# R Mode Vs SAVE Mode – Dyno test



## GTO NEMESIS (Feb 22, 2007)

As I have previously mentioned in a couple of my posts I intend to back to back test many of the mods that claim to add power to the GTR.
As a starting point I point I have dyno’ed my MY13 (2014 plate – with some of the MY14 bits) car.

I have nothing to gain from any of the testing I do. I am not a tuner, nor do I sell parts or tuning services.

I have use of a AWD Dyno Dynamics for my testing and I can run my own cars.

All of my testing will include 5-6 dyno pulls before a modification, then 5-6 dyno pulls after the modification.
The highest number will always be used.

*The following is my benchmark data.*

Nissan claim 550 PS for the MY13 & MY14 GTR











































Dyno is always set to the same bed width:










Temps are always consistent:










Tyre Pressures will always be the same:










Same exhaust trim will always measure AFR:










Bonnet will always be up and boost source will always be the same:









The tests will always be done in Shoot_44 with the [email protected] RR.

The main thing I noticed on the road regarding the SAVE mode is the lack of boost/how slow it builds boost.
On the dyno it is really clear when you look at the boost trace, but interestingly the AFR is much closer to what I would expect to see on a normal car, unlike the flat 10 AFR when on R mode.

Mark :wavey:


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## Simonh (May 24, 2002)

just for the sake of clarity

the 576 was that in R or normal, if not R then what was the WHP of the 576?

Simon


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## grahamc (Oct 1, 2006)

in for the updates

I did similar when I first got my car, but not all the same day, 5/6 runs, etc. Have a gradual progression over months/years on the same dyno.


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## GTO NEMESIS (Feb 22, 2007)

Simonh said:


> just for the sake of clarity
> 
> the 576 was that in R or normal, if not R then what was the WHP of the 576?
> 
> Simon


576.6 PS at the crank.
No PS figure at the wheels but I'll print that out next time I'm down there.

439.6 Wheel HP in R mode.
Normal mode makes no difference in relation to power output, just throttle mapping & gear shifting.


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## Adamantium (Jun 24, 2002)

maybe use power at the wheels for consistency?

Do you always use the same dyno company, if so, which one?


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## Silver R (Apr 23, 2013)

Subscribed


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## GTO NEMESIS (Feb 22, 2007)

I will always display WHP, BHP (crank HP) and PS (crank & wheels).

The Dyno is at Eurospec in Guildford.


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## scoooby slayer (Jun 13, 2009)

what is save mode ?

576hp at 0.9 bar shows how efficient these motors are


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## GTO NEMESIS (Feb 22, 2007)

SAVE mode is what I get if I press down on the left RRR button.


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## buzzysingh (Nov 19, 2012)

Subscribed : >


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## scoooby slayer (Jun 13, 2009)

GTO NEMESIS said:


> SAVE mode is what I get if I press down on the left RRR button.




ah I see, afaik my 09 only has normal and r mode lol 

its still mighty impressive they make 450 hp at 0.5 bar, a vr38 must be about 350 hp na


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## matt j (Oct 19, 2001)

scoooby slayer said:


> 576hp at 0.9 bar shows how efficient these motors are


Don't you mean how inefficient the drive train is?


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## scoooby slayer (Jun 13, 2009)

matt j said:


> Don't you mean how inefficient the drive train is?


lol come on matt you know the correction is just a fixed percentage there is no measureing


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## matt j (Oct 19, 2001)

scoooby slayer said:


> lol come on matt you know the correction is just a fixed percentage there is no measureing


A tuners paradise! 

But at least it confirmed what the dealer said about knocking 100hp off in Save mode, that's why it pulls 34mpg on a run.


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## scoooby slayer (Jun 13, 2009)

matt j said:


> A tuners paradise!
> 
> But at least it confirmed what the dealer said about knocking 100hp off in Save mode, that's why it pulls 34mpg on a run.



"it measures losses on coastdown honest guv" lmao

is save mode there in my 09 car ? 34mpg is mighty impressive for a 3.8 tank


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## Timboy666 (Mar 7, 2014)

scoooby slayer said:


> ah I see, afaik my 09 only has normal and r mode lol
> 
> its still mighty impressive they make 450 hp at 0.5 bar, a vr38 must be about 350 hp na


Your might say snow instead of save


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## GTO NEMESIS (Feb 22, 2007)

Ok, here is a back to back tests with a Y Pipe.

















Notice the difference the Y Pipe makes to R modes peak power - 1 BHP which I put down to the dyno.
But on SAVE mode...

Full discussion on this test here:
http://www.gtr.co.uk/forum/291002-how-much-power-does-y-pipe-add.html


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## Trevgtr (Dec 24, 2012)

Good stuff, shall be watching with interest.


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## GTO NEMESIS (Feb 22, 2007)

Run 16 & 17 on the Boost/AFR graph are with the aftermarket Y Pipe.


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## [email protected] (Jun 8, 2014)

Which Y pipe did you use?


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## Trevgtr (Dec 24, 2012)

Most of the Y pipes have a larger bore than the stock cat back pipe they're joining, creating a slight flow disturbance. From memory it's about a 2.5mm lip, which could be chamfered out by the fitter for smoother flow, but hardly ever is.


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## GTO NEMESIS (Feb 22, 2007)

[email protected] said:


> Which Y pipe did you use?


I don't want to publish this, but I will PM you.
But it's a very common supplier...

It is a non res pipe too.


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## scoooby slayer (Jun 13, 2009)

Timboy666 said:


> Your might say snow instead of save


Ahh yes snow mode I forgot about that lol


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## vxrcymru (Sep 29, 2009)

Hat off to you, thats a lot of hassle but will provide some interesting results for discussion.

What mods do you have planned?


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## paul__k (Dec 8, 2007)

Quality work on the dyno keep it
Up
I don't remember the early cars having AFR at 10 seems very rich no wonder they smoke when you boot it


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## MattGTR750 (Apr 26, 2012)

My car made terrible power on that exact dyno...

Maybe it was in snow/save mode LOL


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## ROG350Z (Jun 15, 2008)

Brilliant be most interesting to see the results in as controlled environment as we have seen thus far. Well done for all the effort - curiosity is a terrible curse ;-)


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## GTO NEMESIS (Feb 22, 2007)

MattGTR750 said:


> My car made terrible power on that exact dyno...
> 
> Maybe it was in snow/save mode LOL


There is nothing wrong with the dyno 
I have personally tested 3 cars at Torque of the Devil, Power Engineering, Eurospec and Ajax racing - All Dyno Dynamics.

The biggest variance from the highest to the lowest was 3 BHP.

The numbers are what they are.

I've seen lots of unhappy people at all of those Dynos on a Dyno day as they "thought" they had more power at a different dyno.
There are so many ways to fudge numbers on dynos, but Shoot_44 with accurate IAT and AIT should always give repeatable results from one Dyno Dynamics to another.

I'm never too fussed about the actual number, but the change in that number based on a set of modifications that I carry out, that's what's important to me.

I love testing stuff :wavey:


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## Adamantium (Jun 24, 2002)

Power engineering run a maha dyno not a dyno dynamics.

Mahas are about the best dynos on the market and they actually do measure coast down losses independently on each axle so the flywheel figure does have sone absolute meaning.

The coast down is specific to each car.

Not sure if power engineering' sis any good as it's very old tech but the latest maha are what the German tuners and the Porsche/merecedes/Audi factories use.


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## GTO NEMESIS (Feb 22, 2007)

Adamantium said:


> Power engineering run a maha dyno not a dyno dynamics.


Your information is about 6 years out if date.
Power Engineering | Tel: +44 (0)1895 255699

But yes, they use to have a MAHA, I have run my cars on that Dyno too.
The MAHA is now what ECUTEK use to test & develop their cars.

Usefull post on the MAHA too but it's not entirely correct ;0)


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## GTO NEMESIS (Feb 22, 2007)

vxrcymru said:


> Hat off to you, thats a lot of hassle but will provide some interesting results for discussion.
> 
> What mods do you have planned?


Thank you. It's a bit of hassle but it's also a hobby so kind of fun too.
Plus I like correcting/confirming the "internet" says xyz thing.

As for mods, my next test will be different air filters/intakes with and without the Y pipe.
Then we will go back to stock everything and write an ECUTEK for it to see what that delivers, then add the Y pipe and RE-ECUTEK, then the air filters and re-ECUTEK.

After that I will look at down pipes and the remainder of the exhaust.
Again back to back testing everything.

If anyone wants anything else tested let me know (assuming it fits my car).


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## Hugh Keir (Jul 25, 2001)

Wow,

Absolutely love where you are going with this thread.

Knowledge of what does and does not work is sooooo interesting.

Would love to get some exhaust back pressure readings on different systems throughout the rev range if you can find a way to add a pressure sensor and log the data.

Bit gob smacked that the GTR leaves the factory with a 10:1 AFR, what a loss of power and waste of money that is!!!!!!


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## Donbona (Apr 18, 2013)

Interesting stuff... 
Before I had my gtr I had a charged M3 which made circa 620bhp on a dyno dynamics. But the guys in the USA with the same set up used to make quite a bit more. Then I found out that they used Dyno jet which I tried.... that gave me around 10% more power. I'm guessing different dyno's can vary quite a bit.


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## GTO NEMESIS (Feb 22, 2007)

Donbona said:


> Interesting stuff...
> Before I had my gtr I had a charged M3 which made circa 620bhp on a dyno dynamics. But the guys in the USA with the same set up used to make quite a bit more. Then I found out that they used Dyno jet which I tried.... that gave me around 10% more power. I'm guessing different dyno's can vary quite a bit.


Yeah, Dynojet do read differently, they also claim Power at the Wheels which is pretty much the same number that we see as BHP on a Dyno Dynamics (On a AWD car at least).





Hugh Keir said:


> Wow,
> Absolutely love where you are going with this thread.
> Knowledge of what does and does not work is sooooo interesting.
> Would love to get some exhaust back pressure readings on different systems throughout the rev range if you can find a way to add a pressure sensor and log the data.
> Bit gob smacked that the GTR leaves the factory with a 10:1 AFR, what a loss of power and waste of money that is!!!!!!


Lots of Jap cars seem to run quite rich. But rich does not always mean less power.
For an example an AFR of 11.7 may not yield anymore power as you may need to pull some ignition. But I will be testing this when I ECUTEK the car.

On my 950 BHP GTO, I get more power at 10.5 AFR (and safety) then I do at 11.7 AFR as I can pile the timing in there and run more boost.

I can test the back pressure between stock and whatever exhaust I end up fitting but having tested this sort of stuff before it doesn’t actually tell you that much (unless you are hunting for a restriction).
For me, the dyno number is of more importance regardless of back pressure.


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## Adamantium (Jun 24, 2002)

GTO,

Thanks for the PE update, I didn't know they'd continued elsewhere, my bad!

Would like to hear what I got wrong about the Maha, always happy to learn.

Re the dynojet/dynodynamics debates, assuming I haven't got this wrong too (not being sarcastic) dynojets are considered optimistic because they were the first manufacturer of easily available rolling roads and were initially calibrated based on the expected power output of certain motorcycle engines. When they didn't give the right power, the output reading was fudged so that people saw what they expected. I believe the trend continued from there and the fudge factor remained in their software. There's a lot of economics at play when you sell a road dyno to a company and it gives low power readings compared to everyone else, it doesn't make your dyno popular.

Anyway, dynojet dynos are inertia based. They work by calculating the power required to accelerate the known rotating mass of the drums that the wheel is rotating on. As a result they cannot be used for steady state tuning, but they can give a fairly decent before and after comparison test. They are also very susceptible to weight and grip differences between runs.

Dynodynamics etc are eddy current based dynos which are driven to brake the driving torque of the wheel, the required torque is measurable and so the torque can be plotted against rpm to determine the power.

They make for better tuning tools as a car can be held at a specific load point and mapped accordingly.

Anyway, I digress....


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## CT17 (Mar 25, 2011)

Good thread.


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## mrobinson2 (Jul 10, 2008)

Brilliant thread mate !

as you said, doesn't matter what the bhp number is, it's the differences in the mods we are looking for.


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## Trevgtr (Dec 24, 2012)

GTO NEMESIS said:


> Lots of Jap cars seem to run quite rich. But rich does not always mean less power.
> For an example an AFR of 11.7 may not yield anymore power as you may need to pull some ignition. But I will be testing this when I ECUTEK the car.
> 
> On my 950 BHP GTO, I get more power at 10.5 AFR (and safety) then I do at 11.7 AFR as I can pile the timing in there and run more boost.
> ...


Why does the GT-R run so rich stock though, I was also surprised when I saw it's 10:1 on stock boost! Wonder what a stage 4.5 AFR is? Do the likes of Litchfield and SVM go 11:1 I wonder?

GTO, I have the same car as you (63 MY13), same colour too lol. I recently swapped my Milltek Y pipe for a GTC Titanium 90mm Y pipe and cat back. It's not everyone's taste as the sound isn't much louder from the outside, although it does now scream through high rpm. The big difference though is in the feel of the car as a driver, it now feels more brutal and harsh with a kind of resonating roar through the whole car. Much more fun. Power is also noticeably up, the mid range overtaking kick is quicker than just a Milltek Y pipe. Would be great to see that dyno'd, but guessing you're not fitting a 90mm cat back?

Great stuff though, keep up the good work


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## Andy (aardvark) (Mar 26, 2013)

Great thread - subscribed.


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## Adamantium (Jun 24, 2002)

Trevgtr said:


> Why does the GT-R run so rich stock though, I was also surprised when I saw it's 10:1 on stock boost! Wonder what a stage 4.5 AFR is? Do the likes of Litchfield and SVM go 11:1 I wonder?
> 
> GTO, I have the same car as you (63 MY13), same colour too lol. I recently swapped my Milltek Y pipe for a GTC Titanium 90mm Y pipe and cat back. It's not everyone's taste as the sound isn't much louder from the outside, although it does now scream through high rpm. The big difference though is in the feel of the car as a driver, it now feels more brutal and harsh with a kind of resonating roar through the whole car. Much more fun. Power is also noticeably up, the mid range overtaking kick is quicker than just a Milltek Y pipe. Would be great to see that dyno'd, but guessing you're not fitting a 90mm cat back?
> 
> Great stuff though, keep up the good work


They run rich for safety. Without a remap it runs even richer as the airflow through the maf is greater causing it to access an even richer part of the map. It's possible the 90mm Titan flowing flowing better still results in a slightly more efficient combination on the stock mapping. You really need to remap to benefit from exhaust changes.


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## [email protected] (Jun 8, 2014)

Maybe some manufacturer will send you a sample to test some time because


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## Trevgtr (Dec 24, 2012)

Adamantium said:


> They run rich for safety. Without a remap it runs even richer as the airflow through the maf is greater causing it to access an even richer part of the map. It's possible the 90mm Titan flowing flowing better still results in a slightly more efficient combination on the stock mapping. You really need to remap to benefit from exhaust changes.


Yes I know it's for safety, but why 10:1? Just seems excessive to me, but obviously it's not plucked out of thin air by Nissan, npi.

I'm no expert but I'd be surprised if it runs richer without a remap. I would have thought it would be slightly weaker, I mean inducting more air or increasing boost results in a weaker AFR, surely? As an extreme example, increase boost to 1.5 bar with no remap and it will det like hell through running too weak. Please correct me if I'm wrong.


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## Adamantium (Jun 24, 2002)

but the minute you flow more air you move to a different sector of the fuelling map, so you can't say for sure that it will run leaner (weaker). If the fuelling was the same, then yes more air flow would result in a leaner mixture but it's not what happens.

the safety net is more likely to be that the stock car doesn't ever access those parts of the map so rather than waste development money on it, they have a blanket value of rich fuelling values in the part of the map they never expect the engine to access which might have a correction value to increase the fuelling in proportion to the maf value and engine speed.

Who knows? the point is, it runs rich at those points in the map.


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## Donbona (Apr 18, 2013)

Adamantium said:


> but the minute you flow more air you move to a different sector of the fuelling map, so you can't say for sure that it will run leaner (weaker). If the fuelling was the same, then yes more air flow would result in a leaner mixture but it's not what happens.
> 
> the safety net is more likely to be that the stock car doesn't ever access those parts of the map so rather than waste development money on it, they have a blanket value of rich fuelling values in the part of the map they never expect the engine to access which might have a correction value to increase the fuelling in proportion to the maf value and engine speed.
> 
> Who knows? the point is, it runs rich at those points in the map.


Is this why the stock car stinks of fuel in the cab when stuck in traffic with hot/warm weather?


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## Trevgtr (Dec 24, 2012)

If the fueling adjusted itself to that extent following a flow increase or boost increase, there would be no need for a remap, still think it will run lean not rich. Stoich is 14.7:1, stock GT-R runs at 10:1, I would guess a free flowing Y pipe and cat back would see nearer 11:1, not nearer 9:1. Sorry, don't want to appear argumentative, just saying it as I see it.

Donbana, you shouldn't be smelling fuel in the cab.


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## Adamantium (Jun 24, 2002)

Trev, there's closed loop and open loop fuelling depending on which cell of the map you are on. The fuelling isn't adjusting itself at all. The map as stock is the same after you've put the better exhaust on. the difference is it wasn't flowing as much before so you couldn't get to the really rich parts of the map until the exhaust went on. Once you reach those parts, even though there's more air, there's even more fuel shifting it towards being richer still.

Closed loop measures lambda and adjusts the fuelling to reach a target. If the target is rich, and it is capable of supplying enough fuel for the airflow, it will run rich.

In open loop, (quite typical on boost due the speed of movement through a zone meaning there isn't enough time to rely on feedback to correct the fuelling) it will simply input the stored value of fuel in the map that relates to the engine speed, mass air flow and throttle position. How it behaves in every open loop mapped zone is purely a function of the stored fuelling level for that cell. 

Historically, it's been found that cell positions in the open loop areas of the map corresponding to higher than stock expected levels of MAF result in the car over fuelling.

If it were closed loop and the car can react enough and faster enough then the lambda value should be unaffected regardless of how well the exhaust flows.

If the entire map was open loop and was accessed by the stock exhaust, then a change to a freer flowing exhaust would give more air without getting any more fuel in the cells where the fuelling was already a maximum, at those points I'd expect it to run leaner, but again that has not been experienced.

Donbona, if you are over fuelling and you've removed at least the stock y-pipe then it might explain you being able to smell fuel when in traffic.

When the cat is saturated you can get unburned hydrocarbon breakthrough meaning unburnt fuel all the way through the exhaust which you could smell.


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## Trevgtr (Dec 24, 2012)

Thanks for taking the time, it would be interesting to see how a 90mm Y pipe and cat back reads on the dyno.

Do you know if the GT-R controls boost automatically? I'm guessing not as I'm now getting about 1psi more boost on WOT in 3rd gear.


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## AdnanK (Jun 11, 2013)

Hi GTO, any more updates to this thread, did you manage to Ecutek the car?


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## LiamGTR (Nov 26, 2006)

Hold on.. Did I read a GTR can get 30+mpg if you put it into snow mode?


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## gtr mart (Mar 29, 2004)

You can get that if you simply resist the temptation of the accelerator.


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## Badders (Aug 9, 2014)

GTO NEMESIS said:


> SAVE mode is what I get if I press down on the left RRR button.


That would explain it then, as that is SNOW mode on mine, so locked diffs and a lot less power and throttle response by design.


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## GTO NEMESIS (Feb 22, 2007)

Hi,
Long overdue update...

I EcuTek'ed the car last September.

This was the result:


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