Rogue_Ant

From the Welt chips I've taken a look at, the AFR targets, timing, everything is identical between the Turbo-S and non-S...
This is to include the near 13:1 AFR table target approaching redline. Adding a 3bar regulator will enrich that about a full point, bringing the target AFR to near 12:1. Which makes sense.
Unless you are going to be very conservative with boost pressure, run the 3bar FPR.

sfierle

Thanks for all the help. I plan to pick up a 3 bar FPR before I install the chips, and run without the wastegate shim. We will see how it goes.

TurboTommy

Well, you pretty much have to install the wastegate shim (or, possibly use some other method of increasing boost), otherwise you'll run too rich with the 3.0 bar FPR (maybe even lose some power)
And, as mentioned, do the exhaust; it'll make as much of difference as the chip added on top

Zuba951

TurboTommy is correct… The waste gate shim is a steel plate made to a specific thickness that when placed between the valve side(bottom) and the diaphragm side(top) of the waiste gate, preloads or recalibrates the spring so the valve will stay closed longer or need a higher boost pressure to open it… The boost gets set to 14.5 lbs from what I remember. At that boost level the stock FPR is fine. If your car is stock you need both chips and the waiste gate shim...

Rogue_Ant

...and this is the exact issue with older chips - they were locked in to a small, specific boost range. Not enough boost, and the timing will be too conservative, and requires one fuel pressure. Raise the boost some, and the timing is more appropriate, but now you to change your fueling.

Zuba951

Dude, I don't understand why you just wrote that...what's with the drama?

There is no issue "they were locked in to a small, specific boost range" Well yes that was the whole idea.

You’re not going to be changing the boost "it’s locked in by the shim" so all the other stuff isn't going to change.

You sounded like VR with his "and when the air flow meter maxes out fueling is out of control" ...lol

Rogue_Ant

Really - I'm not sure why you apparently have a bone to pick with me.
Oh, and don't give me the "airflow meter is maxed stuff", I answered that very question from you years ago: https://rennlist.com/forums/6961024-post78.html


Now back to the point, maybe we can clear up the real differences in chips...

What about this:
On the welt chip, if you are over ~60% throttle what is your ignition timing & target fueling?
Now, if you are over 60% throttle, is the boost always at full boost?

The answer is this (for the Welt chip & other factory-style software):
If your are over ~60% throttle, then the ignition timing and target AFRs are the same, regardless of boost pressure.
Because turbos do not spin up instantly, a set throttle position does not equal a set boost. Furthermore, the load on the engine also has a major effect on the response of the turbo.

For example, in 5th gear, at 60% throttle, the turbo will probably spin up to full boost quickly. But, in 1st gear the turbo will not spin up nearly as quickly, and might not even hit full boost.
The Welt chip does not differentiate between the two scenarios. The ignition timing and target fueling is identical for both cases. This is not ideal, as both fueling and timing need to be load based (especially on a turbo car).
Further, since turbos build boost, anytime the car is in heavy throttle, but not full boost (such as the transition period from vacuum to full boost), the timing and fueling will not be ideal (Welt chip). This is due to the limited "specific boost" tuning.

The fix, is to take into account engine load (boost pressure, cylinder filling, ect) at all throttle positions. This is how my Tunes work, and how every newer engine management system operates.

I even setup a page on my site to explain this in more detail some time ago:

http://www.roguetuning.com/multi-dimensional_mapping

sfierle

Now this is getting more complicated. Once again, I am getting conflicting info. I want to keep my car more stock, and just do a set of chips and exhaust (easy to change back to stock). I really do not want to shim the wastegate too! Is anyone running just the chips with or without the 3 bar fpr?

Zuba951

Joshua
I’m sorry man I didn’t mean to hit a nerve I was just playin, I thought it was funny.
I do understand and appreciate what you are saying and yes you are correct, The dude that started the thread wanted to know about the welt chips. I have them and for a bump up from stock they work fine.
Are they optimal for today’s standards? No but neither is the stock software or the whole car for that matter. It is what it is and I luv the thing. With a stock car he needs to put both chips in and the waste gate shim. That’s per the instructions that came with the chip. Apparently he doesn’t even want to do that so I’m out…
Again I was just playin
Brian

Rogue_Ant

Next time throw me a bone when you are being sarcastic will 'ya!

And I agree that the Welt chips are a nice step-up from factory. But what I don't want to see is someone hurt their motor from an incorrect setup. At factory boost, the Welt chip is probably just fine. Above factory boost, I would run the 3bar FPR.

Tom M'Guinn

Since we are strolling down memory lane, when I got my car, there were three common ways of increasing boost -- a banjo bolt jet like APE, wastegate shims like Welt, and drilling the cycling valve. The Lindsey boost enhancer was also gaining popularity. My how far we've come....

As for the AFM, no question a good MAF will flow more. I was just saying I think the AFM runs out of voltage long before it runs out of air flow capacity. For those not following the point, think of it this way. When the motor hits say 15psi, the barn door will be open all the way and the AFM will produce the highest voltage it can produce -- something just under 5 volts. If you then turn up the boost to 25psi, the DME still sees the same 5 volt signal as it did at 15psi because the barn door hasn't move a bit -- it can't open any more than it already was at 15psi. Since the factory DME does not measure manifold pressure for this purpose, it will give the same timing and fuel at 15psi and 25psi (or 125psi), so you lose the ability to tune the motor after the point where the barn door opens all the way.

Reimu

So what about with a system that does read manifold pressure like the A tune? Is the flapper still a problem outside of the restriction?

Rogue_Ant

The A-Tune uses Manifold pressure along with the AFM. The software then understands different boost pressures and can adjust its fueling targets, and ignition timing accordingly. This is the single biggest difference between the A-Tune and other AFM-chips.

The AFM still has issues with being a volume sensor (since the DME does not measure air-mass directly, it must derive air mass using a few sensors), age and wear, and yes, being a breathing restriction.

Dom1

Dont bother using shims. Use a lindsey boost enhancer, it will increase your boost as well as bring it on sooner. I am using the welts with the boost enhancer, works good. With chips alone you will not benefit much and will probably run rich. The LBE is a simple substitute for shims. If you have a 26,8 turbo you need a 3bar fpr.

BobSantos

I'm basically the same set up. Basically just highway driving and no problems and nice power.