Nissan 370Z Forum - View Single Post

juld0zer · 06-11-2014, 08:47 PM

Hey guys, i have this peculiar problem that has occured twice in the past 2 weeks now.

Background: Car is a 2011 6MT and has Berk HFC, exoticspeed midpipe, y-pipe, G3 intakes. It is currently winter here in Sydney so temps are usually below 20*c when i am driving. I have the fan control mod and the 2300 throttle map curve via Uprev. No other tuning has been done. All maintenance is up to date and correct fluids used except for 5w40 oil instead of 5w30. i always use 98 octane fuel from the same supplier.

The throttle response suddenly becomes really sluggish and the engine feels like it's struggling big time when taking off - especially on anything more than a slight incline. It feels like driving a crapbox 1.5L on a hot day - i have to drive it like a crapbox. Normally i can get it up to speed with minimal effort with less than 2000rpm in each gear. Now i actually have to rev it all the way to 3000+ rpm to even get it to 60kmh. It's so bad it feels like it's going to stall. It usually happens after i have been driving for about half an hour, so the engine and all fluids are warmed up to normal operating temps when it occurs. Oil and coolant temps are below 95*c. Intake air temp is usually within a few degrees celsius of the ambient temp.

Even when i sink my foot to the floor, the car hardly accelerates and takes an eternity to reach 100kmh in even in 3rd. Going downhill, the problem is less noticeable.

I described the problem in another thread which i forgot now, but it feels like the brake switch problem that Digitonium had where the car lags then screams to life after a while. It is not VDC as conditions were dry both times it happened. I also disabled VDC via the button (i know it's not a complete disable) on the 2nd time it happened but that did not cure the lag. I don't think it's my brake switch because cruise works fine and i dont see my brake lights blinking madly or staying on when they shouldnt. For good measure, i also held up the brake pedal with my foot but this didnt fix the problem.
It could also be described as the lag u get on a hot day with heatsoak and a/c blasting - but to a much more severe extent.

It feels like the CVTC system isnt working as it should. Down low (<3000rpm) there is hardly any response. Once it passes 3500rpm the motor screams but it still doesnt go as hard as it should. Travelling at 100kmh in 6th then downshifting to 3rd results in ok-ish acceleration but it still isnt as enthusiastic as it usually is. Revs will climb ok though.

I cured it last time by restarting the motor and the same solution seems to have cured it this time. Last time i didnt have my laptop and uprev cable with me to datalog but this time i drove all the way home to pick up the gear and do some logging - believe me, it was a challenge to not stall the motor because it was bogging badly on each take off. I couldn't stall the motor before logging because the problem wouldnt be there anymore.

From a glance, it does seem that my intake cams are locked at 0 degrees until about 1500ish rpm. Comparing it to some logs i made when things were running well, i should be getting 35+ degrees off the bat.

Can anyone shed some light?

06-11-2014, 08:47 PM	#1 (permalink)
juld0zer Enthusiast Member Join Date: Nov 2012 Location: Sydney Posts: 428 Drives: 11 Nissan 370Z MB M6 Rep Power: 139	HELP! Severe acceleration lag Hey guys, i have this peculiar problem that has occured twice in the past 2 weeks now. Background: Car is a 2011 6MT and has Berk HFC, exoticspeed midpipe, y-pipe, G3 intakes. It is currently winter here in Sydney so temps are usually below 20c when i am driving. I have the fan control mod and the 2300 throttle map curve via Uprev. No other tuning has been done. All maintenance is up to date and correct fluids used except for 5w40 oil instead of 5w30. i always use 98 octane fuel from the same supplier. The throttle response suddenly becomes really sluggish and the engine feels like it's struggling big time when taking off - especially on anything more than a slight incline. It feels like driving a crapbox 1.5L on a hot day - i have to drive it like a crapbox. Normally i can get it up to speed with minimal effort with less than 2000rpm in each gear. Now i actually have to rev it all the way to 3000+ rpm to even get it to 60kmh. It's so bad it feels like it's going to stall. It usually happens after i have been driving for about half an hour, so the engine and all fluids are warmed up to normal operating temps when it occurs. Oil and coolant temps are below 95c. Intake air temp is usually within a few degrees celsius of the ambient temp. Even when i sink my foot to the floor, the car hardly accelerates and takes an eternity to reach 100kmh in even in 3rd. Going downhill, the problem is less noticeable. I described the problem in another thread which i forgot now, but it feels like the brake switch problem that Digitonium had where the car lags then screams to life after a while. It is not VDC as conditions were dry both times it happened. I also disabled VDC via the button (i know it's not a complete disable) on the 2nd time it happened but that did not cure the lag. I don't think it's my brake switch because cruise works fine and i dont see my brake lights blinking madly or staying on when they shouldnt. For good measure, i also held up the brake pedal with my foot but this didnt fix the problem. It could also be described as the lag u get on a hot day with heatsoak and a/c blasting - but to a much more severe extent. It feels like the CVTC system isnt working as it should. Down low (<3000rpm) there is hardly any response. Once it passes 3500rpm the motor screams but it still doesnt go as hard as it should. Travelling at 100kmh in 6th then downshifting to 3rd results in ok-ish acceleration but it still isnt as enthusiastic as it usually is. Revs will climb ok though. I cured it last time by restarting the motor and the same solution seems to have cured it this time. Last time i didnt have my laptop and uprev cable with me to datalog but this time i drove all the way home to pick up the gear and do some logging - believe me, it was a challenge to not stall the motor because it was bogging badly on each take off. I couldn't stall the motor before logging because the problem wouldnt be there anymore. From a glance, it does seem that my intake cams are locked at 0 degrees until about 1500ish rpm. Comparing it to some logs i made when things were running well, i should be getting 35+ degrees off the bat. Can anyone shed some light?