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As the title says, I'm looking for tips on building something approaching 1k hp out of a molested LX9 motor (GM 3500 v6). This is something I wanted to do for some time and I finally have the means to do it. I've played around with a few 3-500 hp motors (v6 & v8) in the past, but I've never attempted something like this. Mostly looking for tips on how to keep this thing from scattering all over the track.
More info-
I was playing around with different piston/rod combos on summit and I found an out of the box combo that works with just having rod bushings made. These pistons with these rods look like the right combo. C/R comes in at about 9:1, bearing size/bore is spot on AND this combo would be good for ~1500 hp for about $1.1k, assuming the block could be made to live. The only thing I'm slightly iffy about is the rod side clearance since they're a bit narrower, but other than that this looks like an excellent combo. ARP studs, mls gaskets, twin t35's will do the huffing and the heads already flow ~220 cfm. The cam I had ground is 230/235 .54/.55 on a 114 lsa. 1 piece billet main girdle will be made. Other tips/ tricks to make this live?
1000 hp maybe on the eagle rods. Idk about 1500. I seen some break at that level in v8's and thats less hp per rod than a v6
In all honesty i would think custom pistons are in order. Most shelf pistons arent rated to handle that cyl pressure
You will atleast want tool steel wrist pins
Think Eagle would bluff on GN rods? IDK, there's a lot of GN's out there running right at the edge. 9310 pins are an option, but custom pistons wouldn't be a problem.
I was also wondering, the mains are cross bolted to the aluminum pan, but they're not truly structural in the way the LS motors are (cross bolted to the block itself). Is this going to be enough with a 1 piece girdle?
Alot of ratings are hit or miss. So many factors such as rpm, type of power adder, piston weight, fuel, tune, etc. all will influence a power rating in a part
You are in uncharted territory here lol idk anyone building stuff like this
Few of my thoughts for what limited utility they are:
-Fill the block before machining with a short fill.
-If the holes in the deck are round, consider deck plugs. They make em for SBC and adding some strength would probably be a good thing
-What crank options do you have? That could go either way
-At 1K you're talking 167hp a hole. At 1500 you're talking 250/hole. Expect a lot of stuff to start becoming wear parts at that point
-You're obviously going to be heavily octane bound. Race gas or Ethanol only for this setup
-Make as much HP N/A as you can. To hit those numbers this probably goes without saying.
-Do you know how thick the deck surfaces are? This could be something you'll struggle with long term
-What power train are you hooking this into? I think that's something you'll need to account fo as well. You're talking a 4L80E, T400 or a Glide at that point depending on what you're looking to do.
-If you're not worried about streetability you may be able to get away with a single. I'd actually think compounding in your case, just because I think you'll hit 30 PSI and pretty easily need more too.
Good suggestions, thanks. The factory crank is a forged piece with 2.25" rod journals so it should be pretty stout, but even at that I'm not 100% confident in it. Ethanol only, I'll measure the deck this weekend. Planning on a 4l80E & a Ford 9" rear. I already have it set up with twins so compound wouldn't be hard. Turbo selection help?
1000-1500hp on a 660 engine? Wow thst would be a statement in time there. And to be honest I think you would have no issue getting 600-700hp safely but more then thst would be wild and I would be concerned about rod deflection, the crank, and the strength of that block.
realize if you set the drivetrain and suspention up correctly and being a v6 itll be light, mine in its hayday was 2920lbs 3100 race weight. If you managed even 900hp you are talking 8-9 second passes all day long. That would be amazing.
1000hp will be tough without massive amounts of efficient boost with the heads, granted they do flow well but they will never be over 260cfm intake 180ish exhaust. E85, 110 or alky would be the manatory as you'll have to run a ton of boost because no matter what you do the resistance will be there at that level. We are talking 30psi or greater, 2 s362-366 62-66mm borg warners twin turbos in your case. A transbrake will help if you ever intend to race it and want a respectable 60 foot.
I'm following this though. The 3900s are amazing engines. Good luck to ya.
Shooting for 1000, we'll see if that's even possible... I'll be pretty sore if I can't get at least 800 out of it.
Not too sure about the strength of the LX9, but in terms of air flow and fuel you should reach your goal no problem. Most Grand National guys, when using the stock block and not a Stage 1 or Stage 2, will normally have the block filled, or at least partially filled. Along with a girdle of course. Those guys have a different approach though, as there is a method to their madness. Even GM grounded the stock GN cam with a 108/109 LSA for a reason. Not going to get into why because that argument has been made countless times on the Buick boards explaining the benefit as to why. But anyway, if it were me, I would consider partially filling the block, bumping the compression up, running E85, and getting another cam. You seem to have a firm grounding in the other areas...
Not too sure about the strength of the LX9, but in terms of air flow and fuel you should reach your goal no problem. Most Grand National guys, when using the stock block and not a Stage 1 or Stage 2, will normally have the block filled, or at least partially filled. Along with a girdle of course. Those guys have a different approach though, as there is a method to their madness. Even GM grounded the stock GN cam with a 108/109 LSA for a reason. Not going to get into why because that argument has been made countless times on the Buick boards explaining the benefit as to why. But anyway, if it were me, I would consider partially filling the block, bumping the compression up, running E85, and getting another cam. You seem to have a firm grounding in the other areas...
- Rob
I agree 100 percent with filling up the block at least part way. Thats something i completly forgot to mention earlier.
IDK on the narrow LSA... this thing will spin a lot higher than most 3.8's and has better heads. Open to being corrected on this, but this is a different animal and I don't think what works on old wedge head motors will work on this thing. On the other hand, this thing will probably run like a Supra- flat until it comes into pressure... torque is better. I'm considering doing a 1/2 fill on the block but I don't want to drag this around on a trailer either. Compression bump? To what?
When i had one of my the last engines running, 3/4/3400 e-85 I had no issue with 12.5:1 with boost. But i bent 4 or the 6 stock forged rods.. that was with about 15psi and the duty cycle with E85 and 80lbs injectors were saying roughtly 550-600hp flywheel on average as i made quite a few pulls before i had issues. (thankfully it never actually broke anything. I tore it apart and noticed the bent rods in the winter time. I should have stayed with lower compression for what i was doing. But I would think you don't want crazy compression like that. 10.5-11:1 is enough in my book considering you are going to run 25-30psi to try for Hp numbers like that. Just my opinion though. And E85 is very fun to use. I never had detonation....ever with the stuff.
20* of timing i ran with the 15psi of boost and 12.5:1 comp. But I did have a mild to decent size cam (for a 3.4L) which bleed off a lot of the compression. My dynamic compression was only 8.4:1 which is more then safe with e85.
My cam was 108lsa dur at .050 228/234 advertised was 290/298 With 1.6 rockers, lift was .539/.550 Thing sounded awsome at a idle, and you could really hear the lsa in it.
Those are some good tunes. These motors really have a nice sound compared to other v6's for some reason. 11:1 is way higher than I considered taking it. Just noticed this got moved to the v6 section lol.
Here's the first version of the girdle, I still need to do some revision to make it manufacturable. Definitely not cheap the way it is, about $1800 for a one off as it sits. Hopefully I can get some other people interested in this to go in on a small run of these. I should be able to drop the price in half if we do 5 or more of these. Looking to have a prototype made, but my 3d printer doesn't have the volume for this.
Very interesting, I'm watching this although I'm of no help whatsoever , what is 'filling the block ' ?
you've answered my girdle question with the pic lol
Is it worth a look at some Japanese engines as alot are 1000hp turboed sixes ? Might be some handy info there .
Oh yeah why the ford rear end ? Is there really not a GM one strong enough ?
It's when you fill the water jackets with Hardblok. Helps eliminate bore distortion. A proper built Ford 9" is indestructible. I'm probably going to stick a zexel-torsen in the rear for now and wait to find the limits on that before moving on. Same with the trans lol. Gradually turning up the wick until the next weak spot shows up.
Very interesting, I'm watching this although I'm of no help whatsoever , what is 'filling the block ' ?
you've answered my girdle question with the pic lol
Is it worth a look at some Japanese engines as alot are 1000hp turboed sixes ? Might be some handy info there .
Oh yeah why the ford rear end ? Is there really not a GM one strong enough ?
Why the ford rear? Because a 9 inch blows any gm rear outta the water and cost less most of the time. I personally have a strange s60. Which is a tough strong rear, will take a ton of abuse and slightly less cost for a drop in rear for a thirdgen.
Also partially filling the waterjacketd (block) helps strengthen the block and give it alot more rigidity. And helps control distortion. Mainly used on race engines only.
If anyone knows someone that would be interested in this spread the word, I'm going to see if Ben at Wot-tech is interested in having a couple on hand and hit up a few other boards. Once I have a prototype I can get this thing moving pretty fast. If we get 5 of these made out of 4140 billets the price drops to $780 each. At 10 it's $570 each.
If anyone knows someone that would be interested in this spread the word, I'm going to see if Ben at Wot-tech is interested in having a couple on hand and hit up a few other boards. Once I have a prototype I can get this thing moving pretty fast. If we get 5 of these made out of 4140 billets the price drops to $780 each. At 10 it's $570 each.
I will let everyone I know that plays with these. That's a good deal in bulk.
This is awesome never thought id see this thread. Cant wait to see what comes of this... may have to try it myself the hybrid is gonna be done soon ill try scoopin me up a 3900 to peice together while im in the service definetly subcribing
Also tying the caps in to the pan rail doesn't seem like any sort of gain to me. The stock pan already ties the caps together, and does a good job of it.
If anything a girdle that ties the caps together lower I think would be more beneficial, but even then, I'm not sure it's needed. It could also be done with a flat girdle that attaches to the caps and/or the main bolts/studs themselves. Much like what is commonly available for SBF engines.
I guess I'm just more of a run it how it is and fix what ever failure point you find type of approach.
TBH, I do have a far off goal similar to yours, and to be honest the block, especially the main caps is the least of my worries for that power goal. I'm more worried about cylinder walls, and keeping the heads planted than I am about the bottom end flexing or experiencing any problems there. I have an interim goal that is much more attainable and then I have a sorta plan to keep upping the power goal until I get to 4 digits.
Lol good old SBF's splitting in half. I don't know of many 2 bolt main motors at 1k where walk wouldn't be a concern. This girdle ties the mains together at the block, it doesn't get lower than that. I was looking at linking them between the side pan mounting points but my initial FEA showed it was pretty much pointless & expensive when the existing points already do it. Might benefit a bit from linking between the caps where the windage tray is but the stock windage tray does that well enough with the side bolts. Integral bedplate girdles are pretty common among tuners & durastroke guys that put down big boost. Nothing is going to stiffen it up better short of completely filling the block. The heads are definitely a concern for me, even with studs & mls gaskets. Ringing the block isn't something I'm interested in though.
From what I've been able to find, Durastroke, and related engines aren't cross bolted from the factory, which the gen3+ 660 is. That cross bolting greatly improves any shifting of the mains, especially due to the multi-plane bolting.
I'm just looking at what I see here and of the 660 block. Like I said before this is one of the LAST places I see an issue, and I'd hate to see you waste thousands of dollars on something that may not be needed.
The girdle that ties the mains together where the windage tray is what I mean by tying them together lower. That would be where I'd do anything, if I was to do anything with the main caps. *shrug* It would both be a lot cheaper and more or equally as effective IMO, as one that ties into the pan rail.
Ah, I see. The tray area is probably the next weak link that needs to be boxed in. There actually isn't much difference price wise-between a halo version and a bedplate, but there is a big difference rigidity-wise between a bolt-on halo and integral mains. I'm definitely not comfortable with powdered metal main caps on a 1k motor. I figure, if I'm doing 4140 mains and a girdle I might as well do the whole thing as one piece. I'll re-run the FEA & costing with different variations and see where it points me.
I do powder compaction in my industry, these have all the hallmarks of powdered parts. They are steel, iron generally isn't used in powder compaction. You could say they're quasi-forged, but the process is very different and doesn't result in the same properties. As far as fracture resistance goes, they're somewhere between cast and forged parts. Plastic deformation is fairly good on these due to a small, uniform grain structure but it doesn't compare to a real forging.
If that's true than IMO, the only thing that's needed is steel (forged or billet) main caps. I honestly believe the current design will handle what you want to do, or maybe need an add on lower girdle, like I've said. I've seen far less stoutly designed blocks handle more power per main cap than you're planning without failing.
It looks like individual caps aren't much cheaper than either of the integral setups I've done and when you add a separate halo the price is actually slightly higher. An integral halo girdle is the cheapest but I'm still doing the FEA to figure out the best route to take. I can lower the price a bit if I lop off the rear main too. Looks to be a pretty stout piece, I may leave it off.
Found someone with a printer that's almost large enough, I have to split the model in half but I should have something useable some time after the holidays.
As silly as it sounds, have you thought about doing a wood form and seeing if there's a foundry near you that could make them from cast iron? Yeah you'd probably want to increase the rail depth, but it would make it very stiff in the end and may be cheaper to do. That said, the qty 10 sounds pretty good for what you're getting.
It would still need machining and the price would probably be close to the same without the benefits of a solid billet piece. Making the rail thicker affects a number of things and 10mm was the best compromise I came up with. I might be able to go a bit thicker though, so long as I don't hit speed bumps lol.
Oh yea!!! I still have 5 forged scat 4340 h beam rods that were machined for the 3.4 3400 I had. The other rod well just say is crippled. Lol from when the crank broke.
Update- I was in an accident last month and had to buy a new daily driver, so cash is a little short but I got a partial prototype made and it revealed a couple oversights on my part. After those are fixed and I get some pistons made I should start looking at having a run of these made.
11-07-2017, 04:33 PM
