Ford GT at Daytona

https://www.youtube.com/watch?v=A-deXDPzYRU

Didn't see this posted, yet.

But it sounds odd... like the engine is crawling (relatively speaking). Looks fast.

Are they rev limited or airflow limited? If so, then they may be benefiting from more boost and less RPM.

I've heard so much whining about it not having a V-8, which I don't really care about as long as it functions on a par with it's killer looks. But the exhaust note, while not bad, just isn't compelling. You'd think that the braniacs at Ford could get it to sing like Pavarotti if they really tried.?

In reply to Kreb:

Since that is the engine that my team was part of to put into production 5 years ago, I'm not complaining about the lack of V8. But as a V6, it sounds odd. And it sounds different than the ones I hear across the street (and you can tell when they are simulating Daytona.

Tuna- you may be right- especially as the lower RPM at the same airflow results in more power, thanks to lower spinning friction. But I'm not sure if it's a fuel flow or air flow restrictor (the FIA have been talking about going to fuel flow for a few years- which I think makes more sense).

I don't give a damn what it sounds like. It needs to win. And who can be mad at it when it looks that good.

I've heard about situations where the rules actually encourage running lower rpm and packing as much air as you can into it. Something about overrunning or overboosting the turbo. Makes sense to me. I just wish I knew more specifics.

Kreb wrote: I've heard so much whining about it not having a V-8, which I don't really care about as long as it functions on a par with it's killer looks.

this^ it could be a steam powered rotary for all i care, i just want it to go fast

I am V8 to the core, but I just want it to win, the symmetry is perfect.

That is an amazing looking car. Something about it reminds me of the F40.

Kreb wrote: I've heard so much whining about it not having a V-8, which I don't really care about as long as it functions on a par with it's killer looks. But the exhaust note, while not bad, just isn't compelling. You'd think that the braniacs at Ford could get it to sing like Pavarotti if they really tried.?

This is my thinking as well, Ford could have made it sound better but didn't. I can only guess that it takes all kinds and there are folks out there who like that exhaust note. Possibly Ford wanted it to be truly distinctive.

Looks so good though, I can forgive the sound.

alfadriver wrote: Tuna- you may be right- especially as the lower RPM at the same airflow results in more power, thanks to lower spinning friction.

I'll defer to your experience on this, but it was always my assumption that the rings contributed the vast majority of engine friction and that ring friction was relative to cylinder pressure, not engine speed.

How far off base is this assumption, or is there something going on with cylinder pressure management (tuning for similar peak pressure, just a longer pressure curve) that I'm not takign into consideration?

In reply to Knurled:

You are missing the bottom end aero component. Which is the biggest component above 2500rpm, generally.

All that air that moves in and out above the piston moves under it, too- but instead of in and out- it goes from cylinder to cylinder. One of the big advantages to a dry sump is that you car run the crank in a vacuum (slightly) which really helps in aero friction. That part is very non linear- goes with the square of engine speed. (it's not counted in pumping losses)

I'd have to look, but I think in many engines, the work to open and close the valves is greater than the rings.

alfadriver wrote: All that air that moves in and out above the piston moves under it, too- but instead of in and out- it goes from cylinder to cylinder. One of the big advantages to a dry sump is that you car run the crank in a vacuum (slightly) which really helps in aero friction. That part is very non linear- goes with the square of engine speed. (it's not counted in pumping losses)

Wow... never really thought of that. Thanks!

It's not being driven hard at all in that video. Compare to this:

https://www.youtube.com/embed/x95ViD9AUsA

It sounds very racerly at full song. What's odd is that low RPM gurgle, almost like the engine is being lugged.

One good thing for this powertrain- it's been racing in DP for two seasons now- makes good power and is reliable. So it's more up to the car.

Kreb wrote: It sounds very racerly at full song. What's odd is that low RPM gurgle, almost like the engine is being lugged.

I'm guessing it's some sort of boost management or traction control tech. Assuming those are allowed in the GTE class. Does anybody else in that class even use any type of forced induction?

Kreb wrote: It sounds very racerly at full song. What's odd is that low RPM gurgle, almost like the engine is being lugged.

Makes me wonder if there is some sort of anti-lag solution being employed?

Just as an aside, I think that it's really bitching that Detroit was able to come up with two of the most visually exciting supercars in the world. (GT and the Vette). Most Euro supercars look overwrought by comparison, like beautiful women who didn't know when to stop when applying garish makeup and clothes.

Kreb wrote: Just as an aside, I think that it's really bitching that Detroit was able to come up with two of the most visually exciting supercars in the world. (GT and the Vette). Most Euro supercars look overwrought by comparison, like beautiful women who didn't know when to stop when applying garish makeup and clothes.

And outperform their counterparts in pretty much every metric.

alfadriver wrote: One good thing for this powertrain- it's been racing in DP for two seasons now- makes good power and is reliable. So it's more up to the car.

This is kind of huge for the program. To have a new car with a reliable well known powerplant makes the job so much easier.

In reply to alfadriver:

Yes, I completely forgot about the crankcase. Well aware of the implications of crankcase issues, I just didn't think that they were THAT important relative to the other losses.

Heck, GM had to do a bunch of work to the crankcase on the LS engines to get air to move through them, given that they bothered to make a bottom end with more metal in it than they used to use in an entire block. And Subaru has a habit of adding more crankcase breathing on the 2.5s when turbocharged...

In reply to Knurled:

My personal story about crank flow- remember the Aston Martin V12? The first one made something like 420 hp.

But it had massive low end breathing problem that when fixed, the engine gained 30hp just with some simple alterations in the block and crank throws to aid in breathing. And that's the engine in the 2001 Vanquish. Almost identical engines, most of the difference was the crank and block layout.

We did both of those engines in Advanced Powertrain.

Piston speed used to be noted with the long stroke engines of the day.

With todays materials and machining along with generally shorter strokes it is no longer noted as being critical.

Exhaust sound. I'm sure the builders of a RACE car are not too concerned how it sounds.

Exhaust sound: Au Contraire. They want people to buy these things. They should sound sexy. To use the relationship analogy, would you prefer your supermodel with a squeaky voice or a smooth, sultry tone?