Is a 4G63A the same as a 4G63T without a turbo?

[XxDEViNWaYNExX]

Just rurious if a 94 Eclipse GS DOHC is the same as far as the motor goes but without a turbo.

 

[drewboi]

the block dosent have oil squirters for the pistons
the piston ring lands are different
it dosent have a knock sensor

 

[XxDEViNWaYNExX]

Well, would I be stupid to pass up a free 1994 GS DOHC Eclipse and keep looking for a 2g GST?

 

[95burgundyesi]

Free is free! take it, and build it slowly over winter.

 

[XxDEViNWaYNExX]

That's what I thought, with the money I save from not having to buy it, I'll be able to do a lot of stuff to it.

 

[luckynumber5]

Compression is higher too. They will take some boost, tuning is key. Just tore down a n/t block that had a 14b added on and the pistons and head were toast, thankfully the pistons didnt fall apart and wreck the block. But the pistons looked like someone had taken a chisel and just went to town on the outside edge of the piston top. The head was just as bad in the exact same area, damn thing got hot. Found out the previous owner ran the damn thing on 15 lbs, not good...

 

[NOSLO2PT0]

Why not just drive it daily?

 

[DSM1G90]

I'd call it a plain ol' 7 bolt 4G63. Ran 9.2 compression, used BPR6ES-11 spark plugs, 240cc injectors, et.al.

When he said the "A", I was wondering if he was thinking about it's replacement, being the Dodge Neon 420A for the 2G NT version ...

 

[XxDEViNWaYNExX]

Compression is higher too. They will take some boost, tuning is key. Just tore down a n/t block that had a 14b added on and the pistons and head were toast, thankfully the pistons didnt fall apart and wreck the block. But the pistons looked like someone had taken a chisel and just went to town on the outside edge of the piston top. The head was just as bad in the exact same area, damn thing got hot. Found out the previous owner ran the damn thing on 15 lbs, not good...

So I couldn't run a boost with too much PSI?

 

[dsm-onster]

The non-turbo pistons like to crack with any bit ofdetonation. This means the gas tanker truck who accidetly puts 87 in the 93 fuel tanks. Or, the day that gets 15*F warmer than when you tuned the car. Or, running in boost slightly longer than you normally do as the intercooler is heat soaked. Or, going up a steap hil and you decide to get a little frisky. Any string of knock could be the last your motor sees.

With that said, if you get a decent front mount intercooler and run a stock turbo tune (very rich) you should be ok with those instances never happening. I would seriously consider pulling the base timing a couple of degrees if you plan on running the stock sidemount.

 

[XxDEViNWaYNExX]

I really wanted a EVO 3 16G, will that be something that would work with a bigger intercooler?

 

[Elek_ron_ix]

Yeah a front mount intercooler would be a good idea for a Evo III 16G. Remember the bigger the intercooler the more time it take to fill with air so boost response might slow down a bit. It also matters what supporting mods you are going to implement with the 16G. Hopefully you read the tech articles and have a good idea of the correct modification path. Remember Maintenance before speed Have fun.

 

[sexi_beast_95]

Or if you want sell the 94 and put that towards the 2g.

 

[Gs Dewd]

or you could find a 6 bolt turbo motor, then visit your local junkyard for a few other odds and ends and put a turbo motor in your gs like I did and call it a day. Then you can run what ever turbo and tuning system you want and have all the advantages a original turbo car has but the satisfaction of building the car yourself.

 

[XxDEViNWaYNExX]

I have a 3000gt Twin Turbo moror outback, I thought about snagging one.

 

[dsm-onster]

or you could find a 6 bolt turbo motor, then visit your local junkyard for a few other odds and ends and put a turbo motor in your gs like I did and call it a day. Then you can run what ever turbo and tuning system you want and have all the advantages a original turbo car has but the satisfaction of building the car yourself.

It would be just as easy without the need of a hoist to pull the head and swap in turbo pistons. But that's just me. I've done both ways. It all works.

 

[DSM1G90]

I've done both ways. It all works.

When you do that, what about the oil squirter thingey - how would you cool down the pistons, or does it really matter?

 

[XiKeiyaZI]

When you do that, what about the oil squirter thingey - how would you cool down the pistons, or does it really matter?

There's so much controversy over Oil Squirters that it's ridiculous. It's about as bad as mentioning the term "Crank Walk".

From the Factory, they are installed to squirt the bottom of the pistons to relieve heat. However, most people say that they aren't needed, especially in forged setups. Also, without Oil squirters your increase your oil pressure a bit which is most often a good thing.

 

[MidShipCivic]

Rods are the same as the turbo engine ring lands don't matter so stop mentioning it, same goes for the compression ratio.

Conventional wisemen talk is ridiculous.

 

[dsm-onster]

Typical from one who never challenges via their actual experience. Here's my experience:

I've cracked pistons between the ringlands and top; where they are thinner than the turbo pistons (right at the crown; with a more conservative setup that saw MUCH less knock than when I was running turbo pitsons; with MORE cylinder pressure (higher torque). This happened several time. Between the identical setup. N/t pistons would fracture with 5-7 knock counts (via scanmaster, timing being pulled 1 degree via ecmlink at 18psi with a small 16g. Yet with the turbo pistons, I saw over 9 counts of knock at 22psi OVER and OVER and OVER again at much higher airflow, much faster 70-90 time, much more ecmlink estimated torque.

I've experienced the weakness of the pistons. I've ran both n/t and turbo pistons is SEVERAL engines. I've run n/t pistons in 4 seperate motors. And I've had professionals tune on both as well as tune myself. Same results every time. Though incredibly conservative measures were taken. N/t pistons will crack with muck less knock. PERIOD.

But, apparently mitsu had npr design their pistons with a thicker ring-to-crown for turbo blocks for no apparent reason. As well, there was no reason the turbo pistons to have reinforcement between the pin bosses. As well, having a thicker crown to undercrown (dish wall) does nothing to increase strength. Proper conclusions to draw because of some random unsubstantiated internet comment.

. . .OK, so now that we all here know the turbo piston is stronger and the n/t is weakenough to crack at only 5counts of knock at lower cylinder pressure. . . . The key is to never get any knock. Yes, you CAN build a setup never to get any knock even if you get a tank of bad gas, or an unusually hot day. But this means running a bit lower boost than you could normally get away with a turbo block with a typical 14b-16g turbo; plus a much larger intercooler. Or, something like water/meth injection. It's not about the compression ratio, no one mentioned that being a problem. But the benefit of higher CR is completely negated because of having to run such a conservative tune or boost to save the WEAK SPACING FROM THE CROWN TO THE TOP RING LAND where the n/t pistons crack when you have minimal det.

 

[JEFFREYCASTGSX]

There's so much controversy over Oil Squirters that it's ridiculous. It's about as bad as mentioning the term "Crank Walk".

From the Factory, they are installed to squirt the bottom of the pistons to relieve heat. However, most people say that they aren't needed, especially in forged setups. Also, without Oil squirters your increase your oil pressure a bit which is most often a good thing.

However you want to look at it, they are there to bulletproof the 4g63. Remember that the engineers thought about what could happen(not always) and what would happen. Factory cast pistons could use them. Not a single LS engine have them, boosted modulars dont have them, modern hemis dont have them. Top-fuel dragsters dont have them. I dont use them, and im on oem cast pistons. 2g 7-bolts sure as hell dont want them.

Typical talk from one who never explains via their experience: giving no experience at all to back the claims.

I've cracked pistons between the ringlands and top; where they are thinner than the turbo pistons (right at the crown; with a more conservative setup that saw MUCH less knock on a cooler day than when I was running turbo pitsons; with MORE cylinder pressure (higher torque).

I've experienced the weakness of the pistons. I've ran both n/t and turbo pistons is SEVERAL engines. I've run n/t pistons in 4 seperate motors. And I've had professionals tune on both as well as tune myself. Same results every time. Though incredibly conservative measures were taken. N/t pistons will crack with muck less knock. PERIOD.

The key is to never get any knock. Yes, you CAN build a setup never to get any knock even if you get a tank of bad gas, or an unusually hot day. But this means running a bit lower boost than you could normally get away with a turbo block with a typical 14b-16g turbo; plus a much larger intercooler. It's not about the compression ratio, no one mentioned that beign a problem. But the benefits of higher CR is negated because of having to run such a conservative tune or boost to save the WEAK SPACING FROM THE CROWN TO THE TOP RING LAND where the n/t pistons crack when you have minimal det.

Detonation destroys anything, especially ringlands. N/T pistons have ringlands much higher (and thinner) on the pistons than do turbo pistons. I remember when i took apart my 7-bolt and my N/T 6-bolt, the entire set of rings from the 7-bolt felt like a set of new rings, the 6-bolt, well um, didnt even make it off the pistons before cracking. So plain and simple, boost with a n/t piston is not what you want, we all know the benefits of higher compression, and we also know the benefits of detonation on weak n/t pistons .

 

[dsm-onster]

Detonation destroys anything, especially ringlands. N/T pistons have ringlands much higher (and thinner) on the pistons than do turbo pistons. I remember when i took apart my 7-bolt and my N/T 6-bolt, the entire set of rings from the 7-bolt felt like a set of new rings, the 6-bolt, well um, didnt even make it off the pistons before cracking. So plain and simple, boost with a n/t piston is not what you want, we all know the benefits of higher compression, and we also know the benefits of detonation on weak n/t pistons .

Not many know that the turbo piston is also reinforced with ridges between the pin bosses on the undercrown and also has a thicker dish to undercrown casting.

 

[JEFFREYCASTGSX]

Not many know that the turbo piston is also reinforced with ridges between the pin bosses on the undercrown and also has a thicker dish to undercrown casting.

I would say thats a given as they are TURBO pistons. My 7-bolt didnt have a single bite or sting from detonation/knock/ping, and they went threw 30psi spikes on the daily, no meth, on 90 oct piss water.