light and strong Audi R8 V8

[Speedr8]

hi guys

here of the fastest and lightest R8 V8

3112 IB (1412 kg)
481 HP (475PS)



Tom

[RIV]

Nice car, why is it so strong?? Do you have a roll cage ?

[Speedr8]

Engine optimization > big throttle valves > large air sensor > very big air filters > air intake

Exhaust manifold into compartment shape and modified exhaust system

I did not install a cage for vehicle interior



Tom

[RIV]

I was just joking about the roll cage, your meaning of strong is a little different to ours, car looks great, nice mods

[S4WON]

Where you from Tom?

[Speedr8]

Boy from Germany

I forgot torque > 365 [lbf ft] (495Nm)

During for acceleration 100-200KM/h 7,9s and 100-250 KM/h 17,6s

All data from 2013

Tom

[adsgreen]

15% increase in torque with no valve changes?
Just exhaust and filters?
given that the normal v8 at 317lb/ft is what? 102% efficient you'd need to up that to 117% to get that torque.

[Graeme4130]

hi guys

here of the fastest and lightest R8 V8

3112 IB (1412 kg)
481 HP (475PS)



Tom

Looks mean, I like the look of that a lot

[Speedr8]

a friend with Audi RS4 B7 has 376 [ibf ft] (510 NM)

My new measurement of the performance and torque carried out on 12.04.2014 with the assumption on 530 NM ( 391 Ibf ft )



Tom

15% increase in torque with no valve changes?
Just exhaust and filters?
given that the normal v8 at 317lb/ft is what? 102% efficient you'd need to up that to 117% to get that torque.

[adsgreen]

376? Now 391?
So you are saying that with a new exhaust and intake some mapping tweaks you have basically the same engine output as an r8 5.2 v10 ??

Increasing torque with an n/a car is bloody hard esp when working with an engine that is already pretty well tuned and operating over 100% efficiency. 5% isn't bad and 10% is very good going.
317->376 without any changes to valves just simply isn't at all likely just with an exhaust and intake.
As for 391 that is going to be pure fantasy.

Get it on an independent well known dyno and then maybe I'd be more interested.

[adsgreen]

Here's another perspective - by changing just the exhaust and air intake you've got an engine that like for like can outperform one of or possible the best na engines ever made for a road car - The Ferrari 458.

[Speedr8]

Hi

Engine R8 V8









Engine RS4 B7 V8





Tom

[adsgreen]

Ok - so replacing 4-2-1 with 4-1 manifold... But I've never seen gains that dramatic and certainly not so great across the board. There are a couple exceptions but in general 4-1 loses a little in the mid range to a 4-2-1 (which is why most oem's are 4-2-1) in order to hit higher top end however in those graphs it simply has fantastical gains everywhere.

[Speedr8]

the engine must unzip throttles are and adjust the camshaft timing it. (ECU )

Tom

[adsgreen]

But look at the maths behind it - 376lb/ft from a 4.2 n/a v8 with 12.5 CR would need to have a volumetric efficiency of 121% in order to get the air in it'd need. There are turbo charged cars out there not getting that.
For 397 you are looking at 128%... That's race car territory...
Yes it can be done but you need valves the sizes of dustbin lids and incredibly careful tuning of everything both inside and outside the engine. Aside from slapping on a supercharger there is no way you can go from 102% VE to high 120's% without cracking open the engine and binning half the stuff you find.

For comparison the 458 is 119% VE which is frankly astounding for a road car.