Teardown and rebuild Thread: Converting GT350 race motor to CPC

[DCShelby]

Hey now, it’s fun changing out the opening and closing shims on a desmo motor, it’s great bonding time.

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[YBLEHSGT350R]

Like issues - great write up and visuals

solving my issue was a stage 3 sleeved build from RPG - blower back on and first tune is 770rwhp - breaking in still, it’s 8lbs light on boost with a 3.5 pulley but ultra strong on the road. I saved the block VIN 00350 by an early detection. Preserved the FPC set up with a fresh crank but stronger built for 1500hp

 

[ShatterPoints]

They're the Clevite H-Series bearings. Good stuff

https://www.summitracing.com/parts/cle-ms2292h




Yep. Unfortunately, I felt like a lot was left up to interpretation with the changeover outside of "reliability" concerns. But I feel confident now with the new insights and my "good ol' college try" that the FPC is truly not a good option for race use--even if you're willing to deal with the harmonics/vibrations.

After my engine failure I started down the "why did that happen" rabbit hole. What you are finding both for FPC in general and for the Voodoo is basically the same as I have learned. In summary it's not specifically a FPC issue outside the fact it takes a more developed approach to run with an amount of reliability. We did not get that with our cars, otherwise the price tag would be much, much higher. The compromise as you have said is these were track day cars, fragile ones at that and not race cars.

In fairness, I'm not sure it's a proper apples/apples. Plenty of high end racing with FPC architecture. But what we have in the Voodoo is not a true FPC or rather it's not the same counterbalancing as the true FPC arrangements everyone else runs. Hence the distinctive sound from the voodoo (compared to the scream from Exotics). As I understand it, Ford basterdized the FPC for some of the benefits but straddled the fence on others. GM on the other hand, incorporated a full FPC in their new LT in the Z06, which is why even though it's a larger motor, it sounds like a small F1 type motor at full wail.

CROSS-plane vs FLAT-plane V8: Corvette C7 Z06 vs C8 Z06 vs GT350 Mustang - Engine balance DEEP DIVE - YouTube

My point is, the FPC could be very viable, but the version we have in the voodoo is only have the improvements coupled with significant remaining balance issues. If they went full on FPC, it would probably hold up just fine to racing purposes.

The more I learn about the Voodoo the less I like it for anything other than sounding cool... :(

 

[A_Bau3]

I have to ask, since HB is switching to a CPC. If the Voodoo firing order is retained along with unequal length headers, I imagine the exotic sound would still be there somewhat?

 

[YBLEHSGT350R]

Compare the sound to a GT500 sound - it’s different as a full throttle pull and pass - I had the cross plane option and went with a new fpc sleeved block and we spun it to 8600 tuning round one. It’s a great motor just can be better built for higher performance and durability.

 

[Egparson202]

Compare the sound to a GT500 sound - it’s different as a full throttle pull and pass - I had the cross plane option and went with a new fpc sleeved block and we spun it to 8600 tuning round one. It’s a great motor just can be better built for higher performance and durability.

That’s great to hear. What’s the use case for your new and improved FPC? Street? Drag? Road course?

 

[Angrey]

I have to ask, since HB is switching to a CPC. If the Voodoo firing order is retained along with unequal length headers, I imagine the exotic sound would still be there somewhat?

I personally think the flathead firing order of the coyote sounds like ass garbage. It sounds crude and unrefined, and reminds me of shitty old misfiring pickup trucks with trashy redneck exhaust. This is my opinion. Compare and contrast the flathead sound to the traditional firing order of the pushrod and modular engines and there's just no comparison. A 4V modular motor sounds magical with the right exhaust.

Having said all that, this is the best sounding coyote I've ever heard and it's a GT350 exhaust system (headers to mufflers) so you might be onto something.

GT350 ARH Exhaust - YouTube

Full ARH GT350 Exhaust on 2015 Mustang GT - YouTube

Paulina's Ride along - YouTube

 

[YBLEHSGT350R]

Street and road course - high revs and high rev decels/downshifts

still drives as before - power band is as insane as always just feel way better about an occasional thrash

 

[honeybadger]

I have to ask, since HB is switching to a CPC. If the Voodoo firing order is retained along with unequal length headers, I imagine the exotic sound would still be there somewhat?

Voodoo firing will not be retained with CPC - it has to be re-pinned to the regular Coyote firing order. It'll more or less be an Aluminator XS motor (just with built internals and blueprinted).

I had the cross plane option and went with a new fpc sleeved block and we spun it to 8600 tuning round one. It’s a great motor just can be better built for higher performance and durability.

My motor was a fully blueprinted race motor with a sleeved block and all high quality parts

 

[A_Bau3]

I personally think the flathead firing order of the coyote sounds like ass garbage. It sounds crude and unrefined, and reminds me of shitty old misfiring pickup trucks with trashy redneck exhaust. This is my opinion. Compare and contrast the flathead sound to the traditional firing order of the pushrod and modular engines and there's just no comparison. A 4V modular motor sounds magical with the right exhaust.

Having said all that, this is the best sounding coyote I've ever heard and it's a GT350 exhaust system (headers to mufflers) so you might be onto something.

GT350 ARH Exhaust - YouTube

Full ARH GT350 Exhaust on 2015 Mustang GT - YouTube

Paulina's Ride along - YouTube

I’ve been looking for these videos for a while now. Comparing it to an old video of Obsessed garage’s GT350 with the full ARH system, they sound very similar. I think the unequal length headers are what really make this platform sound so unique. A GT350 with equal length headers doesn’t sound remotely close to either of these.

 

[honeybadger]

Just a friendly reminder to please keep discussion on topic. Want to make sure this thread is easy to navigate for those wanting to learn about a CPC swap.

 

[UnhandledException]

After my engine failure I started down the "why did that happen" rabbit hole. What you are finding both for FPC in general and for the Voodoo is basically the same as I have learned. In summary it's not specifically a FPC issue outside the fact it takes a more developed approach to run with an amount of reliability. We did not get that with our cars, otherwise the price tag would be much, much higher. The compromise as you have said is these were track day cars, fragile ones at that and not race cars.




The more I learn about the Voodoo the less I like it for anything other than sounding cool... :(

Are you saying all GT350s will fail eventually -
Some sooner some later?

 

[YBLEHSGT350R]

Luck of the Draw - Stories of 200-300 mile lock ups and stories of blown Vodoos that survive daily drives and more. Others go through a quart of oil every tank - others are 50,000 miles strong and enjoy the drive -

 

[DCShelby]

47k miles on my Gen1 engine and little oil usage.

 

[Tractor Junk]

HB,

Are you at the point on this build of dialing it in to a specific racing class... Power to weight TT (NASA), limited rule set/ mods TT (SCCA), etc?

You’ve invested a lot so far, now will this engine build push you in a specific race class direction?

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