WTB or Suggestion: High Compression Pistons

Hi does anyone have a set of high compression pistons laying around or any suggestions?

cg10 ftmofow
mine has cg10,s in and a better inlet cam, and is somewhat quicker than my old (16.0 sec 1/4 mile) blue car
they give you nearly 12:1 c/r apparently http://www.micra.org.uk/threads/43041-Hi-K11-gurus.-i-have-cg-cga-questions
but you need to "press" the wrist pins out tho eh

So you are saying cg10 pistons give much hight compression than the cg13. I always thought they have different bore..

Cheap easy option Dave but a set if cg10 pistons and rings bolt them in. Sat high to 12:1 comp ratio.

Cool..

Ive some if your interested mate?

pm sent

frank2 WROTE:

"cg10 ftmofow

mine has cg10,s in and a better inlet cam, and is somewhat quicker than my old (16.0 sec 1/4 mile) blue car

they give you nearly 12:1 c/r apparently <a href="http://www.micra.org.uk/threads/43041-Hi-K11-gurus.-i-have-cg-cga-questions" title="http://www.micra.org.uk/threads/43041-Hi-K11-gurus.-i-have-cg-cga-questions" target="_blank">http://www.micra.org.uk/threads/43041-Hi-K11-gurus.-i-have-cg-cga-questions</a>

but you need to "press" the wrist pins out tho eh

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Frank you using cg10 pistons and rods or just cg10 piston?

just the pistons mycra, the 1.0 rods are waaay too long

frank2 WROTE:

"just the pistons mycra, the 1.0 rods are waaay too long

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understood, setup like this combined with aggressive moderate-work..can run off factory ecu?

mycra WROTE:

understood, setup like this combined with aggressive moderate-work..can run off factory ecu?

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seems ok mate, but i,ll have some dyno results and a/f/r,s tomorrow
(1.0 pistons, 260deg/10mm inlet cam and subtle exhaust mods)

Cool cool man.

Cool cool man.

Cool cool man.

Whoa calm down son LOL

yeah stupid iphone man its ****...lol

well i,m chuffed with the 80 wheel hp and 115 nm, but the 12 hp transmission losses seem a bit slight ?
the piggyback 2 nd coolant temp sensor gave a nice a/f/r graph tho eh (a nice steady 13:1 fuelling on the 1st run)
more spark retard was added on the 3rd run, which lifted the hp

Nice frank you was this just cg10 pistons? Any headwork?

its with just the pistons and a 260 deg/10 mm lift inlet cam and one of my opened up exhaust mani,s mycra,
but it does show that you can get the fuelling bang-on without having to fork out for a nistune board and remap eh
i,m gonna try a gutted 1st cat and a better exhaust system and some superunleaded at the next 1/4 mile day

that arent too bad at all...what piggy back are u using?

mycra WROTE:

"that arent too bad at all...what piggy back are u using?

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lol mycra its just a 2nd coolant temp sensor mounted inside the cabin that can be substituted for the hot coolant sensor that is fitted in the cylinder head
so the ecu thinks that the engine is still cold when the colder c/t/s is signaling it (and the injectors fuel as if "in cold start" 13:1 afr)
the only drawback is when you hit the throttle it hesitates (see the 9:1 mad rich dip at the start of the graph where the engine hesitates for a second) so i have to fit a switch to that cold sensor that only operates it at full throttle, to avoid the hesitation

mm smart

so pretty much you took the coolent sensor off the head, block it. then mount it inside the cabin and run a switch only to operate at high revs. correct?

mycra WROTE:

"so pretty much you took the coolent sensor off the head, block it. then mount it inside the cabin and run a switch only to operate at high revs. correct?

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no i use both sensors mate, and switch to the cold one when needed (ie, full throttle)
the cam and pistons give plenty of grunt eh, 100+ nm all the way from 3k rpm or before

so coolent temp info is collected from both sensors combined? or are both giving the ecu the same reading?

EITHER one or the other sensor is switched dude (ie the hot one is used most of the time, and the cold one is used only for the last 10mm of throttle pedal)
you can see from the zig-zag lines on the other 2 runs that the ecu is trying to hold the afrs in closed loop (even at full throttle)
tho it wanders very lean @ 5k rpm eh (apparently the maps only extend to about 5k, then they interpolate or something ?)

Frank can you post a picture of the hot and cold sensors ?

mycra WROTE:

"Frank can you post a picture of the hot and cold sensors ?

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there,s a pic of the head one here mate https://micra.org.uk/cmf/message/51788
and the cold one is the same part/sensor, but its not being heated by the engine obviously

haha il have a go at it once mine is all assembled up frank cheers

mycra WROTE:

"haha il have a go at it once mine is all assembled up frank cheers

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np mycra
you can leave the cold sensor switched in/on actually (it just shortens the coldstart enrichment time, ie, closed loop will kick in after 1/2 a mile in the morning instead of 1 mile)
but when you disconnect/switch off the hot sensor and then hit the throttle, thats when the afr goes to 13:1 (and when you back off to cruise, it runs closed loop as normal)

ok so switch off to run 13:1 @ high revs.. off for normal...
and do you wire and isolate both wires or just the one?

you can run them both together mate, and disconnect the hot one with a "push to break" switch in one of its wires (mine,s on the gearknob atm)
and here,s a GA16 printout from the same group dyno day
he got an estimated 19 extra hp for transmission losses (taking him from 69whp to 88bhp)
but i was given only 12 hp for some reason (from 80whp to 92bhp)

yeah finished the motor today... not the power i expected ..
gonna give the sensors a go

oh say picture your current motor... if you were running cg13 bottom but worked head what fuel pressor do you recommend?

mycra WROTE:

"yeah finished the motor today... not the power i expected ..

gonna give the sensors a go

oh say picture your current motor... if you were running cg13 bottom but worked head what fuel pressor do you recommend?

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i dont think fuel pressure will have any effect mycra, you can see on my printout that k11,s run in closed loop all the time (the sqiggly torque and hp lines on those 2 runs correspond with the squiggly fuel ratio lines, and the power drops off when if drops to 17:1 afr)
where,as on the GA16 graph the ecu ran open loop and held the afr to a dead straight 14:1 mixture, and if he ran a bit more fuel pressure it should improve it to a perfect 13:1, we dont have that option eh
you guys with no-nats ecu,s should be running with GA16 ecu,s i reckon

GA16 ecu do they plug straight in? guess not.....

also i feel dump for asking but whats the difference between closed loop and open loop? is that to do with ecu mapping the af via the oxy sensor??

the non nats GA ecu is plug and play i believe mycra
https://micra.org.uk/cmf/message/12198
https://micra.org.uk/cmf/message/20582
and k11,s run closed loop in entirety apparently (lambda controlled a/f/r,s) ie, they have no acceleration enrichment eh

frank2 WROTE:

"and k11,s run closed loop in entirety apparently (lambda controlled a/f/r,s) ie, they have no acceleration enrichment eh

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They do have acceleration enrichment....

SSUK WROTE:

They do have acceleration enrichment....

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well here,s a quote from your friend ED (fusion)

"the OEM map of the K11 is closed loop through its entirety".

frank2 WROTE:

"SSUK WROTE:

They do have acceleration enrichment...."</div>

well here,s a quote from your friend ED (fusion)

"the OEM map of the K11 is closed loop through its entirety".

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That's true but it's still got acceleration enrichment.

SSUK WROTE:

That's true but it's still got acceleration enrichment.

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well thats not evident on my dyno printout (acceleration enleanment more like)

The K11 ecu isn't capable to handle much beyond stock on it's own, this has been proven countless times.

I can assure you the K11 ecu does have acceleration enrichment, and plenty of other things which are able to be optimised. Accel enrichment settings were modified heavily when my car was re-mapped, as they were far from optimal with the setup I was running at the time, e.g. larger injectors for one.