blackdak318

Alright my dudes. Looking for how much power people have made reliably on an LS3 aluminum block. I'm talking 3-4-5 years. Turbo set up.

I found out I have a major thrust issue with my current LS3 and am trying to decide if I want to invest $3,200 into fixing and upgrading, or just take the dive into a Dart LSNext piece for substantially more. Local tuner to me had an F1X on his LS3 416 and it split the liner after about a year at 1100RWHP - Mustang Dyno - 6 Speed.

I'd like to be able to make 1000 rwhp with this and not worry about it through an unlocked 4L80E. I'd say that is about the same as 1100 rwhp thru a 6 speed. I'm not looking to make weekly passes with it on kill but maybe a few times a year turning it up with majority of the time at about 1/2 that power. Let me know your thoughts. I've seen people make 1250+ rwhp thru an LS3 block and claim no issues, and others at way less split the liner. Maybe due to core shift? Anyway post up your power numbers with a turbo LS3 set up and how long it's been kicking.

Detoxx03

blackdak318

Also in case it matters the plan for my current LS3 if I keep it would be:

Send to Mike Lough Racing Engines.

Molnar Forged 3.622 crank
ARP Mains
Pinned Mains
MLRE Oiling Mods
K1 Rods and ARP2000 bolts (re use existing)
Wiseco Pistons (re use existing)

They also would hone/bore/deck/balance everything. All new bearings etc

E85 - Holley controlling everything with a safe tune and timing.

blackdak318

Stick car or thru an auto though? I feel like 1000 rwhp thru my unlocked 4L80 is about 12-300 FWHP which has to be near the limit of a LS3 block.

g23crawler

700 currently, turning it up to 800 next week. Im assuming Chad is tuning it? He felt very safe running my stock ls3 to 800rwhp

Detoxx03

Unreal

I know Joe@CPR split an LSA block at ~1200rwhp. 1000+ on an unlocked 4l80 is probably way past reliable limit.

Glad to see people asking this type of thing. Actual racing and living 3-5 years, and a few dyno pulls are two completely different things.

blackdak318

Unreal - I agree 100%. I've gotten away from the typical talk of... so and so made 1300 rwhp with the LS3 which is implying it is fine. Yes I know on a glory pull it COULD make that and seemingly be fine. You never hear about the issues 1 month to 1 year later and how it blew up and cost the guy his forged rotating assy etc. I'm going to be paying a significant amount on machining this LS3 bock and it would all be trash if I split the sleeve.

g23crawler - Chad is the person I'm talking about, but he is not tuning it for me. Los Vasquez tuned it for me on H&S Auto Dyno (remotely) in Omaha and I've been tweaking things since then. I made 850 rwhp on their mustang dyno running out of turbo and having a few other issues thru an unlocked 4L80. Chad said that would be equivalent to making 950-1000 thru and M6 and I believe it.

Like I said in the original post, unfortunately I've now found out my current rod/piston LS3 is hurt and I'm trying to decide what direction to go. I'm leaning heavily towards just sending it to MLRE but eventually splitting the sleeve is weighing heavily on my mind. I really don't want to go Dart so I'll prolly just fix my current aluminum block up and maybe limit it to 950 rwhp and be happy. Realistically that should be fine for my needs/goals. If I get into one of the local cash days and go a few rounds on 950 maybe turn it up for the last 1-2 passes and pray LOL.

What are your guys' thoughts on doing the dart short block for $5,200 and temporarily putting my GMPP CNC LS3 heads on it? I know not ideal but would get me thru until I could afford a 6 bolt set up, or find a solid used set. Is there another option I'm not thinking of? I don't want to sleeve a GM block, it comes out to a wash or even more expensive than going to Dart route, and the Dart is superior in many many other ways.

g23crawler

Keep it turned down for me during local cash days

blackdak318

It's been pretty fast at I29 on low boost and a super lazy curve. I'm starting to find out that 850 RWHP thru and unlocked 4L80 can still net you a pretty damn fast car!

blackdak318

That's cool and I get it. I wouldn't have any issue pushing on a stock LS3 either. I've got $1,500 worth of forged rods and pistons in my current motor, and am soon gonna have a bunch in machine work as well. I am less likely to lean on it when a trashed block means about $4k in good parts and machine work down the drain (potentially).

Unreal

Hard to beat LSX block. At those power levels it isn't just sleeves/block, but keeping heads on. That is a big issue a lot of people overlook. I trashed my last setup by lifting a head, and it sucks and cost a ton. Eating a set of pistons/bearings/machine work/etc etc. And that was on a high end built LSX setup making 1100+. Even my new LSR combo I may just limit to 800-850 just to keep car fun and put at on of miles on it.

g23crawler

Sent you a PM so I don't clutter your thread...

realcanuk

Think you gotta really decide the use. An street car like mine that sees a few hard pulls and maybe a few quarter mile runs will last fine with good tuning.

Running half mile and mile events is 100 times harder on the engine and I wouldn't even consider it on stock stuff unless you're ready for what may happen to it.

blackdak318

Agree and that is why I'm leaning towards fixing my current LS3. This is 80% street car 20% track car. When I go to the track it's not a competitive money deal either. It's just test N tune having fun with the car. On the street it's turned down and mostly just playing around with guys on cruises and blowing off some stress after work, etc. It would be a very rare event I would have it turned up all the way. Most likely would have to be in a cash days where money was on the line/one off grudge race/ or trying to hit a personal goal with the car (at the track).

I'd like to go 5.50's with this set up.

** Does anyone feel that a 5.3 based motor is that much stronger? I know the sleeves are obviously thicker, but is the difference that pronounced it's worth dumping a bunch of money into a 5.3 rather than just going Dart or LSX? A good forged 5.3 short block is 4-4500 all day from a good builder.

realcanuk

Don't know about a 5.3.

My LME built 402 is based on a stock LS2 block. I think it's 4 or 5 seasons now and it's still perfect. 0 issues. Like I said though, it's not a race car.

blackdak318

I've looked into a nice 5.3 and they're $8,500 out the door when all said and done with fully forged rotating assemble and that is with just Trickflow 220 as cast heads for the thicker deck. You can get into a dart 6 bolt long block for around that. I'm somewhat answering my own questions here but appreciate the input and feed back gents!

Bluewheelz

I personally would go with a Dart LS Next iron block. If you're going to spend that much money on your rotating assembly and machining, another $3-4k is worth the investment and insurance that it will hold up and keep you having fun driving the car rather than working on it. I just popped my LS3 bottom end running 8.5lbs of boost after owning the car for 10k miles. I only plan on doing the engine build once so I'm going with the Dart LS Next Pro Iron block (427) with solid internals. It's not cheap, but it will cost less than building it twice. Just make sure you get a machinist/builder that you trust to build it to spec. There are a lot of "builders" out there that just throw a package together and don't do the small extra steps measuring and balancing everything correctly.

Just my $.02 Let us know what you decide and how it goes.

stevieturbo

Strongest factory alloy block would be the LS9, it aint cheap though.

As for claims of LS3's being happy at 1250+ ? Yea....lets see the evidence to support those claims. I'm sure they can make the power ok..but what other supporting work/mods to do so, and how long have they really held up for ?

5.3's simply by design are stronger...if you're happy with a loss of low rpm torque etc, then they are definitely a cheap option.

blackdak318

The plan is to fix my current aluminum LS3, even if I have to limit power. I think it would be fine after being fixed the way I plan on it to 900-950 rwhp, which will be plenty for me. I agree with the above poster about going Dart, but I just can't justify it at the moment. This is more of a street car for me so I'd rather save the money and just know I can't get crazy with the boost controller.

If my LS3 block is bad I'll buy an Iron 5.3 and go from there.

Current plans for LS3 are:
Re use good parts (hopefully) block, K1 rods with their ARP 2000 bolts, and 2618 Wiseco Pistons
ADD:
Forged Molnar 3.622 Crank
ARP Main Studs
Pin the Mains
Upgrade pins to Tool Steel (current still the stock 700 fwhp rated pins)
Balance,deck everything, etc.
New LS9 gaskets

The motor has GMPP CNC LS3 heads as well which supposedly suck but I'm on E85 and know the tune is spot on. I'm trying not to believe all the internet hype (or lack thereof) and I think these heads will suffice for what I want to do. Again this is mostly a street car so it won't be on kill but maybe a few times a year. It will mostly be me tooling around on the street in the 700-850 rwhp range, which I know will be no sweat for this set up.