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Heh, guess who forgot to turn the rev limiter offset the rev limiter to 6000.
Fuel turned out to be pretty close, timing was what needed the most fiddling.

Also, lucky I got a mate here in Sydney to buy all the gear from here to have a play himself, I had to borrow his VN gear to work out why I couldn't connect to the ecm, seems my usb comms is giving me grief, though for some reason tunerpro beeped on 2 occasions when I opened it, though only after taking a good 20 seconds or so before beeping, put my mates one in and tunerpro beeped pretty much as it was opening.

I did notice that the limiter was a little low, but I assumed that you had a reason.
Have you got a finished bin to compare?

im pretty sure on the one i did, at 1600rpm, it made max torque with 9 degrees more timing that stock ....

v6bucket wrote:Have you got a finished bin to compare?

Yeah I do, though seeing it was a job I got paid for, sort of wouldn't seem right to post it publically.

Holden202T wrote:im pretty sure on the one i did, at 1600rpm, it made max torque with 9 degrees more timing that stock ....

One thing that struck me as odd was how rich it had to be at wot 2400 to 3600, wondering if the throttle body being mounted on top of the plenum was the reason, with what looked like the tube extending part way into the plenum.

You're measuring a/f ratio as a whole not per cylinder some could be real lean and some obviously really rich so you have to richen it all up till the lean ones work properly

Ken wrote:

Holden202T wrote:im pretty sure on the one i did, at 1600rpm, it made max torque with 9 degrees more timing that stock ....

One thing that struck me as odd was how rich it had to be at wot 2400 to 3600, wondering if the throttle body being mounted on top of the plenum was the reason, with what looked like the tube extending part way into the plenum.

Strange, the 3800V6 had issues with cylinder distribution because of the rear mounted TB and the elbow and nasty turn into the rear cylinders. A TB on top facing straight down should minimise the distribution issues.

delcowizzid wrote:You're measuring a/f ratio as a whole not per cylinder some could be real lean and some obviously really rich so you have to richen it all up till the lean ones work properly

Yeah, a scenario I'm familiar with having been involved in tuning HQ racers for the last 22 years, with their crummy siamesed inlet ports and tractor (farm equipment) inlet manifold, didn't expect it to be as much as it was with this motor.

immortality wrote:Strange, the 3800V6 had issues with cylinder distribution because of the rear mounted TB and the elbow and nasty turn into the rear cylinders. A TB on top facing straight down should minimise the distribution issues.

The owner of the motor stated the tube that the TB flange was welded to extended some way into the plenum, eg: an inch or so, which struck me as odd, that's what got me wondering as to whether or not it had some influence in that area.

Those factory elbow tube things were backwards in every regard. They actually cause a distribution problem and reduced performance. What I found is the cause the rear 2 cylinders to run quite a bit richer. Removing it makes all cylinders have pretty equal AFRs. The idea of the plenum is to allow lower density air moving at high velocity to slow down and gain density. Each runner then can rip a "chunk" of volume out of the plenum and so forth. Distribution happens naturally due to capacitive like action of the plenum. Having a pipe a fair way in can cause resonance issues, where different parts with resonance differently and not as one plenum.

Having the pipe extended in 1" should not cause issues, but the factory one with it taking up 40% or so of the plenum volume and effectively creating 2 plenum volumes with 2 completely different resonances was dumb.

The only reason I could thing of is maybe to decrease response and power on the V6 as supposedly people complained about the early VN being too powerful and losing it on take off.

So anyway having those factory ones removed the low/might areas VE increases a bit and needs much more AE as well. So I would not be surprised that you would see a need to richen it up in those areas.

See this dyno run of plastic tube insert vs without. Without is the larger power and torque curve.

Ken wrote:

Holden202T wrote:im pretty sure on the one i did, at 1600rpm, it made max torque with 9 degrees more timing that stock ....

One thing that struck me as odd was how rich it had to be at wot 2400 to 3600, wondering if the throttle body being mounted on top of the plenum was the reason, with what looked like the tube extending part way into the plenum.

How rich are you talking ? or are you just saying the VE needed to be raised alot to get the right afr ?

When i tuned one we found that 4.8afr at wot was nearly its most happy, even though the roughly right max power afr is 5.2 ish

vlad01 wrote: The idea of the plenum is to allow lower density air moving at high velocity to slow down and gain density. Each runner then can rip a "chunk" of volume out of the plenum and so forth. Distribution happens naturally due to capacitive like action of the plenum. Having a pipe a fair way in can cause resonance issues, where different parts with resonance differently and not as one plenum.

Can't say I agree whole heartedly with that explanation, though a debate best left for another time perhaps.

Holden202T wrote:How rich are you talking ? or are you just saying the VE needed to be raised alot to get the right afr ?

When i tuned one we found that 4.8afr at wot was nearly its most happy, even though the roughly right max power afr is 5.2 ish

Both, though the a/f more so, can't say I can ever remember needing to be that rich on a meth carb tune, not that I'm implying it's a problem, just thought it odd.