raising the rev limiter

is there an easy way of raising the rev limit on a 1300 micra with std ignition/ecu? just wondering as mine revs out at about 6500 and it could do with a bit more of a rev range and i dont really want to buy a better ecu just yet.
thanks chip
 

micras69

Deactivated Account
chip,

dismantle the dizzy to get at a little metal disk there should be 4 large slits/gaps in the disc and a little one. you join the little one to one of the bigger ones by removing a little bit of the metal with a stanely blade to make one big one if you get me this raises the limmiter......

or as i did you can place a bit of sparkys tape over the little gap/slit to remove the limmiter all together dont know what it reves to as my tacho needle was off the clock and then got valve bounce :doh:
 
OP
OP
C
so you just lengthen the slit right? i dont like the idea of totally removing the limiter as im not very mechanially sympathetic and would probably rev it too hard:blush:

chip,

dismantle the dizzy to get at a little metal disk there should be 4 large slits/gaps in the disc and a little one. you join the little one to one of the bigger ones by removing a little bit of the metal with a stanely blade to make one big one if you get me this raises the limmiter......

or as i did you can place a bit of sparkys tape over the little gap/slit to remove the limmiter all together dont know what it reves to as my tacho needle was off the clock and then got valve bounce :doh:
 

Ed

Fusion Motorsport
MSC Founder
Official MSC Trader
Just remember that this does have additiional issues. That 5th slit allows the ECU to run fuelling sequentially. With out it the ECU cannot get a 720deg lock, instead it will run batched fired. This doesn't normally seem to be an issue but just thought I would let you know.

At some point ill put a K11 on a dyno and see if running the car with the slit covered changes anything...
 

Sparcoxs

Buy & Sell Member
So you just cover that little hole up or join the big slit with the little slit and you lift the rev limiter??? That's it?? SWEEEET!!! Thanks for the pic Frank!!
 

Alexx117

STI
Club Member
If you join the slits what does it raise it too? As I remember someone saying on here that there's a fuel cut out point around 7500? At least I'm pretty sure that's what was said but I may be wrong
 

frank

Club Member
was it not 7300 alex ? one of matt,s (MPH) posts a while back
and there,s no point really on a 1.3 without cams eh (but WELL worth it on a 1.0 with cams tho :cool:)
 

Harlen

Dr. Zoidberg
Site Supporter
So is this actually worth doing? I run a 1 litre with 1.3 cams, always been tempted to do this as I think the limiter cuts in way to early (about 6300RPM). The engine is still climbing in power and I reckon the peak is about 7200RPM, easily. Would you reccomend cutting across the hole, or covering up the smaller hole? Does it run noticeably worse?
 

frank

Club Member
So is this actually worth doing? I run a 1 litre with 1.3 cams, always been tempted to do this as I think the limiter cuts in way to early (about 6300RPM). The engine is still climbing in power and I reckon the peak is about 7200RPM, easily. Would you reccomend cutting across the hole, or covering up the smaller hole? Does it run noticeably worse?

yours can now breathe the same as a 1.3 (same head, mani,s, valves, ports, cams etc) so with the right fuelling, yours should have about the same hp @ 7500 rpm as a 1.3 @ 5000 rpm :eek:
 

micras69

Deactivated Account
i dont know about the fuel cut like! i was trying to kill a 1L engine and it was reving way past 7500rpm :wow:
 

baguete

Site Supporter
Yes, it cuts at 7300rpm on high gear, because you are at high rpm for too long and the ecu cuts... Yesterday i got a fuel cut on my SR, hill climb on 3rd gear @ 150kmh.
 

Alexx117

STI
Club Member
Yes, it cuts at 7300rpm on high gear, because you are at high rpm for too long and the ecu cuts... Yesterday i got a fuel cut on my SR, hill climb on 3rd gear @ 150kmh.

Is it like a safety precaution? Should you be revving it in high rpm for too long It cuts out?
So it's not like you can rev it in neutral to 7300 and it will instantly cut out?
 

baguete

Site Supporter
Just remember that this does have additiional issues. That 5th slit allows the ECU to run fuelling sequentially. With out it the ECU cannot get a 720deg lock, instead it will run batched fired. This doesn't normally seem to be an issue but just thought I would let you know.

At some point ill put a K11 on a dyno and see if running the car with the slit covered changes anything...

Interesting you say that, when i had that mod, my 1.0 feeled more powerful then with stock dizzy and the ECU set to 8.000rpm. I was told that batch fire give more power, but only at high revs, is this correct? In any way the Micra ECU uses batch fire at a certain rpm?

Is it like a safety precaution? Should you be revving it in high rpm for too long It cuts out?
So it's not like you can rev it in neutral to 7300 and it will instantly cut out?

Never had problems with high revving my engines, the 1.0 (205.000km) does 8.000rpm and the 1.3 (129.000km) does 7.300rpm. In neutral you can rev it and doesnt cut...
 

Alexx117

STI
Club Member
Interesting you say that, when i had that mod, my 1.0 feeled more powerful then with stock dizzy and the ECU set to 8.000rpm. I was told that batch fire give more power, but only at high revs, is this correct? In any way the Micra ECU uses batch fire at a certain rpm?



Never had problems with high revving my engines, the 1.0 (205.000km) does 8.000rpm and the 1.3 (129.000km) does 7.300rpm. In neutral you can rev it and doesnt cut...

Maybe some sort of safety precaution then? If you rev it in neutral and it doesn't cut then maybe it will only cut when held there for a period of time or under load.. Who knows?

Do you think that if you decrease the gap between the two slits that the limiter will increase respectively?
 

baguete

Site Supporter
Maybe some sort of safety precaution then? If you rev it in neutral and it doesn't cut then maybe it will only cut when held there for a period of time or under load.. Who knows?

Do you think that if you decrease the gap between the two slits that the limiter will increase respectively?

Yes, its a safety measure on the ECU, but i dont know how it works (load vs time ??), Ed can respond to that better than me.

The slit size doesnt have nothing to do with the limiter increase, it just gives a 9.000rpm rev limiter. I got NIStune set to 7.300rpm (stock dizzy) and i still cuts if i go for too long on a gear. And some times i cuts really early, imagine i go for some time at 6.500rpm on a hill climb, and then i floor it down, at 7.100rpm it cuts (sometimes even earlier). All depends on the amount of time you are at high rpm. When i had this dizzy mod (before having NIStune) i just covered the square hole, didnt joint the two slits...
 
So is this actually worth doing? I run a 1 litre with 1.3 cams, always been tempted to do this as I think the limiter cuts in way to early (about 6300RPM). The engine is still climbing in power and I reckon the peak is about 7200RPM, easily. Would you reccomend cutting across the hole, or covering up the smaller hole? Does it run noticeably worse?
I blocked of the small hole in the disc and all it would do is tick over but would not rev
 
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