First log after long tube header install, recommendations?

[n8dogg]

2004 Z06, stock engine, K&N intake, LTH's, 180* stat.
11246
I'm happy with how she runs. I think there is a bit more power to unleash up top, she feels to slow down a bit around 5000 RPMs. LTFT's are still good, I figured it would have thrown those out for a loop.

I see a bit of KR at low RPM when I put my foot down. I'm guessing the headers have something to do with that and a false signal. How do I soften the KS?

Before I install the headers I had my WB in place of the bank 2 sensor 1 NB. Fueling was spot on. I didn't have the time to rewire my WB while installing the headers so I actually left it out. Do you think my fueling may be off? I know there is no way to know unless I use a WB, but what are your honest thoughts?

Thanks in advance, I'm still learning :angel_innocent:

[joecar]

Hi n8,

That single KR instance lacks the sawtooth pattern... it is when your PE is overly rich, it may possibly be a single instance of rich knock/misfire.

Your LTFT's look good.

It looks to me from the LTFT's that long tube headers have improved airflow by 3% during CL (corresponding to the lower range); the wideband will show the improvement in the upper range.

Yes, install the wideband, and then try the Calc.VET tutorial.

I'm not too happy about the MAF signal, it shows too much variation; post pics of MAF duct.

Remind me: which wideband do you have...? Flashscan V1 or V2...? What other mods on your Z06...?

[n8dogg]

I'll get a pic of the intake set up tomorrow. Is there a special drill bit one could buy for the 02 bung? I have a LC-1, V2, and as far as mods go just the intake, long tubes, mufflers, 180* stat, throttle body bypass... that's it.

[Mr. P.]

... Is there a special drill bit one could buy for the 02 bung?...
I was able to find a fair quality step-bit at Harbor Freight that worked well, going by memory but I think it's a 3/4" hole.

Mr. P. :)

ps - I just went into the garage and measured an O2 bung with a set of calipers, 3/4" to 7/8" will work.

[n8dogg]

Here you go Joe

http://i224.photobucket.com/albums/dd238/n8chandler/Random/IMG_1313.jpg
http://i224.photobucket.com/albums/dd238/n8chandler/Random/IMG_1311.jpg

I installed my WB today. I may need some help with the Calc.VE tuning. I'll read through the tutorials and gather up some questions. I hope you don't mind.

[joecar]

No I don't mind... in the Calc.VET tutorial have a read of the summary notes also.

[joecar]

From the pic I see the MAF is right behind the filter... air enters the sides of the filter and turns 90° and comes together immediately ahead of the MAF, this is turbulent airflow right there, at least 6 inches of straight travel are needed before entering the MAF...

but, it looks like you can't modify the duct... can you place the MAF at the other end of the duct...? where is the original MAF location...?

Does your MAF have a screen...? If not, then maybe a honeycomb airflow straightener might work, see this:
http://www.ls1tech.com/forums/generation-iii-external-engine/1413807-replacement-air-flow-straighteners.html

[n8dogg]

The MAF placement can only work in front of the duct with the K&N set up. Maybe with some couplers I could rig something up but I want to keep it jerry-rig free. I do believe Vararam came out with a duct that allows you to place the MAF upwards between the duct and throttle body. This is a known issue with the Vettes, even in a stock set-up. Supposedly there is a filter programmed in the PCM for this. Although I am not sure how you'd confirm that. IIRC there is no honey comb, might be worth looking into, thanks for the link.

Here is a log I just made, now that I have the WB installed. To my surprise I am running .5 A/F ratio lower than asked for.
11264

[n8dogg]

OK First question, forgive me for being ignorant. How do I create the calc. PIDs? I am trying the step by step Calc.VE with a new twist from Weatherman and can't figure out how to make the Calc. PID. I saved the text file in the spot as shown and they do not show up in the scan tool.

[joecar]

Too close to the TB is not good either.

[WeathermanShawn]

OK First question, forgive me for being ignorant. How do I create the calc. PIDs? I am trying the step by step Calc.VE with a new twist from Weatherman and can't figure out how to make the Calc. PID. I saved the text file in the spot as shown and they do not show up in the scan tool.

You must save it this location on your computer: Copy that calc_pids.txt file to this location, or copy/paste its contents to the file at this location on your PC: My Documents\EFILive\V7.5\User Configuration\calc_pids.txt

1. Common problems are failure to save to the proper location on your computer. It must be exact.
2. You must 'overwrite' your existing calc_pids.txt file. If you are skilled you can edit your existing calc_pids.txt file. Best to overwrite..Hit 'Save As'.
3. Failure to save to wrong location. Some people just put it in the 'Configuration' Folder, but not in the calc_pids.txt file sub-folder. You must do that.

The other procedure that sometimes you must do is:

I. Validate Pids:

1. Connect Scan Tool to your Vehicle (Select Controller)
2. Turn Ignition Key to 'On'
3. Scan Tool>>Info>>Validate Pids

Make sure you click 'Unsupported' on your pids. Insure you are using the latest software/firmware updates.

If after all that you are still having problems, find someone who knows computers and can help. The above procedures will work 100% of the time.

F.Y.I...To avoid confusion we now call the Tuning Method CALC. VET, not CALC.VE. That should eliminate any confusion.

Good luck..

[joecar]

n8, post your intended calc_pids.txt file here, I'll check it for syntax.

[joecar]

If your MAF is unscreened, see if you can try one of those honeycomb airflow straighteners (the honeycomb is coarse so it does not impede airflow).

[n8dogg]

Thanks guys, I will try the screen. I just got my PID's all set and I am getting ready to do some data logging. Gotta read through the Calc.VET new twist first.

[Gordy M]

If your MAF is unscreened, see if you can try one of those honeycomb airflow straighteners (the honeycomb is coarse so it does not impede airflow).
Joe, The 2002-2004 Z06 came descreened from GM and corresponding firmware was added to the PCM--according to a few people I know who helped develop the calibration. Also, the stock air duct was designed to help staighten the air flow. The K&N filter and air duct often caused tuning problems because of MAF location, hollow airduct and eratic IAT.

A few retired Corvette engineers who race Corvettes usually went to a Donaldson airfilter on a stock airbridge and enclosed the airfilter and cut the shroud to eliminate that problem on the C5 vettes.

[joecar]

Joe, The 2002-2004 Z06 came descreened from GM and corresponding firmware was added to the PCM--according to a few people I know who helped develop the calibration. Also, the stock air duct was designed to help staighten the air flow. The K&N filter and air duct often caused tuning problems because of MAF location, hollow airduct and eratic IAT.

A few retired Corvette engineers who race Corvettes usually went to a Donaldson airfilter on a stock airbridge and enclosed the airfilter and cut the shroud to eliminate that problem on the C5 vettes.Hi Gordy,

Interesting point illusrtated by those retired Corvette engineers...

n8's log file shows the MAF waveform swinging by more than 60 g/s in the upper rpm (where it should become steady)... a 60 g/s swing represents about 15%-20% error, that is a huge variation...

I'm curious if the the firmware can filter that and obtain the correct value...?

so this is a problem with C5/C6 Corvettes in general...?

[n8dogg]

Good info in here guys. Joe, I believe its more of an issue with the 02+ Z06s because they removed the honeycomb for those years in the Z06 only. Although I don't think the MAF placement is ideal for precise MAF readings regardless of C5 models. C6 they went to the card style MAF. There is a kit from Halltech to convert the C5's to a card style with their intake set-up.

Do you think the screen will help a lot, worth the $50? My LTFT's are good and my WB reflects the commanded A/F ratio.

[joecar]

Do you think the screen will help a lot, worth the $50? My LTFT's are good and my WB reflects the commanded A/F ratio. I don't know if the screen will help;

n8,

wow, they want $50 for it...!?!? There must be somewhere where a small sheet of honeycomb can be obtained for a few dollars, they may even trim it into a circle.


Yes, I agree, LTFT/WB do look good, the PCM must obviously be filtering the MAF signal.

[n8dogg]

Yes Halltech wants $50 for the screen. I haven't looked to see if there is any eBay quality replacements :). I may check out a hardware store and make one.

I wish I had a dyno so I could compare different set-ups. I know there are a few topics on the Corvette Forum but not a popular discussion by any means.

[Gordy M]

Hi Gordy,

Interesting point illusrtated by those retired Corvette engineers...

n8's log file shows the MAF waveform swinging by more than 60 g/s in the upper rpm (where it should become steady)... a 60 g/s swing represents about 15%-20% error, that is a huge variation...

I'm curious if the the firmware can filter that and obtain the correct value...?

so this is a problem with C5/C6 Corvettes in general...?

I will be at a club meeting next Tuesday and see if I can get an answer.

[joecar]

Yes Halltech wants $50 for the screen. I haven't looked to see if there is any eBay quality replacements :). I may check out a hardware store and make one.

I wish I had a dyno so I could compare different set-ups. I know there are a few topics on the Corvette Forum but not a popular discussion by any means.N8,

Have you see this, they're only $10: http://www.saxonpc.com/100mm-cells-for-100.html

[n8dogg]

Thanks Joe

Wish I had seen that a week ago. I got in touch with Halltech and they gave me 50% off their product. it just arrived today. I will probably install it later tonight or tomorrow and log the results.

That link may be useful for others. Good find!

[joecar]

n8, can you post pics of the Halltech...

[n8dogg]

n8, can you post pics of the Halltech...

Sure. I'll take some pictures when I get home.

[n8dogg]

1140211403