"Bogging" in first gear

bushman66 · 06-06-2012, 11:30 AM

I will take it in, just to be safe, but I'm betting they don't find anything. I'm launching at say 2000RPM (not riding the clutch too much), then punching it. The "bog" is so pronounced that it almost throws me forward into my seatbelt, then throws me back into the seat when it "catches".

My twin turbo Porsche just accelerates smoothly off the line and its a turbocharged engine where you would expect turbo lag. The 370Z, being normally aspirated, should accelerate more smoothly than that. Really the best analogy I have is when we used to mess with 60's musclecars and Holley carbs, we'd get that "bog" off the line when you'd slam your foot to the floor and we would tune it by changing out power valves, jets, etc. until we got that smooth application of power. I'd never expect a modern EFI to bog like this off the line...

fuct · 06-06-2012, 11:35 AM

Quote:

Originally Posted by bushman66

I will take it in, just to be safe, but I'm betting they don't find anything. I'm launching at say 2000RPM (not riding the clutch too much), then punching it. The "bog" is so pronounced that it almost throws me forward into my seatbelt, then throws me back into the seat when it "catches".

My twin turbo Porsche just accelerates smoothly off the line and its a turbocharged engine where you would expect turbo lag. The 370Z, being normally aspirated, should accelerate more smoothly than that. Really the best analogy I have is when we used to mess with 60's musclecars and Holley carbs, we'd get that "bog" off the line when you'd slam your foot to the floor and we would tune it by changing out power valves, jets, etc. until we got that smooth application of power. I'd never expect a modern EFI to bog like this off the line...

im not bogging like this, maybe there really is a problem.

IDZRVIT · 06-06-2012, 03:19 PM

Quote:

Originally Posted by bushman66

I will take it in, just to be safe, but I'm betting they don't find anything. I'm launching at say 2000RPM (not riding the clutch too much), then punching it. The "bog" is so pronounced that it almost throws me forward into my seatbelt, then throws me back into the seat when it "catches".

My twin turbo Porsche just accelerates smoothly off the line and its a turbocharged engine where you would expect turbo lag. The 370Z, being normally aspirated, should accelerate more smoothly than that. Really the best analogy I have is when we used to mess with 60's musclecars and Holley carbs, we'd get that "bog" off the line when you'd slam your foot to the floor and we would tune it by changing out power valves, jets, etc. until we got that smooth application of power. I'd never expect a modern EFI to bog like this off the line...

Try launching at 3000-3500 rpm and report back. I don't think you're revving high enough. My 'vette will bog if I launch below 3000 and hence, I've never launched below 3000 in the Z. It never bogs at 3000 and above.

bushman66 · 06-06-2012, 03:42 PM

Quote:

Originally Posted by IDZRVIT

Try launching at 3000-3500 rpm and report back. I don't think you're revving high enough. My 'vette will bog if I launch below 3000 and hence, I've never launched below 3000 in the Z. It never bogs at 3000 and above.

Thanks, I agree. I guess my contention is that a modern EFI engine should not "Fuel bog" at any RPM when you slam your foot into it...if that makes sense

370Z Purist · 06-06-2012, 07:28 PM

Quote:

Originally Posted by bushman66

Thanks, I agree. I guess my contention is that a modern EFI engine should not "Fuel bog" at any RPM when you slam your foot into it...if that makes sense

If you let RPMs drop below 2k while off throttle and in gear, engine braking characteristics will change (harder braking after 2k, less braking before 2k). I've since gathered more or less that it's probably a VVEL profile change. If I do launch, I launch at 3-4K. No problems for me, unless I forget to turn off VDC

pedZ · 06-06-2012, 08:49 PM

Hey Bushman, I have some feedback from the UpRev tune. The tune definitely helped the issue. There still does seem to be a lag in the lower RPMs but it's not nearly as noticeable. I guess the best way I can explain it is that it has been smoothed out so that you don't notice it. In fact, the car is much smoother throughout the entire RPM range.

My car was running rich before the tune (in the 11s) and is now between 12.5 and 13. This helped out the car a lot and I gained 12hp overall from the tune.

bushman66 · 06-06-2012, 09:16 PM

Quote:

Originally Posted by pedZ

Hey Bushman, I have some feedback from the UpRev tune. The tune definitely helped the issue. There still does seem to be a lag in the lower RPMs but it's not nearly as noticeable. I guess the best way I can explain it is that it has been smoothed out so that you don't notice it. In fact, the car is much smoother throughout the entire RPM range.

My car was running rich before the tune (in the 11s) and is now between 12.5 and 13. This helped out the car a lot and I gained 12hp overall from the tune.

Thanks! This is good news...I'm just debating whether its worth it or not to risk the remainder of my warranty with a tune...

pedZ · 06-06-2012, 09:21 PM

Quote:

Originally Posted by bushman66

Thanks! This is good news...I'm just debating whether its worth it or not to risk the remainder of my warranty with a tune...

Yeah, there doesn't seem to be any definitive info on whether is causes warranty issues or not. I only have about 4400 miles on my Z and decided to chance it. Here in SoCal there are some dealers that are mod friendly.

ANMVQ · 06-08-2012, 07:42 AM

Quote:

Originally Posted by pedZ

Hey Bushman, I have some feedback from the UpRev tune. The tune definitely helped the issue. There still does seem to be a lag in the lower RPMs but it's not nearly as noticeable. I guess the best way I can explain it is that it has been smoothed out so that you don't notice it. In fact, the car is much smoother throughout the entire RPM range.

My car was running rich before the tune (in the 11s) and is now between 12.5 and 13. This helped out the car a lot and I gained 12hp overall from the tune.

About the UPREV tune, I'm on a few other forums and one guy said Nissan has a brake over ride( THis is for us auto guys) That when on the break the TB will only open 10%, Anyone else heard this, This would be why when I'm on the break the car will only rev to 2k, What the heck are they thinking installing something like that on a car, Really, Not like I want to do a burn out( AWD) but at least be able to lauch the car. Wonder if this is a table that can be change with UPREV.

bushman66 · 06-09-2012, 02:31 PM

Quote:

Originally Posted by pedZ

Hey Bushman, I have some feedback from the UpRev tune. The tune definitely helped the issue. There still does seem to be a lag in the lower RPMs but it's not nearly as noticeable. I guess the best way I can explain it is that it has been smoothed out so that you don't notice it. In fact, the car is much smoother throughout the entire RPM range.

My car was running rich before the tune (in the 11s) and is now between 12.5 and 13. This helped out the car a lot and I gained 12hp overall from the tune.

PedZ...did you ask specifically if there was any additional tuning they could do to 100% eliminate this issue?

pedZ · 06-09-2012, 04:24 PM

Quote:

Originally Posted by bushman66

PedZ...did you ask specifically if there was any additional tuning they could do to 100% eliminate this issue?

I did not. I main goal from the tune was to just get the car running as best as possible.

Phaddi_inc · 06-10-2012, 11:31 PM

Quote:

Originally Posted by bushman66

PedZ...did you ask specifically if there was any additional tuning they could do to 100% eliminate this issue?

Im curious if its just related to oil temp...do you have an oil cooler installed? I notice this happens to me when oil temp reaches 220 and above (doesnt take long 5 minutes driving in town). it lags when in first, and the revs 'hang' a bit after coming off the throttle. this year I switched to red line oil and installed my gen3 intakes , I dont remember it being as bad last year but it could have been...Im hoping to install an oil cooler this summer, and maybe insulate/heat wrap my intakes. I've noticed slight lag in the past and considered getting that sprint booster, but now its seems much worse especially when the oil gets to 220 so I dont think that would solve this issue.

phaddi_inc

06-06-2012, 08:49 PM	#6 (permalink)
pedZ A True Z Fanatic Join Date: Jan 2011 Location: Southern California Posts: 3,366 Drives: 11 Tour/Spt/Nav/6MT Rep Power: 28	Hey Bushman, I have some feedback from the UpRev tune. The tune definitely helped the issue. There still does seem to be a lag in the lower RPMs but it's not nearly as noticeable. I guess the best way I can explain it is that it has been smoothed out so that you don't notice it. In fact, the car is much smoother throughout the entire RPM range. My car was running rich before the tune (in the 11s) and is now between 12.5 and 13. This helped out the car a lot and I gained 12hp overall from the tune. __________________ 2011 Brilliant Silver Touring/Sport/Nav/6MT --- Build Journal F.I. SS 18" CBE \| Takeda CAI \| Z1 25-Row Oil Cooler \| Swift Springs \| Hotchkis Sway Bars \| H&R 15mm DRS Spacers F&R \| RJM Clutch Pedal \| UpRev Tune

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06-06-2012, 11:30 AM	#1 (permalink)
bushman66 Base Member Join Date: May 2010 Location: AZ Posts: 112 Drives: 2012 370Z Red Sp Pkg Rep Power: 16	I will take it in, just to be safe, but I'm betting they don't find anything. I'm launching at say 2000RPM (not riding the clutch too much), then punching it. The "bog" is so pronounced that it almost throws me forward into my seatbelt, then throws me back into the seat when it "catches". My twin turbo Porsche just accelerates smoothly off the line and its a turbocharged engine where you would expect turbo lag. The 370Z, being normally aspirated, should accelerate more smoothly than that. Really the best analogy I have is when we used to mess with 60's musclecars and Holley carbs, we'd get that "bog" off the line when you'd slam your foot to the floor and we would tune it by changing out power valves, jets, etc. until we got that smooth application of power. I'd never expect a modern EFI to bog like this off the line...