slowfive0 Posted March 26, 2012 Report Share Posted March 26, 2012 http://ls1tech.com/forums/forced-induction/1359652-aes-390ci-now-callies-dragonslayer-crankshaft.html Anyone run a 390" combo in a truck/suv? Specifically, a forced inducted application? Quote Link to comment Share on other sites More sharing options...
zippy Posted March 27, 2012 Report Share Posted March 27, 2012 http://ls1tech.com/forums/forced-induction/1359652-aes-390ci-now-callies-dragonslayer-crankshaft.html Anyone run a 390" combo in a truck/suv? Specifically, a forced inducted application? I don't know of anyone on here that has ever built one of those. I don't think anyone on here is going to build something to the power level that creates enough cylinder pressure to warrent running a shorter stroke. The reasons that would warrent building a 390 would be someone building a motor for 1500-2000hp since it would be a good way of having better ring control over a 4" stroke at that high of cylinder pressure, building a motor for what I'd call "diesel towing" (I'll explain that in the next paragraph), or class racing where cubic inch limitation is a big deal. As for building a motor for diesel towing. If you had say a 2500HD or 3500 series truck and were towing loads through mountains you would run into situations where you may run at peak boost for say 8-10 miles. Here is an area where EGT's are a primary concern. You'd want as many cubes as you can get away with so that you have power without having to get into boost because running in boost requires a richer afr to occur than running in vacuum where you can keep in closed loop at stoich. If you build a gas Gen III/IV motor to run like a diesel you'd want to use all the stroke possible and yet make sure you had plenty of room for the pin and piston skirt. You'd then pick a compression ratio of say 9.2:1-9.8:1 and a bigger single turbo with a larger A/R. The bigger turbo and larger A/R would be required to help keep EGT's down. The compression is important in the idea of keeping as much as you can to make the power and not so much that you are required to pull alot of timing which will also raises EGT's. The next thing you'd do is build the motor with piston oil squirters. This is to keep the piston cooled which in turn will reduce hot spotting, something that is a big cause to creating detonation. Controlling the cylinder temperatures allows for more timing going again back to reducing EGT's. The 390 for example would have a longer stroke than stock allowing for more torque and a shorter stroke than say a 408 allowing for a longer connecting rod. The longer rod increases piston dwell timing which in turn increases efficiency. A 390 inch Gen III iron block motor with piston squirters, 9.8:1 compression, big flow cylinder heads such as TFS235's, small camshaft, S85 turbo (or jackshaft 2300 with 102mm throttle body and spacer), could easily handle pulling heavy loads and running hills at 10psi of boost for extended periods as you would in a diesel truck (this is why I call it diesel towing). Getting the fuel milage of a diesel isn't something we'll be seeing for a while. I expect someday that with direct injection and turbo's gas engines will be nearing the fuel milage of diesels. Quote Link to comment Share on other sites More sharing options...
slowfive0 Posted March 27, 2012 Author Report Share Posted March 27, 2012 Thanks for the informative reply Zippy. Great perspective on this topic. One thing I notice right now with my combo is that at hwy speeds, the fuel mileage just SUCKS!!! It is soooo close to going into boost at 75-85mph it isn't funny. Don't get me wrong, I can easily keep it out of boost, but very little throttle will put it near 0" and my fuel enrichment as you spoke up kicks in and it's super fat. At those speeds, I'm running around 10" vacuum at steady throttle/flat ground. At idle, I see around 15". I'm thinking some of this is due to the small blower pulley spinning the blower up so fast, but........I'd really like this engine to move this truck around a little easier (especially out on the hwy) it is my daily driver after all and sees a lot of miles! Seems to me, that a longer arm (stroke) will fit this need....... So, what you're saying is in my case (not doing crazy amounts of towing usually) and not trying to make 1500hp, I would be better off with the 4.0 stroke over the 3.8.....That being said, it seems like a bigger stroke might be right up my alley. Thinking an LSX tall deck with a 4.25 stroke and some pro heads. Then down the road some sort of forced induction on top of that Thoughts? Quote Link to comment Share on other sites More sharing options...
zippy Posted March 28, 2012 Report Share Posted March 28, 2012 The tall deck built well will rock. You have found the key to boost and I'm impressed. The key to a good street boosted motor isn't to see how it goes at wide open, it's to see how well it runs down the road. You want it to make enough power to be able to run down the road in plenty of vacuum. Building a tall deck will make a ton of power everywhere. The key to making that work is going to be the biggest set of heads you can afford for it and a mild cam. You will need a big set of headers to get the results you want. You'll need a set of headers custom made anyway since it is a tall deck block and at that point you might as well go for a 2" primary 3 1/2" collector. Go for it, go big or go home. lololol Quote Link to comment Share on other sites More sharing options...
slowfive0 Posted March 29, 2012 Author Report Share Posted March 29, 2012 Thanks Zippy! Being as I plan to run boost in the future I obviously don't want to go to crazy with the stroke. I'm thinking 4.125" bore x 4.250" stroke = 454" or something in that vicinity. I think that will probably be the max stroke I will want to run especially with thoughts of future forced induction plans. I think the additional stroke and bad ass heads will result in an amazing street engine though----Thoughts? I really like those pro heads from WCCH. $3500-4000 but they look to be the hot ticket! Or maybe some MAST heads.....Thoughts? I agree that the head will probably make or break this combo. I will need to spend the dough and go big or just go 408 with more conventional parts! LOL! Another area of concern whether I stay NA or go turbo is the intake. It seems like none of the intakes out there are adequate for these big cube monsters..........Since I'm not going for all out records or anything, I'm leaning towards that LSX102 truck intake. Not sure if it is compatible with the heads I'm looking at though. Maybe only compatible with the cathedral port heads which then adds another issue. If I go with the TVS2300, then I'm concerned about the blower being a restriction (sort of like a radix on a 408/427).......... Thoughts? Either way, I think a 408/TVS 2300 or 408/Turbo combo would be bad ass! I can't imagine how a big cube combo would be with regards to that "area under the curve". The torque should be up everywhere which should make for an amazing daily driving experience!!! The tall deck built well will rock. You have found the key to boost and I'm impressed. The key to a good street boosted motor isn't to see how it goes at wide open, it's to see how well it runs down the road. You want it to make enough power to be able to run down the road in plenty of vacuum. Building a tall deck will make a ton of power everywhere. The key to making that work is going to be the biggest set of heads you can afford for it and a mild cam. You will need a big set of headers to get the results you want. You'll need a set of headers custom made anyway since it is a tall deck block and at that point you might as well go for a 2" primary 3 1/2" collector. Go for it, go big or go home. lololol Quote Link to comment Share on other sites More sharing options...
slowfive0 Posted March 30, 2012 Author Report Share Posted March 30, 2012 Driving home tonight and I was paying closer attention to the boost/vacuum gauge. At 80mph at steady throttle/flat ground it was running right at 10" of vacuum. A slight grade reduced it to 8". I rolled into the throttle gently and I had 5psi of boost almost instantly! Nuts!!! That was one observation. The other observation was how nice this drives at cruise with the converter locked up. I was rolling along in 4th gear (converter locked) at around 2000rpm and had to slow for traffic (never hit brake), as I rolled back into the throttle a little (converter still locked) I was at about 1200rpm. The GT2/3 cam is so smooth and the radix makes so much torque that it can pull down that low pretty nice at light throttle. Giving it some throttle it pulled smoothly and gained rpm at a nice rate. I can only imagine or maybe I can't (LOL!) how a tall deck motor in the 454" range with great flowing heads and either a TVS2300 or Whipple or Turbos would feel. The 454" alone should pick up the torque in the neighborhood of a 100 ft lbs just from the cubes I would think. Obviously, what power adder, heads, cam, etc will dictate the power band and what not, but I would imagine that I could pick up a TREMENDOUS amount of power all across the range. The way it drives now is nice, but I bet it would be INCREDIBLE with the big cubes and the right combination of power adder....... Ahhh, day dreaming up different combos and planning is half the fun of this hobby. Regarding the video from Wegner Motorsports (see below) where they make 1000 hp, IIRC the guys I spoke to said it is actually a tall deck RHS motor in the 441" range. The big cubes weren't necessary, but that is what the customer wanted. They had it iced down, were spinning the shit out of the blower and were running race gas to get those numbers, but impressive nonetheless! What really impressed me on this combo was the torque down low. OMG!!!! Are you kidding me----that torque would move mountains!!! Thoughts? Surely someone has done a big bore/stroke TALL DECK motor with excellent heads for one of these trucks??????? With boost of course Quote Link to comment Share on other sites More sharing options...
slowfive0 Posted August 18, 2013 Author Report Share Posted August 18, 2013 Anyone run a big cube/blower combo out there? Getting ready to build a new motor and trying to nail down combo. Thanks. Quote Link to comment Share on other sites More sharing options...
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