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ECU: CR from 8:1 to 10:1

How to make improvements to your car.
jass
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Re: ECU: CR from 8:1 to 10:1

Postby jass » Fri Jul 19, 2013 3:19 pm

OK, it has already few miles behind...
Good news - idles well, goes normal between 3000-6000 when not under full load. Havent tested it really to the red line and full load there.
Engine sounds tight and healthy (or least as the engines of the other cars with normal CR).

Bad news:
At low revs under full load (2-3-4-5-6 gear below 2500) it slows down, then starts ... "coughing" and would not really accelerate.

What did to solve that:
1. Filled the tank with 98 octane fuel.
2. Fully removed the timing adjustment electronics.
3. Timing set to 9.

Now it still has this issue, coughs below 2500 revs, but least accelerates and reaches higher revs.
Over 3500-4000 it feels rev-happier and stronger. Have set my knock sensor (visual warning only), but dont really expect knock at higher revs.

What will I do more?
Just in the process of re-soldering back my 8Hz crystal. It is a simple ECU mod, that extends the ECU tables (in my case they were stretched from 7200 revs to 7850 revs) and does good on a normal NA, as they run extremely rich.
Now hoping to have some more fuel at lower revs to help with eventual knock (although the cough doesnt really sound as such and the sensor is not responding on it).

As about the engine - everything, except the oil pump was shaved, honed (head, block, valve seats, crankshaft), changed on it.

The battle continues though, going to install the ECU and test the car with full stock ECU.

Ben, I roughly estimated with the shaved block and head approx 10.6:1 CR. Still think it could run with the stock ECU (of course the potential of the mod will be only released with aftermarket one), but it is probably at its limit. Why would you expect leakdowns from a new build engine?
Last edited by jass on Mon Jul 22, 2013 9:19 pm, edited 1 time in total.
jass
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Re: ECU: CR from 8:1 to 10:1

Postby jass » Fri Jul 19, 2013 4:58 pm

http://www.youtube.com/watch?v=tJqcnuZI ... e=youtu.be

Setting back the stock ECU frequency/fuel enrinchment didnt help.
How possible is the timing belt to have been set wrongly (although they have opened my MX5 engines more than 5 times already...).

More interesting, how would the exintake mod affect this.
jass
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Re: ECU: CR from 8:1 to 10:1

Postby jass » Fri Jul 19, 2013 6:39 pm

This should be probably taken into the equation too (or not):

"...This makes perfect sense to me since I never understood why I made so much more power with just a simple head shave. You see, shaving the head retards the cam timing too. A .020" shave will net you timing retard in addition to raising the compression ratio (BTW, each cam gear tooth is equal to 12 degrees, that is why everyone who had their belts off one tooth lost so much power)"
(copied from Solomiata)

as it runs perfectly with advance set to 18 and more.
Just tested it.
jass
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Re: ECU: CR from 8:1 to 10:1

Postby jass » Sat Jul 20, 2013 7:37 pm

The "problems" are now avoided with the Bipes set to dynamically bump up the timing to 18 degrees and down to 10 at 3600 revs and to rev limit. Still driving on 98 octane fuel though (OMV calls it 100 lol.)

Just got a call yesterday, my MS2 is ready and the harness will be ready end of next week.

The overall impression now is - the car has gained torque throughout the rev range, responds faster and feels generally livelier.
Havent done the performance tests as it is not running on temperature stable oil yet.

P.S. Interesting article about the mods I had done to my engine before and their power gains:
http://forum.miata.net/vb/showthread.php?t=186399
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BenF
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Re: ECU: CR from 8:1 to 10:1

Postby BenF » Mon Jul 22, 2013 11:52 am

jass wrote:Why would you expect leakdowns from a new build engine?


this was my mistake - I read your OP as you were putting new pistons into your old engine, I.e. just a flash over with a hone rather than any machine shop bore work as with a rebuild, hence querying leak down :handgestures-thumbup:

Very interesting post BTW as you're doing this the way I think we'd all like to - finding power through creativity rather than the chequebook! Definitely watching with interest as there's common ground here with what I've got (or will have, lol) afoot :coffee:
jass
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Re: ECU: CR from 8:1 to 10:1

Postby jass » Fri Jul 26, 2013 2:21 pm

Thanks Ben, there is indeed lot of potential on those engines that can/should be uncovered for free or some small money...

However I am placing the end of the saga here - no more drama, actually there was no need for the whole drama as all runs fine with the stock ECU now. It was obvious not a timing issue, rather fuel/spark, so I cleaned the spark plugs and the wires as a first measure and all was good again.
Now still running 18 dynamic retard to 3600 rpm on 10.6:1 CR engine with 98 octane fuel with no problems, there should not be issues with the stock ECU in this case at all.
Next to report:
- 1/4 mile times with the changes (after the oil change tomorrow)
- Will try with 95 fuel with the next tank
- Exintake is ready to go in (in the name of science with stock ECU, lol)
- MS2 to come

As it can be pushed harder now the feeling is, it has gained some overall strength. That makes me think probably already at the level of my milestone car - the bone stock 1.6 AE86.
jass
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Re: ECU: CR from 8:1 to 10:1

Postby jass » Fri Jul 26, 2013 2:35 pm

Btw. sparkplugs - for the engine with raised CR should I go for colder spark plugs than BKR5E-11?
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BenF
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Re: ECU: CR from 8:1 to 10:1

Postby BenF » Fri Jul 26, 2013 7:37 pm

I'd suggest sticking with the 5- it's already a hard plug, and 4's are not so easy to get hold of. If it was me (and it will be) I'd keep reading the plugs as you go?
jass
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Re: ECU: CR from 8:1 to 10:1

Postby jass » Thu Aug 01, 2013 11:27 am

Plugs are in, I had to change the wires. Car runs smooth on Motul syntetic not and we did the before/after performance measures.

- The ~400m are approximate (measured with GPS and car tacho), but same for both measures. The 400m times dont represent 1/4mile times for this car, they should be ( :confusion-confused: I guess a second?) higher.
- Two people in the car in both cases.

Before (average from 6 runs)

1.8, 6 speed, 1.6 flywheel and clutch, small ignition advance, crystal mod

0-100kmh average of 9.45 sec.
0-400m average of 15.46 sec.


After (average from 5 runs)

1.8, 6 speed, 1.6 flywheel and clutch, bone stock ECU
+ ~10.5 CR (raised from 9)

0-100kmh average of 8.2 sec.
0-400m average of 15.15 sec.


I was not so convinced before about the big advantage of this mod, but the difference seems to be measurable. Looking forward to the next track day, where I had constant times for almost one and a half seasons with the previous engine, so any difference should be well measurable there as well.

I think the car ready for the ex-camshaft mod now. :auto-layrubber:
Last edited by jass on Thu Aug 01, 2013 11:43 am, edited 1 time in total.
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BenF
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Re: ECU: CR from 8:1 to 10:1

Postby BenF » Thu Aug 01, 2013 11:33 am

0-100...m rather than mph, lol!

if not, build me an engine!!! :handgestures-thumbup:

Good work fella :obscene-drinkingcheers:
jass
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Re: ECU: CR from 8:1 to 10:1

Postby jass » Thu Aug 01, 2013 11:45 am

:oops: :-D Ups ... corrected!
Thanks for mentioning it, buddy - it is 100kmh (or 62.1 mph).
jass
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Re: ECU: CR from 8:1 to 10:1

Postby jass » Sun Feb 21, 2016 7:37 pm

Few years after and more impressions some feedback. I friend of mine repaired his MK2 1.8 engine to OEM specifications with only Mazda OEM parts and both cars are having the very same times up to 100mph /probably even after/.

So its just 1.8 MK1 engine with high CR /10.6:1 estimated/ due pistons and skimmed head and block.
Probably worth it mod for MK1 engine, if repair is due, as the pistons were so cheap /170 USD/.

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