 9.5:1 motor.

[WDRacing]

You want ghetto fabulous, try raisning the compression and having 3-4 cold start injectors spraying alcohol starting at 5-9-13-16 psi. Using junk yard parts we're talking 300 bucks for a high compression mid boost motor...lol.

[Dragon_284]

Good ol backyard bubba tech. Cant beat it lol.

[WDRacing]

That would actually work I bet. Use a windshield resovoir to hold the alky, grab fuel line from whatever car, take an old fuel pump, grab the cold start injectors from a Saab, use wiring from whatever car and all your left with is the pressure switches. Use Hobbs switches or similar...done.

[sil80drifter]

or you can have the stock pistons/rods/bearings/rings cryo treated for like 15 bucks/set. that'll def. make them last longer. that's what i'm gonna do, and find out just how much longer.

sil80

[Nismo_Freak]

or you can have the stock pistons/rods/bearings/rings cryo treated for like 15 bucks/set. that'll def. make them last longer. that's what i'm gonna do, and find out just how much longer.

sil80

My bet is on ... 30 seconds.

[KATwo40]

lol.

Dude, you're putting too much worry into this internals deal. If you're shooting for around 325whp, just use the stock internals. It will hold up just fine. There's no such thing as a "low cost buildup." It's either "a build up" or it's "stock." Either do the buildup all the way (like to the tune of around 2k$ or just use the stockers.

[WDRacing]

lol.

Dude, you're putting too much worry into this internals deal. If you're shooting for around 325whp, just use the stock internals. It will hold up just fine. There's no such thing as a "low cost buildup." It's either "a build up" or it's "stock." Either do the buildup all the way (like to the tune of around 2k$ or just use the stockers.

I couldn't agree more...

[Dragon_284]

The reason I worry is because people I know around here have gone down the road of stock internals with boost and have just blown their motors to ****. Granted alot of them dont treat their cars the way I treat mine but still the thought of my motor going pop does bother me. Also I wasnt really pulling for a "low cost buildup". I was fully aware of the amount of money it would take to build the engine. The reason for the cast piston question was because I had found some 9:1 pistons for the ka24e that nismo made. Now it never said if they were forged or cast but im pretty sure they are cast because of their price tag. I dont think anyone answered my question above, which was, if the stock rods are forged and shotpeened then would nismo oem replacments be the same way? Also I have really never done any tuning to my car. So all the burning eproms, electonic fuel controllers, and piggybacks seem really complicated to me which im sure they are not that bad but for me at my current level they are. So thats another thing that worries me. If I cant tune my car well I could possible blow my engine which is why I want to make sure I set my engine up the right way.

[sil80drifter]

I think what they are trying to tell you is: If you are unable to deal with tuning, nothing will help you to keep your boosted KA-T from blowing. Forged/Cast/cryo/witch spells/kissing every bolt on the KA will all fail if the engine is not tuned properly.

The forged components are there just to withstand the rigors of high HP applications, they are not a fail-safe protection against ignorance in regards to tuning. Ignorance is not used here to insult you, but to underline the fact that without knowledge about the components of a performance engine, one cannot properly set it up.

The forged parts are just a small part of what making a KA F/I is about. You have to have good mechanical knowledge, but learn about tuning before you learn about forged things. Tuning is much more important than components. In fact it's probably the most important thing you can learn about when trying to put together a KA-T.

sil80
Modified by sil80drifter at 3:10 PM 2/3/2005

[Dragon_284]

Yeah I understand that and take no offense to your statement. Im willing to take the time and effort to learn to tune I just thought that having some internals that were tougher than stock stuff would give a little more lee-way in my first attempts at tuning my car. I understand the basic concepts of it. Like retarding timing to decrease the chance of detonation, having the right air fuel mixture, and boost settings. I have just never had the chance to practice it. But like I said im willing to learn and I pick things up pretty quick too.

[sil80drifter]

Then you are well on your way. For a basic understanding/reinforcement of knowledge about engine components and mechanics/basic fuel delivery I would start with http://www.howstufworks.comThen just start googling up stuff like "basics of engine fuel delivery" or "engine tuning explained" or "car tuning"I've come up with stuff like

http://www.tuninglinx.com/html/articles.html

from the above searches, and I'm sure there are better phrases to look for.

And of course, this board is an excellent source for research as well, but don't limit your self to any one board, because nobody has everything, although this board is among the best out there.

Set some goals like "today/this week I wanna know about ignition/fuel delivery/suspension/etc" and just go at your own pace.

good luck.

Nismo Freak: no faith in cryo?

sil80
Modified by sil80drifter at 10:03 AM 2/6/2005

[Nismo_Freak]

Then you are well on your way. For a basic understanding/reinforcement of knowledge about engine components and mechanics/basic fuel delivery I would start with http://www.howstufworks.comThen just start googling up stuff like "basics of engine fuel delivery" or "engine tuning explained" or "car tuning"I've come up with stuff like

http://www.tuninglinx.com/html/articles.html

from the above searches, and I'm sure there are better phrases to look for.

And of course, this board is an excellent source for research as well, but don't limit your self to any one board, because nobody has everything, although this board is among the best out there.

Set some goals like "today/this week I wanna know about ignition/fuel delivery/suspension/etc" and just go at your own pace.

good luck.

Nismo Freak: no faith in cryo?

sil80

Honestly, you would be better off just getting a set of forged pistons. The process of forging far outweighs any cryo treatments benefit. Plus this allows you to run a freshly machined bore.

Cryo-treating parts is a well used process for things like gears, pinions, etc.

[Xero]

a cryo treated forge piston would be better than a cryo treated stocker

the thing that ALL of it comes down to is, tuning. You cannot make alot of power off of some rising rate FPR and straight poor tuning. Which is what all the blown up KAs were trying to do, overboosting for the mods they had, it's a strong motor, but like any other one, it can't take much abuse by way of poor tuning

[sil80drifter]

Cryo treating a stock piston = $5 per piston, and $2 per set of rings (so $8 for all 4 ring sets). Total = $28 plus shipping. All I care about here is strengthening the ringlands a bit, and making the rings less prone to wear.

Forged pistons/rings = $ALOT. A set for $500, i believe?Bang for the buck? You decide.

http://www.onecryo.com

Take a look at their prices.

sil80

[WDRacing]

Once I hit 350WHP I'd go with a new set of pistons, somthing with a stronger ringland. Reguardless of cryo treatment.

[sil80drifter]

Undoubtedly, in fact I wouldn't go over 300rwhp on them to be safe. But that's exactly my point; for a moderate setup (which is the case for very many of us), we do not need to spend gobs of money.

sil80

[WDRacing]

If I have the block apart, I'm getting new pistons.

[sil80drifter]

New stockers are $20-$30 a piece (including rings). Add the previous amount to $80-$120, and you're on a very decent (brand new) stock cryo piston setup, and about $400 ahead of forgies. It all depends on your goals.

sil80