"Bogging" in first gear
 

Wondering if anyone else has experienced this. When I am taking off in 1st gear, the car seems to "bog" until the revs come up. This is with moderate to heavy throttle, I am not babying the car. It seems to have started after the CBE was installed. The feeling is the same as from my old muscle car days when the car ran too lean off the line.

I'm wondering if the ECU just needs to relearn with the new exhaust? I've tried to drive the car more aggressively to help it...if this is the case, how long before the ECU catches up with the mod?

All I know is, I will not be engaging in any stoplight action now...the car won't get off the line to save itself now...

All other behaviors, idle, driveability etc are normal. All I have now is this "hole" in first gear...

first was already a crummy gear in our cars. the loss in back pressure can give it a boggy feeling down low in the RPM's but nothing really that bad.

im sure youve tried just reving higher to negate the bogging, no?

Yes, even with a healthy dose of throttle...it just feels like a huge dead spot in the power until it "catches".

try resetting the ecu and see if it relearns and compensates any better. it probably won't, but it's the easy first step before getting more into troubleshooting.

Yeah...going to try this tonight...

By any chance were you low on gas? I had the same thing but it only happens when I'm low on gas. I'm assuming it's because the car is alot lighter without gas so the clutch engages alot faster.

Nope. Full tank

Is your VDC on or off?

VDC on. Dry conditions...

Turn it off! I launch at 3000 rpm or so in my 6-sp. Never bogged yet. Dual 100' strips of rubber no problem with a stock Z.

Yeah, i would try turning vdc off. Be careful though.

Ive had the same issue lately, it seems to start before installing my 1st mod. I was thinking it would help the issue. Some say a exhaust or tune will fix issue. I want to hear from someone that has had issue and is not resolved.

Its not due to the VDC...its an actual hole in the power delivery, the engine actually bogs down, then catches, even if I'm giving a lot of throttle input. It feels like the car is running too lean...

I know exactly what you are talking about bushman. I notice the same problem at lower RPMs. Specifically in 1st, 2nd, or 3rd gear. I'm actually getting a Uprev tune tomorrow so I'll report back to this thread on whether it helps or not.

^ sub'd

I'm stuck...I'm pretty sure a tune would fix this issue, but at 6K miles, I'm still way inside warranty. :mad:

The vdc will actively cut power. What you are talking about happens all the time to me. Even though you are on the pedal there is no respose. It's drive by wire. If you get on the gas smooth enough it doesn't happen. When you turn vdc off the tires will spin all day without any weird power cuts. Maybe you guys have something more extreme going on and there maybe a problem but it doesn't sound too different from what I have seen. I have read on here that a heavier flywheel can help minimize the bog down on a hard launch, but it will take longer to spin up.

OK, I'll try this out...thanks JHH343. If this is the case, then VDC is WAY too conservative...

There is a lot of discussion about how intrusive it is on this forum. You can't even completely turn it off without removing something under the console. If you can be real smooth with the steering/throttle inputs, it will leave you alone. It still gets me from time to time though. Hope it solves your problem.

VDC off...still getting the "bog". I'm convinced its in the factory tune...

Do have a manual or an automatic?

This may answer your question:

Throttle Response: DE/HR vs VHR

6 Spd Manual...Sport Package. This is completely frustrating...may have to go the custom tune route, warranty be damned...

You might want to let Nissan look at it first, just to be on the safe side.:tiphat:

THIS is exactly what I am feeling, its a huge dead spot off the line (independent of the throttle position) until it "catches" and accelerates. This piss poor factory throttle mapping really kills the enjoyment of the car. I guess my only alternative is to roll the dice and do the custom tune (Uprev?) or live with it until the warranty expires. :mad:

:iagree:

Bushman66, take his advice.

some people have reported better throttle response with the sprint booster. while I haven't used it personally, I figured I'd just throw that in here.

A ton of variables, so I would run through everything to pinpoint the problem. If you haven't done so already, check the intake side of the equation for anything coming loose or a dirt filter. I found leaves in the intake the first time I cleaned it out. It might even be something as simple as a bad batch of gas. It just seems odd that an CBE alone would throw off the ECU that much.

Are you trying to lauch the car off the line...and if so @ what rpm?

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.

I bog like that also, but Auto, If I just slam it down the car goes nowhere for like 1-2 secs then takes off, If you slowly get on it" Stated above" it should solve that, But so hard to east into it off the line, I tried to do it at the track when I was there,But could not ease in,, LOL I either slammed it 2 times and the other 3 I idle-rolled out nad then hit it, But all three of those I lose traction,, LOL spinnng everywhere.

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

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 :tup:

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...

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.

The 370z has a heavy flywheel at 30 lbs so thats no help to get things moving on the MT starting low in the revs.

It's also dual mass, intended for driving comfort. Until you get that thing spinning...

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.