Rpeck

I am trying to tune my setup 2X 720cc primaries and 2 1000cc secondaries. I am taking it on the Dyno .. but the only shop with a DynaPack in my area cannot get me in untill late December so I was hoping you guys could list your current setup & mods to get me in the ball park untill December.

I didnˇ¦t figure anyone has my exact setup .. thatˇ¦s why I asked about 4 X 720ˇ¦s thatˇ¦s prolly the only thing close to what I have.. I will just divide the difference to adjust my 1000ˇ¦s based on your 720ˇ¦s

Thx a lot for the help,

And I will be sure to share my tuned info with you guys after I hit the Dynopack for a few Hrs. in December.

Even just some 720 secondary numbers might help .. if noone is running 4 of them.

Rpeck

Okay … asuming I am running stock type boost levels while the primary injectors are running, does this make sense? 720-550/720 23.6% ?? or is there other things such as air flow Etc. I need to consider in this?

I am speaking only of the primay injectors and not exceeding 6 PSI of boost before the secondaries kick in.

Am I on the right track? Or is there way more to consider?

Rpeck

Okay I got to thinking again. $130/Hr at 3 Hrs + 60 for the Bung (dyno) thats $450! whats a wide and running now days? Fug-It im gonna order a wideband tommorow. anyone recomend a decent one I can tune with .. that they know works on a 88 TII? I'm going ot make it with a quick relese type setup .. so I can just buy spare bungs and use it on other cars. Thats the new plan.

Scott 89t2

the FJO ones are good for around $700usd if you don't have a cat you could make something to hold it in the exhuast tip so you can use it on other cars. that's what the dynos do anyways.

Scott 89t2

to start off with.... below 3800 rpm you have 30% more fuel then stock, and above that you have 53% more fuel.

so you could set those negs (-50 for 3800+) in there and you'd have a stock map. unless I did that wrong LOL....

before you have 1440 vrs 1100, and after you have 3440 vrs 2200

Rpeck

So do the primaries squirt at full power once the secondaries kick in? Or do they just squirt a certain amount? Or nothing?

NZConvertible

Below 3800rpm the primaries fire sequentially. Above 3800 all four batch fire at half the pulsewidth the primaries were firing at before the changeover. So for example if the primaries are opening for 10ms just before 3800, all four will fire for 5ms just after 3800. This means the total amount of fuel being injecting doesn't actually change during changeover. Of course this only works with equal sized primary and secondary injectors.

1100cc/min (stock primaries) is 76% of 1440cc/min (your primaries), so you'd need to set the S-AFC to -24% to get to stock levels <3800rpm.

2200cc/min (stock primaries and secondaries) is 64% of 3440cc/min (your injectors), so you'd need to set the S-AFC to -36% to get to stock levels >3800rpm.

Rpeck

Thanks, that gives me a good place to start ... I will go far on the rich side of those numbers for now..

Scott 89t2

that can't be right LOL.... 3440 is over 50% more then 2200...


but wait... if you put it at -50 then it would only be at 1720. hmm.. I need to go back to school LOL


edit (for the 4th time) I'm gona shut up now lOL.

NZConvertible

If anything can screw with your mind, it's percentages!

You need to remember the S-AFC is reducing the flow of the bigger injectors, not increasing the flow of the smaller ones. So you need to take 1240 (36% of 3440) from 3440 to get 2200. That's what the S-AFC is calculating.

Don't worry, I had to run the numbers a few times before I was completely sure...