cc-rider

Putting together a 416 stroker LS3 for my Camaro. I’ve got a 2.8L Kenne Bell supercharger on it. Blew the stock engine. So going to forged internals and get it ready to handle the boost. Going to be running about 9.5:1 compression in it. Manual 6 speed with 3.73 rear end. LT headers, high flow cats, x-pipe and flowmaster pro series mufflers. Not sure on boost. Was running 9.5 psi when it blew. Thinking something similar. Maybe a tad higher with the internals built to take it.

Need to decide on a cam...

Lots of threads out there on blown LS3 cams. But not finding a lot on stroker engines.

Goals:
This will be a tire frying playful street car. And that’s it. Main goal would be good power under the 2500-6000 rpm curve. I’d rather sacrifice a little top end for some bigger torque in the mid. Yet want it to rev out reasonably as well and not fall on its face. I’d like a little noise at idle. But don’t want anything really sloppy. I also want longevity to be there and not have to worry about worn valve tips, etc.

Been looking at lots of cams out there. The BTR stage 3 PDS torque cam has caught my eye. Also the Cam Motion 224/238 and 228/242 PD cams as well. Thoughts?

I know a custom grind from one of the guru’s would probably be best. I’ll look into that too. Just wanted to throw out my build and goals and see if anyone has some known good results from shelf cams. Thanks!

DualQuadDave

iTrader: (6)

I wouldnt stroke it, at least in a LS3 block w/ boost. More power in getting the blower ported/cam/tune right/heads. The cyl walls are thin on an LS3, the extra stroke doesn't help. Just do a forged stock stroke crank and maybe a Wiseco Boostine or Callies Ultra rod and pick a decent piston and run decent size gaps w/ Total Seal stainless top ring. Find a better tuner, it should not have blown up in the first place. Go big on the fuel system and injectors. And huge on the throttle body, 105-112mm is big power increase. FYI, a stock crank should be fine at your level, just run an ATI or Innovators West balancer.

cc-rider

I’m still getting the engine pulled out...but I think I took out the crank. Sounds like a lower end rod knock when I start it now. But won’t know until I tear it apart. So if it needs a crank, then I’ll stroke it because...well, why not. I hear you on the thin cylinder walls but the LS3 416 stroker has plenty of miles on it and seems proven. Perhaps I’m wrong. I’ll read up some more. If the crank is still good then I’ll certainly consider reusing the stock crank and getting a nice set of forged rods and pistons and keep it a 376.

As far as tuning...yes, certainly the tuner was at major fault. Because the tuner was me! I studied up and learned how to do it...got myself HP Tuners. Actually ran it for 4 summers perfectly. Then I decided to see how much timing it could take. And I knew I was pushing it...so its all good. I was kind of expecting it. I wanted a forged assembly anyway. One cold fall evening with dense air and a huge high rpm burnout did it! But point taken...I’ll probably have this motor tuned by a pro with intent to balance power and longevity

DualQuadDave

iTrader: (6)

i'm a DIY'er too, so don't be ashamed of pushing too far. Happens, then you learn. I really do not recommend stroking it. It's not going to really go that much faster with the more cubes, it's already restricted on the inlet side so making the bottom bigger is not really doing anything except causing more side load on the thin walls. Trust me, just do a stock stroke forged crank and make it flow more. It's easy way to more power, you can run less boost, less heat soak, more timing, less problems. Win-win.

FYI, 416's are proven in NA combo's. I am actually looking at building one myself. Boosted LS's are a different animal, especially the alum blocks.

cc-rider

I hear you. I’d love to tear into the engine and find the crank to be intact. Although probably also disputed, I think the LS3 crank is known to be good to almost 1000 hp. But if I do have to buy a crank, would be hard to pass up the extra displacement for the same price. But I admittedly am getting tired of tearing into engines and longevity is creeping higher up on the list of trade-offs.

MixedE36

I have a good LS3 crank leftover from my 416 build. You can save some money if your crank is not salvageable.

cc-rider

Thanks. PM me. Let’s chat.

old motorhead

iTrader: (10)

I agree on keeping stock cubes. The blower size and how fast you spin the blower will determine your power level. Also agree on the need for a bigger throttle body. At about 550 rwhp, the 90mm throttle body becomes a restriction. At 640 rwhp, I measured 4" of vacuum between the throttle body and the blower. Get rid of that and you get another pound or two of boost which gets you another 20 to 40 hp.

A really big cam makes very little more power vs a more sensible grind. Just makes more noise. I've had several TVS2300 blown LS engines. I'd cam it with mid 220's on the intake with mid 230's on the exhaust. LSA at 115 or 116. If I put another one together it will have a 224/238 116+2 with lift around .615 on both sides. A cam like that is easily tunable for perfect or near perfect manners. Won't leave much on the table power wise either.

cc-rider

Thanks for the info and advice. I think you guys have me convinced to just go with stock 3.622 crank. We’ll see how my crank comes out. But lots of forged stock throw cranks available too.

I hear you on the cam numbers too. Seems there are a lot of cams in the 224-230 intake, 115-118 LSA, with overlap in the -5 to +1 range that do well.

I’ve also been studying up on is dynamic compression ratio. Another question...anyone have some guidance on what range I should shoot for for the DCR?

old motorhead

iTrader: (10)

I've had Pat G spec several PD blower cams for me. The DCR is always at 8:1. I've done several of my own. Always at 8:1. The cam I suggested in my previous post will come in at 8:1 DCR. Not saying that nothing other than that will work. That's just what I've seen to work and work well.

cc-rider

Thanks. Assuming for 91-93 pump gas?

old motorhead

iTrader: (10)

My last supercharger was a Heartbeat TVS2300 on an LS3 with mild cam and bolt ons. I initially had it tuned on pump 93 and it made low 640's at 9.5psi. Added meth and it made 664. For 20rwhp, I think meth is a waste on a PD blower. Plus, there's no easy fail safe to protect you if the meth system fails. With a centrifugal blower or turbocharged rig, you inject the meth into the intake after the air is compressed. IAT's get quite a bit lower than ambient air temp. In the tune, you add timing if the intake air temps are low and take it all out if they are high. The delta in IAT's is huge between meth on and no meth.

You don't get that big IAT change when you inject the meth before the blower. Little to none in my experience. So there's really no way to fail safe the system with a PD blower. You do get the added octane, but if you add timing to take advantage of it....and it's not there, all manner of crappy things can happen. That's when you can stick a bore-o-scope down a spark plug hole and you're staring at a piston ring because part of the top of the piston is gone. Been there, done that.

If I put another one together, flex fuel will be high on the list of must haves. Matter of fact, it will be at the top of the list. Running E85, you get higher octane. Although it isn't measurable, you also get a cooling effect. With that system and a good tune, you can run any thing from straight pump gas to 100% E85 and all points in between. It's simple, it works, and it's not that expensive to do. I know some guys using it that see 750rwhp on just over 10psi with mild blower cam and bolt ons. With all that crazy power down low, it makes your ride feel a thousand pounds lighter. Acceleration seems effortless when you can have a little or a lot of boost at any RPM above idle. Your right foot controls it.

ddnspider

iTrader: (26)

20whp with the meth is simply a side benefit. Water/meth injection has a SIGNIFICANT benefit of cushioning the chamber and preventing detonation. There are also several fail-safe options that will protect the motor. All depends how creative and invasive you're willing to be.

old motorhead

iTrader: (10)

I'd run low temp ww fluid before running straight meth. That ww fluid has some meth as well as water in it. I wouldn't tune for the added meth though.

ddnspider

iTrader: (26)

Agreed. -20F WWF is good stuff and like 30% meth.

Scvette

I lost my stock Ls1 that I had a 2.8 KB blower. This is on my 99 Vette. Wasn’t even getting on it and a roller tip on my lifter fell apart taking my cam out. I’ve since bought a Lsa short block out of a 2013 Cts-v that had 48,000 miles on it. Anyway it’s at a machine shop getting honed and checked out, haven’t decided if I’m going to go with forged rods and pistons yet, might just re ring and put it in my car with the Kenne bell blower. My Ls1 had a pretty good size cam and I was running meth. I was over 600 rwhp and I’m hoping for more with the Lsa and good heads.

old motorhead

iTrader: (10)

You'll need to use catty port heads or change the lower bowl of your blower to match the square port heads of the LSA engine. Not even sure if that's possible on the 2.8L KB.

Scvette

im looking into getting work done to the lower manifold. Hopefully something can be done to make it work with square port heads. If not I’ll just get some good cathedral port heads.