I'm working on a portfolio piece at the moment, which involves an engine and a fast car. Nothing insane, just about Gallardo territory. I've been thinking of specifying a Flat-8 engine for it, for the sake of being a little different.
Now, what I want to know, is is a 3 litre twin turbo plausible for a mid range supercar? The current Gallardo is 5 litre N/A V10, but the MP4-12C is only a 3.8 twin turbo. Would it be plausible for a 3-litre 8 cylinder, twin turbo engine to compete with the likes of the Gallardo with current technology?
That's really all I need to know. Thanks for any input.
Just a note; this is purely a digital portfolio piece, not a real-world mod I want to do :P I just want to make sure I don't make myself look a fool for speccing a completely ludicrous engine for the concept.
If a 3-litre TT Flat-8 won't have the balls to be on par with the current Gallardo, then I'll have to rethink the drivetrain.
[EDIT] Also, if anyone has any references of contemporary flat engines that would be helpful as well. Aside from the Porsche flat 6s, I can't think of any other high-performance boxers on the market at the moment? I need to see some overall layout and detail shots of the drivetrain and packaging. I guess as far as the gearbox and rear suspension is concerned it wont be much different than a V engine, but references are always helpful.
Here's a layman's opinion:
You can get the Gallardo kind of power from a 3 litre engine. F1 cars have around 3 litres I think and have even more power if I'm not mistaken.
However...
I wouldn't buy a 3l supercar just because I would look like a joke between other supercar owners.
Yes. If I had that kind of money, I wouldn't go below 5 litres and a V8. I like big burbling engines. The high-revving screamers don't do much to me. Not saying they are worse, it's just a matter of taste and I like big engines. Macho bullshit.
I'm a fan of the burbly ones too, but I'm trying keep the environmental/fuel economy side in mind without going with electric technologies. (I know I know, it's a supercar, that's not important, blah blah blah ) The main reason is I like the name "30-8" for the car, and I want to have the numbers mean something. "50-8" just doesn't have the same ring to it.
Any idea on the displacement of those V8s? The engine in the 908 is the only significant automotive reference to a flat-8 I've been able to find.
Next stupid question: Do exhaust pipes need to be circular in cross-section for any specific reasons? (Handling of pressure, etc) Are there any adverse affects of flattening the pipes out at all?
I'm not a complete numpty, I've just never really looked into this stuff before.
Tbh it sounds like want to decide the type of engine based on style instead of engineering criteria. Form over function so to speak.
Of course the biggest thing you need to remember is where the engine comes and does it matter. Flat 6 litre v16 engine sounds totally awesome concept for example but to get one you need to make your own. Same with flat 8 cyl engine. Hard to get one of those anywhere. If you are prepared to accept more conventional solutions you can always pick a v8 with the specs you want from some engine builder or manufacturer. Add couple turbos on it and call it maggot speziale.
But of course if the engine itself needs to be the differentiating factor inside the car that produces the wow factor then a v8 is probably not what you want. I don't think are any major engineering restrictions to get desired amount of hp from any engine configuration. I think your only limitations are on the production side.
Flattening the exhaust pipes will just make them heavier because you want certain cross-section area and for elliptic shaped exhausts you need more steel. Basically if you flatten a circle the area inside the ellipse is smaller than the circle so you need bigger circle to begin with. Of course flattening the exhausts creates problems elsewhere as well. Routing them through the car can be a bit troublesome because their dimensions change depending what direction you turn them.
In a matter of speaking, yes; I want to opt for a 3 litre so the name that I like makes sense. The source of the engine doesn't matter; as this is purely specs in a digital concept. I just want those specs to be believable. No real engineering going to be happening here. I'd opted for a flat configuration for the beneficial lower centre of gravity, smooth running and because it's uncommon; the only real significant automotive Flat-8 is from the 908, and flat configurations in general are not that widespread. It's something different, which is why it's been chosen.
The practicalities are not too too important since this is just specs and a roughed in visual to accompany it. So long as the numbers make sense that's all I need.
Thanks for the explanation. I'll stick with the cylindrical pipes, then, on account of weight-savings (again, not a big impact, as you might not see them at all anyways, we'll see how in depth I go with detail in the engine bay. I might only do the top of the engine in detail as that's all you'll see).
F1 cars have got ~900-1000 HP from a 1.5 turbo engine, however reliability is always a concern (i.e. they would last a single race). Production wise, all I can think of was the FQ4000 - but this *had* to be run on 99RON fuel and had a service interval every 7,500 miles.
However, with big enough turbos it's possible to get pretty much any power from any engine (reliability aside).
Yes, but plausibility for a street-going car? Reliability is more important for high performance cars now than it used to be. This is intended to be a road-going vehicle, not just a track car. I just want to be sure that the spec is within the realms of the plausible before I go spouting it
its perfectly plausible, and considering the trend of downsizing I guess we will see engine sizes like that in the near future.
A flat-8 is not very efficient when it comes to engine bay space I guess, it needs a relativ big base area, but may keep the engine bay short in height.
This is also my concern, I have a similar design project (but kitcar based on a Impreza drive train) and a boxer engine gets very wide. However make the car a bit longer and you get very good cog.
A flat eight with dual superchargers mounted with water based intercooler would be a serious brick of power. The benefit of that setup would be avoidance of long turbo lag inducing pipes.
you could reduce intake piping if you keep the turbos ontop of the cylinder banks and use air-to-water intercooler. I dunno how much crossover pipes are needed or if one could keep both cylinder banks completely independent
its not only power, but its the simple fact that in a 500 hp subaru its rough but able, in a 500 hp lambroghini its smooth, comfortable even!
flat 8 would be a chugger of a lump... more at home in a toyota liteace van where space is everything then a supercar...
why not mate 2 cosmo lumps together ?? ( you know, x2 3 rotar engines... ported and polished... no need for turbos... ) highly unpractical but feck me... it'd do some speed before you blew the seals.
Perhaps too late and not so relevant but lots of what would now be considered unusual engine configurations were run back in the 50s and earlier. Finding reliable information on such engines can be hard though.
Thanks for any input.
) The main reason is I like the name "30-8" for the car, and I want to have the numbers mean something. "50-8" just doesn't have the same ring to it. 
