Can Tunerpro be set up to run an odd fire v6 ?

Syclone309 · Post by **Syclone309** » Tue Mar 13, 2012 5:45 am

I loved using Tunerpro Rt on my last Syclone build . After lots of trial and error , i was finally beginning to understand the black art of tuning. Some broken parts eventually lead me to a rebuild and i changed a few things during the process .

Now , with my new build and it's odd fire configuration , I would love to continue using Tunerpro . It is still the same 4.3L v6 bowtie block as before, just now with all new internals . I did search using all combinations of the term odd+fire , but saw no mention of this anywhere and decided to come out and ask . I also would have no issues with monetary compensation if the feature needs to be code written or created somehow . I have no desire to switch to a xfi or bs3 system . Thank you for any help in advance .

Post by **robertisaar** » Tue Mar 13, 2012 6:45 am

IIRC, aren't all 4.3s even fire? or do you have some kind of mix-n-match of parts?

and besides, tunerpro itself wouldn't be the issue, it would be the ECM. it wants to see an equal amount of time between all reference pulses. that part could be relatively easy to work around by having a crank trigger made that gives out a signal of even pulses based on crank position, however since you couldn't run the same amount of time between spark firings, or have any way of identifying which set of cylinders is about to go TDC, it would be a waste of time.

Six_Shooter · Post by **Six_Shooter** » Tue Mar 13, 2012 2:14 pm

Tuner pro has no effect on whether an engine is even or odd fire, that is, or would be part of the bin file programming.

What you would need to find is a BIN file that would be set-up to understand the oddfire timing of the pulses from the ICM. I don't know of any offhand, since any oddfire engines I can think of where carburetted.

Syclone309 · Post by **Syclone309** » Tue Mar 13, 2012 3:18 pm

The odd fire crank and its 90*/150*/90*150*/etc. timing patterns were originally intended for a carb back when Chevy cared about having a V6 racing program . What little I've found on the internet about any 90* common pin v6 in a production vehicle is the Delorean and Dodge dakota around the 2001 body style if i recall correctly . Some foreign models may have supported it as well , all were older and nothing i was familiar with .

I have a msd oddfire distributor and a holley cam trigger setup already .A crank trigger is the only thing i see mentioned on the net that i do not currently have . My msd digital 6 does have a setting on the side for odd-6 configuration , making all of this work together is just something i wanted to be 100% on before trying anything .

Syclone309 · Post by **Syclone309** » Tue Mar 13, 2012 3:48 pm

As far as hooking it up to my ecm and running it as-is , the ecm will still see the no.1 cylinder as the same in regards to tdc , and the dist will fire the plugs at the correct time with its offset rotor design . What i scratch my head on the most is the batch firing configuration and how it will load the runners differently on the 90* separations versus the 150* ones .

At first i was thinking half of the cylinders would be firing late as the exhaust valves were open but as i wrote it out on paper it came out the opposite .
120*-240*-360*-480*-600*-720*
90*-240*-330*-480*-570*-720*
Half of the cylinders wont have been effected and the other half will be firing 30 degrees early . Why i couldn't just leave well enough alone ,i have no idea . In case i haven't mentioned it , this is also twin turbo'd . This florida sun must be getting to me .

I know someone has the know-how to see where the correct changes need to be made , i just dont know to persuade them .

Six_Shooter · Post by **Six_Shooter** » Tue Mar 13, 2012 9:13 pm

The problem with using a bin file/ECM that is not programmed for oddfire is that the ECM will see the engine as if it was revving up and down quite quickly, due to the timing of the reference pulses, being oddly spaced, the ECM will see this as a change in engine speed. The time between ref pulses is not equal, in an oddfire set-up.

The cylinder firing won't be affected, as in they won't be firing early or late, since the dizzy itself will take care of that, the ECM will have a hard time with controlling timing accurately though.

I really think you're going to be into going aftermarket EFI.

I think the Megasquirt can control an oddfire engine, but I haven't used one personally, since all of my engines are even fire and run GM ECMs on them.

turbodave · Post by **turbodave** » Wed Mar 14, 2012 3:23 am

robertisaar wrote:IIRC, aren't all 4.3s even fire? or do you have some kind of mix-n-match of parts?

.

No, the chevy 4.3's are odd fire, that is to say, common crank throws for the adjoining rods. I'm also wondering how he may have changed the internals that make his present 4.3 any different from his previous 4.3

The Buick 3.8/4.1's are even fire. They use split crank pins. Each rod has its own crank pin split from the one next to it.

Post by **robertisaar** » Wed Mar 14, 2012 6:24 am

http://en.wikipedia.org/wiki/General_Mo ... 262_CID.29

wikipedia wrote: The 4.3L V6 has a 4.00-inch bore and a 3.48-inch stroke, identical to the 350 cid Chevrolet V8 engine. To create a true even fire engine, Chevrolet produced a crankshaft with 30-degree offsets between each rod pin. Consequentially, rod journals were increased to a larger 2.25 inches.

now, i know wiki isn't generally the most 100% accurate source...

EagleMark · Post by **EagleMark** » Thu Mar 15, 2012 4:53 pm

Call Affordable Fuel Injection and see if they still have the parts for a crank trigger, they used to sell a complete TBI system with it...