Its about time we had the talk... about transient throttle - Miata Turbo Forum - Boost cars, acquire cats.

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Old 07-25-2009, 08:45 AM   #1
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Default Its about time we had the talk... about transient throttle



So I've been playing with these settings for a while. Since my clutch line snapped the only enjoyment I can get out of my Miata is sitting the driveway revving the crap out of the car. What better way to justify the experience then to mess with the transient throttle settings.

Here are what I've narrowed down as necessities in good transient throttle response:

Start with a good AFR. You can idle your 600's at 15.3:1 sure. Your cool, save the trees. Starting with such a lean AFR only compounds the issue of going lean right after Tip in. Try to keep your AFR somewhere richer then 14.7:1 always. This keeps the manifold "wet" which is always a good thing.

Transient throttle settings:
Take a look at the screen shots attached.

The car seems to respond the best to maximum gain on both map and throttle. The key to this though is to set a throttle cutoff of 30%. So after your foot goes past 30% this is now completely eliminated. This is usually ok, because if your foot is past 30% your probably out of the rev range where enrichment is required or your in gear.

I have a feeling MAP needs a similar cutoff once I can actually drive my car again. At some point you just don't want the ECU pouring on the fuel while your turbo is spooling. You just want it to adjust for REALLY rapid changes like those brought on by throttle changes. The rest your fuel map can deal with.

One of the most important features to getting good throttle response was setting the enrichment period to 150ms. 200ms, and 100ms just did not work as well. 150ms was the sweet spot.

The Asynch was about what you would expect. it is nearly the asynch that came from adaptronic basemaps, but scaled for Deatschwerk injectors.

If you are not running the Deatschwerk 600cc injectors then your values WILL be different.

Can anyone independently verify this works for their car?
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Its about time we had the talk... about transient throttle-tran.jpg   Its about time we had the talk... about transient throttle-async.jpg  
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Old 07-25-2009, 10:53 AM   #2
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two things!

1. before tuning ANY transient throttle settings, you have to have a DIALED IN FUEL MAP. Why? Well here's why: when you snap the throttle open, whatever load/rpm cells the cursor jumps through are the ones that dictate your primary throttle enrichment. if those are wrong, you're going to be fighting this thing forever. So... off-idle, you want to verify that the 80-100 kPa cells for all RPM values are dialed in. this may require a wired-open wastegate and a few wot runs from low RPM. Just do it. Thank me later.

Second: Your asynchronous enrichment gain % value is set to zero. I believe the software assumes "30" when you do that.
Quote:
Originally Posted by installers manual
The gain of the asynchronous pump refers to the change in TPS value that is required to inject the squirt duration in the asynchronous table. If the gain is set to 0, then it is assumed the gain has not been setup and is taken to be 30.
so you might as well set it at 30 so you know what it really is
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Old 07-25-2009, 11:01 AM   #3
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Travis,

Will try this in a few hours and post back...

Thanks for the hard work!
Cheers,
Matt
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Old 07-25-2009, 01:19 PM   #4
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I didn't play with the asynch gain yet... I guess I just past over it. It maybe possible to reduce the TPS enrichment that way. I guess I need to experiment a little further. I still felt the slightest hesitation on throttle tip in, but this cleared it up alot.

Also I experimented with transient advance, but it yielded no real advantages that I could pick up on.

Travis
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Old 07-26-2009, 01:10 AM   #5
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Damn, I wish I would have seen this before I went out tonight to work on this (and only this) part of my tuning. It's better, but I would have been able start with a better foundation.

That, and Matt's suggestion of the 80 and 100 kPa. Mine might not be perfect so redoing it all again. Good call on wiring open the gate.

So, even though I started out wrong, it is better. My enrichment from 1500 > 3500 when I get on it is good. I still have this damn lean when just barely touching the throttle. It's a bitch when trying to drive "normal" from a stoplight.
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Old 07-26-2009, 12:31 PM   #6
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stein, in your logs what RPM are you feeling the hesitation at? is it just off idle RPM?
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Old 07-26-2009, 06:50 PM   #7
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Quote:
Originally Posted by y8s View Post
stein, in your logs what RPM are you feeling the hesitation at? is it just off idle RPM?
No. It's anytime at any RPM where I go from 0% throttle to any throttle. With the tuning on the asynch last night, if I jam on it, it works fine. It's just the slightest touch that is bad. Even with the cruise on, if it coasts downhill with no throttle, when it engages again, it will go lean even if RPMs are at 3,500 going down the highway. It's most noticeable off idle as there isn't any RPM to help keep it from stumbling or dying.
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Old 07-26-2009, 08:17 PM   #8
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Use ally my settings, and set the async gain to 90. I got flawless response all the way up.
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Old 07-26-2009, 10:38 PM   #9
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Quote:
Originally Posted by TravisR View Post
Use ally my settings, and set the async gain to 90. I got flawless response all the way up.
I thought lowering the gain increased the effect.

ie when the tps rate matches the gain value, you get 100% of the asynch. if your TPS rate is double the set gain, you get 200%. and if you jab the gas at half the set gain, you get 50% of the enrichment.
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Old 07-27-2009, 12:16 AM   #10
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The way Rob at adaptronic explained it to me there are actually two different enrichment modes. There is the TPS and MAP enrichment, which is handled completely seperately from the asynch enrichment. The Asynch enrichment is just a single manifold wetting pulse. The TPS and MAP based enrichments at the top actually occur over a period of time.

So the asynch is just there to get rid of that very very first initial lean spike, then the TPS and MAP enrichments come in and follow through.

I don't know what is going on with the gain value but as I increased it on my settings the initial lean spike went down, and all hesitation was slayed on tip-in.
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Old 07-27-2009, 12:30 AM   #11
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Here's how the manual defines it. For me, a lower gain seemed to help control off idle afr's. I've got mine set to 6.

"The gain of the asynchronous pump refers to the change in TPS value that is required
to inject the squirt duration in the asynchronous table. If the gain is set to 0, then it is
assumed the gain has not been setup and is taken to be 30."
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Old 07-27-2009, 12:33 AM   #12
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Quote:
Originally Posted by sv650_ck View Post
Here's how the manual defines it. For me, a lower gain seemed to help control off idle afr's. I've got mine set to 6.

"The gain of the asynchronous pump refers to the change in TPS value that is required
to inject the squirt duration in the asynchronous table. If the gain is set to 0, then it is
assumed the gain has not been setup and is taken to be 30."
I saw that, too. I set mine at 2. Still sucks *** off idle.
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Old 07-27-2009, 12:34 AM   #13
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Can someone try putting it at a 100 and see how the car responds?

It could very well be that at lower numbers it was injecting way too much fuel. The O2 sensor was then detecting a very lean condition because the cylinders wern't burning. (Lots of O2!) So when I gained it up the AFR's got brought back down into the burnable range and the meter goes back to rich again.
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Old 07-27-2009, 12:59 AM   #14
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Quote:
Originally Posted by TravisR View Post
Can someone try putting it at a 100 and see how the car responds?

It could very well be that at lower numbers it was injecting way too much fuel. The O2 sensor was then detecting a very lean condition because the cylinders wern't burning. (Lots of O2!) So when I gained it up the AFR's got brought back down into the burnable range and the meter goes back to rich again.
Hell, I'll try anything now. Will do tomorrow.
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Old 07-27-2009, 09:36 PM   #15
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Hmm, went to try the settings but my car is running bad... reallly bad! I think that my one injector is messing everything up and so after dropping it...the injector is goin in for repairs. Seems my pintle cap is screwing up my fuel flow.

Hope to be back online to try more settings but for now the yellow car is down for the count :( Just felt that I owed a comment since I offered to report back earlier.

Cheers!
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Old 07-27-2009, 11:24 PM   #16
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Did you contact Deatschwerks directly? I hope that fixes everything.
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Old 07-27-2009, 11:24 PM   #17
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Tried it. No change when toggling back and forth between 2 and 100.

Two things that I did observe:

Changing Idle Control in Aux Out from 1K to 2K did flatten the idle out a bit, but some other thing were kind of funky so I went back to 1K. It's the best for me.

Cleaning up the 60 and 80 kPa areas around idle, 1500 and 2000 did help a bit. Still goes lean but doesn't buck as bad. So, a good tune, like Matt said, is critical.

One thing:

When setting the 2000, 2500, 3000 and 3500 40kPa (and 60 kPa with the AC on), the car isn't revving completely smooth. I'm getting that baaaababaaaababaaaaabababaaaa sound like a little miss. I did replace the plug wires with 10K mile NGK's from ZX-Tex (replaced my 30K NGK's) and it hasn't changed. I need to pull plugs and likely just replace them. They are new BKR7Es with 3K on them, gapped to .028" on stock coils. Coil replaced 25-30K ago.

WOT it sound fine. I THINK that I heard that sound under low load going for a test drive after I noticed it today, but that could be my imagination now that I noticed it.

It may be contributing to my problem. I have a hard time dialing in a steady idle again.

EDIT:

Just reading the grounding thread again made me think. I have done zero to my car with regards to checking, cleaning and replacing ground wires. It is as it came from the factory 10 years ago. What should I look at specifically?
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Old 07-27-2009, 11:30 PM   #18
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Quote:
Originally Posted by TravisR View Post
Did you contact Deatschwerks directly? I hope that fixes everything.
Called them today and they are going to look at the injectors for me. Shipping them out tomorrow evening and hope that this solves the problem. Only thing I can imagine is that the bent pintle cap is blocking my fuel flow and sorta makes fuel drip down the intake

Will surely know in a few days when they come back and I stop dropping them!

Cheers,
Matt
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Old 08-02-2009, 01:32 PM   #19
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I tried my settings on the road today, and they work really well for me. The car really responds. I did mess with my asynch a bit on the enrichment. I set it to maybe 20? Its funny how you just start automatically compensating for the lull in transient response, and not realize it until the lull is gone. It revs really fast off idle, engaged the clutch at 3k on accident pulling out of the drive way. Good irk for my loving neighbors.

As far as ground wires You could just check the resistance from ground to the motor or to the chassis? Do all of the grounds, and if one seems high maybe try to clean it up. Maybe kind of similar as to how you would check for good spark plug wires?
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Old 08-12-2009, 10:11 PM   #20
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stomp3.xls


Would somebody be so kind as to take a look at the attached and let me know where I need to focus my attention?

This is a log of stomping on the throttle at idle. Initial AFR looks ok to me, but then there's a huge lean spike half a second later. I'm attempting to crispen up throttle response as hell and toe is very laggy right now. It feels like the motor sucks air for a split second before reacting, making rev matching a guessing game.

Thanks for any input.
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