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Hi,

Yesterday we completed another stage of our cars development as per the dyno sheet below.

The car is now equiped with : Full HKS GT600 kit ( with cats ), Sumo Cobb mapping, HKS Ti Exhaust.



The power figure shown is at the wheels ( not flywheel ) and was done using our in house dyno ( SuperFlow ).

Of course we are not sure what the real flywheel figure is however when time permits in future we will be hooking the engine up to our in house engine dyno whereby we will get an accurate idea. If you wanted to guess, I suppose 20% losses would make it around 680bhp, 25% = 720 but thats not fact until we run the engine dyno side so we'll stick with the wheel figure for now :)

Whilst the engine tuning has been taking place we have started to complete some of our inhouse engineered R35 parts which we will be available in the New Year.

Feel free to ask any questions :)
 

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Discussion Starter #4
Losses

I think you'll find that the tranny losses on the R35 have been measured at only 15% 'ish. Still, 620bhp at the fly is good! :thumbsup:
Hi,

Thats why I was specific to make a point of not using them as fact.

Please tell me, who has confirmed them to be 15%, where can I find this factual information, link?

Thanks
 

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I've watched just about every dino pull video there is on YouTube, and the one I'm referring to is the US auto magazine investigation into the true power output of a standard GT-R. They used a dyno with the "run-down" function, to be able to calculate true fly wheel horses. It came out to a tranny loss of about 15%. Have a look on YouTube, and no I'm not finding it for you coz I'm at work and YouTube is blocked. :p
 

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I agree that a proper engine dyno is the only way to get a proper flywheel figure. Anything else is just educated (or not) guessing!

Congrats on the result. Sounds like a lot of power for few mods.
Did you feel the actuators added any power even with a "WG3" type remap?

I look forward to seeing your facilities in the New Year! :thumbsup:
 

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Wheel figures are the only ones whihc count for me anyway.

How is the relaiability at these levels? Will the car be clocking up a lot of miles? It would be interesting for prospective customers as I don't think the durability has really been tested yet?
 

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Wheel figures are the only ones whihc count for me anyway.

How is the relaiability at these levels? Will the car be clocking up a lot of miles? It would be interesting for prospective customers as I don't think the durability has really been tested yet?
Yes but what type of rolling road do you think produces the most accurate "at the wheels" figure? What corrections would you allow for atmospheric pressure, height above sea level, ambient temps etc?

The only legitimate use of a rolling road is to measure changes, preferably on the same day, but certainly on the same RR.

As for reliability, there are dozens of USDM GT-Rs running at "700+" whp without issues beyond clutch slip in some at the higher end of the scale. The first ones beyond 700whp have been that way for about a year now. Certainly the engines themselves seem very tough.
 

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I've watched just about every dino pull video there is on YouTube, and the one I'm referring to is the US auto magazine investigation into the true power output of a standard GT-R. They used a dyno with the "run-down" function, to be able to calculate true fly wheel horses. It came out to a tranny loss of about 15%. Have a look on YouTube, and no I'm not finding it for you coz I'm at work and YouTube is blocked. :p
dont be fooled into thinking that run down is 100% effective, it isnt. it doesnt matter how many you tube videos you have watched.

kev
 

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Yes but what type of rolling road do you think produces the most accurate "at the wheels" figure? What corrections would you allow for atmospheric pressure, height above sea level, ambient temps etc?

The only legitimate use of a rolling road is to measure changes, preferably on the same day, but certainly on the same RR.

As for reliability, there are dozens of USDM GT-Rs running at "700+" whp without issues beyond clutch slip in some at the higher end of the scale. The first ones beyond 700whp have been that way for about a year now. Certainly the engines themselves seem very tough.

I say wait for germans to have this kind of power. They use it on miles and miles .... not just 400m
 

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dont be fooled into thinking that run down is 100% effective, it isnt. it doesnt matter how many you tube videos you have watched.

kev
Aye, for sure. It's a lot more accurate than guessing. :)
From memory, they initially clocked 506bhp at the flywheel, guessing tranny losses. At a later date, they used a different dyno which measured 15% tranny loss, which gave 485bhp at the flywheel. A lot closer to what Nissan officially quote. All other variables of the day taken into account, this seems about as accurate as one could expect. I use a road dyno, which has been shown to be within 5% of a "tested against" rolling road. The accuracy isn't as important as being able to see if mods have improved or buggered things! LOL
It needs to be repeatable, thats all.:thumbsup:
 

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Well done Sumo Power, great result :thumbsup:

We have just completed a similar Turbo conversion on a GTR and to say they are rapid is huge understatement :D

12 years of using different dynos as made me a little cynical of actual figures. Best to use them as a tuning tool and for comparing data rather than headline numbers. It's difficult to talk about transmission losses as a set % as that assumes friction is linear which it isn’t. I’m sure forums will be having the same debate in another 12 years time :)
 

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Good work Sumo, I look forward to further developments and an accurate engine dyno run.
 

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Yes but what type of rolling road do you think produces the most accurate "at the wheels" figure? What corrections would you allow for atmospheric pressure, height above sea level, ambient temps etc?

The only legitimate use of a rolling road is to measure changes, preferably on the same day, but certainly on the same RR.

As for reliability, there are dozens of USDM GT-Rs running at "700+" whp without issues beyond clutch slip in some at the higher end of the scale. The first ones beyond 700whp have been that way for about a year now. Certainly the engines themselves seem very tough.
Well I don't want to get into a dyno debate, as i've wasted many hours of my life there :D But when you are up at these sort of figures, a WHP figure is generally a good guide. Knowing the last .1 of a bhp isn't relevant. Using calculated ATF figures is where it goes very wrong. In terms of ambient compensation, a well setup Dyno Dynamics RR seems to get very good repeatable results. You just have to make sure your IT and AT are very close or things start to get screwed up.

Bench dyno's are all well and good, but just not a practical solition for most tuning places - plus how do you account for things like the exhuast system? It's nice to know the engine figure, but for the end user it's not that relevant imo.

For most of us, the most relevant figure is what is going to the wheels, with the car in a completed state. And that is an easier figure to find...

If you are a tuning outfit / trader, your interest is selling accurate figures. For that I wouldn't use my own in house dyno, I would take the car to a couple of independant dyno's so give some comparable results.
 

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The only real proof is terminal speed at the drag strip! :thumbsup:

I'm just saying one Dyno Dynamics RR might not be directly comparable to another one.

That's why I just use the same one (Surrey Rolling Road) and use it to measure differences.
 
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