Fuel Consumption went up after the header+tune?

[steve99]

Originally Posted by PetrolioBenzina

I'd like to try that tune! Totally stock 17 86.

are you on stock oft tune ?? which revision v4 ?

[Spec C Wannabe]

Originally Posted by tomm.brz

I'm sorry i created confusion in the op's mind. He created this thread because of something I wrote that was somehow misleading
my car does NOT drinks like a V8 and I created confusion saying about my INSTANT consumption relevations. And i should had not do that

So, OP, don t worry you won't consume like a V8 if you change header and tune the car
The post of mine you cited, I repeat, was only to say that specifically after putting Wayne's Rom cam timings, my fuel consumption rised a bit compared to OTS cam timings, during low speed low load city driving, but gained a lot of smoothness and driveability from them

As an OP, I get your message. Your original message got me lose my sleep over it because I don't want to turn my car into a V8 drinker.

Never mind, I am cleared and can have my rest now.

[Spec C Wannabe]

Originally Posted by steve99

If you get way worse fuel economy after installing header, cgeck your ltft if its running high like 10% or npre especially at lower. \rpm, you likely jave amd exhaust leak. Generally this wil caise o2 sensor to see fresh air so ecu tginks car is rin ing lean so ot add lots of fiel via high positive ltft.

And dont ise o2 sensor spacers when you have tune, and never put spacer or adapter in front o2 sensor, ive had seceral cars turn up from exhaist shop installs with spacer in front 02 it thows fueling way off.

Is it OK if there is a bung extension for the rear O2 Sensor?

[steve99]

Originally Posted by Spec C Wannabe

Is it OK if there is a bung extension for the rear O2 Sensor?

If its in rear 02 sensor its ok but not needed.

If its in front 02 sensors its going to stuff up the sensor reading , front 02 is the main fueling sensor

[tomm.brz]

Steve a question i dont find a good answer..
In aftermarket header specially on uel, what is the best position for the FRONT o2 sensor? In the single tube hole or where the tubes merge just at the end near the overpipe?

[Wayno]

Originally Posted by tomm.brz

Steve a question i dont find a good answer..
In aftermarket header specially on uel, what is the best position for the FRONT o2 sensor? In the single tube hole or where the tubes merge just at the end near the overpipe?

Closer is better. Most aftermarket makers will try to put it the same distance from the exhaust port as stock, which means single runner unless you have 4-2-1 with short primaries, which UEL's are not.

[tomm.brz]

Originally Posted by Wayno

Closer is better. Most aftermarket makers will try to put it the same distance from the exhaust port as stock, which means single runner unless you have 4-2-1 with short primaries, which UEL's are not.

Thanks wayno, my question is that i have a HKS uel boxer spec header. The official instructions of this headee says to put A/F sensor (i guess they mean front sensor?) to the second hole near the overpipe and the o2 (i guess rear o2) to the closer singlw runner hole) and they specifically give you an extension for the grey cable that is for the front sensor to let you put the front sensor on the further hole Near the overpipe

And that is the opposite of what you are saying.. But if you think it is bettter to put the front sensor on the single runner (on my hks uel header it is on a short runner) i could try it..
Now i have the front sensor near the overpipe and actuallt my closed loop feels not so smooth, the acceleration with low throttle feels sluggish and not regular

[Wayno]

Originally Posted by tomm.brz

Thanks wayno, my question is that i have a HKS uel boxer spec header. The official instructions of this headee says to put A/F sensor (i guess they mean front sensor?) to the second hole near the overpipe and the o2 (i guess rear o2) to the closer singlw runner hole) and they specifically give you an extension for the grey cable that is for the front sensor to let you put the front sensor on the further hole Near the overpipe

And that is the opposite of what you are saying.. But if you think it is bettter to put the front sensor on the single runner (on my hks uel header it is on a short runner) i could try it..
Now i have the front sensor near the overpipe and actuallt my closed loop feels not so smooth, the acceleration with low throttle feels sluggish and not regular

Install in the same confirguration as factory. Primary before secondary.

[tomm.brz]

I ll upload soon what hks writes. It s the opposite of what you say!
but i would be glad hks is wrong and you are right since my closed loop specially doesn t feel so great, and I m over 235 reflash on my car so I did experiment a lot
I would just like to know why HKS says so

[sandy s]

I could see unproved fuel consumption when I installed the V2 stage 2 tune over stock. Car used a lot less fuel and ran better.

[Kodename47]

Originally Posted by tomm.brz

Thanks wayno, my question is that i have a HKS uel boxer spec header. The official instructions of this headee says to put A/F sensor (i guess they mean front sensor?) to the second hole near the overpipe and the o2 (i guess rear o2) to the closer singlw runner hole) and they specifically give you an extension for the grey cable that is for the front sensor to let you put the front sensor on the further hole Near the overpipe

And that is the opposite of what you are saying.. But if you think it is bettter to put the front sensor on the single runner (on my hks uel header it is on a short runner) i could try it..
Now i have the front sensor near the overpipe and actuallt my closed loop feels not so smooth, the acceleration with low throttle feels sluggish and not regular

The problem is that you really don't want the main O2 feedback based on a single cylinder. I think that is more of a concern than having the distance from the valves. I run a single O2 sensor and if I had that manifold I'd bung the port in the single runner and fit the sensor in the collector.

[tomm.brz]

So that is the official instruction from hks





So the front lambda goes to near the overpipe, as kodename says. I did this way.
And actually this way makes the front lambda more close to. The exhaust holes Because of the shorter runners. The other hole on this header is on a longer runner so that would make the front lambda actually more further from the engine.
Wayne says to put on tbe single hole on the longer runner I think, against what HKs and kodename say. Who has right?

[Kodename47]

Originally Posted by tomm.brz

Wayne says to put on tbe single hole on the longer runner I think, against what HKs and kodename say. Who has right?

If you read what Wayno wrote, it's not disagreeing with me. Primary O2 in a single runner is bad, end of. Some manifolds have it at the primary collector in a 4-2-1 but you want the sensor to read as many cylinders as possible.

Think about it this way, if that single cylinder happens to run much richer than one of the others, then you'll have one that is running consistently lean. If you have it in the collector then at least that is averaged out.

[tomm.brz]

Well i could misunderstand but wayne said "primary before secondary" that sounded to me that he meant in front o2 in the single runner

Anyway i just will keep the front o2 as i have now then, on the collector at the end as HKS says