Messing around with my 1.6 SOHC - got some cheap HP

[torpedan]

That guy is full of it.

On a turbo car a good goal for a A/f is in the 13's for a n/a applicatoins its very diffrent.

[What]

Originally posted by torpedan:
That guy is full of it.

On a turbo car a good goal for a A/f is in the 13's for a n/a applicatoins its very diffrent.

Hrmmm... I did over thousand dyno runs at http://www.monsterhorsepower.com

A lot of factory turbo vehicles ('yota, DSM, etc), come 10-10.5:1. General safe power tuning will vary per motor, but 11.5:1 12:1 is a safe ratio. 13:1 would be a go to the track or make big dyno numbers on good gas kind of a/f...

I wouldn't want to be 14:1-15:1 under full throttle NA. Naturally aspirated you can run the 13:1 a/fs as a good power tune safely.

Stock your car should be around there. My 1.6sohc runs as rich as 11:1 on the street at times.

I could list a whole lot of cars that run 11.5:1 even NA from the factory... suffice to say... 13:1 is not good safe tune for turbo, but is definetely acceptable for NA.

Good luck on your project...

[rukick]

With my stock ecu they told me my Fuel/air was 14.5 and with the protege ecu it was 15.5. How do I get the F/A down to 13?

[What]

They measure from the tail pipe I assume.

Do you have a catalytic converter?

Any leaks in your exhaust?

[rukick]

They measure from the tail pipe I assume. - yes

Do you have a catalytic converter? - yes, stock.

Any leaks in your exhaust? - I don't think so, I just had custom 2" pipes put on from the cat back and a performace, high flow muffler about 7 months ago.

Thanks for any help you can offer.

[What]

Basically I was just thinking that perhaps you are not as lean as you are.

Depending on how effective your catalytic converter is, it could be burning off a little fuel so the reading from the pipe can be a bit leaner than it is.

That or their 'sniffer' doesn't go far enough up the exhuast and gulps in bit of air. That and also the dyno equipment can get plugged up from time to time... so on, so forth.

I've had cars that the a/f varied by as much as a full point from reading from the front of the car to the back of the tailpipe (exhaust leaks/whatever).

How was the a/f at idle? Did you see it at a cruise before giving 'er s--t? If it was close to 14.7:1 in those conditions... I'd say it was probably reading accurately enough.

If you are worried about the problem, and believe it was very accurate, then the cheapest solution for you would be just to try upping fuel pressure a bit. You should be able to get the results you need. Otherwise, on Mazda electronics it becomes more of a larger injector and subtract MAF signal kind of scenario it would seem... bunch more $$$.

[rukick]

Thanks for the info. What benifit would a safc2 have for a 1.6 sohc n/a if any?

[What]

Mmmmm, I'd have to measure voltage on the flapper door maf on mine to see if there is any room to increase the signal. To my knowledge, the MAf voltage is maxed once the flapper door is open all the way. Therefore.. idle, part throttle you can make increases... but WOT, you can't increase on an already maxed signal. I'm definetely not a fan in comparison to hot-wire or other MAF setups.

I hooked up a SAFC on a BPT in the summer... ran TPS input to a MAP sensor for linear rise (instead of on/off TPS), and part throttle tuning it worked ok, but under full throttle I couldn't really make the changes I wanted. Maybe that's just on the BPT, but...

for simplicity I'd still stick with the FPR. If you want to go turbo BP or somethign down the road, there are some other options.

[monty73741]

you can install a rx-7 maf on...it will be non-trap door style.......do a search & you will find what version u need

[atlantamx3]

Originally posted by monty73741:
you can install a rx-7 maf on...it will be non-trap door style.......do a search & you will find what version u need

What??

NO!


The 2nd Gen Rx-7 VAF IS a trap door style.

[papa roached]

yea, its a trap door style, its just got a bigger opening and that style isnt so bad for restriction, at least teh door swings out of the way mostly, check out a VAF from a KL, now thats restricting

[torpedan]

Originally posted by What:

Originally posted by torpedan:
That guy is full of it.

On a turbo car a good goal for a A/f is in the 13's for a n/a applicatoins its very diffrent.

Hrmmm... I did over thousand dyno runs at http://www.monsterhorsepower.com

A lot of factory turbo vehicles ('yota, DSM, etc), come 10-10.5:1. General safe power tuning will vary per motor, but 11.5:1 12:1 is a safe ratio. 13:1 would be a go to the track or make big dyno numbers on good gas kind of a/f...

I wouldn't want to be 14:1-15:1 under full throttle NA. Naturally aspirated you can run the 13:1 a/fs as a good power tune safely.

Stock your car should be around there. My 1.6sohc runs as rich as 11:1 on the street at times.

I could list a whole lot of cars that run 11.5:1 even NA from the factory... suffice to say... 13:1 is not good safe tune for turbo, but is definetely acceptable for NA.

Good luck on your project...

Safety has a lot to do with tuning Running the leaners a/fs removes the margin of safety. And in a N/A case the margin ism uch more forgiving.

[What]

[/QUOTE]Safety has a lot to do with tuning Running the leaners a/fs removes the margin of safety. And in a N/A case the margin ism uch more forgiving. [/QB][/QUOTE]

Like I mentioned... hp tuning or track tune... I wouldn't do it for serious road racing or daily. Each different motor design and it's natural mechanical octane characterstics play a huge role in what you can and can not get away with. If you ever start to tune enough cars, you'll also notice that certain engines like certain A/Fs due to such magical mechanical predeterminations.

Generally 13:1 is very good place to make power NA... and on a lot of pump gas turbo cars, 11-12:1 is not only a good place not only for safety but for power as well becuase you have the safety to make that power.

It all depends. I say try the richer a/f. I've seen 13:1 make power even on NA time and time again.

[Yoda]

Actually the sliding cone VAF isn't as restrictive as you would think. I you grasp the basic concepts of aerodynamics the cone and shape of the barrel actually work together to flow more air than if it was totally open. I'll have to dig through my flow bench notes to remember just how much more. I don't know if you have ever see the VAF from a (FD) RX-7TT or a (Cosmo) 20B TT but the sliding cone VAF for these engines are smaller diameter on bother ends when compaired to the KL VAF. Even the smaller JE VAF on the K8 and 200hp JE-ZE flow more than the KL VAF.

Originally posted by papa roached:
yea, its a trap door style, its just got a bigger opening and that style isnt so bad for restriction, at least teh door swings out of the way mostly, check out a VAF from a KL, now thats restricting

[white94mx3]

ok, 1 question... I have the DOHC model, Would the ecu from the BP help it out alittle? I hate the lag it has between 2500-3750. it sucks...