IMSA DPi Discussion - Page 80

knighty · 3 Jan 2017, 15:59 (Ref:3699937)

Quote:

Originally Posted by TF110

It needs it. The engine is small and a single turbo, the Nissan is twin.

It will be fascinating to see how the engines fair against each other. With the released boost figures, which I believe are a pressure-ratio, not gauge-pressure, as they state "boost ratio", you can work out the effective engine capacities after boost is factored in and compare to the other NA options

Mazda 2.0L x 2.661 = 5.322 Litres

Nissan 3.8L x 1.810 = 6.878 Litres

Cadillac is NA 6.2 Litres

Gibson is NA 4.0 Litres

So to me it does appear the Nissan engine is really worth watching, I believe they will have a noteworthy acceleration advantage, it might not necessarily be seen in top speed, but it should acellerate with gusto, a bit like the diesels used to.

Mike E · 3 Jan 2017, 16:18 (Ref:3699943)

Quote:

Originally Posted by knighty

It will be fascinating to see how the engines fair against each other. With the released boost figures, which I believe are a pressure-ratio, not gauge-pressure, as they state "boost ratio", you can work out the effective engine capacities after boost is factored in and compare to the other NA options

Mazda 2.0L x 2.661 = 5.322 Litres

Nissan 3.8L x 1.810 = 6.878 Litres

Cadillac is NA 6.2 Litres

Gibson is NA 4.0 Litres

So to me it does appear the Nissan engine is really worth watching, I believe they will have a noteworthy acceleration advantage, it might not necessarily be seen in top speed, but it should acellerate with gusto, a bit like the diesels used to.

For what it's worth, the Gibson is 4.2 litres.

http://www.gibsontech.co.uk/gibson-2...unched-le-mans

knighty · 3 Jan 2017, 18:33 (Ref:3699966)

Quote:

Originally Posted by Mike E

For what it's worth, the Gibson is 4.2 litres.

http://www.gibsontech.co.uk/gibson-2...unched-le-mans

Yeah I thought it was 4.2L also, but the IMSA BOP document said 4.0L !!!!

Damian Baldi · 3 Jan 2017, 23:18 (Ref:3700016)

Quote:

Originally Posted by knighty

...I believe are a pressure-ratio, not gauge-pressure, as they state "boost ratio"...

You mean that pressure-ratio includes the atmospheric pressure? So this way, 2.6 bars is in reality 1.6

JHamilton · 4 Jan 2017, 02:57 (Ref:3700043)

Quote:

Originally Posted by canaglia

BTW, GM and amg gt3 engines share same displacements and layout...
amg gt3 got 2x36, cadillac dp got 2x31.9.... gt3 power output should be in a 520-540 range. Well, knowing that GM 6.2 is a road derivated engine and not a bespoke one like the new zytek/gibson, how could get close to 600hp with those restrictors?

That would be hard to answer as there are too many variables. They are both 90° V8s with a similar bore and stroke but that's about it. The GM engine is OHV which makes it difficult to compare.

**PascaLM** · 5 Jan 2017, 16:24 (Ref:3700339)

Quote:

Originally Posted by Damian Baldi

You mean that pressure-ratio includes the atmospheric pressure? So this way, 2.6 bars is in reality 1.6

I don't know if there is a official calculation, but I think that a pressure ratio includes the atmospheric pressure. For atmo engines, it's one, and for turbocharged engines it's 1+pressure over 1000 mbars.

canaglia · 5 Jan 2017, 16:42 (Ref:3700344)

cadillac DP got a restrictors break... with old 2 x 31.9 the engine wasn't even close to 550hp very likely...

Matt · 5 Jan 2017, 16:44 (Ref:3700345)

let them boys cook

canaglia · 5 Jan 2017, 16:47 (Ref:3700346)

anyway, watching old world GT1 bop sheet, maybe I'm wrong... old 2010/2011 GT1 cars had restrictors size in a range of 2 x 29-31... and were in a 570-600hp range.
Guess restrictors size alone doesn't say too much about the real power output...

MaskedRacer · 5 Jan 2017, 18:32 (Ref:3700360)

Quote:

Originally Posted by Matt

let them boys cook

Just this once I hope the DPI/LMP2 cars blow up for the Daytona 24. Would love to see the GTLM winner get a crack at overall win. Do I think that will happen though. No. I feel at least one of the Caddys or the ESM Nissan will make it to the end relatively unscathed.

But as the field clears up on Sunday morning we could get some good extensive green flag hopefully which will really put the DPI cars to the test mechanically.

Matt · 5 Jan 2017, 19:22 (Ref:3700372)

Updated look for the 31 and 70 prototypes.

SoD

PR1

55 Mazda

Another angle of the 70 Mazda

Damian Baldi · 5 Jan 2017, 20:24 (Ref:3700387)

Great pictures. If you look at the Riley's picture, you will notice that they opted for the large and straight front fenders.

Speed-King · 5 Jan 2017, 21:58 (Ref:3700397)

Quote:

Originally Posted by Damian Baldi

If you look at the Riley's picture, you will notice that they opted for the large and straight front fenders.

Oooooph... guess it wouldn't be a Riley if it was good-looking. I'm sure it'll go like hell, though.

Matt · 5 Jan 2017, 22:50 (Ref:3700410)

LM/Low-drag configuration.

TF110 · 5 Jan 2017, 23:32 (Ref:3700422)

I think I like the #70 better than the #55.

JHamilton · 6 Jan 2017, 00:17 (Ref:3700429)

Quote:

Originally Posted by TF110

I think I like the #70 better than the #55.

I kind of agree but I think something is off with the color in that photo.

DistortedSmile · 6 Jan 2017, 00:31 (Ref:3700430)

Quote:

Originally Posted by TF110

I think I like the #70 better than the #55.

Agreed, they should've gone with the darker metallic red they were using previously.

TF110 · 6 Jan 2017, 01:49 (Ref:3700440)

Here's another one from imsa's twitter

hondafan37 · 6 Jan 2017, 02:17 (Ref:3700443)

Quote:

Originally Posted by TF110

Here's another one from imsa's twitter

Fantastic!!!! I like this livery!!!

bentley speed 8 · 6 Jan 2017, 04:20 (Ref:3700453)

And when Riley makes a good looking car, this happens. Well most low drag kits recently don't look too good (see Audi)
The Mazda is stunning, but I don't like that shade of red nor the grey one that much.

AoB Special Stage · 6 Jan 2017, 05:23 (Ref:3700460)

Quote:

Originally Posted by TF110

I think I like the #70 better than the #55.

I prefer the silver, definitely.

FormulaFox · 6 Jan 2017, 11:08 (Ref:3700509)

Quote:

Originally Posted by bentley speed 8

And when Riley makes a good looking car, this happens. Well most low drag kits recently don't look too good (see Audi)
The Mazda is stunning, but I don't like that shade of red nor the grey one that much.

Sadly there are no true "low drag" designs anymore thanks to the needs of adapting to the fender holes. Just "really high drag" and "slightly less really high drag."

RWill2073 · 6 Jan 2017, 12:22 (Ref:3700530)

I like it when cars divide the colors at the slope of the car so it makes clear where the fin starts. Helps to show the shape of the car itself.

And Mazda needs to put some color on the nose to outline the shape of it instead of leaving it black. From a distance, that styling, which is stunning, will not show up, just blend in with the openings underneath the body.

wdave0 · 6 Jan 2017, 14:01 (Ref:3700559)

Quote:

Originally Posted by bentley speed 8

And when Riley makes a good looking car, this happens. Well most low drag kits recently don't look too good (see Audi)
The Mazda is stunning, but I don't like that shade of red nor the grey one that much.

Mazda is really keeping to the spirit of DPi by using actual factory paint colors rather than race only colors - too bad they aren't as attractive.

MoMedic9019 · 6 Jan 2017, 15:01 (Ref:3700581)

Quote:

Originally Posted by wdave0

Mazda is really keeping to the spirit of DPi by using actual factory paint colors rather than race only colors - too bad they aren't as attractive.

Yes. Soul Red is still a color and it photographed beautifully. Problem is, it's one of the hardest colors to paint right which sucks because it's gorgeous.

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