PaintballaXX

Personally, I believe the flat plane can and would make more engine power. In addition, the ITBs and a lighter crank will definitely give the engine the snappiness that you want from it. However as GS pointed out, the harmonics produced by such an engine will have a high magnitude. The ls7 has big pistons that wont be balancing each other out. Same for the con rods. An engineer would evaluate the dynamic characteristics of both configurations as well as perform a simulation of both before deciding whether a prototype of the flat plane is even worth the time. Obviously not everyone is an engineer, and even those who are may not have access to reliable simulation software for personal use. That puts you at a disadvantage.

Haven driven both the ls series and high output inline 6s, I know where you are coming from. Even given that the ls cars are extremely fast, some prefer to cater the entire driving experience to there likenings. That's perfectly acceptable, and no one can tell you how to enjoy something or how to spend your money for your enjoyment.

However, if you installed ITBs and a lightweight flywheel, the engine would more than likely have the response characteristics you desire.

SteveRiellyNZ

Comments from another forum on this:

"I learned from the previous owner today that my single plane crank was manufactured in 2000 and came from the Lingenfelter 358 CID Chevy Pro Stock truck engine program. Previous owner was involved in Pro Stock Truck engine building and recalls John Lingenfelter ran single plane cranks, just not very often.

Of all forms of racing with V-8s, in my mind, drag racing would be last venue I thought I'd see a single plane V-8 crank being used. :shock: John L. is definitely one of the leading gurus regarding SBC performance, he must have saw something worth while to at least try it. ;-) "

SteveRiellyNZ

Thanks exactly why I'm researching this, at one person on this thread has something intelligent to say.

Yes, I'm going to match ITB's light weight forged pistons etc etc into the mix. I dont think its going to be as effective only doing part of it.

AirBusPilot

You can build what you want, and I'll follow it with some interest. Where you began to lose me was your claim about the skyline and it's performance relative to the Z06, which was clearly not based on reality.

PaintballaXX

The flywheel alone is going to change the driveability of the car so significantly that you might deem it too dramatic. No need to spend money on pistons.

SteveRiellyNZ

True, but from what I've found, I need the piston too, due to the balancing issues with flat plane.
If it was short stroke, a balancing rod isn't necessarily needed, but longer stroke can be. This is unlikely to be easily added to the LS7 block, so going light weight associated parts may negate that being necessary as well.

A couple of people do say it shakes a lot, but that's in track cars where engines are bolted right to the body, not the shock style mounts you would use on the street. And of course big end cams.
So it may not be noticeable, or a problem overall compared to some lumpy cams which give some of those old rodders that really cool rocking motion.

PaintballaXX

You may have misinterpreted my first post of today. I was saying spending money on a flat plane is likely premature. Rather, ITBs and a lightweight flywheel alone will make the engine feel as snappy as the ones you are accustomed to. The flywheel will take care of the inertial affects that you see manifested as slow engine response. The only thing it wont do is make more power, but then again, cams can do that much cheaper. Two mods is much cheaper than a whole new engine, and in this case can give the same results with less drawbacks.

glass slipper

Just because you can name drop does not add any more credibility to your post. There are a lot of names mentioned in many discussions and again, it doesn't add any credibility to those discussions. However, I have read the discussion where Lingenfelter tried a flat plane crank...he went back to a cross plane, did you pay attention to that?

So now these companies are going to forge a flat plane crank for you. They're going to make the dies for a single crankshaft and charge you $2500/$4500 for a 4330/4340 crank...what world do you live in??? They're going to machine a crank out of billet steel, that's what they're going to do. And I can tell you already Bryant is the one charging $4500, I've been around the block a few times. You probably don't know the difference between 4330 and 4340 so I'll give you a good piece of advice, use the 4340 crank. And Bryant will be the one using 4340...you get what you pay for.

The links you posted say nothing about making flat plane cranks for the LS7 and you also didn't provide links to sprint/race cars using a flat plane crank in an LS7. As I expected, they don't exist but hey, the best defense is a good offense only your offense fell on its face. I'm a Mechanical Engineer who minored in internal combustion engines and I'd love to have an educated discussion with you about this...I just don't have time to wait for you to get educated.

Focus your research on the 2nd order imbalance and you'll see why this is an abortion. The pistons are too heavy, the rods required for the RPM you want will be too heavy, the stroke is too long and the rod/stroke ratio is too low...you have the perfect recipe for an engine that'll shake itself to death. There's a reason Ferrari uses strokes around 3" and bores around 3.5" with relatively long rods in their flat plane V8s. Basically, the 2nd order imbalance comes from the piston speed of the pistons approaching TDC being different from the pistons approaching BDC as dictated by the rod angles. As the stroke gets longer and the rod gets shorter, the problem is exacerbated. The weight of the piston and the reciprocating portion of the rod affect the imbalance and the forces grow as RPM increases, it's the opposite of a cammed engine that smooths out as RPMs increase. You will learn how to do this analysis in 2nd year engineering in a course called Dynamics.

It's interesting you want knowledgeable persons for info then post the link with the motorcycle crank. Did you notice he was an engineering STUDENT??? While he presented a few good facts, a lot of what was in that blog was pure BS...don't put a lot of credibility on blogs. If you continue to pursue a flat plane crank, I wish you luck...you're going to need it.

McMung

SteveRiellyNZ

You asked for the name...I gave you the names....not really my problem if you want to get all upset about it.

Yes I have researched all that. I do know john changed back, and I do know that info was on a motorcycle ( I actually said that in the thread ), and yes, he's a student.
He's studied, he's learnt and sharing what he knows....who cares if he's a student, he's still right.

If you wanted to share you knowledge like you just have, you would have done so in the first post...but you didn't, just started ranting.
So, moving on to talking to the race teams themselves that do this. You dont seem to think they exist, but then the guys making the cranks are selling them to pixies I guess.

I have looked at balancing, I also pointed out difference in ferrari stroke vs LS7, and have mentioned the shaking.

Got all the costs, I'm the one who posted them, and why there's a difference.

Every point you've just mentioned, I have already been through in the search for knowledge about it....and just like I first mentioned, you've just offered nothing constructive.
I thought this was a forum for sharing knowledge and learning...my mistake, its for boosting egos, so I'll leave you all to it.

glass slipper

The reason I didn't say anything before is because you're too stupid to talk to but I have a limit as to how much BS I can read before I have to say something.

KRAYZ308

That's exactly right. Ferrari used the flat plane in their V6, (before most of you were born) and later V8 engines as an extension of their V12's They require a heavier crank because of the balancing that is necessary. And it works. The low torque numbers reflect the short stroke on their V8's. All drag racers know that more RPM wins. For road racing, HP & RPM lives and wins. Yes torque out of the corners is good, a broad RPM band with flat HP numbers is better because fewer shifts are better. Look at the Mazda rotary. More HP than torque. And in a light chassis, a real contender.

KRAYZ308

I watched the 24 hours of Le Mans a few weekends ago, I didn't see any Japanies cars beat Corvettes, Porches, Ferraris or BMW's let alone Audi or that French brand.

SteveRiellyNZ

Exactly what I'm talking about. Supercar V8 teams here use flat plane as well, and so I've been put in touch with one of the top teams to be able to talk to them about it.

So, blend the two. Larger capacity ( more HP and torque ), but the response up the RPM scale that euro engines are known for.
That's exactly what I'm looking into.

Some people are more content with posting pictures of kittens.

SteveRiellyNZ

Maybe not...but then again vette use cross plan, and ferrari use flat plane, and its that information I'm looking into.
Both top, and worthy contenders, both top of their field.

Hercules Rockefeller

When it comes to performance, there is no debate, the flat plane crank is superior to the cross plane. Anyone who says otherwise is just flat-out wrong, and has no idea what they are talking about. There really isn't anything else to say there. Sure there may be some advantages to using the cross plane for "smoothness" and ease of use, but at the end of the day you will get more power with a flat plane crank. Period. Can you remember the last time an engine with a cross plane crank won the *a* race in indycar or formula 1? No? Me neither.

The LSx engine design works ok, but it is an old, inefficient design. A modern engine with features like a flat plane crank, dual overhead cams, direct fuel injection, etc. will generate a lot more power, but the added power comes at an added price. At the end of the day, the only reason a lot of us can afford to drive a car like the Z06 is because of the low production cost of the engine.

I think the LSx type engine has finally seen the end of its life and it's time for GM to retire this ancient design. Look at the new Ford Mustang GT 5.0 engine; it's using variable valve timing, direct fuel injection, and a DOHC layout to get 412 HP! And keep in mind they can put that thing in a car and sell it retail for less than $30k! Compare that to a $40k LS3-equipped Camaro, which gets only 10 more HP despite it's extra liter of displacement and extra $10k cost. GM is going to lose this war if they don't get off their *** and build something suitable for the 21st century.

4GS7

550-600whp at high RPM? Seriously?

Do you know how many people make those numbers with milled heads to bump the compression, a decent sized cam, a FAST 102, and headers? There is NO need to go into the bottom end to make those numbers NA. These are reliable, HPDE-able builds too, not just donkey dick cams to make cars run low 10s.

MitchAlsup

Ahem: 444 in Boss 302 format.

glass slipper

The first thing I'm going to do is reveal how full of BS you are. The LS3 Camaro isn't $40k, try $31k. Check out this link with pricing: http://www.motortrend.com/cars/2011/...aro/index.html
And the Mustang is right at $30k so it isn't much less. The really funny thing is the Camaro is kicking the Mustang's butt in sales so I don't think GM has to worry about losing the war. You may not be full of BS, you may just be a liar...pick one because you're definitely one or the other.

When it comes to making the most power, the cross plane crank is superior. Indy/F1 racing is not the pinnacle of engine HP, top fuel drag racing is. With an estimated 8000 HP, guess what engine is at the top of the heap...a lowly overhead valve American V8 with a cross plane crank. This a "run what you brung" wide open class and any flat plane DOHC engine could be used yet you don't see any of those "high tech" modern engines anywhere in the field...not even in Pro Stock. You and Stevie boy just don't get it, a flat plane crank just won't work in large displacement V8s. You guys are like a pack of dogs that treed a racoon that went into a hole in the tree...you just keep barking and barking meanwhile too stupid to figure out you're never gonna get it.

What is it about the LSx engines that is inefficient??? As you already noted, it cost much less than DOHC engines. It also makes more HP in a lighter more compact design than any engine out there. It's cheaper and easier to work on. I'm not sure how many people would chose an expensive, heavy, large engine that's too complex to work on and parts are way more expensive and less plentiiful. Oh wait a minute, yes we do know...the Camaro is outselling the Mustang even though it costs $1000 more.

Before you think I'm just a fan boy of OHV engines, my Corvette has a DOHC engine in it. It doesn't take a genius to see what a great design the LSx is but it certainly requires a brain.

glass slipper

But that one is over $40k...over $10k for 32 HP???