Flat Plane Crank LS1

[czan]

why not start with a Coyote motor - you have all the goodies in there except the "Flat plane crank".
Rebuild it with a custom made Flat Plane Crank and there you have your dream!

Coyote at 8200rpm http://www.gt40s.com/forum/gt40-tec...ote-5-0-litre-8-stack-injectors-8200-rpm.html

 

[JustinH]

why not start with a Coyote motor - you have all the goodies in there except the "Flat plane crank".
Rebuild it with a custom made Flat Plane Crank and there you have your dream!

Coyote at 8200rpm http://www.gt40s.com/forum/gt40-tec...ote-5-0-litre-8-stack-injectors-8200-rpm.html

Add three additional custom cams needing design and manufacturing though... Probably a wash on cost.

 

[Rudy]

Granted the twin overhead cam and variable valve timing is awesome on that Coyote, but you still would have a higher rod ratio of 1.62:1 Coyote and 2.05 SBC 618. This may yield higher piston accelerations and piston sidewall forces. Don't know actually how much until you put it into a program or I think that it can be done by taking derivative of the piston position to get velocities and then derivative of the velocity to get accelerations. It's a sinusoidal pattern. Its been a while but to put it simply its something like this. Lets say you have two identical bicycles but the only difference is that one bicycle has the seat at its lowest position and the other has the seat at the extreme highest position. The Coyote is the low seat position and the SBC 618 is the high seat position. Now take both of those bikes and riders and have them pedal down a hill and see which one wobbles the most in trying to pedal fast? Can you see what's happening? Also, another thing to consider is that the SBC 618 will have a much larger piston surface area due to its bore. I think that the SBC 618 has a 21% larger piston surface area. Well if you think about hydraulic jacks, which one gives more force for the same pressure? The larger diameter jack will. That is what is happening with the larger piston diameter. Also the larger piston diameter gives you the opportunity for larger valves. I've simplified this quite a bit because I failed to mention about the Coyote having a larger stroke which will give you more torque but then that gets way more complicated and frankly I don't know how to explain that easily. But that Stang was wicked. 620HP NA, WOW. This SBC 618 thing is going to be something. I eagerly waiting to hear it.

 

[Roger]

It's a sinusoidal pattern.

Without wishing to be pedantic, the big issue with the standard crankshaft and conrod design is that the piston motion isn't sinusoidal. V and crank angles are usually chosen to cancel-out as many harmonics of the motion as possible between the banks. A lower stoke to conrod length ratio also helps.

 

[Troy Truglio]

what style valves are you considering- titanium?

Ferrara super comp hollow stem is the choice for now based on their recommendations.

 

[Troy Truglio]

From what I have read and who I have talked to I am thinking a stroke of about 3.25 might be all you really want with a flat plane crank.

The coyote is a 3.62 bore and then add a 3.25 stroke. That would be like 4.3l. Smaller and could rev nice to like 10,000. You would still need the custom crank, con rods and pistons since it is destroked. The better valve springs to rev higher with better valves so that is 2x the cost. Then add in 4 custom cams at 4000 instead of 1000. Then how to tune it? The hptuner is 500, do they have that for the coyote? So when added up it would cost more, but rev higher.

 

[Mark Hamstra]

Actually, a 3.25" stroke, stock bore Coyote would be just a whisker over 4.4l. The Coyote block can handle up to a 94mm bore with ductile iron sleeves. Combine that with a flat plane crank of 81mm stroke, and you've got a flat plane, DOHC V8 with exactly the same bore and stroke as the engine in a Ferrari 458. It would probably be difficult and expensive to get such a Coyote to rev all the way to the 9000rpm redline of the 458, but over 8000rpm should be quite achievable since the Coyotes in the normally aspirated Cobra Jets already do 8000. It would also be difficult or impossible to maintain in the 4.5l flat plane Coyote the streetability of the Ferrari engine while still getting the full 562hp of the Ferrari, but I bet you could get to 500hp without outrageous and unruly cams.

 

[Troy Truglio]

Coyote then less Hp and just as complex if not more with more valves. Then more expensive. If would need to see the valve spring to cam lobe design to see what they have. I revved the Toyota 3sgte to 10,500, but I had to do a shim less bucket conversion that had no shims and I ordered longer valves and shaved thr stem length to match each valve. Too forever but worked good. That method works if there are suitable shim less buckets. When doing the v6 I was going shim less and planning on revving to 95000-10000 but it got costly, hence why I am here now.

 

[Mick Ridley]

Troy,

Now that you know how your going to build the engine..short stroke..9.000 rpm etc.........

What time scale are you thinking off to get the engine up and running ?

Look forard to seeing pics as the engine progresses

Best of luck

mick

 

[Troy Truglio]

Troy,

Now that you know how your going to build the engine..short stroke..9.000 rpm etc.........

What time scale are you thinking off to get the engine up and running ?

Look forard to seeing pics as the engine progresses

Best of luck

mick

Well now that I have learned more about the valve train the more I have learned I can rev. I will still rev to 8500.

I just got a set of blank 799 heads, same as 243 ls6 heads. I will CNC port them. I am also getting a bare ls1 block. So I will build up the flat plane on the side. I do plan to get the trans am running here soon to make sure it is ok. I plan to put in a stock ls1 and work out the kinks in the car that way first. Then build up the flat plane on the side. Putting it together does not take long at all. The item that takes some time will be intake, but I need the stock engine installed so I know fitment for the plenum, then make bucks, then molds, ect, to get it done. I get my slc in like dec so I am thinking springtime to get it all done.

 

[Ian Anderson]

Troy

Now you have the basis sorted and the rev range you will utilise - what transaxle will you fit behind it so as to best utilise your expected power output with the available gear ratios - or are you looking to "make" a gearbox too?


Ian

 

[Troy Truglio]

Troy

Now you have the basis sorted and the rev range you will utilise - what transaxle will you fit behind it so as to best utilise your expected power output with the available gear ratios - or are you looking to "make" a gearbox too?


Ian

Ian
I have a g50/20 LSD box. Part of the benefit of revving higher is that you can more match the trans so I plan to leave the gear ratios the same. Also less torque down will help with trans as we are not hurting it so much. So it is a good thing. I am deciding on clutches though. Mine comes with a clutch so I am thinking I will get a new disc, just which I am not sure yet. Gearing on the chart shows 202mph at 7000rpm so in 6th gear limited to only 245mph. Haha. I do not think I have the power, but who knows. Maybe the drag is low enough.

http://www.californiamotorsports.net/late G5020 stock.pdf

 

[Rudy]

Troy

"... or are you looking to "make" a gearbox too?


Ian

:lol::lol::lol::lol::lol:

 

[Troy Truglio]

:lol::lol::lol::lol::lol:

Not that. Engine, lots of stuff. After that maybe some carbon interior bits here and there, but that is a long way off and when the car is good and running.

 

[Troy Truglio]

Some help here, if you know. I am going to use an ATI super damper, but which one to choose? I am thinking the 30% underdrive since I am going to rev so high and will have a little higher idle. I see on the ATI site it has a chart with different size options and weight options. I would want the lightest to keep the weight down for fast revs, but 2 or 3 rib? Do we run AC all off the same belt? Anyone know which part number?

On the engine, nothing really new except for adjusting a few things. After picking out the valve springs I decided to use 1.8 rockers for a little more lift and more power from 6000 up. So with the intake runners short and more lift cam specs maybe in the 644hp and 450tq range. We will see.

I also decided to go with JE for custom pistons and will really light and have all their new piston technology.

I will be testing 8 different exhaust combos on the dyno for sound and performance. Header 4-2-1 and 4-1, with x pipe and without, and simple single 3" muffler each side or dual 2.5 mufflers each side. It can be 8-4-2-1-2-4 or other combos. I am fabricating up my own headers and exhaust so it should be fun.

I am working out details on the intake. I am considering making the runners in the intake variable length with a stepper motor and controller. So maybe go from like 5" to 8", but the gains are not all that much do I might just leave it at a set point. If I can figure out a good way to make the difference longer then I might. If short I can just use a selonoid and rpm switch to go from long to short at a given time. Might do that to keep complexity down and still get benefits. I have a friend who is a ME and EE helping with this part.

 

[Rudy]

Troy have you talked with the ATI folks? I think that the size of the damper has more to do with the weight of your reciprocating assembly, especially the weight of the crankshaft, and the stiffness of the assembly. The damper acts as a shock absorber but for a vibration in a circular pattern as opposed to a typical shock absorber vibrating in a linear motion.

Can't wait to hear what the final sound will be? Have you thought about tuning out the low frequency waves the same way that Ferrari does? I believe that they have a resonator before the muffler that is tuned to cancel out the low frequency waves so that you hear more of a high pitch sound?

 

[Troy Truglio]

Troy have you talked with the ATI folks? I think that the size of the damper has more to do with the weight of your reciprocating assembly, especially the weight of the crankshaft, and the stiffness of the assembly. The damper acts as a shock absorber but for a vibration in a circular pattern as opposed to a typical shock absorber vibrating in a linear motion.

Can't wait to hear what the final sound will be? Have you thought about tuning out the low frequency waves the same way that Ferrari does? I believe that they have a resonator before the muffler that is tuned to cancel out the low frequency waves so that you hear more of a high pitch sound?

That is a good point on the ATI balancer. My crank builder said to use ATI a while back and I will ask him which one and also call ATI.

On the exhaust the resonator is a good idea and I will look into that. I did call a few places, like Burns, and asked when they design a system can they design for a different sound or pitch and they do not there as it is more for hp. I do have the different exhaust systems in mind and will try out different systems until it sounds the way I want. I think I will start out with the 8-4-2-1-2-4 at first as that is just how the Honda HSV-010 is and then start changing stuff around after.

On the engine still working out head items. I think I am going Ti intake valves now to make it as light as possible. Maybe still SS hollow stem super comp exhaust as that is already lighter and the real limiting factor is the weight of the intake valve portion.

Up at 4am today to leave for a road trip to Road America. 18 hour drive so I hope it is all it can be.

Troy

 

[Rudy]

Good Luck with your race!

Looked into how to get the sound you want and saw this thread.

exhaust note - HybridZ

"To replicate the Ferrari exhaust note exactly will take 1) Single plane crank with shorty equal length headers and a short overall length exhaust system, (shorter length is higher pitch). 2) 180 degree headers of equal length, as short as possible with the primaries to retain as much high pitch as possible along with as short of overall length. This will get you 90% there. 3) 8 into 1 headers all primaries being equal length, again as short as possible. 4) Some mufflers such as Spintech have a unique of absorbing the tones that give the domestic V8 that old boat drumble giving a more distinct crisp smoother "raaaaaaaap" to the exhaust note with a hint of off beat rumble. Listen to youtube sound clips of c-5 &C6 Vettes with spintechs for an example.

Not positive about diameter and it's effect on exhaust note/tone. Pretty sure smaller equates to higher pitch due to higher velocities, if that is indeed the case, finding that balance of small but so small it is restricting.

Spintech is a chambered design, I dont recall if they offer a Stainless version, if so Stainless will last much longer than mild steel, 15+ yrs. Not sure how long the mild steel versions would last, 5 years?

So shorty equal length headers that as soon as possible go into one collector, an x pipe, and then to a chambered designed muffler. Do muffler lengths and tips change the pitch? Im not sure, I would suspect it would, but only slightly. Most likely would the tone coming from the shell of the muffler/exhaust as it rings from the sound traveling within, most likely noticeable only standing right next to the muffler if..."

Obviously you won't need 180 degree header or x-pipe. With respect short equal length headers take a look at this Ferrary V8....seems like they are in a hurry to get the primaries collected ASAP.

I'm thinking that you can make a resonator muffler that you can vary its depth, somewhat like a can within a can. Make it so that it doesn't leak exhaust and so that you can adjust it's depth real time as you are tuning. Then when you get the sound that you like, you'll have the "magic" dimension. Maybe it will work. Just throwing that out there

 

[Troy Truglio]

Rudy. Thanks for the tips and ideas. The range for the header for higher rpm is in the 20-24" length so I can start out with a 4-1 real short equal length and try this out first. I will look into the canister when done to see how it sounds.

As far as the other engine updates. I will not be revving to 9,000. Just costs too much for Ti valves at a $3000 increase for them. If I go ferrea super comp hollow stem with the weight and right springs 8200-8400 will be the red line and that will be fine. Peak Hp is around 7800 so I will be happy with that. Ti would be nice but at about $200 per valve with thr valve cost and valve seats it was just too much for me at this time for that last 500rpm. It will still have the power and feel I want with this setup.

 

[Rudy]

What is the status of the engine build?