1G What Would you do? Run it or Rebuild?

[Artofschiffy]

Some of you may have seen my previous post about discovering "63D" NA 9:1 pistons in my 6 bolt block from a rebuild done by the previous owner. When I bought the car the wastegate actuator wasn't connected to the flapper and shortly after I reconnected it, lovely boost came on and I feel like that may have been one of the reasons why I popped my head gasket since the motor couldn't handle the stock boost/added heat on a stock NA setup. I know some of you said it's not a major issue if I watch my tune but will I be able to safely boost with this setup? Other than the design of the NA piston, I am also hesitant because I am going to be running shitty cali 91 pump gas with 9:1 compression.

I was hoping to build a motor after I graduate college with forged internals but I don't currently have the funds for those parts. If I were to do a rebuild right now I'd probably just use NPR 7.8:1 1g pistons. The car is currently stock, if I were to keep the NA pistons I'd probably start upgrading everything other than the motor so it'd be ready a fresh rebuild and larger turbo.

I do have a palm emulator on my laptop with mmcd so I can monitor knock and what not. Ecmlink will be one of my next upgrades.

Is it worth swapping the pistons on a fresh rebuild or would I be better off running it until it needs a rebuild and start upgrading supporting mods?

Thanks!!

 

[Dstarperformance01]

Rebuild for sure.

 

[jimsgsx]

Common sense question, wait to destroy it or do it the right way. Cmon man dont make dsmers look foolish.

 

[Artofschiffy]

Common sense question, wait to destroy it or do it the right way. Cmon man dont make dsmers look foolish.

Apparently some dsmers are foolish as it was already rebuilt with the wrong pistons. It's not like I planned for this to happen but doing supporting mods first in preparation for a forged rebuild may be a better alternative to a rebuild on a freshly rebuilt motor. I'm not going to be driving it hard or anything and it's probably going to see less than 2,000 miles a year before a new build

 

[19gsx91]

Being forced to play devils advocate.. the "true" Dsm thing to do is run it and have one being built on the side ready to go in. If it's a 1g.

If it's a 2g? carefully. slowly. meticulously pull everything apart. take it to a machine shop. spend a butt ton of money on a machinist that isn't familiar with our platform. after you have over 3k in the engine work alone put it back together so it can survive 1000 miles before it blows again.

You said 7.8 CR so it's obviously a 1g. Even the NA 4g63 motors were fairly stout. If you have a method of tuning, and can play it safe for a while until you have enough money to do it right? do that.

If you have enough money to do it correctly now? I'd suggest doing it now. But no, I think if you kept boost low and your tune conservative you would be able to get by for a while..

 

[Tyeler18]

^^ This. The crown of 1g NA pistons is the weak point, detonation or high cylinder temps is going to waste those pistons fast. If you're OK with a mild setup until you graduate/can afford to build an engine than by all means run it, just don't go crazy. They can and will last under moderate power as long as you keep the tune happy, just don't expect to throw a 6262 or something on and expect it to hold. The 9.0:1 CR makes for a great street setup for out of boost power. All depends on if you plan on pushing this car in the near future.

 

[91talonts1]

Is this a 1g or 2g? If it's just a getting around car, I would run them. If it's something you're going to be playing with, it learning to tune on. I'd want something with a little more room for error. Not that the turbo pistons are going to be bullet proof, just a little more forgiving. If nothing is wrong with the block, and you already have in apart, swapping in turbo pistons should be as easy as removing the rods, hanging the new pistons on them, maybe a hone, and then reassembly.
Tuning software will help greatly with keeping it safe. I was asking about the generation as the stock 1g timing maps are pretty aggressive from what I remember.

 

[Artofschiffy]

Being forced to play devils advocate.. the "true" Dsm thing to do is run it and have one being built on the side ready to go in. If it's a 1g.

If it's a 2g? carefully. slowly. meticulously pull everything apart. take it to a machine shop. spend a butt ton of money on a machinist that isn't familiar with our platform. after you have over 3k in the engine work alone put it back together so it can survive 1000 miles before it blows again.

You said 7.8 CR so it's obviously a 1g. Even the NA 4g63 motors were fairly stout. If you have a method of tuning, and can play it safe for a while until you have enough money to do it right? do that.

If you have enough money to do it correctly now? I'd suggest doing it now. But no, I think if you kept boost low and your tune conservative you would be able to get by for a while..

It's a 90 TSi AWD with the original block! I plan on picking up a block and building it when I can find one for a decent deal. Going to go all out on a different block once I have the funds.

I have mmcd on a palm emulator but I'm definitely getting link and wideband before any thoughts on a new turbo setup.

Definitely don't plan on pushing my current setup. I should probably buy a mbc so I can turn the boost down . Thanks for the reply

^^ This. The crown of 1g NA pistons is the weak point, detonation or high cylinder temps is going to waste those pistons fast. If you're OK with a mild setup until you graduate/can afford to build an engine than by all means run it, just don't go crazy. They can and will last under moderate power as long as you keep the tune happy, just don't expect to throw a 6262 or something on and expect it to hold. The 9.0:1 CR makes for a great street setup for out of boost power. All depends on if you plan on pushing this car in the near future.

When I got it I was extremely surprised with the throttle response but now I know why . Now that I know what I have I don't plan on pushing it. It's not my DD so I think it'll last until the money starts flowing in. Thanks for your input

 

[91talonts1]

Definitely don't plan on pushing my current setup. I should probably buy a mbc so I can turn the boost down . Thanks for the reply

If you just connect the wastegate directly to a boost source, it will run on the spring pressure of the gate. Which is as low as it will go.

 

[Artofschiffy]

Is this a 1g or 2g? If it's just a getting around car, I would run them. If it's something you're going to be playing with, it learning to tune on. I'd want something with a little more room for error. Not that the turbo pistons are going to be bullet proof, just a little more forgiving. If nothing is wrong with the block, and you already have in apart, swapping in turbo pistons should be as easy as removing the rods, hanging the new pistons on them, maybe a hone, and then reassembly.
Tuning software will help greatly with keeping it safe. I was asking about the generation as the stock 1g timing maps are pretty aggressive from what I remember.

It's a 1g 6 bolt. My 1g is a project so I'd rarely be driving it until I graduate and get the funds for a total rebuild. I've read that the 1g timing maps are pretty aggressive but still need link to tune. There's a shop by my house that tunes evos so I may just pay them to do a very mild tune so I won't be walking on thin ice. Thanks for your input

If you just connect the wastegate directly to a boost source, it will run on the spring pressure of the gate. Which is as low as it will go.

I'll keep that in mind after it's all put together. Low boost and low rpms will hopefully help with my setup. Thanks!

 

[White flour1gawd]

rebuild

 

[Artofschiffy]

Is this a 1g or 2g? If it's just a getting around car, I would run them. If it's something you're going to be playing with, it learning to tune on. I'd want something with a little more room for error. Not that the turbo pistons are going to be bullet proof, just a little more forgiving. If nothing is wrong with the block, and you already have in apart, swapping in turbo pistons should be as easy as removing the rods, hanging the new pistons on them, maybe a hone, and then reassembly.
Tuning software will help greatly with keeping it safe. I was asking about the generation as the stock 1g timing maps are pretty aggressive from what I remember.

Not gonna lie I do want to have some fun with this car and I plan on learning how to tune with it too. Still on the fence about it but I feel like a swap should be done. NPR 1g pistons would be a safe move on my part.

The cylinder walls look pretty good. Smooth, no lip, I can still see the deglazing from the last hone and there doesn't appear to be any virtical scratches. I should still probably mic it but do you think I would be okay without a hone?

Have you ever done this swap with the engine in the car or do I need to pull it?

Thanks in advance

 

[Artofschiffy]

rebuild

Plan on it!

 

[Artofschiffy]

Rebuild for sure.

Gonna try and do a rebuild. Saving up though!