Engine Rebuild for turbo capabilities

[ShadowRS99]

Now I here many, many things through this site and others that the 420a engine in my car will not handle more than about 8psi. This is when they refer to the lack of forged internal and strengthened headgaskets and other parts that are more turbo suitable. So from fellow 420a turbo builders or anyone who knows:
If I rebuilt my engine with forged internals and upgraded headgasket, plus anythything else I need like stronger sleeved cylinders, shouldn't I be able to run a turbo setup of more potential? I'm not looking for 500 horsepower on this car but I want a fun sporty car and it is hard to say your car is sporty when you put out 100 to your front wheel and get 0-60 in like 9 seconds. If you see where I'm coming from here. Thanks in advance for all of your help, Thank you.

 

[tec_41]

8psi is generally the max for stock injectors. The bare minimum fuel setup for running a turbo is 12:1 FMU and a Walbro 255hp. Most generally agree the stock block can handle about 10psi before you start pushing it's limits, and this requires a good tune. So without some kind of standalone like Megasquirt or Portfueler, you really can't run more than 8psi.

To give you an idea, on 8psi with the basic setup I clocked a 0-60 time right around 5s. Once you slap even a simple turbo setup on the 420a it really comes to life.

If you are wanting to rebuild the engine for boost you certainly can with low compression pistons and whatnot. But if all you're looking for is a sporty ride it's not required.

 

[LiquidX]

The other restriction is the fact the NA pistons have higher ring lands and cannot take much added stress before cracking. By putting in stronger rods and pistons you'll be able to handle a lot more. I'm not sure about how durable the 420a crank is however.

 

[tec_41]

The other restriction is the fact the NA pistons have higher ring lands and cannot take much added stress before cracking. By putting in stronger rods and pistons you'll be able to handle a lot more. I'm not sure about how durable the 420a crank is however.

Good point.

The crank has never been a weak point for the 420a, this is one thing that can easily be looked past in a build.

 

[LiquidX]

Good point.

The crank has never been a weak point for the 420a, this is one thing that can easily be looked past in a build.

Thank you, that is good to know.

 

[bullettdsm]

If I rebuilt my engine with forged internals and upgraded headgasket, plus anythything else I need like stronger sleeved cylinders, shouldn't I be able to run a turbo setup of more potential?

Yes (without the sleeves. Only reason you would run sleeves if if you screwed up a cylinder and wanted to retain the block).

Oh yeah, our cranks are good up to at least 800whp. There was one Neon guy who was breaking cranks but he was around 1000whp with a very high redline (they figured it was the harmonics breaking the crank). So don't sweat the crank.

MB

 

[ShadowRS99]

I know about all the fuel system and all that, but what I'm saying is:
If
EVERYTHING, Block, head,fuel and all.
Would it be able to handle more? Like the 4g63t?

 

[LiquidX]

Why wouldn't it? You are strengthening the weak points of the motor that would fail due to the excess pressure. I assume you are going to do stronger head studs as well?

Just remember, any motor (within reason) can become capable of 500+ HP.

 

[ShadowRS99]

Yeh I did even think about head studs.
Could you please ( for my information ) List some things that I am probably overlooking on weak point and what I need to strengthen?

 

[nemesis7]

yes you should rebuild your motor for really high boost turbo capabilities, any thing from 5 to 10 psi on a stock 420a can boosted. Now 10 to 20 or even 30 psi cant do on a stock 420a, you need to rebuild the internals, JE pistons Eagle Rods etc. putting all that pressure into those cylinders you will bend your stock internals so yes it is great for a rebuild if you want to have some real fun in a sporty car.

 

[ShadowRS99]

Alright you guys, Thanks for the help.

 

[Shake_Zulla]

I know about all the fuel system and all that, but what I'm saying is:
If
EVERYTHING, Block, head,fuel and all.
Would it be able to handle more? Like the 4g63t?

The only BASIC difference between a 4g63 and a 420a besides forged pistons and rods (as far as power potential goes) is that a 4g63 is a closed deck block and a 420a is a semi-closed so if you where looking to hit over 700hp the 4g63 would be a stronger construction. I am not saying that a 420a cant handle that however. It similar to saying that someone prefers to haul heavy stuff in a 3/4 ton instead of a 1/2 ton. Also before you ask you cannot fill a semi-closed like you can a open deck block. Head will work, however, if you have the block out 2gnt.com has some good suggestions on affordable upgrades you can do to it including pt cruiser lifters and rockers. Im confused why you know all about the fuel system but still ask if the block, head, and FUEL would be able to handle more. You need a better fuel pump and a way to get more fuel to the pistons whether it be a FMU or other means. After 5-8psi you will need to replace other things in your fuel system like injectors but a 4g63 would have to do the same. People will tell you that a 420a is a crappy block, however, there are a lot of cars that don't have a closed deck block such as the WRX's and STI's so try not to listen to those ignorant people.

 

[ShadowRS99]

Sorry I wasn't clear but I meant if I upgraded my fuel system along with lower and higher end upgrades for strength if I could pull out some better boost numbers, sorry. That is very helpful though.I never knew there was a such thing as a semi-closed and open deck blocks. I will have to look that up and do a little reading. (please excuse some lack of knowledge here, I'm only sixteen and don't have many car friends, especially DSMer's).
Thanks for you help though. I was thinking of saving up some money to go ahead and upgrade the fuel system with the 4g63 injectors if they would fit and getting the 255 Warlboro pump and AFPR. Not sure which brand would be best for the AFPR though.

 

[Shake_Zulla]

Sorry I wasn't clear but I meant if I upgraded my fuel system along with lower and higher end upgrades for strength if I could pull out some better boost numbers, sorry. That is very helpful though.I never knew there was a such thing as a semi-closed and open deck blocks. I will have to look that up and do a little reading. (please excuse some lack of knowledge here, I'm only sixteen and don't have many car friends, especially DSMer's).
Thanks for you help though. I was thinking of saving up some money to go ahead and upgrade the fuel system with the 4g63 injectors if they would fit and getting the 255 Warlboro pump and AFPR. Not sure which brand would be best for the AFPR though.

Hey no problem most of us here are still learning things about this car. The only advice I would give is to stop trying to make your motor the same as a 4g63 and instead make improvements that will be ideal for your setup. Take a little extra time to research what injector size would be best for your setup instead of trying to match the 4g63. When the gst guy ups his boost he buys bigger injectors so don't worry about that. Just take it slow and follow in the foot steps of those who have done it before you. Good luck man.

 

[ShadowRS99]

Alright thanks, I will keep that in mind.