My Creampuff NA Build

My set-up runs a bit rich (P0172/0175 rich bank CELs). I have put ~6k miles with no mechanical or performance problems or anything, but am having some additional tuning done next Friday. I have to pass emissions since I moved and can't pass with it throwing the codes. I am guessing trimming the pulse back just a bit will allow the adaptives to stay within range on the PCM without throwing the codes.

I thought that Sound set the idle mixture when they dyno'd/tuned it.

I think the tuning was primarily for WOT. When it was originally tuned ~3 years ago, while they have lots of experience with AEM, ProEFI, etc, I think the their knowledge was limited using the VEC. This is just a guess, but I think the original tuner (not Lar) may have under-estimated the ability to help tune idle and part throttle conditions with the VEC. The reason I say "guess" is the for 3 years with the original tune I have been happy and wouldn't have done anything at all if not for the emission requirements.

banton said:

I think the tuning was primarily for WOT. When it was originally tuned ~3 years ago, while they have lots of experience with AEM, ProEFI, etc, I think the their knowledge was limited using the VEC. This is just a guess, but I think the original tuner (not Lar) may have under-estimated the ability to help tune idle and part throttle conditions with the VEC. The reason I say "guess" is the for 3 years with the original tune I have been happy and wouldn't have done anything at all if not for the emission requirements.

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No disrespect, but, unless something changed - the VEC cannot change idle speed and can only modify the LTFT for a given point in time. In addition, for closed loop tuning the VEC does two dimensional adjustments and to do true tuning you need three dimensioal capability. I have run the VEC as long most and it is very limited except for WOT tuning and even there the delay kills you.

Jack B said:

No disrespect, but, unless something changed - the VEC cannot change idle speed and can only modify the LTFT for a given point in time. In addition, for closed loop tuning the VEC does two dimensional adjustments and to do true tuning you need three dimensioal capability. I have run the VEC as long most and it is very limited except for WOT tuning and even there the delay kills you.

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No disrepect taken. I know the idle speed can not be modified, but can the idle be tuned or perhaps the fuel pulse trimmed to put it in range of the closed loop adaptive range? If not, is the SCT capable of resolving the condition that is generating the rich bank CEL's? I'd soon park the car and get it tuned using the SCT than spend money on a retune/dyno time using the VEC to only discover it can't handle what I need....and more cost to buy the SCT package and pay for another tune.

PS. Sorry, I didn't mean to hijack this thread Viper Tony.

banton said:

PS. Sorry, I didn't mean to hijack this thread Viper Tony.

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You didn't. You actually reminded me to get my tuning done and it will be done in April.

Open your VEC software with your tune and go to the fuel tables. You can mess with STFT by modifying the fuel load and fuel RPM tables to get your rich/lean idle a bit closer to what the 02 are chasing. At idle for instance, get to the RPM table that is closest to your indicated RPM...I think the VEC shows 750 and then 1000 as available to modify. I use the 750 cell. Now put a percentage in that field...say 50%. Now go to the load table and look for the MAP that corresponces to your MAP at idle. Probably between the -12.5 and - 15 cells. In those cells put a small negative value...say -.8. What the engine now sees are a reduction of delivered injector pulswidth of 50% of -.8 or -.4ms at that MAP and RPM. You can see how this can be used to manipulate closed loop setting for idle. I do this all the time and have scaled the VEC tune to smoothly transition from closed loop to open loop as I near WOT/boost. It takes time to scale this way, but you can clean up transition from closed to open loop in the same manner across RPM and load settings. It takes time, but the VEC can be used to some extent to work closed loop tuning...limited, but it can do some. For just WOT tuning, its much easier since you are not chasing closed loop trims and just dialing in final AFR across pre-set load and RPM settings.

EllowViper said:

Open your VEC software with your tune and go to the fuel tables. You can mess with STFT by modifying the fuel load and fuel RPM tables to get your rich/lean idle a bit closer to what the 02 are chasing. At idle for instance, get to the RPM table that is closest to your indicated RPM...I think the VEC shows 750 and then 1000 as available to modify. I use the 750 cell. Now put a percentage in that field...say 50%. Now go to the load table and look for the MAP that corresponces to your MAP at idle. Probably between the -12.5 and - 15 cells. In those cells put a small negative value...say -.8. What the engine now sees are a reduction of delivered injector pulswidth of 50% of -.8 or -.4ms at that MAP and RPM. You can see how this can be used to manipulate closed loop setting for idle. I do this all the time and have scaled the VEC tune to smoothly transition from closed loop to open loop as I near WOT/boost. It takes time to scale this way, but you can clean up transition from closed to open loop in the same manner across RPM and load settings. It takes time, but the VEC can be used to some extent to work closed loop tuning...limited, but it can do some. For just WOT tuning, its much easier since you are not chasing closed loop trims and just dialing in final AFR across pre-set load and RPM settings.

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Contrast the above with the following SCT features:

1. Multiple 3 dimensional tables, therefore, allowing tuning flexibility for part or wot and closed loop or open loop.

2. Control of the time delays the PCM uses before implementing fuel or timing changes. This enhances the transition from part to full throttle

3. The ability to shut off the LTFT, this allows you to generate a 3 dimensional a/f table of STFT with a third party software. You then use this to modify the base injector map fields. This gives you the ability to make a modified engine run smoothly in closed loop. You can then fine tune the a/f through several other tables, but, this is where you start.

4. Adjust idle.

5. Adjust fan turn-on. You can control engine temp very well with this feature. This is especially nice if you drag race, you can get the engine relatively cool in the staging line.

6 Turn off skip shift.

Tuning time is dramatically reduced, plus, a whole bunch of us had a built in hesitation after installing the VEC. My throttle response is way better after removing the VEC and tuning with SCT. I picked up a minimum .2 sec and 3 mph in the quarter after going to SCT. I will admit the VEC is a nice window switch and in its time it was the only option.

Jack is 100% correct. The VEC is (by today's standard) a carb when fuel injection is the standard. Just addressing the question. On a non-related note....The AEM up for sale is really keeping me awake at night.... just saying.

Thank you EllowViper and Jack, your info is appreciated. I think I should just move on to the SCT for the best chance to get the results I need. Now I just need to find a trusted SCT tuner in my area.

DC could likely do it over the phone for the most part

banton said:

Thank you EllowViper and Jack, your info is appreciated. I think I should just move on to the SCT for the best chance to get the results I need. Now I just need to find a trusted SCT tuner in my area.

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I personally use Dan at Viper Specialty for my SCT tunes, but I know Dan at DC and Sean at Roe have VERY good reps for it too. If you have your dyno graph showing your A/F ration throughout the run, they can right you a killer tune just by looking at that. I tried to get some dyno time yesterday, but the guy couldn't squeeze me in. I've never had mine on one and I have a canned tune from Dan right now, but I've done some other mods since then and really want to get a dead on tune this time. Maybe next week.

I would think for WOT tuning a dyno sheet with A/F ratios could be dialed in pretty good remotely. Unfortunately, I believe my specific rich bank issue combined with wanting to improve some part-throttle/driveability conditions would be challenging and would require a lot of back and forth, even with data logs. But then again, I will ask the experts.

Looks like I am tuning next month. Plum: I may turn this into a dyno day...it'll probably be in Greenwich, CT. FYI.

Come on Tony, it's April.
We need closure on this build - it's driving me nuts and it's not even my car.
Howz the tuning going?
I'm gearing up to do something similar with Gen3 heads next winter and am keen to hear all about your exploits.

Ade.

PS Just fitted Air/Oil separator - first class - cheers.

MADMAX said:

Come on Tony, it's April.
We need closure on this build - it's driving me nuts and it's not even my car.
Howz the tuning going?
I'm gearing up to do something similar with Gen3 heads next winter and am keen to hear all about your exploits.

Ade.

PS Just fitted Air/Oil separator - first class - cheers.

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I'm working with Todd @ A&C Performance on the tuning. Soon grasshopper.

ViperTony said:

I'm working with Todd @ A&C Performance on the tuning. Soon grasshopper.

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Nice! He will be doing mine too...just bought my SCT Tune from him last week.

I'm considering having my car shipped out to him as well this summer.

So, I finally got to the dyno this morning. And the results are INCONCLUSIVE. Yep, what a crappy day. Fortunately, nothing went wrong with the Viper. Preface: I did my heads/cam work late last summer and while the Viper drove fine I never made it to the dyno before winter came. Fast forward to this year...I was blown off 5 times (three times last fall and twice this past spring) by a tuner. (This is another story). I waited as long as I could but with ViperDays this weekend I needed a safe tune and I could wait no longer for this AWOL tuner. Fortunately, Todd @ AC Performance came to the rescue. Even though he's located in CA and I'm in CT we arranged for him to tune remotely. I found a great dyno facility with competent operators and strapped the Viper down at 10am this morning. I don't know why, but I was as nervous as baby sheep around Plumcrazy (LOL). All kind of thoughts were going through my head...Did set valve lash correctly? Did I miss any bolts ? **** what if the engine blows? But once the car went WOT the sound was sweet music to my ears. We did two pulls.

Looking at the monitor I was really surprised just how pig rich the AFR was. I knew it was a bit rich at WOT but this was nuts. The AFR was between 10.2 and 11. It looked ugly. It put down 538rwhp and 535rwtq. I send the results to Todd and he assures me to not sweat the numbers as the AFR is just not where it needs to be. Todd works his magic, sends me an SCT tune...and this is where it gets fun: I could not load the SCT to the SCT Handheld programmer. Try and try as we might but "Failed to download" was the message of the day from the handheld. Nobody in CT has these DCX handhelds in stock. I went to my original tuner where I purchased it from and he verified the handheld was ***** and only SCT could fix it.

So here I am...with the Viper on the dyno waiting for Todd's magic, supposed to be driving down to NJMP for ViperDays and this POS handheld craps out on me. To say I was disappointed in an understatement.

Todd, bless his soul, has been an absolute saint to work with. He's over-nighting me an SCT programmer with preloaded tunes to test on the dyno and it should be here first thing tomorrow morning. If all goes well on the dyno tomorrow morning I may just make it in time for Viper Days and get some track time in the afternoon and Sunday. I just hope the numbers pick up and, more importantly, that the AFR gets MUCH better.

I cannot thank Todd @ AC Performance enough for his help, knowledge, patience and resourcefulness. He's gone out of his way for me and the man knows customer service. I owe him dearly. Hopefully, I'll have good news to post tomorrow morning. Stay tuned. (no pun intended)

Good luck man. Your up there with my HP.

the tuner who blew you off all these times needs to be shot. his word is obviously **** i wouldnt even ask the guy anymore, heck with him.

todd @ A&C is tops, youre in good hands. just need a little more time now.

Is this a common issue with the SCT? I have seen some of the Viper Truck guys getting *****'d controllers too.


Hope you get it worked out and get your tune squared away.

I guess they either work or they don't. I haven't had a single issue with my SCT X2...and I've been erasing, changing, uploading, and just doing a bunch of trial & error stuff without a problem. I have not tried to upload a remote tune however.

Red Snake said:

Is this a common issue with the SCT? I have seen some of the Viper Truck guys getting *****'d controllers too.

Hope you get it worked out and get your tune squared away.

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I don't know if it's a common issue but I'm not the first person to have this particular issue with it. Todd @ AC Performance FedEx'd me a new handheld with three custom tunes loaded into it (Track and two aggressive tunes). It was supposed to be here at 8:30am this morning, nothing yet. Figures.

i love the idea of the SCT and id use it to control fan on/off type thinggs but im n ot sold on tuning with it. especially for SC builds.

tony, ever consider AEM ? i know there has to be a few guys in your area who can tune well with it.

plumcrazy said:

i love the idea of the SCT and id use it to control fan on/off type thinggs but im n ot sold on tuning with it. especially for SC builds.

tony, ever consider AEM ? i know there has to be a few guys in your area who can tune well with it.

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AEM is ubber overkill for me and very $$$. SCT is fine for me just wish there were more experienced SCT tuners in CT.

Update, it turns out there was a shipping error and the controller won't be here until Monday. Until then.

ViperTony, how did the SCT tunes work?

Regards,
Aaron

Tony have tried Dan with DC Performance?
I used them for my SCT tune and I have no problems.

Sorry guys, been buried at work. I went to the dyno two weeks ago. I'm using Todd @ AC Performance who's been SCT tuning remotely and he's a class act. Can't say enough positive things about him. We got to 550rwhp but Todd was operating blind being remote without logs. There's probably another 30rwhp or so to be had. I'm going back with my logging software next week and see what we end up with.

Thanks for the update Tony - I'm reading your progress on this thread with great interest as I finally have all my spares ordered for my NA build this winter.
Good luck next week and keep us posted.