Flat plane crank V8 vs LT2 V8 reliability
 

I recently saw a youtube vlog can't remember from who, but any way the guy says he doesn't think the flat plane crank motor, (likely in the Z06 and up) will hold up nearly as well at the LT2, as the Flat Plan design is inherently weaker. I don't pretend to be knowledgeable in this area would like to know what others with actual expertise in this area think. I hope this has not already been posted as it really brings out the trolls. If it has just ignore it.

It all depends on how high you rev an engine. If you never visit the 8,000 rpm red line of a Ferrari, it will last a lot longer than if it lived there. Same will apply to a Chevy fpc. Look at the trouble ford has with their FPC engines.

If the fpc was so great and reliable there would be a lot more of them, out there.

Also ford put a cross plane crank in the GT500. So they must not have too much faith in there fpc.

Even though I would love to own one. The sound is amazing.

I wonder if the best sounding car ever has a fpc. It must because it revs to 9000 rpm. Lexus LFA. You tube that car.

I love the sound of the FPC too which is one of the reasons I am considering holding off until the Z comes out (have an order in at the dealer for C8 Vert). I have always really loved the Vette sound, I had a 68 427 with Tri power putting out about 500 hp and it actually sounded better than my C7 at least to me, but the FPC is just sooo much better to my ears.

I’m getting a c8 stingray. But will be upgrading to a z06 in a few years.
But only if it does go fpc.
Because that sound is amazing. And the performance is too.
I’m sure the c8 will also sound great. Even better when they start developing aftermarket exhaust for them.

Problem with the FPC is vibration, which destroys engines. So, everything must be lighter, stronger, better, and is generally much more expensive. You also need a dohc head to spin the engine high enough for the benefits and the displacement is generally smaller to lower the weight of the pistons. Even wonder why a FPC V12 is only 5 liters? Smaller pistons means less mass to control. You can build a big piston, large bore, cross plane without huge counterweights and vibration issues. Hence the benefits of the standard cross plane crank. BTW: MOST 4 bangers have flat plane cranks, but they also have only one piston/rod per crank journal. Hence they can rev higher. The 2.3 Ecoboost enginei is also a flat plane crank. Don't hear much boasting about that though.

Nascar engines regularly turn 9,000 rpm, with pushrods and cross plane cranks.The good 'ole boys building those engines must be using black magic or something.

There is a reason Ferrari, et al, build their 700 HP FPC DOHC TT V8's at 4 liter or under.

The aventador, has a flat plane v12, that revs to 8,500. But it’s a monster, 6.5 liters.

I believe it is the flat plane crank that is inherently better balanced allowing the use of less counterweights, less rotating mass, and consequently higher rpm capability than a cross plane. A cross plane inherently produces more low end torque. In the flat plane V8, cylinder firing order is always one bank to the other side. In a cross plane, the firing order only has 4 cylinders firing in order across from each other while the other four fire 2 after each other on each side...(wordy I know) .hence the different exhaust note between the two types of crank shafts. The flat plane scavenges the exhaust better as well because it is always firing one bank to the other side. In the cross plane there is a couple hiccups in the scavanging process when the cylinders are firing after each other on the same side. This becomes a progressively bigger issue at higher rpms. Bottom line: higher low end torque lower reving V8’s: cross plane....Higher horsepower higher reving V8’s: flat plane. Cool factor: flat plane. Just my opinion on the last statement.

The GT500 makes it's HP peak at 7400-7500. Spinning to 8250 like the Voodoo isn't necessary. Ford has done an admirable job addressing the Voodoo issues. And lets remember the early issues of 15 and 16 voodoos werent' really engine issue as opposed to oil line recall issues. Model year 17 of the Voodoo seems to be the problematic year. 2018 saw new ring and piston packs. Model year 19 saw the updated block from theGT500 which just amounted to londer head studs for the forced induction of GT500. The engine has been great to live with. Though I'd shy away from a 17 model year. Something went a miss there with regard to maybe Ford tried to cheap out on somethings. And I wouldn't worry about the R at all. Even for the 17 model year. Despite what was "publicly" said. The regular 350 motors and the R motors differed on some internals. Model year 19 saw the regular 350 motor and the R motor actually are the same.

if GM comes out with FPC pushing 550-600 HP naturally aspirated in the GS or a Z06, I'm so there in line for it.

One of the limits on size for European manufacturers has to do with EU and China tax laws which get more and more punitive as displacement increases as well as the endless rules and regulations in the EU. I have had many Ferraris over the years and their engines are extremely robust. That being said, the quality of assembly and materials cuts no corners.

So what would be the big advantage of a Z06 FPC running 550 over the 495 C8 Z51other than the suspension and tires etc. And would it not be harder to get low end torque. Just asking dont pretend to be any kind of engine expert.

FPC motors rev to redline quicker and go to higher RPM's than CPC motors. Sound is unique. Living with my R for a year now, the shift strategy is different than with our M7 Z51 C7 we have. The Voodoo FPC motor's normal operating range is higher than the LT1. The HP and TQ peaks are much higher in the RPM spectrum. Below 4k RPM is kinda meh... But living in the upper ranges, especially on the track is a really visceral experience.

this is great info and thanks for that info, but in actual driving experience what would be noticed? not as much low end torque? so it won't jump off the line as quick since it needs more revs? not as linear in the power band? I guess as a driver how will the experience differ, other than what I consider to be a cooler sound. Also I realize we are not talking about a Prius but it seems that the engine needs more revs to perform does that mean lower gas mileage? I didn't buy my C7 as an econo car but the LT1 and 2s having the ability to shut down 4 cylinders during highway driving is a nice feature my C7 would get 31mpg at 70-75 on the Exp way.

My last two fun cars s2000 & e92 M3 both have NA engines with power peaks @ 8300 RPM. What it meant for me was more visceral feel, more importance on maintaining momentum due to less torque to pull you out of turns, and more emphasis on shifting and staying in the power band. To launch off the line requires high rpm clutch drops so that when the tires hook up engine is in the heart of the power band. Because the power is up high the gearing has to be very low as a result the 2.0 liter 4 in s2000 gets mid 20s mpg at best And the 4.0 liter v8 in the M3 had a gas guzzler tax. Side note there was a test where a Prius and an m3 were on a track. Prius was driven flat out and the M3 was required to keep up with it. The gas guzzling M3 returned higher mpg from the test. :)

I think the reason GM is going to use the FPC motor is they can get alot more hp than the ls2. But less lower end torque than the ls2.
They will make up for the lost lower end torque with electric motors upfront.
Then they can keep the same DTC transmission The electric motors will not put any strain on the DCT.
The end result is way faster acceleration. With the crazy FPC sound. And keep the same DCT.

The talk of electric motors up front are being spoken about for the Zora if it ever really lives and would run $150k+
What I'm talking about or trying to get info about is the probable 600hp NA flat plane in the Z06 not a ZR1 which might likely be twin turbo or the ZORA which might add the electric motor to a ZR1 setup. The reason I'm asking is I am on the verge of cancelling my Z51 vert order and putting down $ for a Z06. I just don't want to lose low end back road fun performance even though the FPC 600hp would be way better on a track, I wouldn't track it more than a couple of times a yr.

l think what makes the answer difficult is that nobody has mass produced a 600 HP NA FPC V8 over 5L. So there are no exact points of reference. If we assume the displacement is 5.5l and that GM can overcome FPC vibration issues for an engine that size, extrapolating the Ford voodoo 5.2l v8 power would give a 5.5l 558hp & 453tq. If you stretch that to 600hp you are going to move the power band higher with HP peaks in 8000rpm range and torque probably lower in number with peak in the 5000rpm range. Saying this because you would probably need a shorter intake track that’s has been tuned for higher rpm airflow vs low/midrange. Also your cams will have to be more optimized for top end. The best advice I could give would be to drive a current Shelby gt350. A Z06 with 600hp NA is going to feel more “peaky” than the Ford but the Gt350 would give the sensation of what a larger FPC engine feels like. Good luck on your choice.

I can't wait for it to not be fpc