light and strong Audi R8 V8

Models: V10 plus, GT, GT Spyder, V8 Limited Edition, Exclusive Selection Edition, China Edition and LMX
4.2 V8 32v Naturally Aspirated - 414 bhp (2007-2011) - 424 bhp (2012-2014)
5.2 V10 40v Naturally Aspirated - 518 bhp (2012-2014) - 542 bhp (Plus 2012-2014) - 562 bhp (LMX 2012-2014)
5.2 V10 40v Naturally Aspirated - 533 bhp (2015-)
5.2 V10 40v Naturally Aspirated - 602 bhp (Plus 2015-)
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Speedr8
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light and strong Audi R8 V8

Post by Speedr8 » Wed Feb 26, 2014 6:21 pm

hi guys

here of the fastest and lightest R8 V8

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

Image

Tom

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Re: light and strong Audi R8 V8

Post by RIV » Thu Feb 27, 2014 7:46 pm

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

Speedr8
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Re: light and strong Audi R8 V8

Post by Speedr8 » Fri Feb 28, 2014 7:17 am

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

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Tom

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Re: light and strong Audi R8 V8

Post by RIV » Fri Feb 28, 2014 9:11 am

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

S4WON
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Re: light and strong Audi R8 V8

Post by S4WON » Fri Feb 28, 2014 9:25 am

Where you from Tom?

Speedr8
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Re: light and strong Audi R8 V8

Post by Speedr8 » Fri Feb 28, 2014 10:15 am

Boy from Germany :bigwave:

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

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Re: light and strong Audi R8 V8

Post by adsgreen » Fri Feb 28, 2014 11:26 am

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.

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graeme4130
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Re: light and strong Audi R8 V8

Post by graeme4130 » Fri Feb 28, 2014 12:45 pm

Speedr8 wrote:hi guys

here of the fastest and lightest R8 V8

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

Image

Tom
Looks mean, I like the look of that a lot
-------------------------------------------------------
Gone - 11/06 B7 RS4 Avant - black/black (Daily drive & kids taxi)
Gone - 05/13 B8 RS4 Avant - Suzuka grey (Daily drive & kids taxi)
Gone - 01/14 B8 RS5 Coupe - Short term car
Gone - 09/14 B8 RS4 Avant - Misano Red/Ceramics (Daily drive & kids taxi)

Current - 04/18 B9 Rs4 Nardo Grey
ZX10R Race bike - 210bhp and a few skid marks on the seat ;)

Speedr8
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Re: light and strong Audi R8 V8

Post by Speedr8 » Fri Feb 28, 2014 1:16 pm

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 ) :boots:

Image

Tom



adsgreen wrote: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.

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Re: light and strong Audi R8 V8

Post by adsgreen » Fri Feb 28, 2014 1:51 pm

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.

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Re: light and strong Audi R8 V8

Post by adsgreen » Fri Feb 28, 2014 1:56 pm

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.

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Re: light and strong Audi R8 V8

Post by Speedr8 » Fri Feb 28, 2014 2:37 pm

Hi

Engine R8 V8

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Engine RS4 B7 V8

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Tom

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Re: light and strong Audi R8 V8

Post by adsgreen » Fri Feb 28, 2014 3:41 pm

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.

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Re: light and strong Audi R8 V8

Post by Speedr8 » Fri Feb 28, 2014 3:49 pm

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

Tom

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Re: light and strong Audi R8 V8

Post by adsgreen » Fri Feb 28, 2014 4:01 pm

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.

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