turboing non turbo 2.4

[Mopar318]

Ok, so my ACR has a 2.4 stratus engine. Have all the parts sitting here If I want to turbocharge it. Anybody know what kind of stress the stock 2.4 can take? 8lbs of boost would probally be the maximum. Also what can be used from the factory 2.4 non turbo converting it to the 2.4 turbo internals?

[1FastCSX289]

Just pick up a set of SRT-4 rods and pistons. Hone the cylinders and swap in new SRT rod bearings and piston rings and its all set for serious boost. Everything else will work fine. Some guys go for the SRT oil pump/sump and add the piston oil squirters, but its not necessary.

[Mopar318]

Just pick up a set of SRT-4 rods and pistons. Hone the cylinders and swap in new SRT rod bearings and piston rings and its all set for serious boost. Everything else will work fine. Some guys go for the SRT oil pump/sump and add the piston oil squirters, but its not necessary.

Wow, thats pretty simple. I figured the crank would be different. What about the difference in heads?

[1FastCSX289]

Wow, thats pretty simple. I figured the crank would be different. What about the difference in heads?

No issue that i know of using an N/A head. I just did the swap into my CSX and I wanted to do it as inexpensively as possible. All I did changed were the rods and pistons. Everything else is stock 2.4. Seems to be running well, but I only have it set to 12 lbs of boost while I tune it. I have read that it should be able to handle 350 HP or so.

[turbovanman²]

Wow, thats pretty simple. I figured the crank would be different. What about the difference in heads?

Nothing, maybe valve material but that's it. Almost everyone runs N/A valves and they seem to hold up. Weird, lol.

You can pick up a set of factory rods and pistons for cheap, it was listed in another thread asking the same questions, :D

http://www.turbo-mopar.com/forums/showthread.php?t=50611

[SebringLX]

Just pick up a set of SRT-4 rods and pistons. Hone the cylinders and swap in new SRT rod bearings and piston rings and its all set for serious boost. Everything else will work fine. Some guys go for the SRT oil pump/sump and add the piston oil squirters, but its not necessary.

^^ This. All I did with my Sebring was swap in a set of OEM SRT-4 Internals.

[contraption22]

Just have this known... the SRT pistons are high-quality hypereutectic pistons, which is alot like saying "the best tasting light beer".

They do work, and they survive very well due to the idiot-proofing engineeried into SRT-4's engine management, but they do not take kindly to dentonation.

And the ski-jump shaped piston crown is less than ideal for serious performance efforts.

[Nemesismachine]

No external oil drains? Just the line for the turbo (and turbo drain, obviously)?

[contraption22]

No external oil drains? Just the line for the turbo (and turbo drain, obviously)?

External oil drains are only required on the DOHC hybrids because the oil drains in the 2.0/2.4 head do not line up with the passages in the 2.2 block.

[Mopar318]

The plan will be a SRT4 turbofold. Ill just run low boost. Probally no more than 12psi.

[Mopar318]

So it looks like with the pistons/rods from Modern Performance Ill be around 600 for the whole short block build after some light machine work.

[cobra2411]

Just have this known... the SRT pistons are high-quality hypereutectic pistons, which is alot like saying "the best tasting light beer".


Detonation also beats the crap out of the bearings... So even if you have forged pistons it's not a license to let detonation run wild....

My reason for wanting to run them is cost. Junkyard motor and $300 set of pistons and rods... So what if it goes Ka-boom after a while or if my tune isn't right. :evil:

[1FastCSX289]

My reason for wanting to run them is cost. Junkyard motor and $300 set of pistons and rods... So what if it goes Ka-boom after a while or if my tune isn't right. :evil:

This was pretty much my line of thought as to why I went with this set up. I actually opted for used SRT internals. 100 bucks for all 4 pistons and rods. If I crack a piston or melt a head or.....whatever.....its all junkyard parts.

[cobra2411]

Yup... From the beginning my attitude has been "I don't care if it blows up; hell I expect it to, I just care how often it blows up..."

I'm going to start by turning up the boost dial to about 25psi... Then I might mix in a little nitrous... 400+hp is a lot for these things and lots of stuff can and might blow up.

Take a look at Brent and his 3.0's... Ask anybody and they'll tell you he's using the wrong stuff... But it holds together if the tune is good. You can frag any motor with detonation; I don't care how bullet proof you think it is. Yeah forged internals put up with a lot more crap and may save the day if you get carried away over say a cast or hypereutectic setup but it doesn't mean the cheap stuff doesn't work...

[turbovanman²]

Take a look at Brent and his 3.0's... Ask anybody and they'll tell you he's using the wrong stuff... But it holds together if the tune is good. You can frag any motor with detonation; I don't care how bullet proof you think it is. Yeah forged internals put up with a lot more crap and may save the day if you get carried away over say a cast or hypereutectic setup but it doesn't mean the cheap stuff doesn't work...

Yes, cheap works BUT if you make one tiny mistake, BOOM, with forged pistons, you have a window, to say, add more fuel, take out timing etc before it goes boom, unless you keep your foot into it.

Also, cast or hyper pistons, at a certain level, you will peel the tops off, good tune or not.

[contraption22]

Don't you guys put a price on your own time to go yarding for an engine, cleaning, rebuilding, sealants, gaskets, hardware? Not to mention downtime where your replacing pistons instead of enjoying your car? I do. And forged pistons seem cheap in comparison.

[cobra2411]

I do put a value on my time but there are plenty of SRT4 guys running 400+ hp on stock bottom ends. I understand if they're going POP left and right, but there not. I've talked to guys with over 50k miles and 100+ passes with over 400hp on stock bottom ends.

I'm building a car from scratch and it's 500 here, 500 there, 500 over here... I can't see spending another 500+ to upgrade to forged pistons when I can reliably meet my goals with stock parts. If the NA stuff was all that was out there ok, but the SRT stuff can take some abuse. Yeah forged pistons are better but that's not to say that my motor is going to blow up the first time I get on it just because it's got hypereutectics in it...

[1FastCSX289]

Don't you guys put a price on your own time to go yarding for an engine, cleaning, rebuilding, sealants, gaskets, hardware? Not to mention downtime where your replacing pistons instead of enjoying your car? I do. And forged pistons seem cheap in comparison.

I think my job allows me to put less value on that time.....I teach auto tech so I have the luxury of bringing the car into work, having the kids tear it apart, etc. I dont have money.....but i have lots of time to work on the car.

[Mopar318]

I want this to be a daily driver, not a race car. Although i would like to drive to events to do some auto x. Just going to run the stock boost level, use the stock srt turbo, intake manifold, injectors and tune with megasquirt.

Ill get the engine apart and have it cleaned, honed, and any other machine work that may need done.

[A.J.]

I do put a value on my time but there are plenty of SRT4 guys running 400+ hp on stock bottom ends. I understand if they're going POP left and right, but there not. I've talked to guys with over 50k miles and 100+ passes with over 400hp on stock bottom ends.


But those factory SRT cars have upgraded computers tuned and tested by Chrysler. Chrysler is not going to sell a stage 2 or 3 kit that's going to grenade the engine. We on the other hand have to tune our 8v computers (or megasquirt) from scratch to run a DOHC set up. And in that process we are going to experience detonation along the way until we get it right.

I'm currently kicking around if I'm going to go with forged pistons or just ceramic coat the factory SRT pistons. Also I don't like the shape of the factory ones. I understand why Chrysler did it but they may not be the best design for what I want to do.

A.J.

[1FastCSX289]

There is no reason why you need to run into serious detonation while tuning. AS long as the fuel and timing are initially set very conservative and then conservative adjustments are made......and we dont get too greedy on the tune......combined with the knock sensor to as a back up.....we can get a nice tune that will allow the motor to survive. My reservation would be with the stand alone set ups like mega squirt that dont have any knock control. There is no back up for errors in tuning or in the event you lose a fuel pump or regulator. I lost a couple of 8v motors with my sds system. Mostly due to inexperience, but knock control probably would have saved me.

[cobra2411]

Exactly... I'm going to be running Megasquirt and plan on copying DJ's audio knock sensor so I will be able to tune on the fly more or less and know when I'm flirting with detonation. Pistons aren't the only thing to worry about in the 2.4's at 400+hp. The bedplates can split and if you think you can rattle the motor because you have forged pistons in the car well... You just might split the bed plate in two and dump those nice pistons onto the ground... Then there is the oil pump, the balance shafts, the crank, etc... We're talking about close to 200 hp/ liter here. It all comes down to the tune and hypereutectics can and do live at 400+hp. Hell there are guys running up to 600hp with them. You just can't rattle the motor.

I'm going to hone the block myself and when I'm done I'll have a running long block for less then the cost of a forged piston and rod set. I understand they're hypereutectic and sensitive to detonation so I'll keep my tune conservative and sneak up on it. I understand and agree that forged pistons are tougher and more resistant to detonation and other tuning errors but there have been others that have made 400hp, 500hp and even up to 600hp with the same parts and they've stayed together. I'm not venturing off into the unknown hoping it might work; I know for a fact if I keep it detonation free I can meet and beat my goal of 400hp. I don't get what's so hard for people to understand about that.