1/4 mile gains not what I was expecting

[njedwardz]

Hey all,

I recently had a cam/converter swap done on my 2013 Corvette A6, and I was a little surprised by my 1/4 mile times...cam is a Stage 3 by Bourque's Hot Rods: (23x/24x .62x/.61x 115), converter is a 2800 stall ProTorque single disc that I'm not locking at any point during the runs.


http://i168.photobucket.com/albums/u185/njedwardz/cam%20comparison%20chart.jpg (http://s168.photobucket.com/user/njedwardz/media/cam%20comparison%20chart.jpg.html)

here's a vid:

https://www.youtube.com/watch?v=bRzbthaW3IU


Maybe my expectations were too high.
At the same track last year, mid summer (similar DA), I was running around 12.6xx, with 2.0 60'. Now, I'm running 11.99x with 1.89 60'. I kinda expected more of a gain here (there are guys on CorvetteForum running 10.9 passes with similar power/mods), so I'm thinking something may be off.


The two runs in the video were back to back, both 11.99x @ 119, preloading to ~1600 RPM then rolling into it - no spin at all that I could hear or see in my datalogs. I did one run just flashing the converter without preloading and it spun the tires all the way through 1st, so I'm thinking that may give me a stronger launch with DRs.

Here's datalogs of both runs, as well as my engine/trans tunes, pids, and dash pages: https://www.dropbox.com/sh/v7lq4nshtnf4ubb/AADnuTpUpw1LmgjYsLD9WWYwa?dl=0

Is something off in my tune? I don't see anything that raises any alarms in the scans, but I'm fairly new to all this.

[joecar]

I don't know about the tune (the download from the dropbox is stalling), but I most likely would have gone for 3600 stall.

What is the axle gear ratio...?

[njedwardz]

Gearing is 2.56 (terrible, I know). Car is a street car and, indeed, my only vehicle, so I didn't want to go any more aggressive than a 2800. I don't really care about track times, but I just figured they should at least be a little better than 12 seconds lol. Figured I'd check in here and see if any of you experts saw anything obviously wrong.

See if this works better; same folder but just uploaded here in zip format:

19727

[Manuel]

Hey Joecar, is his commanded PE, 0.88 across all rpm, a bit lean for a cammed car?

[rrmccabe]

Looking at the dyno charts I really dont think your gains are that far off using the converter you are running.

[njedwardz]

I forgot to mention that those dyno graphs are from data obtained on a loaded super flow dyno with an eddy brake. Before the cam went in (the graph with a peak of around 400 RWHP), the car was making 440 on a dynocom (similar to a DynoJet configuration). So I expect that on that dyno it would currently put down 480-500 (I'll never know, since that shop closed right after they took $4k from me without completing any work). That's in line with what most guys running a cam with these specs are putting down on bolt-on LS3s like mine.

Not it that it should make any difference, just wanted to clarify a bit.

[joecar]

Gearing is 2.56 (terrible, I know). Car is a street car and, indeed, my only vehicle, so I didn't want to go any more aggressive than a 2800. I don't really care about track times, but I just figured they should at least be a little better than 12 seconds lol. Figured I'd check in here and see if any of you experts saw anything obviously wrong.

See if this works better; same folder but just uploaded here in zip format:

19727Ok, I was able to download this zip file to my PC...

A high quality 3200 or 3600 stall in a street car is not that bad, you'll be surprised.

Gearing will not make as much difference as stall... and a higher stall makes much more difference than gearing.

Also remember that the 6L80/6L80 has 4.027 first gear ratio.

[joecar]

Hey Joecar, is his commanded PE, 0.88 across all rpm, a bit lean for a cammed car?

I would like to see commanded Lambda at 0.86 at peak torque... but 0.88 is ok for peak power;

Your PE table B3618 is set to EQR 1.1367 which is Lambda 0.8797 (i.e. 1/1.1367);

set your B3618 to EQR 1.1628 (i.e. Lambda 0.86).

[joecar]

Your spark spark advance at high load and high rpm is about 19*... I think you can run 24* (especially if you run PE at lambda 0.86, i.e. EQR 1.63).

[joecar]

Also, during the gear upshifts, the ECM is reducing torque via spark advance (-12*)... I did notice from your video that each upshift seemed just a little slow (not as firm as I would like)...

for the A6 I'm not sure of the best approach to reduce the torque reduction... I don't know if playing with the torque model in the engine tune would help at all.

[joecar]

In your HPT trans tune, goto Trans->Torque Management and you will see Torque Reduction...

underneath that you will see Upshift: Enabled

you could try to disable it, but you have to be careful...

I would rather leave it enabled and instead find the table that it uses to remove spark advance and edit it instead, but I don't see a table for that.

[joecar]

Summary:
- spark advance could be 24* at WOT with commanded Lambda at 0.86 (EQR 1.163).
- upshift torque reduction is too severe (it sends spark adavnce to -14*; something like 15* would be more appropriate).
- a higher stall would help (even with 2.56 gearing).

[joecar]

Some overall gear ratio comparisons:

4L60E: 1st gear 3.059
axle 3.23 * 3.059 = 9.88
axle 3.73 * 3.059 = 11.41

6L80: 1st gear 4.027
axle 2.56 * 4.027 = 10.31

so your 2.56 axle gear is not a significant impact.

But looking at the TQ curve on your dyno chart, a 3600 stall would help quite a lot.


I agree with this person:

Looking at the dyno charts I really dont think your gains are that far off using the converter you are running.

[njedwardz]

Some overall gear ratio comparisons:

4L60E: 1st gear 3.059
axle 3.23 * 3.059 = 9.88
axle 3.73 * 3.059 = 11.41

6L80: 1st gear 4.027
axle 2.56 * 4.027 = 10.31

so your 2.56 axle gear is not a significant impact.

But looking at the TQ curve on your dyno chart, a 3600 stall would help quite a lot.


I agree with this person:

WOW! that's a wealth of info there. I have all that torque reduction in there because I was trying to emulate what GM is doing on the 2014+ C7 Vettes, but I don't think the ECM is advanced enough (or it could be that the DI system gives it that much better control of fueling, which I'm sure it does.) I will likely reduce the amount of spark retard (there's a master torque reduction timing table or a minimum final timing table, don't remember which but I know where it is in the software). Also, HPT allows me to adjust the torque management requested by the trans to any value between 0-100%, so I may try something like 70% reduction instead of 100% like it's currently commanded to do.

As far as the timing/fueling goes, to make sure I have it straight, essentially adding in a bit of extra fuel should allow me to get a bit more timing out of the motor while still steering clear of detonation.

While I have your attention, I've had some issues with converter lockup (I know my current tune is set to never lock; I did this so that I'm not just burning up clutch material). From my research on here, HPT, and the 6l80etuning forum, GM changed the programming drastically for 2011+ models, which makes the TCM not respond to zeroing out the slip tables. Because of this, aftermarket single disc converters (like mine) don't seem to want to properly lock. I see 200-500RPM of slip anywhere above 25% throttle, which means that it's constantly slipping if I'm cruising at 90+ on the toll roads. After a while, the TCM decides that it's been slipping too much and goes into limp mode, which forces me into 5th gear and a few other things. I've tried forcing it to lock using the DVT controls and it's the same story; slip any time I exceed 20-25% throttle.

According to what I've found, there's no software suite out there that is able to adjust the necessary tables to prevent this from happening. Sooooo basically my plan is to ProTorque this week to see if they can build me a triple disc converter that doesn't mind a little bit of slip, and that can also lock at low RPM, low throttle to High RPM, WOT, and anywhere in between. If they can't do it, there's a 60 day unconditional return policy that they have, which I unfortunately may have to take advantage of. Either way, if I have to replace the converter, I think I will go to at least a 3200 stall as recommended here and on CF.

Anyway, my question here is: am I on the right track with this issue; I.E., there is no way to make an aftermarket single disc work properly with a 2011+ 6L80? That's the answer I got on 6l80etuning, but I'm just making sure I don't needlessly have my trans pulled AGAIN and swap converters AGAIN when this could just be a simple fix.

Here's the latest tune that I have that still commanded lockup:
19733

Thanks for all the help so far! y'all are awesome.

[Tre-Cool]

dynocom dyno's are crap for doing power runs. especially if your doing a power run with no load as it spins the motor up way to fast to do any real data logging of the afr/timing.

i think you'd be better off with a 3400rpm converter too, yours doesnt look like it's launching any harder than a stock one.

I can give you some assistance through team viewer if you want to try and resolve the lockup problem. in the meantime take a look at the following thread on hpt forum.
http://www.hptuners.com/forum/showthread.php?55149-6l80e-shifts-killing-me

[njedwardz]

dynocom dyno's are crap for doing power runs. especially if your doing a power run with no load as it spins the motor up way to fast to do any real data logging of the afr/timing.

i think you'd be better off with a 3400rpm converter too, yours doesnt look like it's launching any harder than a stock one.

I can give you some assistance through team viewer if you want to try and resolve the lockup problem. in the meantime take a look at the following thread on hpt forum.
http://www.hptuners.com/forum/showthread.php?55149-6l80e-shifts-killing-me

I agree with you about the dynocoms...it may cost me 3x more to make runs on the superflow, but the operator lets me run for as long as I want and he lets me actually make the runs myself - something I'd never had the opportunity to do at the other shop. That, and the superflow is just a superbly built machine.

regarding the converter, the one run I did without any brake stall launched a good deal harder than the others but spun the tires all the way through first, so I think I'm just traction limited - could be completely wrong though as I only have maybe 20 drag strip passes under my belt total...haven't even developed a consistent technique yet lol

I'd certainly be happy to give it a shot to try and fix the lockup. Out of interest, what jumps out at you as something we could adjust to try to get it to behave? It would make me indescribably happy to get this thing running without 1. paying a mechanic to swap converters/waiting for a new one to get build or 2. dropping my transmission in my garage for the first time ever on floor jacks lol. Get this thing to lockup right and I'll definitely paypal you for your time.

From that thread, I gather that adjusting the pressure preset settings makes a pretty substantial difference in the shifting. Most of my tune is an adapted version of a 2014 C7 tune (that is, I interpolated the pressure/timing values to match the RPM/torque/etc. values in the C6 tune). I haven't yet adjusted any of the preset settings, and although I'm VERY happy with the shifts I have now, the amount of positive feedback in that thread makes me want to give that a go just for fun lol.

[rrmccabe]

So I expect that on that dyno it would currently put down 480-500

I really dont keep up with the Vettes but what was the crank HP on that car stock? Wasn't the base C6 430 HP? If so what kind of gains are you expecting out of a cam to make 500 to the wheels?

Sorry if I missed the model or something in your specs.

[joecar]

...

Also, HPT allows me to adjust the torque management requested by the trans to any value between 0-100%, so I may try something like 70% reduction instead of 100% like it's currently commanded to do.

...Where is this table, I could not see it in your HPT trans tune...?

Or is it in your HPT engine tune...? Can you post this also, please.

[njedwardz]

Where is this table, I could not see it in your HPT trans tune...?

Or is it in your HPT engine tune...? Can you post this also, please.

Engine tune should be in the same file as the trans tune (HPT is weird and doesn't save them separately, but you can choose which controller to write to. I only write the TCM with HPT and only the ECM with EFI - complicated, but that's the way that's worked best so far lol).

In HPT -> trans -> torque management -> Adder Modifier.

A value of 0 means maximum (100%) TM is requested. A value of 0.3 means 70% of TM is requested. 0.5 requests 50%. 1.0 would request NO torque management in the relevant cells. Got this info from the 6L80etuning forum I'm a part of.

rrmccabe: bone stock, the car put down 366/380 on the dynocom. After bolt-ons/tune, it put down 440/450. With no modifications, the car put down 400/390 on the superflow - I assume it was making the same power that it did before, so it's reasonable to think that I would see a similar percent increase on any dyno. The car made 440/400 after the cam on the superflow, which is a 10% increase. So, I think it would be making around 480/450 on the dynocom, and possibly more considering those are simple inertia based dynos.

Here's the tunes I'll be flashing in today. Will report back with impressions.
19746

[joecar]

ah, ok, Modifier...

[rrmccabe]

rrmccabe: bone stock, the car put down 366/380 on the dynocom. After bolt-ons/tune, it put down 440/450.

OK fair enough. Had no idea that there was that much power to be gained in tune and bolt-ons on the C6. I would have guessed 60-70 flywheel HP tops.

Well keep working at it. The real results will show up with your track passes. Enjoyed your video by the way.

[njedwardz]

OK fair enough. Had no idea that there was that much power to be gained in tune and bolt-ons on the C6. I would have guessed 60-70 flywheel HP tops.

Well keep working at it. The real results will show up with your track passes. Enjoyed your video by the way.

Lol thanks. I just kinda wanted better numbers. I think there's actually a lot to be gained just with technique and drag radials. It's hard to be consistent when you've never really had any practice.

If the weather is nice, I may make some passes at a different strip this weekend. For some reason, my car always makes faster passes at one track than the other one, even though the DA is always pretty much the same. Like I said, consistency is the #1 thing I need to work on lol.

[joecar]

...

In HPT -> trans -> torque management -> Adder Modifier.

A value of 0 means maximum (100%) TM is requested. A value of 0.3 means 70% of TM is requested. 0.5 requests 50%. 1.0 would request NO torque management in the relevant cells. Got this info from the 6L80etuning forum I'm a part of.

...

Can please you point me to the 6L80 tuning forum, thanks.

I would try 50% torque reduction and see how much spark timing it pulls on each shift, and take note if it firms up each shift.

[njedwardz]

Can please you point me to the 6L80 tuning forum, thanks.

I would try 50% torque reduction and see how much spark timing it pulls on each shift, and take note if it firms up each shift.

http://6l80etuning.com/

It does require a subscription to post to the forums and the article section which breaks down some of the tables, but I've found it to be worth having.

[joecar]

http://6l80etuning.com/

It does require a subscription to post to the forums and the article section which breaks down some of the tables, but I've found it to be worth having.How much does a subscription cost...?

[rrmccabe]

How much does a subscription cost...?
"For a small fee of $99.99 you will have a FULL YEAR of access to pages full of frequently asked questions, tuning articles, tune/config files, tutorials and images and 2.24, Beta, and 3.0!"

[njedwardz]

How much does a subscription cost...?
As said above, $99/year, and $49/year thereafter. You might find that steep or cheap, or somewhere in between. I've found it very helpful as an amateur, but those like you who already really know what they're doing won't get as much benefit.

In other news......

Today I had the owner of ATC here in Lafayette take my car for a drive and do some testing and he confirmed that the converter in here is bad. At the shop owner's recommendation, I will be replacing it with a factory CTS-V converter that is fully capable of handling the power and locking under any/all conditions. Yes, I know that it's not a very high stall (2600 or so), and my car will be slower. I don't care about 1/4 mi times - just that my car runs the way I want it do. I have read about quite a few people who have swapped to this converter with perfect results; I'm not looking to experiment with other products that may or may not work for me.


Tomorrow I will be calling ProTorque to inform them that I want to send this converter back for a full refund because I am not happy with its performance. When I pay $1000 for a product, I expect it to work the way it needs to. In this case, I expect it to be able to lock under any load conditions at any RPM and not slip or otherwise not work. Anything else is simply unacceptable.


The CTS-V converter has a dual-clutch setup from the factory, and it is substantially more aggressive than what comes in the Corvette. I KNOW that a 3200 stall would make my car faster in the 1/4 mile, but that's only 0.0000001% of what I use this car for. I put over 20,000 miles on this car every year, and whatever converter goes in it MUST be able to handle whatever I throw at it. I'm not willing to pay shops thousands of dollars in labor to try out multiple converter setups when there is one out there made by GM that will do what I want it to.

I will be calling Circle D Specialties tomorrow as well and talking to them about restalling said CTS-V converter - supposedly it's something they've been doing quite a bit for guys like me. Should be able to get it to the 2800-3000 RPM range, according to their website.

Might not be the route that some would take, but I know it will work for what I want it to do. This would be a whole different story if the car wasn't my only mode of transportation, but that's where I'm at right now.

[rrmccabe]

I might have missed it as I was focused on HP (LOL), but why is the ProTorque not functioning properly?

Stalls come in a wide variety of stalls, tightness and personalities including abrupt and soft lockups. Of course they stall at different speeds as you increase power too.

I have a Trailblazer that has had 3 different converters in it not counting the stock unit. All of them functioned as they should but only the last one "as it needed to". No fault of the stall manufacturer.

You make it sound like its a substandard product. What did I miss?

By the way you will like the folks at Circle D. Great company.

[njedwardz]

I might have missed it as I was focused on HP (LOL), but why is the ProTorque not functioning properly?

Stalls come in a wide variety of stalls, tightness and personalities including abrupt and soft lockups. Of course they stall at different speeds as you increase power too.

I have a Trailblazer that has had 3 different converters in it not counting the stock unit. All of them functioned as they should but only the last one "as it needed to". No fault of the stall manufacturer.

You make it sound like its a substandard product. What did I miss?

By the way you will like the folks at Circle D. Great company.

Basically, when the converter goes into lockup, if I give it more than 25% throttle, the clutch allows 200-500RPM of slip (I have desired slip tuned to 0 and the apply ramp set up so that it's always getting full pressure when commanded to lock). I'm not saying the product it substandard - just that this particular converter is not working with this car for some reason. I've had the trans checked out by a couple shops that do 6L80 builds and they confirm that it is indeed a converter issue and NOT something with the trans itself or the programming.



I spoke to Chris at Circle D this afternoon. He said I COULD do the CTS-V converter and have it restalled to around a 2800 - it would cost me around $950 total without an install (my guy charges me $550 to R&R a converter). He recommended I spend the extra $250 to get their pro-series triple disc around a 3200 stall.


Opinions?

[rrmccabe]

OK missed that you had so much slip locked up.

Be careful you dont over do the lockup. As you said you drive it 20,000 miles per year and track is not as important.

I personally started with a 3200 Yank in my current TBSS, went to a 3600 Vig triple disc because the 3200 was not enough stall. I hated the Vig triple disc so much because of the abrupt "bang" when it locked up that I jerked it out and went back to another Yank but 3600.



Chris is a stand up guy so you might ask him about the lockup. I am sure he will be straight with you.

[dian]

any update on this? did you add the timing and what did that do? it sure is nice to see a 40 hz logg.

[njedwardz]

any update on this? did you add the timing and what did that do? it sure is nice to see a 40 hz logg.

Had to go and read through the thread again to remind myself where it all was a year ago. I didn't post back at the time because I was working to get pro-torque to replace the converter due to non-functioning lockup, and they did. I ended up with a 3200 stall, triple-disk carbon converter that is an absolute beast.

I don't remember what my time slips were, but somewhere in the 11.8 range. Now, this is with very gentle launches, as with this converter I'm incredibly traction limited on street tires.

Fast forward a few months and I had a lifter go bad on me, so we pulled the motor apart, replaced the lifters, went to an even more aggressive cam, and custom CNC ported LS3 heads. Car dynoed right at 500 RWHP on the same Superflow as the runs I posted initially. Now, I'm consistently running 11.75 passes on the same tires, with 1.8 60' times..so running those times with that slow of a 60' tells me that the car goes just fine.. Next upgrades will be drag radials for sure. I added a Tacoma to the garage so this is more of a plaything now, so if it's down for repairs for a while it's not the end of the world.

To to answer your question more directly, I did add timing and enrich slightly, and I did notice a performance difference. The state of the tune at that point I'm not sure, as it's a good bit different with the new heads.