Teardown and rebuild Thread: Converting GT350 race motor to CPC

[honeybadger]

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?

Loosely prepping it for TTU/STU. It could also be detuned for TT1/2. In the nearer term, it's more likely to be run in SLB/Gridlife Limited/Unlimited and NASA TTU/TT1. Obviously it won't be competitive with cars making 1000+ whp, but my goal isn't to win with it, but more build the gnarliest multipurpose machine I can. The winning unlimited time attack cars are too purpose-built to be fun outside of competition. I still want this thing to be able to run 30 sessions flat out or give hot laps during my instructing.

In a few years, I might be detune it and run it in NASA for some W2W so big things like the cage and suspension geometry will be retained with that in mind, but it's not a near time goal.

For 2023, my goal is to be consistently even with GT4 lap times at COTA.

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[JCSIX13]

HB

DO you think a MFP MFP-WHIPPLE-CS Crank Support Kit would of helped the crank last?

https://www.lethalperformance.com/m...mustang-gt-with-whipple-g3-g5-6-rib-kits.html

 

[honeybadger]

HB

DO you think a MFP MFP-WHIPPLE-CS Crank Support Kit would of helped the crank last?

https://www.lethalperformance.com/m...mustang-gt-with-whipple-g3-g5-6-rib-kits.html

This is a bit outside my expertise since I'm not an engineer/educated in materials science, but I don't believe so since the stress is coming from inside the crank case not external stress on the end of the crank. I was told that the vibrations created by this engine due to its stroke and firing order are too much for any reasonable attempt at dampening. My understanding is that all those OEM dampeners (crank balancer, motor mounts, dual-mass flywheel, exhaust mid pip dampeners, and trans mount dampener) were developed to deal with the Voodoo's specific vibrations. While it sounds like this was enough to make the engine viable for mainstream use, there's nothing that can be done to make it work long-term in race applications.

 

[Hack]

HB

DO you think a MFP MFP-WHIPPLE-CS Crank Support Kit would of helped the crank last?

https://www.lethalperformance.com/m...mustang-gt-with-whipple-g3-g5-6-rib-kits.html

I started to say yes it would, but now I'm thinking no it wouldn't. That support will help with bending loads on the end of the crank, but not with torsional loading originating from the crank throws / combustion events within the engine.

This stuff is so complicated the best way to figure it out would be to model it in CAD and run FEA structural analysis. You know that Ford engineers have done all that work along with a lot of physical testing on dynos and in cars.

 

[Tomster]

This is a bit outside my expertise since I'm not an engineer/educated in materials science, but I don't believe so since the stress is coming from inside the crank case not external stress on the end of the crank. I was told that the vibrations created by this engine due to its stroke and firing order are too much for any reasonable attempt at dampening. My understanding is that all those OEM dampeners (crank balancer, motor mounts, dual-mass flywheel, exhaust mid pip dampeners, and trans mount dampener) were developed to deal with the Voodoo's specific vibrations. While it sounds like this was enough to make the engine viable for mainstream use, there's nothing that can be done to make it work long-term in race applications.

And for that reason they only ran that engine for 1 year in race conditions. It was a nightmare.

 

[Jim]

5.2 cross-plane crank power

 

[Angrey]

5.2 cross-plane crank power

They're not apples/apples. One is SAE the other STD. STD smoothing is generally a gimmick/trick by shops to bump the numbers for marketing because a good number of customers won't know the difference. SAE smoothing 5 is generally considered the proper/benchmark correction factor.

 

[wingnutt]

Subscribed…if for nothing more, than the awesome

 

[Donm308]

Do you think the changes in your motor has caused these issues or its just inherent flaws of the FPC design compounded with the wrong material being used? The only other high revving N/A I know is Porsche’s GT3 engine which takes quite a bit abuse but I have never seen this type of damage. You also had other issues in your videos if I recall correctly where the oil pick up tube had broke apart.

By the way, my whole family watches your videos including your laps with our surround sound speakers. Your videos are my favorite and I have a GT3RS and a ZR1 in my garage. That says a lot about your content!

I’d like to subscribe, what the tag line / channel name etc?

 

[gimmie11s]

They're not apples/apples. One is SAE the other STD. STD smoothing is generally a gimmick/trick by shops to bump the numbers for marketing because a good number of customers won't know the difference. SAE smoothing 5 is generally considered the proper/benchmark correction factor.

At ~500 hp, the difference isn't more than 10 or 15 hp max.

Close enough to apples/apples.

 

[Angrey]

At ~500 hp, the difference isn't more than 10 or 15 hp max.

Close enough to apples/apples.

I don't agree but whatevs. When trying to compare two different mods or motors or whatever, if they're not using the same correction factor, it erodes the evaluation.

Again, STD smoothing is generally a tell tale sign that someone is making marketing material as it outputs higher.

You could take an intake, dyno it on SAE, take another identical intake, dyno it on STD and show everyone the gains, knowing that the number is different but the car is exactly the same.

This happens quite often when people are trying to sell products (or make an argument).

 

[gimmie11s]

I don't agree but whatevs. When trying to compare two different mods or motors or whatever, if they're not using the same correction factor, it erodes the evaluation.

Again, STD smoothing is generally a tell tale sign that someone is making marketing material as it outputs higher.

You could take an intake, dyno it on SAE, take another identical intake, dyno it on STD and show everyone the gains, knowing that the number is different but the car is exactly the same.

This happens quite often when people are trying to sell products (or make an argument).

I agree the STD is giving artificially high numbers, perhaps for marketing, but its not more than 15hp or so at that power level.

Agree.. whatever lol.

Doesn't matter much to me.

 

[Cobra Jet]

@honeybadger

Unless I have missed it in your discussion for your engine rebuild - are you going to do VCT lockout again as you did in 2020/2021:
https://www.mustang6g.com/forums/threads/anyone-run-locked-out-vct.150060/

From an overall perspective when you locked the VCT system before and your driving time with such, were you satisfied with the lockout results? Your last post of the hyperlinked thread, it seemed (then) that you were satisfied, but I wasn't sure how much additional driving time you got in with the lock outs after that last post.

Fast forward to today and not seeing any updates in the lockout thread, I was curious... Would you recommend or defer others from doing it?

 

[honeybadger]

@honeybadger

Unless I have missed it in your discussion for your engine rebuild - are you going to do VCT lockout again as you did in 2020/2021:
https://www.mustang6g.com/forums/threads/anyone-run-locked-out-vct.150060/

From an overall perspective when you locked the VCT system before and your driving time with such, were you satisfied with the lockout results? Your last post of the hyperlinked thread, it seemed (then) that you were satisfied, but I wasn't sure how much additional driving time you got in with the lock outs after that last post.

Fast forward to today and not seeing any updates in the lockout thread, I was curious... Would you recommend or defer others from doing it?

Interesting question looking back from where I am now. Objectively, I'd say it was worse because I lost a good amount of mid range. But given all the issues I had with VCT, I still ended up liking it. I had zero issues last year with the electrical system - compared to 5 the previous year and half. It was also a pretty fun power curve. It was more friendly to getting on throttle hard early as the torque didn't want to break the tires loose as easily. And that engine would rev like no other Coyote-based motor I'd ever used. It was much less vibrate-y up top.

At the end of the day, my advice would be to just swap to a CPC. I plan to bring VCT back with the new engine as I don't think I'll have the same electrical issues I had before with the FPC

 

[Cobra Jet]

Interesting question looking back from where I am now. Objectively, I'd say it was worse because I lost a good amount of mid range. But given all the issues I had with VCT, I still ended up liking it. I had zero issues last year with the electrical system - compared to 5 the previous year and half. It was also a pretty fun power curve. It was more friendly to getting on throttle hard early as the torque didn't want to break the tires loose as easily. And that engine would rev like no other Coyote-based motor I'd ever used. It was much less vibrate-y up top.

At the end of the day, my advice would be to just swap to a CPC. I plan to bring VCT back with the new engine as I don't think I'll have the same electrical issues I had before with the CPC

Thanks for the detailed response, appreciate it and it will possibly help others in the future with similar VCT lock-out questions on existing or eventual motor builds.

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