Tuning stock ecu

moonbeam807
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Joined: Mon Jul 22, 2013 7:54 pm

Tuning stock ecu

Postby moonbeam807 » Mon Jan 23, 2017 3:49 pm

Does anyone have an easy way of leaning the tune up on a 4age? I have a relatively stock combination in my MR2 race car and running it on the chassis dyno the other day, the A/F ratio was quite a bit rich in the mid to upper RPM range. The dyno operator said there is a few more HP to be gained if we can lean the mixture a little. Is there any simple way to lean the mixture on a 1986 MR2? we played with ignition timing and cam timing and have those where they make the most power.

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s24a
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Re: Tuning stock ecu

Postby s24a » Mon Jan 23, 2017 5:05 pm

You might try carefully reducing the fuel pressure. You would have to acquire an adjustable pressure regulator if the one you have doesn't have an allen wrench adjuster (inside the vacuum port).
Be careful to make sure that the WOT A/F is still below 13:1 for safety.

Hank
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jondee86
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Re: Tuning stock ecu

Postby jondee86 » Tue Jan 24, 2017 2:29 pm

moonbeam807 wrote:The dyno operator said there is a few more HP to be gained if we can lean the mixture a little.

Kind of depends on just how rich you are running...

Image

As you can see from this graph, you need to be running rich to be in the best power
zone, and being a bit either side of the best power AFR for your engine does not
have a big effect on power. As you have a race car, WOT is your happy place, and
having the mixture a little on the rich side is a good safety measure.

Cheers... jondee86
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oldeskewltoy
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Re: Tuning stock ecu

Postby oldeskewltoy » Tue Jan 24, 2017 5:12 pm

A few hp mean nothing if the result is a burned piston...........

Image
OST Cyl head porting, - viewtopic.php?f=22&t=300

Building a great engine takes knowing the end... before you begin :ugeek:

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totta crolla
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Re: Tuning stock ecu

Postby totta crolla » Wed Jan 25, 2017 2:51 am

I don't want to take this off topic but are you sure that the TVIS is opening ?
Can you post a graph of the power and AFR ?

SgtRauksauff
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Re: Tuning stock ecu

Postby SgtRauksauff » Wed Jan 25, 2017 12:39 pm

does the MR2 still use the MAF sensor with the trapdoor? I know on the Mazdas, that have a very similar setup, if you pop the top off of it, there's a gear/detent/spring setup. this gear can be clicked a couple of detents, and then your a/f will change, since this is how the ECU is getting airflow information.

here's a small vid of an explanation of it, not the greatest quality, but will get the point across:
https://youtu.be/cyRxVTh8jXQ

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jondee86
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Re: Tuning stock ecu

Postby jondee86 » Wed Jan 25, 2017 4:52 pm

Regarding this ^^^^ clocking the MAF mod... just be aware that clocking is most
often used for getting MORE fuel and not LESS. Putting in more fuel is relatively
safe, but taking fuel out can lead to problems unless you can monitor the AFR
accurately (= WBO2 gauge). The MAF is factory calibrated and sealed to prevent
fiddling, but since yours is 30 years old, you are likely out of warranty anyways :)

Cheers... jondee86
Give a person a fish, they eat for a day. Suggest they search before posting, and they learn a skill for a lifetime.

moonbeam807
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Re: Tuning stock ecu

Postby moonbeam807 » Thu Jan 26, 2017 5:03 pm

Thanks for all the information and opinions. I returned to the cassis Dyno last night and made a few more runs after installing a 4-2-1 header. Good news is it gained 1.8 WHP and 2.3 pounds of torque, and lightened the car by 15 pounds. (126.5 WHP/111.3 Torque max) Bad news the AF ratio is still down at 12.4 to 11.9 @6000 to 7000 rpm, tail pipe and O2 sensor are BLACK! I believe the TVIS is working as a couple of the graphs dip @4500 rpm, and I don't think we could get these numbers with it closed? I'm going to look at an adjustable pressure regulator and look at the MAF to see if I can adjust it reliably. I think there might be a little more power in the TVIS manifold with the sharp trailing edges causing turbulence around the injectors. I do have a wide band system on it so I can view and gather data while on track. Unable at this time to post a graph as the system says the file is too big. Will post more later.

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jondee86
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Re: Tuning stock ecu

Postby jondee86 » Mon Jan 30, 2017 11:43 am

moonbeam807 wrote:Unable at this time to post a graph as the system says the file is too big.

You need to upload your images to some host such as photobucket, and then copy/paste
the [img]image%20reference[/img] link provided by the host into your thread here.

Cheers... jondee86
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