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pretty sure if it hears a knock then the ecu pulls timing and dumps fuel

i've been running it for a couple of weeks and i leave it mainly on low cos if i'm on the highway and go to overtake it will at 10psi before you know it

and how i see it 40% throttle with 10psi or 60% with 5-6psi - cos the stock maps are so rich once you get up to ~10psi its gotta use less fuel

i did a trip to the coast, 150kms each way and used about 17 litres to get there which included going through some fun twisties - only 2 ppl in the car but 1 huge ass 12 man tent, 4 surf boards, 1 body board, 1 esky, clothes, doona and other random shit and not driving lightly really

on the way back i think i got closer to 10 (something like 10.2 or 10.5)

Yeah i agree with you there. I can't remember who exactly told me not to do it; but I thought the ecu in stock form ran on two maps, ie normal and knock. So by manually eliminating one of those map's, there's a slight risk. Hell i could be wrong. If i could manually run my car at 5-6psi and have another map running at 8-10psi, i proberly would, as im normally driving pretty conversavtivily / as effieceint as possible. That is why i bought the nistune, so depending on whats best advised i may also run that switch like yours as i like that idea.

pretty sure if it hears a knock then the ecu pulls timing and dumps fuel

i've been running it for a couple of weeks and i leave it mainly on low cos if i'm on the highway and go to overtake it will at 10psi before you know it

and how i see it 40% throttle with 10psi or 60% with 5-6psi - cos the stock maps are so rich once you get up to ~10psi its gotta use less fuel

i did a trip to the coast, 150kms each way and used about 17 litres to get there which included going through some fun twisties - only 2 ppl in the car but 1 huge ass 12 man tent, 4 surf boards, 1 body board, 1 esky, clothes, doona and other random shit and not driving lightly really

on the way back i think i got closer to 10 (something like 10.2 or 10.5)

yeah when knock is detected it retards timing and uses richer mixtures, also lowers the rev limit (only by 200rpm lol). i have also heard it stops the high boost solenoid from switching over leaving it at 5psi.

also your thinking about it all wrong tom, adding more boost/airflow isn't going to lean out a rich AFR. regardless of the boost your running, 5psi or 10psi, a stock map is going to run rich on boost. More boost = more airflow = higher load point. which means the stock maps load points are accessed further up the load axis, where they are richer. with your example of 40% 10psi and 60% 5psi, you find they are accessing load points with values very similar.

Just an example: i went from the stock turbo ~11-12psi, with AFR's pulled back to about 11.5-12:1 once on boost. Fitted my GT35 running 14psi and with same map i was running before, it was too rich once on boost. the increase in airflow meant i accessed a higher load point on the map which had a richer setting.

Yeah i agree with you there. I can't remember who exactly told me not to do it; but I thought the ecu in stock form ran on two maps, ie normal and knock. So by manually eliminating one of those map's, there's a slight risk. Hell i could be wrong. If i could manually run my car at 5-6psi and have another map running at 8-10psi, i proberly would, as im normally driving pretty conversavtivily / as effieceint as possible. That is why i bought the nistune, so depending on whats best advised i may also run that switch like yours as i like that idea.

Scott it does run two maps, normal and knock. but by grounding out the boost solenoid you wont eliminate the use of the knock maps. if you happy with the performance of the stock dual boost control leave it and get it tuned at that. if not, either ground out the solenoid or replace it with aftermarket boost control and then get a tune. there is no point stuffing around with two boost levels.

yeah when knock is detected it retards timing and uses richer mixtures, also lowers the rev limit (only by 200rpm lol). i have also heard it stops the high boost solenoid from switching over leaving it at 5psi.

also your thinking about it all wrong tom, adding more boost/airflow isn't going to lean out a rich AFR. regardless of the boost your running, 5psi or 10psi, a stock map is going to run rich on boost. More boost = more airflow = higher load point. which means the stock maps load points are accessed further up the load axis, where they are richer. with your example of 40% 10psi and 60% 5psi, you find they are accessing load points with values very similar.

Just an example: i went from the stock turbo ~11-12psi, with AFR's pulled back to about 11.5-12:1 once on boost. Fitted my GT35 running 14psi and with same map i was running before, it was too rich once on boost. the increase in airflow meant i accessed a higher load point on the map which had a richer setting.

sorry, i think i worded what i said a bit clumsily.

i was under the impression that the maps got exponentially richer the more airflow (boost) the ecu sees

by having control of the boost and limiting it to 5psi all the way it means that i can have it so i can only use 5psi for overtaking - i found this handy because i could hit 10psi below 4500 rpm before i started fiddling

what i was trying to say is that if you use more throttle but less boost then you will use less fuel than less throttle but more boost (as the stock ecu gets really rich once its seeing 10psi of airflow)

  • 3 weeks later...

I just did the drive from Sydney to Albury last night and this morning.

I started the trip having driven about 150km around Sydney and with economy of 14.7L/100km.

When I got on the freeway, I set the cruise control on a real 113km/h speed (indicated 120km/h).

Did not think I would make it to Albury on this tanks but ended up with 10.4L/100km and made it with 8 liters left in the tank.

The car was loaded with 2 adults + 2 children + a boot full of clothes and belongings.

Not a bad result and significanlty better than the last trip with 2 bikes on the roof. (13.6L/100km)

Maybe the spacer has a bit to do with the improvement....

  • 2 weeks later...

That sounds like good economy with what's on board.

I've just filled up for the 6th time with the following results: 10.13, 9.97, 9.47, 10.44, 10.59 and 9.32. The last was after cruising the M7 Wednesday night at 120Kmhr. That's a mixture of BP ultimate and Shell V-Power. I drive to Nth Ryde twice a week from the upper Blue Mountains and had one trip to Nowra through Kangaroo Valley. Around the mountains the consumption is 10-12. This is the first time I've had an auto so I'm still coming to grips in how to drive without the auto kicking back too much.

I did notice driving the M4 near Kingswood, where the police markings for aerial radar, that the speedo is out by possibly 5%. Though the car has a sticker from TruSpeed verify the speedo passes certification that would have some qualify +/- % value.

I just did the drive from Sydney to Albury last night and this morning.

I started the trip having driven about 150km around Sydney and with economy of 14.7L/100km.

When I got on the freeway, I set the cruise control on a real 113km/h speed (indicated 120km/h).

Did not think I would make it to Albury on this tanks but ended up with 10.4L/100km and made it with 8 liters left in the tank.

The car was loaded with 2 adults + 2 children + a boot full of clothes and belongings.

Not a bad result and significanlty better than the last trip with 2 bikes on the roof. (13.6L/100km)

Maybe the spacer has a bit to do with the improvement....

took the stag for a lash to the sideling the other day - its basically a cool section of slightly twisty highway then prob a good 10 km of cambered turns and hairpins :laugh:)

was in 2nd and 3rd the whole time and either hard on the loud pedal or the brakes and only used about 20 litres which averaged me about 16l/100km (which is pretty good seeign as its running rich as a mofo, and involved about 30 or 40 mins of flat out driving and probably 40 or 50 mins at highway speeds)

cant wait till i get a tune sorted, get some more power and less fuel consumption :mrt:

hey guys, just thought id add for anyone considering it, after reading this thread i decided to replace my O2 sensor to see if it made a difference, i now get 400+ ks a tank as apposed to around 300, massive increase for 200 bucks worth so well worth getting checked out if ur getting terrible economy, thats for spirited driving on highway and around town too no granny driving

hey guys, just thought id add for anyone considering it, after reading this thread i decided to replace my O2 sensor to see if it made a difference, i now get 400+ ks a tank as apposed to around 300, massive increase for 200 bucks worth so well worth getting checked out if ur getting terrible economy, thats for spirited driving on highway and around town too no granny driving

did you go genuine Nissan O2 sensor?

or what part did you use?

thanks :)

what mods?

what mix of driving?

Yeah CCL11QE, that's very impressive. Care to share what's been done to your car. Best I'm getting is around 420-450 (12-14L/100km on average) in my 260RS.

ive posted mods a few pages back,

got pod, fmic, boosted slightly more then stock, dump off the turbo, gutted cat and hks exhaust, thats about it.

i dont drive her too too hard but i still give her a push here and there....

Man, I hate it when you post in this thread! :ermm:

you love it

Interesting thing I just noticed. Previously I've been using el cheapo mineral based engine old but decided to change to the Valvoline semi synthetic. I've done 450kms and the computer indicates there's 100km's left, then you have the usual reserve after that. Before I would get to about 450kms and the computer would indicate that I need to refuel soon. This is in full 100% city driving as well.

So would changing to synthetic oil increase economy? I'll have to give a couple of more full tanks and see the results again.

Interesting thing I just noticed. Previously I've been using el cheapo mineral based engine old but decided to change to the Valvoline semi synthetic. I've done 450kms and the computer indicates there's 100km's left, then you have the usual reserve after that. Before I would get to about 450kms and the computer would indicate that I need to refuel soon. This is in full 100% city driving as well.

So would changing to synthetic oil increase economy? I'll have to give a couple of more full tanks and see the results again.

Why would you skimp on something as important as engine oil?

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