Parity Review Has Been Called

[V8 Fireworks]

Originally Posted by bluesport

Chaz didn't have any tyre issues at Bathurst in 2021.

Chaz Mostert: "...but they’re so different, the cars out there.”
https://www.speedcafe.com/2023/07/21...ngine-changes/

Is Chaz implying there is a significant difference between the two models, in contradiction of the "best parity ever" claimed by Jamie Whincup?

[Tourer]

Originally Posted by V8 Fireworks

Chaz Mostert: "...but they’re so different, the cars out there.”
https://www.speedcafe.com/2023/07/21...ngine-changes/

Is Chaz implying there is a significant difference between the two models, in contradiction of the "best parity ever" claimed by Jamie Whincup?

He could well be (although he could be referring to the different engine setups there were evaluating at the test). If he is implying difference between Camaro and Mustang, as has been said by a few before (including me) there is a fair element of lobbying in comments made by teams / drivers using each make of car. As a result, a fair few large grains of salt need to be taken with comments made publicly about there being a big problem or from the other side, there being no problem.

Just how it goes - has been the same for decades when there's parity considerations underway.

[bluesport]

The Chaz report.

https://www.speedcafe.com/2023/07/21...ngine-changes/

[Mixer]

Wow imagine finding an improvement after ignoring sensible advice in the first place.

Who knew.

[bluesport]

Originally Posted by Mixer

Wow imagine finding an improvement after ignoring sensible advice in the first place.

Who knew.

A smaller throttle body allows for a smoother delivery of power, who gave this advice previously?

[Osborne Reynolds]

Originally Posted by bluesport

A smaller throttle body allows for a smoother delivery of power, who gave this advice previously?

Craig did. Ford USA did not.

Any half-decent uni student in Formula SAE could explain it.

A very ROUGH way of estimating the effectiveness of the CONTROL system hardware (not software) in this case is:

Throttle Diameter ^2 / Restrictor Diameter ^2

Anything over 2 is a handful
Anything over 2.4 is a very difficult
Anything over 2.8 is a near impossible

This rule will works pretty well across engine sizes provided:
Natural aspiration
The restrictor is the primary restrictive element (ie Ports / valves / plenums are not introducing excessive 'restriction')
Flows are well developed
Excessive head loss on expansion isn't occurring

You can 'pedal map' your heart out, but if the hardware is fundamentally sized incorrectly, you're gonna face real difficulties.

I'd suggest that both engines could benefit from a 70mm-75mm.

[bluesport]

Originally Posted by Osborne Reynolds

Craig did. Ford USA did not.

Any half-decent uni student in Formula SAE could explain it.

A very ROUGH way of estimating the effectiveness of the CONTROL system hardware (not software) in this case is:

Throttle Diameter ^2 / Restrictor Diameter ^2

Anything over 2 is a handful
Anything over 2.4 is a very difficult
Anything over 2.8 is a near impossible

This rule will works pretty well across engine sizes provided:
Natural aspiration
The restrictor is the primary restrictive element (ie Ports / valves / plenums are not introducing excessive 'restriction')
Flows are well developed
Excessive head loss on expansion isn't occurring

You can 'pedal map' your heart out, but if the hardware is fundamentally sized incorrectly, you're gonna face real difficulties.

I'd suggest that both engines could benefit from a 70mm-75mm.

Thanks for that, good to have someone that knows what they are talking about enlighten us on the issue.

[Osborne Reynolds]

Thanks Bluesport.

This is a ROUGH measure.. a 'start point'... or 'back of the envelope calculation'

The restrictor on these new v8s is very short (so it acts like a smaller restrictor). So, in this case, with 2.5 ratio, it's probably acting more like a 2.6-2.7 ratio.

You could also see the evidence of poorly sized throttle in a fuel map.. you'll see a characteristic jump at low load (small throttle angle), because there is a jump in mass flow rate of air being taken in.... which makes a jump in torque / power output.

If you persist with a large throttle, and try and 'iron out the problem' and 'create more feel' by using 'pedal mapping'.. you will reach a point where the control system wont function well. Every aspect of the digital control system uses interpolation, combined with a high rate of update. And for this to work, you can't have large jumps across the tables from which you are attempting to interpolate.... that's a reason... again the root cause is poorly sized hardware

You could also try to improve the situation by adding more load points... or by using MAP for load point... but there is a limit to how effective this will be.

Another complication is regarding plenum volume... as the plenum volume increases, there is a 'lag' in mass flow rate response when you 'blip' the throttle. My limited (and ancient) experience with Motec was that there exists correction factors for rate of acceleration, but nothing for the 'lag' produced by small restrictor / large plenum. (god help anyone trying to make this work without using a MAP sensor)... The best way to avoid a whole lot of complication is to keep plenum volumes as small as possible without introducing head loss from tight bends

[Osborne Reynolds]

I honestly hope having 80mm throttles on both engines will result in tighter and fairer racing. There is a heap of difficulty in trying to create #parity for two fundamentally different engines.

It's pretty easy to throw mud, but that helps nobody. And making the best if this situation is VERY difficult for all the stakeholders. And to be fair, considering the complexity of the project, there hasn't been a lot of human and financial resources available.

I once had a mentor describe complex engineering projects as being like a combination of giving birth and peeling an onion. 'Giving birth' because it always takes about 9 months until you breath a sigh of relief, to only then find out the hard work has just begun. 'Peeling an onion' because after you remove a layer and shed tears, you find a seemingly endless number of layers below.


Best of luck to all the teams and thanks to all the engineers in this awesome category.

[bluesport]

Throttle body change approved.

https://www.v8sleuth.com.au/latest-f...ed-for-sydney/

[GTRMagic]

What will the next ‘reason’ for disparity be after Eastern Creek?

[Kingair]

Let me see night racing, the Ford Mustang headlights when they blip them from low beam to high beam will cause a loss of power to the engine!

Larko will have a technical explanation for this on the whiteboard, Skaife will add his two cents worth.

Race 3 for the weekend will see all Camaro’s staring in pit lane, with drivers blindfolded and given hand signals by respective pit crew when to start the race on lap 2, of the five lap race.

[V8 Fireworks]

Originally Posted by GTRMagic

What will the next ‘reason’ for disparity be after Eastern Creek?

Probably trying to figure out why the revs are slower to drop on the Coyote, which must be affecting engine braking.

If that is it just the nature of the stroker 5.4L crank and how many counterweights it needs to have, then adding more heavily weighted flywheels to the LS engines would seem to be the solution.

The Chevrolets are still running lightweight 4kg flywheels it seems according to Bradley Jones -- so weighting that up to 12-20kg (with the lead slugs added around the perimeter of the flywheel) might do to the trick to match the inertia of the Ford engines?

[V8 Fireworks]

In any case:

• 5.2L^ Coyote block has a 94mm (3.700") bore
• Stroker 98.4mm (3.875") Coyote cranks are available (like this Brian Crower), an increase from the stock 93mm stroke on the 5.2L

This gives the 5.4L capacity if I understand correctly?



^ (presumably Herrod's are using iron sleeves instead of the spray-on plasma arc liners which are, presumably, not suited for multiple rebuilds?)


It seems some Ford enthusiasts are annoyed that the taller factory 5.4L block from the BA Falcon days is no longer available. That had a deck height of 256.0 mm (10.079") compared to 227.0 mm (8.937") on the 4.6/5.0/5.2L.

Ford Racing should be investing in more engine related options and custom parts for guys like us. taller blocks to build a 6.0L coyote for example

https://www.mustang6g.com/forums/thr...131732/page-14

It seems some tuners build 5.7L Coyotes using the Coyote block & a 4.1" stroker crank, but the rod-to-stroke length ratio is presumably even more horrible than on the 5.4L.


Stateside engine builders also seem to not be keen on the plasma arc liners of the 5.2L block:

There seems to be a consensus among the builders I have spoken to that it would be best to sleeve the block if building a stroker due to concerns the PTWA liner won’t take the additional stress .

[bluesport]

Originally Posted by GTRMagic

What will the next ‘reason’ for disparity be after Eastern Creek?

The smaller throttlebody may make the mustang slower out of the corners, that's probably why Ford opted for the larger one initially?

[Ares]

You would think a smaller throttle body would be more responsive, more airspeed. Better low to mid range and a little less top end at full revs maybe than the bigger throttle body? Depending how they were specked in the beginning.

Boy I don't like the sound of a 20kg flywheel in my race car thank you very much. Who is going to supply that? Farmall?

[bluesport]

Originally Posted by Ares

You would think a smaller throttle body would be more responsive, more airspeed. Better low to mid range and a little less top end at full revs maybe than the bigger throttle body? Depending how they were specked in the beginning.

Yeah, more responsive out of the corners and the trade-off could be top end speed.......we'll have a better idea come sunday night.

[V8 Fireworks]

Originally Posted by Ares

Boy I don't like the sound of a 20kg flywheel in my race car thank you very much. Who is going to supply that? Farmall?

What ever is needed to make it equivalent in inertia to the stroker Coyote.

[Tourer]

Originally Posted by V8 Fireworks

What ever is needed to make it equivalent in inertia to the stroker Coyote.

They might go down that kind of path at some stage (results from transient dyno testing may assist once received) but 20kgs is a massive amount - can't see anything like that being needed, given how close in performance the cars / engines are.

Might be that nothing further is needed after latest aero and engine tweaks - time will tell.

[bluesport]

Originally Posted by Tourer

They might go down that kind of path at some stage (results from transient dyno testing may assist once received) but 20kgs is a massive amount - can't see anything like that being needed, given how close in performance the cars / engines are.

Might be that nothing further is needed after latest aero and engine tweaks - time will tell.

When will the transient dyno testing take place?

[Tourer]

Originally Posted by bluesport

When will the transient dyno testing take place?

Don’t know - can’t recall any specific timeframe from when they said they’d be doing it.

[V8 Fireworks]

De Pasquale doesn't seem convinced by the specification changes:

Not [expecting] much. I think it will help in some certain situations, but in terms of raw performance and lap time, I can’t expect too much happening.

The driveability at certain times has been not that great, and you see that at certain times.

“But, in terms of performance and keeping up with the other cars, driveability’s not the biggest issue we have.

[The biggest issue is] keeping the rear of the car under control, which I think everyone’s aware of. Driveability is a good thing, obviously when you are up against the wet conditions, tyre’s completely gone… All that comes into question.

But on a brand-new tyre, when you’re hustling, there’s not much not much performance gain there.

https://www.speedcafe.com/2023/07/29...al-difference/

I'm not sure if De Pasquale has driven the other body style so that he can compare whether it's the same or not, but it's a worry!

Why wasn't the decision taken to mandate 32-valve DOHC 5.0L engines, with the Coyote as the benchmark, and have KRE (re)develop the Northstar 32-valve V8 (the GM engine most similar to the small Ford modular) into a racing engine? The GM Northstar engine was already used in Grand Am racing previously, after all.

It seems quite unreasonable to disadvantage Ford, just because the Northstar V8 wasn't well received enough to earn a permanent place in the GM lineup and completely replace pushrod Chevrolet small block production, unlike Ford's definitive modular engine.

At least one of the two brands had a grasp on mass manufacturing 32-valve DOHC V8 engines, with all of the significant advantages of the 32-valve quad cam VVT layout, after all! It seems illogical to disadvantage Ford just because GM couldn't make that work.

[Tourer]

Originally Posted by V8 Fireworks

Why wasn't the decision taken to mandate 32-valve DOHC 5.0L engines, with the Coyote as the benchmark

According to Roland Dane, the original intention was to have a control engine, using the Coyote - if what he says is completely accurate, then plans for engine development and direction were changed fairly late in the day.

Originally Posted by V8 Fireworks

At least one of the two brands had a grasp on mass manufacturing 32-valve DOHC V8 engines, with all of the significant advantages of the 32-valve quad cam VVT layout, after all! It seems illogical to disadvantage Ford just because GM couldn't make that work.

Cuts both ways - not convinced that a 32-valve DOHC engine IS the way to go in a racing series with a 7,500 rpm rev limit. Pushrod engines have a significant benefit in CoG and most likely weight overall with the benefits of 4 valve DOHC only really becoming strong at higher rpm. Both Ford & Holden had working pushrod engines that served the category well for many years. In some respects, would have made sense to continue with that design architecture.

One of the characteristics of some 4 valve engine is that throttle modulation at lower rpm can be more like an on/off switch in racing applications - nothing, nothing, then whoa - the power's all there. Sounds quite similar to the characteristics that the Ford teams have been trying to deal with. The differences between the cars and the engines are quite small clearly, as performance remains close but it could be that it is taking some time to get what is new engine architecture for the teams involved bedded down and overcoming the inherent disadvantages of the 4 valve DOHC in a rev-limited racing environment.

[GTRMagic]

Of interest… is the Coyote in the MARC car, in some TA2s and those in S5000 afflicted by this ‘driveability’ complaint?

What size throttle body is in use in those applications?

[V8 Fireworks]

Originally Posted by Tourer

Cuts both ways - not convinced that a 32-valve DOHC engine IS the way to go in a racing series with a 7,500 rpm rev limit.

Yep, that should be at least 8,500 if not 9,500rpm. They would sound better too!

The point is for technical parity and perfectly equal performance in every way, in any case. 2 x 32-valve engines would make that easier.

Originally Posted by Tourer

According to Roland Dane, the original intention was to have a control engine, using the Coyote

Which makes no sense. The only logical control engine would be a neutral engine like the Nissan VK56. Why wasn't Todd Kelly contracted to provide a fleet of control engines?

How can you have a control engine that isn't neutral?!

For reference, Hartley Engines supplies 4.0L 10,000rpm Nissan VK engines for dirt track racing in NZ... and they sound glorious!