Hi there. My LSJ Atom is currently undergoing a custom turbo conversion and I'm debating which direction to go with the engine. The turbo is a Forced Performance GT3076R with Tial housing. Exhaust manifold, full exhaust, intake manifold, and other misc stuff will be all custom welded. The shop is guessing that this turbo will be good for 450whp or more on race gas. What do you guys think?

Obviously, this is not the least expensive way to build a turbo Atom and so I'm running up against a debate with my budget (and, more importantly, the keeper of my budget ) I'd rather not just leave the engine stock and turn down the boost although it would save significant $. In fact I'm not even sure if I'd need to do that as I'm not totally clear on what the stock LSJ can take, although I've read it would be melting stock pistons at 450whp? Is this true? If so, would just swapping in a Gen 3 LSJ shortblock be sufficient or would I need to go with a fully built block (like ZZPs race block wit hall the fixings)? I'd love to avoid the fully built motor as it is really expensive and seems like overkill. I'm just aiming to have a reliable 400-450whp, not aiming for huge numbers that are unusable on the platform. While I've got the engine out, is it worth doing head work?

I really appreciate any advice you folks can offer. This is a great forum and I've really enjoyed reading it and dreaming/planning what I want to do to my car. The time is finally here! Thanks.

 

not too sure of your location but E85 will get you to your numbers easier and will help keep the motor cool. The tune is the key part for any build. I would do some research depending on your location im sure we can all recommend the best of the best for you.

im def. interested to see the build progress. The LSJ engine is a pretty good plant to build off of.

 

Just make sure you have a good working fuel gauge and run e85. Why good working big fuel gauge? Because fun time = no gas time real quick.

Is it going to be a track car or around town car? Power depends on what kind of stuff you're doing with it. I'd go with a smaller turbine housing so it spools faster.

 

E85 is an option where I live but I'd rather not go there as, in my opinion, it will really hurt the resale potential of the car due to geographic restrictions. Not that I'm looking to sell it in this lifetime, just being realistic. However, could I go with an E85 build that would still do well on pump gas? I've done a little research on E85 but not a ton much for the reasons I just mentioned. Thanks!

 

E85 allows you to add more timing which = more power.

You can go back and forth from pump to e85 whenever you want, just run the tank to empty and put the other tune on and fill up w. the correct gas.

when you go to sell it no one will ever know what kind of gas you had in it before unless you tell them. The LSJ loves E85.

Injectors and little stuff will be needed, maybe a new fuel pump and stuff like that but nothing crazy.


i bet you this thread has all the info you will ever need on your build lol https://www.cobaltss.net/forums/2-0l...thread-258476/

 

yea fuel is quite important for making safe power. lots of people make 400-450 on rather stock internals pretty safely it seems. always keep an eye on your afr and you should be safe. pistons, rods sleeves and rings would be a must though if you really want peace of mind though, but hey, crank your current engine up and if/when it blows, have a new gen 3 built and ready to drop it!

 

Don't listen to this guy ^ pretty sure he has some serious mental issues.

The power it can handle depends on a lot of variables, hit Mr. B up on here and he can get you a block that will handle what that turbo can throw at it and i'm sure for a reasonable price.

If you want to keep the block stock you need to figure out how much air the turbo will be moving and then how much timing your tuner will be adding. A consideration if staying on the stock block is an EGT gauge, easy to monitor your engine health (also assuming you already have a wideband, if not get one)

 

Okay then mr know it all.

 

subd for pics of ongoing build and said ****!

 

Just taking one of your questions: I don't know about the power capabilities of the stock LSJ, but there are stories of people bending rods on the "gen 3" blocks (I use quotes because what we call Gen 3 isn't really GM's Gen 3 Ecotec, more like a revised Gen 2). To my knowledge, the changes were powder forged cast rods and thicker cooling jacket walls to combat cracking that some of us have dealt with in the LNF. In doing that they got rid of the iron sleeve and anodized the cylinder walls instead. I'm not aware of any strength comparisons between the two rods, but I don't think you'd gain anything between stock LSJ vs stock A20NHT ("gen 3" block). Built is a different story. If you swap rods and pistons then the newer block should do better.

EDIT: The stock LSJ isn't sleeved, is it?

 

Here are some pics of the build in progress. Work is being done by Fathouse Fabrications.

 

just throwing more power at those isn't always the way. its already light in the ass. the 3.5r is quicker than the atom 500 despite being 150hp down on it. there is also a shop that does the 750hp version somewhere in NC I think. you could call them and see what they suggest for a more sane build.

 

the only rod bending stories on the gen3 blocks ive read about is the rod not handling much abuse, the gen3 block is a different casted block then the gen1 or 2 blocks it is no longer lost foam casted it is sand casted the 2.0 is a coated cylinder wall and the 2.4 uses a cast in place iron sleeve like the ls engines no one has proved that the gen3 is better then the lsj which has been pushed to over 500hp on a complete stock block and with the deck closedor better sleeves it will handle well above 900hp

the lsj lnf 2.2 2.4 all used .060 thick sleves

 

Fat house is about 30 min from me. OP are you from around this area?

 

ZZPerformance has said the Gen 3 short block in its stock form can handle over 500whp. Guys have pushed that out of Gen 1 LSJ's with ease also. Yes the Gen 1 is sleeved. As stated up earlier if you have access to E85 USE IT. You can always flip back to pump gas if you want. It's a great way to make power and keeps your motor very happy.

I have a turbo swapped Balt running an S252ET turbo and stock Gen 3 short block. I made 406whp/340wtq on E45 with it last summer and the car never skipped a beat. But even a stock Gen 1 motor will serve you just fine for your power goals if treated right.

 

ZZP has since told people that the rods are bending at 400HP, according to crashher0. They could be doing some CYA. There is also a thread here that got fairly heated about it (the subject was LDK rods but the arguments were tune vs. material). All of this is anecdotal. If the powdered cast rods are done right they can be stronger than the traditional forged cast rods, but considering my recent luck with GM's ability to cast properly I'm going to be skeptical.

 

Where has ZZP stated that? And if that was the case you would think they still wouldn't advertise 500whp capable on their website still. I think it was Tim at ZZP, ran a stock Gen 3 block in his LNF over 500whp for quite some time with no issues. That's where the statement came from.

 

I don't know. You'll have to talk to the people involved. That's why I said it's all anecdotal.

 

For sure. Even so everyone can have different experiences and opinions. I'll just keep pushing my Gen 3 motor lol

 

OP, very nice looking exhaust! Are the plans to leave it exposed, or wrap it?

 

I'm definitely going to leave it unwrapped. I mean, look at that thing! Hot.

Who is Mr. B, I can't find that username?

 

that work is pure sex man. awesome build! those welds and manifold look ****!!!

 

post # 13

 

Mr. B is mrbelvedere ^

 

450 can be had on a stock long block with ease. Get some decent valvetrain and cams in there and you're golden. If you're not going e85, a radial fuel system is not needed, just a good tune. 80lb injectors are enough, and a walbro 255 pump will do it just fine on the style style system.