GT350 vs. Z/28

[thePill]

I think there's a reason BMWs S65 (&P65 FPC race motors), McLarens 12C/650S/675LT and Ferraris 458/488 have much shorter strokes and rev higher than 8,000rpm... Its
not just piston weight, especially since some of the mentioned motors have similar 92-94mm bores.

Not many FPC V8's approach 5 liters. At this point, a reduction in anything would increase RPM. Although, maybe not output...

Having "similar bores" and a 92-94mm spread isn't being similar. There is a large displacement difference between 92 and 94mm. Any reduction in any rotating mass will reduce vibration. Vibration being one of the major limiting factors... Some of that counter balance can come out as well.

The Boss 302 had already exceeded max output levels, no need for 520+hp.

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[Stuntman]

Not many FPC V8's approach 5 liters. At this point, a reduction in anything would increase RPM. Although, maybe not output...

Having "similar bores" and a 92-94mm spread isn't being similar. There is a large displacement difference between 92 and 94mm. Any reduction in any rotating mass will reduce vibration. Vibration being one of the major limiting factors... Some of that counter balance can come out as well.

The Boss 302 had already exceeded max output levels, no need for 520+hp.

Are you suggesting that the bore size is more crucial than stroke in reducing rotational mass, vibration, and allowing for more RPMs?

Porsche GT3 RS 4.0 (4.0L F-6): 8,500rpm - 102.7mm x 80.4mm (bore x stroke)
BMW S65 M3 (4.0L V8): 8,400rpm - 92.0mm x 75.2mm
McLaren 12C/650S (3.8L FPC V8): 8,500rpm - 93.0mm x 69.9mm
Ferrari 458 (4.5L FPC V8): 9,000rpm - 94.0mm x 81.0mm


There seems to be a pattern there. All these engines have over a 10mm shorter stroke than the Coyote/Voodoo's 92.7mm stroke. The 6cyl Porsche is there for a RPM vs. bore/stroke comparison.

 

[Grimace427]

I still don't understand why there is a huge price difference between a base 30k gt and a base 52.5k gt350? If you look at assumed specs of the gt350, the 65 hp horsepower difference doesn't make sense to charge more than 20k! If you look at ecoboost to gt which is like 4k difference in cost but 125hp difference in horsepower! To get a gt350 you ll be paying $346 extra per hp! Something is not right here! If a base ss camaro comes out with the lt1 450hp 450 lbft, for a little over 30k then it might turn out to be the best bang for your buck and then followed by the gt as well!

We don't have an official base price for the GT350 yet.

 

[thePill]

Are you suggesting that the bore size is more crucial than stroke in reducing rotational mass, vibration, and allowing for more RPMs?

Porsche GT3 RS 4.0 (4.0L F-6): 8,500rpm - 102.7mm x 80.4mm (bore x stroke)
BMW S65 M3 (4.0L V8): 8,400rpm - 92.0mm x 75.2mm
McLaren 12C/650S (3.8L FPC V8): 8,500rpm - 93.0mm x 69.9mm
Ferrari 458 (4.5L FPC V8): 9,000rpm - 94.0mm x 81.0mm


There seems to be a pattern there. All these engines have over a 10mm shorter stroke than the Coyote/Voodoo's 92.7mm stroke. The 6cyl Porsche is there for a RPM vs. bore/stroke comparison.

I think you are making this into something it's not.

If the 5.2's bore is reduced, it will in fact free up rotational mass. That is the only point here, nothing to do with stroke.

This engine in general has a larger bore. The key here is to be still over 5 liters and still have a near square bore/stroke.

Decreasing the Voodoo's stroke would cost significantly more since further R&D would need done on the Coyote. Far more than a simple bore increase which they have done.

If Ford backs the Voodoo down to a 92.7x92.7mm, it leaves the displacement at exactly 5.005. That small reduction in piston mass would probably translate to an RPM increase just as long as fuel delivery isn't an issue.

A good reason to increase the Coyotes bore is, as was mentioned above, to open up the valves and eliminate shrouding. If I was Ford and had PTWA but DI wasn't going to be ready until the Camaro, I'd increase the bore to help flow. The stock Yote can't spin to 8200 or make much stock power passed 7200. In order for the current Voodoo to feed 8200rpm, it needed more fuel (gas and air). Right now, Direct Injection is in the deck.

All the engines and manufacturers above couldn't build a square FPC engine let alone V8. Reducing the stroke to that level benefits rod:stroke but, it isn't square and it isn't over 5 liters. Nobody but Ford has done this...

 

[garagelogic]

Well i think people have really high expectations on the gt350 and we ll wait and see what it is really offering! I m not a die hard Ford, GM or Dodge fan! I am an honest consumer who wants the best for the money! I currently love my stang even though the gears grind the transmission makes a thud noise and other stuff also i m sure the gt350 will have those problems as well and paying that much money on that car doesn't make sense to me!

Well then, by all means you should not buy one. There will be plenty who will.

And help us out here, best WHAT for your money? Best track performance, best strip performance, best ride quality, best ergonomics, best features? What you judge as best is determined by what the individual is looking for from the vehicle they choose.

 

[Stuntman]

I think you are making this into something it's not.

If the 5.2's bore is reduced, it will in fact free up rotational mass. That is the only point here, nothing to do with stroke.

This engine in general has a larger bore. The key here is to be still over 5 liters and still have a near square bore/stroke.

Decreasing the Voodoo's stroke would cost significantly more since further R&D would need done on the Coyote. Far more than a simple bore increase which they have done.

If Ford backs the Voodoo down to a 92.7x92.7mm, it leaves the displacement at exactly 5.005. That small reduction in piston mass would probably translate to an RPM increase just as long as fuel delivery isn't an issue.

A good reason to increase the Coyotes bore is, as was mentioned above, to open up the valves and eliminate shrouding. If I was Ford and had PTWA but DI wasn't going to be ready until the Camaro, I'd increase the bore to help flow. The stock Yote can't spin to 8200 or make much stock power passed 7200. In order for the current Voodoo to feed 8200rpm, it needed more fuel (gas and air). Right now, Direct Injection is in the deck.

All the engines and manufacturers above couldn't build a square FPC engine let alone V8. Reducing the stroke to that level benefits rod:stroke but, it isn't square and it isn't over 5 liters. Nobody but Ford has done this...

Interesting. Ferraris 488 GTB went down on bore and up on stroke (86.5mm x 83.0mm) for a relatively square FPC V8. And they lost ~1,000rpm from the redline of the 458.

 

[Erik427]

A 4 valve shouldn't have major shrouding issues. Yes, it will be tighter than the 94mm bore but, it should be on par with the Coyote. 2mm is the thickness of two dimes, I'm sure the heads can accommodate.

The rod to stroke ratio is a concern too.

 

[thePill]

The rod to stroke ratio is a concern too.

Oh yes, but it is difficult to have all three at this point. Granted, the Coyotes isn't bad to begin with.

 

[thePill]

Interesting. Ferraris 488 GTB went down on bore and up on stroke (86.5mm x 83.0mm) for a relatively square FPC V8. And they lost ~1,000rpm from the redline of the 458.

An increased stroke will cause that... In this case, we only need to reduce the bore and keep the stroke. If all goes well, once DI is fitted, fuel delivery won't be an issue at 8000+RPM.

Either way, the GT350's V8 will need some detuning or restrictions once it starts racing.

 

[Stuntman]

An increased stroke will cause that... In this case, we only need to reduce the bore and keep the stroke. If all goes well, once DI is fitted, fuel delivery won't be an issue at 8000+RPM.

Either way, the GT350's V8 will need some detuning or restrictions once it starts racing.

But the Coyote/Voodoo already have a longer stroke... I think the point that was made before was a shorter stroke would allow more RPMs a lot easier than a reduction in bore.

Are you saying the Voodoo can't rev above 8K without DI?

 

[Erik427]

An increased stroke will cause that... In this case, we only need to reduce the bore and keep the stroke. If all goes well, once DI is fitted, fuel delivery won't be an issue at 8000+RPM.

Either way, the GT350's V8 will need some detuning or restrictions once it starts racing.

You can count on that. Maybe chevy will be granted the 454 LSX?

 

[Trackaholic]

An increased stroke will cause that... In this case, we only need to reduce the bore and keep the stroke. If all goes well, once DI is fitted, fuel delivery won't be an issue at 8000+RPM.

Either way, the GT350's V8 will need some detuning or restrictions once it starts racing.

If you are starting with the Voodoo as we speculate it is (94 x 92.7), and you want to lower displacement and increase RPM, then the most effective way to do it is to lower the stroke not the bore.

Reducing bore does gain some in terms of mass reduction, but does nothing for piston speeds or accelerations. Reducing bore also reduces potential valve area (not sure if Voodoo is using larger valves or not, but more valve area is one of the key advantages to having a larger bore).

Reducing stroke will reduce piston speeds and accelerations, as well as allow a shorter deck height (or, if you maintain the deck height, it will allow for an improved rod:stroke ratio). And it does this without affecting the valve area and breathing capability of the engine.

If Ford wanted a smaller, higher revving engine, then the best way to do it would be to reduce stroke first.

-T

 

[Sasuketr]

Well the, by all means you should not buy one. There will be plenty who will.

And help us out here, best WHAT for your money? Best track performance, best strip performance, best ride quality, best ergonomics, best features? What you judge as best is determined by what the individual is looking for from the vehicle they choose.

Best of everything a complete package like the GTPP is delivering now. Do you really think if you don't pay the premium interior upgrades or other stuff just like the GT has, Ford is going to give you all for free? Add 4 grand on top of the base gt350 price which is 52.5 grand maybe even more. What i m saying is the base price should have been a lot smaller.

 

[Sasuketr]

For the new z28 size prediction i am attaching this picture here. Enjoy.

 

[Fox5.0]

For the new z28 size prediction i am attaching this picture here. Enjoy.

I thought camaro's felt small inside to begin with... if it shrinks that much I think only women and small men will fit in it:headbonk:

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