Nissan GT-R Forum banner
1 - 20 of 103 Posts

·
Registered
Joined
·
97 Posts
Discussion Starter · #1 ·
This is in regards to my 2012 GT-R with 3200 miles on it now. It seems to have two personalities, I'm talking to Boulder Nissan about the issue, I just wanted to see if anybody else was experiencing this. I know the car requests 93 octane, but it works so well half the time with our 91!

Following is a summary of what I just sent to Boulder Nissan:

The car really does seem to have two modes: high boost and low boost. Nothing in between. High boost allows ~13.5psi, low boost allows 9psi. This is full throttle, in any gear, any traction situation. High load triggers the low boost situation. I'm assuming it is octane related, as changing the gas always changes the attitude. When in low boost, stopping the engine restarting allows just a touch of high boost before going back in to low boost.

At High Plains Raceway, the display would show just over 13psi, then there would a shake/hesitation, then it would only go to 9psi with a significant loss in power. It was the difference of 136mph and 124mph on the short course straight.

Weather:
http://www.shoeish.com/uploader/images/weatherlog.jpg

Day 1:
Fill up with 91 at Byers
Drive 20 miles to track
Session 1: Two laps in high boost, falls to low boost.
Add 3 gallons of 100 octane unleaded to just under 1/2 tank of fuel
Session 2: Full boost the entire session. Run down to below 1/4 mark on fuel gauge.
Drive to byers, refuel with 91, drive back to track, top off with 100 octane (1.25 gallons)
Session 3: Two laps in high boost, falls to low boost.

Day 2:
Fill up with 91 in Denver
Drive 50 miles to track
Session 1: Three laps in high boost, falls to low boost.
Add 4 gallons of 100 octane unleaded to just under 1/2 tank of fuel
Session 2: Full boost the entire session. Run down to below 1/4 mark on fuel gauge.
Drive to Byers, add 8 gallons (up to 1/2 tank or so), drive back to track. Add 2 gallons race fuel.
Session 3: Full boost the entire session.

When I brought the car for the 1000 mile service it was in "low boost mode."

The brand or location (wy and co, anyway) of gas purchased doesn't seem to matter. Sinclair, Conoco, Shell, Exxon...

Here is another mystery: The same Exxon, on the same day (drove outof town, then back, and filled up), even gave different results. I filled up from near empty as I was in "low boost" mode, had high boost for the entire 240 mile trip (high load through a canyon), filled up when I got back, and ran into low boost mode again.
 

·
GTR Nerd
Joined
·
5,335 Posts
. I know the car requests 93 octane, but it works so well half the time with our 91!
Day 1:
Fill up with 91 at Byers
Drive 20 miles to track
Session 1: Two laps in high boost, falls to low boost.
Add 3 gallons of 100 octane unleaded to just under 1/2 tank of fuel
Session 2: Full boost the entire session. Run down to below 1/4 mark on fuel gauge.
Drive to byers, refuel with 91, drive back to track, top off with 100 octane (1.25 gallons)
Session 3: Two laps in high boost, falls to low boost.
Sounds like it is knocking/ and going to the low boost/timing map. Interesting. First I remember hearing of this happening on a R35.

Interesting to know if this might happen to any California guys, with our 91 octane also.
 

·
Registered
Joined
·
589 Posts
I had a similar thing happened to me a few times, I posted about it a few weeks ago here:

http://www.nagtroc.org/forums/index.php?sh...c=50720&hl=

It hasn't popped up since and at the time I did not check boost levels. I put in a midpipe last week and the car has been running very strong, I do believe it could be the same thing as at the track my trap went from 119 to 108.
 

·
Registered
Joined
·
1,882 Posts
I tagged the rev limiter at the drag strip and after that the boost would not go over 6 psi... after restarting the car, back to normal, haven't had it happen again...
 

·
GTRLIFE BOTM August 2015
Joined
·
1,042 Posts
I tagged the rev limiter at the drag strip and after that the boost would not go over 6 psi... after restarting the car, back to normal, haven't had it happen again...
I have a 2012 with 2000 miles now. I live in Az so I can only conveniently get 91 octane...and I think you all know how hot it is here. I noticed yesterday getting on the freeway (about 96 degrees) that under full acceleration (mid 2nd gear pull) my car retarded the timing about 3 times before I let off the throttle. I could feel the 3 quick power cuts during the pull. After, my car would only boost 9psi, just like you described. I was about out of gas so i went to the gas station and filled up. After restarting my car, I was back at full boost again.

You are dead on with your observation.
 

·
Registered
Joined
·
107 Posts
I was just about to post about a similar problem..

After a few days with midpipe and catback installed I suddenly feel a lack in power.
I live in europe so I use shell V-Power only 99octane.

It seems to be stuck in this low boost mode.

Any ideas how to get it back on full boost have tried 4 or 5 restarts but changes nothing.

Is Shell cheating with there gas?
 

·
Registered
Joined
·
97 Posts
Discussion Starter · #7 ·
I was just about to post about a similar problem..

After a few days with midpipe and catback installed I suddenly feel a lack in power.
I live in europe so I use shell V-Power only 99octane.

It seems to be stuck in this low boost mode.

Any ideas how to get it back on full boost have tried 4 or 5 restarts but changes nothing.

Is Shell cheating with there gas?
My power always comes back, even briefly, with a restart. Change your fuel brand, that station may have got a bad batch. I try and find stations with a hose for each grade, so I don't get any of the low grade stuff in.
 

·
GTRLIFE BOTM August 2015
Joined
·
1,042 Posts
My power always comes back, even briefly, with a restart. Change your fuel brand, that station may have got a bad batch. I try and find stations with a hose for each grade, so I don't get any of the low grade stuff in.
My power came right back after a restart. I haven't experienced it again, but Az weather has cooled off this last week so I will respond back if I experience it again.
 

·
Registered
Joined
·
159 Posts
Just wanted to post up that the same issue just happened to me here in OKC. Just filled up with 91 octane and now I am on the low boost and timing map. I guess the only thing it can be is the hot temps with the low octane. 91 must be right on the threshold for normal power and all it takes is a little bit of contamination to kick us down into low boost mod. Thats my thought at least.

I have alot of Torco but I dont wanna waste it on this bad batch of gas (if thats what it turns out to be) so I am just going to have to use it up then refill at another station. If it does it again then I guess I will have to supplement it with the Torco for summer temps.
 

·
SF Bay Area Member
Joined
·
548 Posts
I'm in California and also noticed a situation where the car wouldnt go as hard as it usually did after I floored it. I assume you guys arent seeing any warning lights regarding "Low Boost Mode"???
 

·
Registered
Joined
·
159 Posts
You are correct there are no warnings. You can tell an fairly significant loss of power and confirm it on your boost gauge. Did the previous year cars do this as well?
 

·
R35
Joined
·
1,319 Posts
I never understood why some states only provide up to 91 octane. How is that supposed to help with emissions?
 

·
Registered
Joined
·
159 Posts
I doubt very seriously the reason for 91 octane states had anything to do with the environment, it had alot to do with padding the pockets of politicians imho. But thats for another thread!

Just to update today i am back to boosting normal and temps are in the 100's. So I have no idea how the car determines high or low boost as I am on the same fuel as before.
 

·
Registered
Joined
·
1,138 Posts
I'm still in break in, so I have not seen this problem yet, but I would like to know why the car is limiting the power, it must think something is wrong.

Has anyone contacted the dealer, I'm sure they could find out what the car is limiting the power for.
 

·
GTRLIFE BOTM August 2015
Joined
·
1,042 Posts
Posting again, it's been 100+ here (108 today) and I get this low boost thing almost daily. It is immediately corrected by restarting the car, but it is VERY annoying.
 

·
Registered
Joined
·
589 Posts
Posting again, it's been 100+ here (108 today) and I get this low boost thing almost daily. It is immediately corrected by restarting the car, but it is VERY annoying.
I talked to my tech about it, he says they haven't heard anything about it. I suggest someone who can replicate this problem take there tech for a ride and show them that it is real.
 

·
Registered
Joined
·
159 Posts
I have my 1000 mile check up in a day or so and i have a good relationship with my tech, I will bring this to his attention. But save for an ECU update from nissan I dont know what other resolution there will be. The car is trying to protect it self with this low boost mode, its not necessarily a flaw.
 

·
GTRLIFE BOTM August 2015
Joined
·
1,042 Posts
I can make mine do this every day here in Az. If I go WOT in 1st, it won't do it. But WOT in 2nd it will sometimes happen. WOT in 3rd it will go into low boost mood every time if the weather is hotter than about 100. It's been 105+ here lately...really, really, really annoying.
 

·
Registered
Joined
·
1,640 Posts
This problem seems to be widespread... Makes me think its a defect of some sort that should be recalled. Nissan guaranteed 530 hp in all 50 states with 91 octane.
 
1 - 20 of 103 Posts
Top