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HawkHill posted:I offer you, the Jaguair, Jay Eitel's V-12 Corvair ... http://www.corvaircorsa.com/V-12-01.html Holy poo poo, that's a work of art!
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Jul 16, 2019 21:38
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Powershift posted:Yeah, but the thought is it might gently caress with the load calculations of the rear engine having another 200hp coming into the front of the crankshaft. Once i get more things running i'll probably call SCT or Bama and get their thoughts on the situation. This is such a neat problem. For argument's sake, assuming the first engine was fired up first, wouldn't the sensors on the other engine basically take the first one into account for you? Since you'd be spinning the rear flywheel, the second engine would "know" it's being spun and adjust itself accordingly? It wouldn't take into account the extra 200hp, but would it matter? I imagine the second engine's sensors would adjust for the incoming RPM, it wouldn't matter what torque was applied to the crankshaft, your power would be additive anyway. Or is this completely wrong?
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Jul 17, 2019 00:52
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OK, so real thing about how ECUs work... I'm assuming it's MAF. The ECU looks at the RPM, looks at the airflow, figures out engine load from calculated airflow per revolution, uses that to a lookup table for spark timing and what AFR it should target, then squirts in the amount of fuel per the AFR. It doesn't actually know or care if it's being motored or idling or what. If it's speed density it looks at manifold pressure and uses a different sort of lookup table. Still doesn't care if it's being motored or not.
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Jul 17, 2019 02:00
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I believe you want the engines to fire every 30 degrees. What you don't want is two pistons firing at the same time, so the rear crank sees double the design torque in one instant. Cranks do twist and flex and spring back, I think you'll have a very short engine life if you clock them identical. Fun as hell thread.
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Jul 17, 2019 02:12
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If you were to run them on dual independent ECUs the chances of the timing matching up is pretty slim, if you run them off a single ECU then you're going to run into that issue. I honestly can't loving wait to find out where this is going to go.
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Jul 17, 2019 03:26
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LloydDobler posted:I believe you want the engines to fire every 30 degrees. What you don't want is two pistons firing at the same time, so the rear crank sees double the design torque in one instant. Cranks do twist and flex and spring back, I think you'll have a very short engine life if you clock them identical. This is actually a really good point and a good argument for either a totally rigid coupling between the two or something with a tuned damper like a dual mass flywheel between the two. I hadn’t considered the harmonics, which is silly because my Stinson has a restricted rpm range with the metal propeller for exactly that reason - it sets up nasty harmonics and actually cracks the crank.
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Jul 17, 2019 04:02
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Honestly, this sort of thing has been done a number of times with a pair of V8s, carbureted. I’m betting it won’t be that much of a problem with two independent fuel-injection ECUs, especially if the coupler used has just a bit of flex in it. Probably not even if it does. Only way to really know is to try it. I’d probably build a cradle to test and run them before shoving them in the car, maybe drag that to an engine sumo of it isn’t too expensive or onerous, just for giggles. I think it’ll work, and I can’t wait to see it running. This kind of poo poo is extremely my bag. I wish I were somewhere close to help!
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Jul 17, 2019 15:13
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Darchangel posted:I’d probably build a cradle to test and run them before shoving them in the car, maybe drag that to an engine sumo of it isn’t too expensive or onerous, just for giggles. I think you just came up with a new sport, and I'm certainly up for watching it.
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Jul 17, 2019 16:17
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EVERYWHERE 
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Darchangel posted:engine sumo This thread is so exciting, its got grankshafts and engine sumos.
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Jul 17, 2019 16:45
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Engine sumo... Ahh. Chain two cars together and the one that pulls the other out of the circle wins.
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Jul 17, 2019 20:14
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*blows salt out exhaust into ring*
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Jul 17, 2019 20:17
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Darchangel posted:Honestly, this sort of thing has been done a number of times with a pair of V8s, carbureted. I’m betting it won’t be that much of a problem with two independent fuel-injection ECUs, especially if the coupler used has just a bit of flex in it. Probably not even if it does. Only way to really know is to try it. Yeah, that's the plan. I was gonna find a cheap miter saw and mock up the engine bay out of 4x4s. that way i could get everything right up to the exhaust collector built outside of the car. it's pretty simply, the frame rails are pretty much straight, and there are no shock towers or anything to work around. Just a crossmember, brake booster, wiper motor and HVAC box
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Jul 17, 2019 22:07
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meatpimp posted:I think you just came up with a new sport, and I'm certainly up for watching it. wesleywillis posted:This thread is so exciting, its got grankshafts and engine sumos. Resting Lich Face posted:Engine sumo... Ahh. Chain two cars together and the one that pulls the other out of the circle wins. I meant "dyno" of course, but was "helped" by Apple's auto edit: Also, now I want to see two running engines chained together and just sort of flailing around in a ring until one gets knocked out.
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Jul 18, 2019 00:11
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Darchangel posted:I meant "dyno" of course, but was "helped" by Apple's auto Get me a chain, a sawzall, and 2 FWD cars.
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Jul 18, 2019 00:16
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This is gloriously bat-quano. Appropriately, Ford itself has tried something like this in the T-drive. Think: AWD, 12 cylinders, engine waaaay up front, four foot long doors and velour. The Lincoln Nuvolari.
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Jul 18, 2019 02:52
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madeintaipei posted:This is gloriously bat-quano. Appropriately, Ford itself has tried something like this in the T-drive. Think: AWD, 12 cylinders, engine waaaay up front, four foot long doors and velour. The Lincoln Nuvolari. Make that v12 out of two slant sixes bolted together and it could be a NU-VOLARE! Ok, I'll see myself out now.
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Jul 18, 2019 11:27
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wesleywillis posted:Make that v12 out of two slant sixes bolted together and it could be a NU-VOLARE! Someone will just bolt two v12s together and park next to you.
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Jul 18, 2019 11:41
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wesleywillis posted:Make that v12 out of two slant sixes bolted together and it could be a NU-VOLARE! VW did it with a pair of VR6s and had the gall to call it a W-12. Still a V, guys. Elephanthead posted:Someone will just bolt two v12s together and park next to you. See, now *that* would be a W-engine.
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Jul 18, 2019 19:01
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https://www.youtube.com/watch?v=hSprOTA-X8M this guy used a guibo/flexdisc from a Monaro/GTO. I'd personally run independent ECUs for each V6 so there isn't any worry about timing.
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Jul 18, 2019 19:52
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That’s one of them I was thinking of.
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Jul 18, 2019 20:24
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Darchangel posted:VW did it with a pair of VR6s and had the gall to call it a W-12. Still a V, guys. Bolt them together at the crank case and make it an X type radial engine.
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Jul 18, 2019 22:40
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I may or may not have done this with 2 rotary engines... but no photos were allowed  . Can't wait to see how it turns out.
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Jul 19, 2019 04:08
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Is it possible to just tell a single aftermarket ECU that its connected to "a" 12-cylinder engine?
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Jul 19, 2019 04:11
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Darchangel posted:
It's been done, probably too big for the lincoln though. https://en.m.wikipedia.org/wiki/Allison_V-3420 Edited out post numbers because mobile was being a bit goofy but they should be on the same page.
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Jul 19, 2019 05:09
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I could probably make it fit. 0.41 lbs of fuel per hour per horsepower sounds less than ideal
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Jul 19, 2019 05:12
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Lake of Methane posted:Is it possible to just tell a single aftermarket ECU that its connected to "a" 12-cylinder engine? You'd need a rigid connection between both cranks, as is the two ecu approach allows it to handle a slight difference in angle between the cranks, as with a flexible connector you'll have a varying amount of flex between the two dependant on the engine load. With a flexible connection harmonics may be an issue hence the suggestions of added flywheel/mass to help dampen those effects. With a rigid mount you'd have to be more careful with ensuring the two motors don't move with respect to each other, you still want that with a flexible connection but it's not as critical.
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Jul 19, 2019 06:03
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with the 2 ECU approach, isn't it gonna sound like... 2 V6s at nearly the same time? In other words just an unholy ruckus?
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Jul 19, 2019 18:09
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lordofthefishes posted:
Yeah, now we’re talking! My Rhythmic Crotch posted:with the 2 ECU approach, isn't it gonna sound like... 2 V6s at nearly the same time? In other words just an unholy ruckus? That’s sort of what I said a ways back. If they are timed the same, it *should* just sound like a 6L V6, but if you time them, I believe it was 30-degrees out, you get a V12 firing order.
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Jul 19, 2019 19:28
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This is going to make for an interesting exhaust setup as well, right? (Which will then also affect the sound...) Setting it up to scavenge one engine from the exhaust pulses of the other engine would probably lead to the most V12 sound, though I make that guess based on basically zero knowledge.
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Jul 19, 2019 20:10
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Krakkles posted:This is going to make for an interesting exhaust setup as well, right? (Which will then also affect the sound...) I was thinking of just going straight down and back off the first engine into a 2:1 collector just off the second, then into a Y-pipe. 6 firing pulses per revolution plus unequal length headers = V12 subaru? This is the stock DB9 manifold, and it's considered one of the best sounding cars of all time.  Not anything super fancy, seems all about space constraints. I have a lot of options either way because not only are there are ton of aftermarket headers for the 3.0, it seems i could just flip the manifolds upside down and switch sides if i wanted to do something fancy. At this point It's all about getting started and running on the cheap because nobody really knows exactly what will happen. If it works and works well, i can start adding cheap performance bits. Also, looking at pics of the upper intake manifold, i might be able to just pull it off the rear engine and flip it 180 degrees, and not need the Jag/Lincoln manifold.  e: even easier, i might be able to flip the front one around, not have them foul, and have the 2 throttle bodies side by side. Powershift fucked around with this message at 00:38 on Jul 20, 2019 |
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Jul 20, 2019 00:34
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somewhere in this exhaust setup should be a resonator. Find that guy on these forums that was designing a race moped and hydroforming the exhaust for it and get him to tune this thing for sound.
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Jul 20, 2019 01:22
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I apologise if I missed it in my cursory glance of the thread, but if you pull tech from tractor pulls you'll start finding answers on how to link engines. https://www.ustsubaki.com/roller-chain-couplings.html The sprockets provide torque transfer and the chain allows mild misalignment. Also tractor pullers noticed no performance differences with how their engines were clocked. Exhaust note will be the controlling factor. You could also consider a crossbox configuration in which engines are side by side. You'd have to measure it out, but those are more reliable as they all get their own crankshaft and no sharing. The crossbox uses existing transmission mounts and give you a solid structure in which to build upon. um excuse me fucked around with this message at 07:09 on Jul 20, 2019 |
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Jul 20, 2019 07:07
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um excuse me posted:You could also consider a crossbox configuration in which engines are side by side. You'd have to measure it out, but those are more reliable as they all get their own crankshaft and no sharing. The crossbox uses existing transmission mounts and give you a solid structure in which to build upon. I get the Lincoln is a big fuckin' car, but it's not that big
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Jul 20, 2019 11:25
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I figured it'd be a longshot, but the side by side set up is sooo much better than longitudinal that if there was even a chance it could work it would be the way to go. Mounting engines longitudinally presents challenges in that you have to rigidly mount the engines together, then that subassembly has to be mounted to the chassis using traditional engine mounts. It's doable, but a pain in the butt to install. The wood mockup is going to be critically important for this design.
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Jul 20, 2019 13:07
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Well the engine bay is 5 feet long, but only like 3 feet wide, so side by side is out. And yeah, the engines will be tied together on a single mount before going in the car. part of the reason for the soft coupling is vibration isolation as well. I'm only putting 200ish ft/lbs through it.
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Jul 20, 2019 13:17
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Just went through the thread and actually read it. Your ECUs clock rate is low enough where it isn't calculating every cycle. All it cares about is how much air it's getting, and how much fuel to give it. The ECU on an older car is basically designed to make the engine run away and explode if the throttle wasn't physically blocking air. The throttle position sensor is for calculating pressure which is used to figure out volumetric efficiency to determine how much fuel to use. That's the equation going on in the front half. The back half includes O2 sensing which isn't actually needed to run an engine at all. You'll notice when you throw a code for a bad sensor, the engine doesn't stop running. It doesn't need it. The O2 sensor is specifically for dialing in emissions and fuel efficiency. The system will switch between rich and lean to keep the catalytic converter happy and fuel consumption down after the engine is warmed up. I guess is what I'm saying is they really don't care about whether or not the engine is being driven by external forces unless the ECU belongs to a manual transmission car. A manual ECU will cut fuel. For the fuel pump, you 100% want a common source. Not only is it cheaper and easier to run, you don't want to generate a condition where one engine is off, especially if it's driving the coolant or power steering or vacuum lines for braking. Though coolant is irrelevant if you're going with the auxillary pump. Just make sure your fuel pump has the flow rate necessary. I'll have to go back and read but you also definitely want a return based fuel rail to maximize robustness of a system that doesn't understand it's feeding two engines.
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Jul 20, 2019 14:49
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um excuse me posted:I apologise if I missed it in my cursory glance of the thread, but if you pull tech from tractor pulls you'll start finding answers on how to link engines. Keep in mind chain couplings, like virtually all metal-metal contact couplings, are not maintenance free and require periodic cleaning, inspection and regreasing. They are relatively simple and good bang for the buck for high-torque couplings.
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Jul 20, 2019 18:49
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I just checked this thread last night and you are telling me we don’t have 2 engines in a Lincoln yet? I’m getting impatient!
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Jul 20, 2019 20:15
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The side by side idea makes 2x inline 6s sound very interesting. 4jz no poo poo.
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Jul 20, 2019 20:35
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slidebite posted:That is what I was talking about chain couplers in that other thread. Chain couplings are greats because they can handle over a thousand of foot pounds of torque while maintaining a little flexibility and arresting vibrations that aren't rotational. All the while it takes no nuts or bolts, and a single pin to remove. Not to mention cheap to replace.
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Jul 20, 2019 20:55
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