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Post by chris71 on Aug 11, 2017 20:55:15 GMT
Hi. Was going through one of the many MX5 groups on twitterface and someone was saying that they had done by Skuzzle a remap of their standard ecu to rev up to 8,500 rpm. What would benefit of this ?
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Post by martiny on Aug 11, 2017 22:13:19 GMT
So far as I'm aware the only benefit is to racers who don't want to run out of revs in a corner before they can change up. Oh, and bragging rights I suppose. There isn't any more power up there on a stock engine.
PS Should say that's what I know about NA/NB cars anyway. NC is foreign territory to me.
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Post by minty on Aug 12, 2017 19:05:29 GMT
^this^
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Post by atlex on Aug 12, 2017 23:02:38 GMT
you can't remap the stock ecu, but there was meant to be a 'crystal' chip you could replace to get it to hit higher revs. I think it's bollox but Fizbne might know more. Only sane thing is to get an programmable ecu with a raised rev limit, but, tbh, you probably don't want to raise the rev limit unless you do things with the head.
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Post by FFS Corders on Aug 12, 2017 23:31:00 GMT
The MK1 ecu crystal can be changed to one of a different frequency
This tricks the ECU into thinking the revs are lower than they actually are so there is a change to the fuelling across the actual RPM range
Plenty of info out there to look up but essentially it gains a couple of bhp, higher rev limit and gives the car a more 'eager' feel
As for MK3, no idea, but Skuzzle can indeed remap these
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Post by minty on Aug 13, 2017 6:06:51 GMT
My crystal appears to have been changed to one that lowers Rpm and decreases bhp.
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Post by Rickster on Aug 13, 2017 21:49:28 GMT
Skuzzle chipped my 1.6 92 a few years back, he also tightened the afm clock spring - added a few Bhp and made the car definitely feel more eager and revvy Has to be done on the dyno with timing etc
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Post by minty on Aug 13, 2017 21:54:09 GMT
Interesting, I didn't know much could be done with the stock ECU
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Post by martiny on Aug 13, 2017 23:17:40 GMT
There is a bit more that can be done, depending on the model. You can overclock the ECU with a crystal change as described, and that makes the ECU think the engine's running slower than it really is (because it thinks time is running faster than it really is) though that doesn't work with a factory immobiliser because it screws up communication between ECU and immobiliser.
With the original 1.6 you can swap the ECU microcontroller for a daughterboard made by Grid which allows the rev limit and the fuel and timing maps to be reprogrammed. Quite an old device now, don't know if it's still available. You can do all that on an early 1.8 too but it involves desoldering the EPROM chip, replacing it with a socket, manually editing the required bytes of machine code and burning a new chip with the new tune. I got involved some years back in trying to decode the '94 ROM and it was a slooow business. Got to the stage where you could at least nobble the checksum in Roadster ECUs which stopped you tinkering with the code, and you could change the rev limit and play with timing and fuel. I think some others took the project further and may have started a retuning business but I gave up when I started seeing machine code in my sleep and just bought a Megasquirt instead.
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Post by Fizbne on Aug 14, 2017 8:41:53 GMT
you can't remap the stock ecu, but there was meant to be a 'crystal' chip you could replace to get it to hit higher revs. I think it's bollox but Fizbne might know more. Only sane thing is to get an programmable ecu with a raised rev limit, but, tbh, you probably don't want to raise the rev limit unless you do things with the head. Heyyy, Fizbne here. Nah it's not Canoe Spheres at all - As stated, it raises the rev limit, along with everything else in a way. e.g. Standard fuel cut gets disabled at 2,000RPM on a standard car (you can tell as once it hits 2k it'll burp on overrun once it starts fuelling again), but raising the rev limit with a crystal swap to give you an extra 1,000RPM will raise that fuel cut thing to 3,000RPM. It also changes the fuelling across the range and will run leaner as a result, meaning MOAR POWERER. This coupled with an AFM tune, and timing set on a dyno will produce pretty damn good gains tbh. My old Roadster went from 88WHP to 103WHP with an AFM Tune, and timing advance on Skuzzles dyno. My car also had a stainless equal length 4-1 manifold, full "straight through" cat-back, and a Jackson Racing intake (5hp increase at top end). Midrange was super strong, and the top end screaaaaaaaaaaamed. It ate most 1.6's for breakfast kekeke. Then I lunched the engine and replaced it for a high comp NA engine. UNSTOPPABLE POWER. Saying that, just because you have an 8,500 RPM rev limit, doesn't mean you should take it there. Max RPM the stock B6 can handle is abouuuuuuuut 7600, 7850 MAX in my opinion. Anything over that, and hello oil starvation. What are conrods? What even are cam journals etc. etc.
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Post by NurseHolliday on Aug 14, 2017 11:27:07 GMT
I definitely saw the wrong side of 8k when my throttle pinned open :-(
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Post by chris71 on Aug 14, 2017 19:27:03 GMT
Well. Thank you very much gentleman. Was just a simple question I asked as didn't really understand it,and it has opened up another potential mod on the cheap for "MOAR POWERER"
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Post by minty on Aug 16, 2017 19:06:26 GMT
I'm still holding out for Jacks ME221 group buy.. 😀
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