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My day out at the dyno + mpg issues - filters


ersen.o

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Hey guys, mates called me up yesterday and asked me if wanted to go dyno for £30, thought why not!

 

Y HR is completely standard apart from when i put dual pop chargers in there, ii noticed the power loss and removed these a few months later, now all i have is cosworth filters!

 

anyways, car went on the dyno and was only running 296bhp! this kind of disappointed me but at the same time the graphs showed that my A/F mixture was POOR! it was at a low 10-11, it should be 14! they told me this is defiantly the reason for the power loss and told me it needs to be fixed QUICK

 

anyways, i blame the popchargers, as soon as i put them in my MPG dropped too from 18-20 to around 12-13mpg!

 

i went outside and did some research on the web and found a reset/learning procedure PDF, did this and on the way home i was back up to 20MPG!!

 

soooo just a word of advice to those of you running any mods, filters, or have removed them! make sure you complete the Air Idle Volume Learning reset! it has made my zed worth driving again!

 

its on my350z forums:

http://m.my350z.com/forum/attachment.ph ... 1112550889

 

 

:p

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Zeds always run rich, its just the way they are. No filter be it element or cone, will mess with the AFR very much as the car controls it via closed loop (when warm) O2 sensors and MAF. So long as you dont mess with the MAF (and assuming its not duff), the car will control the fuelling to try to achieve its AFR. If you've run the filters for anything more than a day the ECU will have corrected itself and be back on target AFR. Resetting it wont make any difference after a few more days when it once again returns to its target fuelling. UpRev is the only way to sort it properly.

 

Do a search for the Dyno results thread and you will see what I mean, as most of them have UpRev which is then correcting the AFR for something a little less rich.

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Might just be a coincidence that something else was up that the reset helped with. How often do you reset the MPG gauge? Your aveage sounds very low, unless hooning it everywhere on cold engine or mainly track driving, I would expect to see somewhere around 20MPG which you are currently getting.

 

Fitting a pop charger to my 350z and Still Gen3's to the 370z, I didnt notice any real difference in MPG, certainly nothing like what you've seen. Its more likely something else is the culprit for the heavy usage.

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Could be, i reset the mpg on every full tank, i do drive the car hard but on a warm engine, i do start work at 3-4am sometimes and only takes me 3 minutes to get to work, so the engine sometimes doesnt get a chance to warm up but i take it easy at that stage, maybe it was something else that the reset helped with, i hope so!

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Ah will be the cold starts and short drives more than likely. The Zed runs rich all the time and uber rich when its cold. Wont have a chance to get warm with only 3 mins to work. I notice my MPG plummets if I do driving that doesnt get the car warm :surrender:

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Ah will be the cold starts and short drives more than likely. The Zed runs rich all the time and uber rich when its cold. Wont have a chance to get warm with only 3 mins to work. I notice my MPG plummets if I do driving that doesnt get the car warm :surrender:

My journey to work is a short one also and I get low MPG when using it to go to work. Would an uprev help to make it run leaner during a cold start and so help with fuel economy quite a bit with cold starts especially?

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Ah will be the cold starts and short drives more than likely. The Zed runs rich all the time and uber rich when its cold. Wont have a chance to get warm with only 3 mins to work. I notice my MPG plummets if I do driving that doesnt get the car warm :surrender:

My journey to work is a short one also and I get low MPG when using it to go to work. Would an uprev help to make it run leaner during a cold start and so help with fuel economy quite a bit with cold starts especially?

I dont think you can no. It will run open loop until the cats are heated up. This is where it burns quite a bit more fuel than when warm, when it then switches to closed loop where the target AFR can be set. I would ask Mark@Abbey if theres anything that can be done, but my guess is that its just the way it is as you need to let the cats warm up.

 

If you are close to work I would suggest cycling. I would love to be close enough to work to ride every day and leave the car for weekend fun, but its a 35 mile round trip for me and its a bit :cold:

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You want the car to run rich when cold really as it helps protect the engine until everything's nice and warm. FWIW a 3 min drive to work is likely to do more harm than good to the engine as it's never getting a chance to circulate warm fluids properly, which you're seeing as vastly increased fuel consumption. I would definitely look into other means of transport if possible, even a £150 shed of a car just to get you there and back could cost you less in the long term. Another issue (by design) is that with rich running at start you're also looking at a higher risk of damaging the cats too, which isn't going to be a cheap fix either.

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Ah will be the cold starts and short drives more than likely. The Zed runs rich all the time and uber rich when its cold. Wont have a chance to get warm with only 3 mins to work. I notice my MPG plummets if I do driving that doesnt get the car warm :surrender:

My journey to work is a short one also and I get low MPG when using it to go to work. Would an uprev help to make it run leaner during a cold start and so help with fuel economy quite a bit with cold starts especially?

I dont think you can no. It will run open loop until the cats are heated up. This is where it burns quite a bit more fuel than when warm, when it then switches to closed loop where the target AFR can be set. I would ask Mark@Abbey if theres anything that can be done, but my guess is that its just the way it is as you need to let the cats warm up.

 

If you are close to work I would suggest cycling. I would love to be close enough to work to ride every day and leave the car for weekend fun, but its a 35 mile round trip for me and its a bit :cold:

That just sounds like a good excuse to get berks/ decats! That should liven up the K1, it's not quite got my ears bleeding yet :dry:

 

Cycling is something I've considered with the cycle to work scheme but I definitely don't see it happening in winter when it's dark on the journey home. My journey takes more like 15mins really but quite a bit of that is warming up or waiting at lights it seems.

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Sounds more like heat soak issues to me to be honest, this is an issue with CAI on the 350zeds used in built up area's , you never get enough air flow over the filters to cool the air intake temperature back down.

 

But the HR motor always run very rich stock , dont understand why Nissan tuned them this way to be honest, maybe to keep the Cats warm and working.

 

Stock airboxes work fine in my eyes .

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