Intake, Header, HFC, CBE = Too Lean?

Red370 · 03-25-2010, 05:11 PM

Quote:

Originally Posted by theDreamer

CobbTuning.com - AccessPORT > Tune > Self-Tuning - Cobb PC software.

never noticed that, i <3 you.

Red370 · 03-25-2010, 05:12 PM

Quote:

Originally Posted by Zsteve

Alex when you did your AFR scans how were they done?

I never had them read on a dyno, just seen what they were when I plugged in my AP, never checked them at WOT because the numbers fluctuate so rapidly, im sure I could probably datalog and pull it up on my laptop if i wanted to.

Zsteve · 03-25-2010, 05:15 PM

Quote:

Originally Posted by Red370

I never had them read on a dyno, just seen what they were when I plugged in my AP, never checked them at WOT because the numbers fluctuate so rapidly, im sure I could probably datalog and pull it up on my laptop if i wanted to.

I'll ask AA how to logg that on the device. I dont think you need a computer, I think you can logg it on the device and then transfer it somehow.

Red370 · 03-25-2010, 05:19 PM

Quote:

Originally Posted by Zsteve

I'll ask AA how to logg that on the device. I dont think you need a computer, I think you can logg it on the device and then transfer it somehow.

Oh i know it logs on the device, the box it comes in comes with a pc to device plug so you can transfer the data.

Zsteve · 03-25-2010, 05:55 PM

Quote:

Originally Posted by Red370

Oh i know it logs on the device, the box it comes in comes with a pc to device plug so you can transfer the data.

Im waiting on mine right now at the house.

Red370 · 03-26-2010, 01:55 PM

Did some datalogging today, here are some numbers i'd like you guys to take a look at, I did a few 1st gear WOT runs just to get an idea of what my AFR's were looking like, take a look.. The Mid 14's at 6500rpms make me nervous..

Columns:
1. Seconds 2. Coolant temp 3. Intake temp 4. Ignition Advance 5. Oil Temp 6. RPMs 7. MAF 8. Vehicle speed 9. AFR 10. AF Correction

semtex · 03-26-2010, 02:03 PM

Quote:

Originally Posted by Red370

Did some datalogging today, here are some numbers i'd like you guys to take a look at, I did a few 1st gear WOT runs just to get an idea of what my AFR's were looking like, take a look.. The Mid 14's at 6500rpms make me nervous..

Columns:
1. Seconds 2. Coolant temp 3. Intake temp 4. Ignition Advance 5. Oil Temp 6. RPMs 7. MAF 8. Vehicle speed 9. AFR 10. AF Correction

Hmm...kinda hard to tell. I think you need to sort the data. The rpm isn't showing from lowest to highest. Plus, it's only showing what appears to be a narrow slice of the rpm range in the 6000's.

If it helps you at all, here's my latest dyno showing AFR, and this was after getting a tune so the AFR is adjusted to where it ought to be.

Modshack · 03-26-2010, 02:08 PM

Quote:

Originally Posted by semtex

Hmm...kinda hard to tell. I think you need to sort the data. The rpm isn't showing from lowest to highest. Plus, it's only showing what appears to be a narrow slice of the rpm range in the 6000's.

If it helps you at all, here's my latest dyno showing AFR, and this was after getting a tune so the AFR is adjusted to where it ought to be.

In addition, first gear is a poor one to get decent logs from. You really want the car under load. Suggest 3rd gear or higher if you have the room..

semtex · 03-26-2010, 02:09 PM

Quote:

Originally Posted by Modshack

In addition, first gear is a poor one to get decent logs from. You really want the car under load. Suggest 3rd gear or higher if you have the room..

I missed the part about being in 1st gear.

chris410 · 03-26-2010, 02:19 PM

Quote:

Originally Posted by F.I. Inc.

No you do not. If you run the HFC's and CBE your car will not become too lean. The ECU will correct and do it's job. Here is why the intakes change the A/F ratio's so much more than the exhaust system.

Inside your stock intake tube is a MAF (Mass Air Meter) As the air rushes by it, it samples that air. It works directly with the ECU and is calibrated specifically for the car. If you change altitude your cars A/F ratio will change. Meaning being at sea level opposed to driving in the mountains. In the higher altitude your car will actually be richer. Here is why, the air is thinner up there, your car naturally will take in less air. It naturally wants to lean out due to this and in most cases the ECU will compensate by dumping too much fuel and make the car rich. The MAF and ECU are designed from the factory to do this. However, they only work to a certain extent being that the elements from one place to the next are too different. If it worked perfectly your A/F would be optimum wherever you drove.

Now if you put an aftermarket CAI on the car that changes the location of the MAF or the tubing diameter it will change everything. The car is not calibrated for it. In the case of the Stillen Gen III intakes with exhaust & headers the intakes are causing the car to run way too lean. This is why you need a re tune so at the least amount you can bring the A/F ratios back to where they need to be. I know this how you may ask, over the past two days I dynoed a car that had Stillen Gen III intakes with our exhaust components and the car was borderline unsafe in terms of A/F. We re tuned the car, picked up alot of mid range power and low end torque just be getting the A/F back in the 12's. To be continued I am sure...

Thanks, Tony

Well said Tony, everyone needs to keep in mind that most dyno graphs of the G3 intake show a "peak" gain which means next to nothing for overall performance. The K&N drop-ins are your best route to go with the stock intakes along with a CBE and HFC.

However, like Tony said...if you change the location and process of how the car reads the air ratios, you are at risk of running lean because the car may not be adjusting the fuel ECU map correctly. You have two ways of determining this, either pull your plugs and read them (basically if you are running lean you will see a whiteish plug) or get to a dyno and get an a/f reading. If you are running lean, the car "should" pull timing which means you are losing power. Don't make your mods work against you!

You will not be able to put more power using an intake, HFC, and CBE IF the car can adjust air/fuel correctly. If you go the supercharger/turbo route of course the game changes quite a bit. So, for those of you going with the G3, you should at least get your air/fuel readings to make sure you're not going lean. Better safe than sorry!

Red370 · 03-26-2010, 02:29 PM

Quote:

Originally Posted by Modshack

In addition, first gear is a poor one to get decent logs from. You really want the car under load. Suggest 3rd gear or higher if you have the room..

Oh ok, i'll try to get it out on the highway after work and post my results. Sorry for the shytty excel numbers, i'd sort the numbers to descending but I dont have the full version

semtex · 03-26-2010, 02:38 PM

Quote:

Originally Posted by chris410

You will not be able to put more power using an intake, HFC, and CBE IF the car can adjust air/fuel correctly.

I disagree.

I started off with a CBE and HFC. I never dyno'd before this, only after, so my baseline is with the CBE and HFC.

Baseline: Max = 291.7whp. My only mods were the Stillen cat-back exhaust and the Berk HFCs.

Then I went and added the G3 intakes.
After: Max = 306.4whp.

Net gain = 14.7whp.

Then I added headers.

This first graph shows HP and A/F:

This one shows torque:

So I should be running really lean now, right? And when I get a tune and get my AFR adjusted, my HP should go back down as a result of the AFR correction, right? But it doesn't. And keep in mind that AFR correction is pretty much the only thing a tune is good for right now, because timing adjustments just get bounced back, so it's not like we're offsetting HP loss via AFR correction with HP gain via timing advancement.

Sharif at Forged Performance did my tune, and he made sure the AFR is where it ought to be.

Final number: 318.1

Unless I'm missing something, it does not appear that my gains from the G3 intake were at any point negated by AFR correction, which leads me to conclude that the gain I got from the G3 was legit, and not simply because it caused my engine to run lean.

KEVTEX · 03-26-2010, 04:45 PM

+1 rep for lots of real numbers to clarify benefits of cai after cbe+hfc's.

Red370 · 03-26-2010, 05:26 PM

ouch, somebody just got

Zsteve · 03-26-2010, 06:10 PM

so semtex is your AFR starting at 14 and then at high rpms going down to around 12? I thought it was suppose to go up when you get on it? When I was checking my AFR yesterday it would flucate alot but always seemed to settle around 14.xx, is this good or bad?

03-26-2010, 01:55 PM	#111 (permalink)
Red370 A True Z Fanatic Join Date: Jul 2009 Location: Kaiserslautern, Germany Posts: 4,391 Drives: your mom to church Rep Power: 296	Did some datalogging today, here are some numbers i'd like you guys to take a look at, I did a few 1st gear WOT runs just to get an idea of what my AFR's were looking like, take a look.. The Mid 14's at 6500rpms make me nervous.. Columns: 1. Seconds 2. Coolant temp 3. Intake temp 4. Ignition Advance 5. Oil Temp 6. RPMs 7. MAF 8. Vehicle speed 9. AFR 10. AF Correction __________________ 2011 Mustang 5.0 \| 3.55's \| Lethal Performance off road H-Pipe \| Magnaflow Muffler Delete \| JLT CAI/Bama tuned 417whp/ 404 ft/lbs

03-26-2010, 05:26 PM	#119 (permalink)
Red370 A True Z Fanatic Join Date: Jul 2009 Location: Kaiserslautern, Germany Posts: 4,391 Drives: your mom to church Rep Power: 296	ouch, somebody just got __________________ 2011 Mustang 5.0 \| 3.55's \| Lethal Performance off road H-Pipe \| Magnaflow Muffler Delete \| JLT CAI/Bama tuned 417whp/ 404 ft/lbs

03-26-2010, 06:10 PM	#120 (permalink)
Zsteve A True Z Fanatic Join Date: Sep 2009 Location: TX Posts: 3,298 Drives: the 2 balled club Rep Power: 22	so semtex is your AFR starting at 14 and then at high rpms going down to around 12? I thought it was suppose to go up when you get on it? When I was checking my AFR yesterday it would flucate alot but always seemed to settle around 14.xx, is this good or bad? __________________ 2010 LS3 C6 Silver coupe corvette

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03-26-2010, 04:45 PM	#118 (permalink)
KEVTEX Base Member Join Date: Nov 2009 Location: Montgomery, TX Posts: 119 Drives: 2010 370Z 7at sp pg Rep Power: 16	+1 rep for lots of real numbers to clarify benefits of cai after cbe+hfc's.