: What AFR are you guys running? holy crap these mods pull



obd2
04-08-13, 12:42 AM
i am in the final stages of tuning (i finally got my MAF and VE tables dialed in perfect, in other words whatever AFR is commanded the engine received without missing a heart beat) running 22.5 timing without any Knock (and knock sensor was not tweaked decided to keep it at stock knock setting) on 91 octane with meth Alky pre boost
Question is what are you guys tuning for AFR.... I decided to really be conservative and run 11.30 AFR throughout power band
AM I BEING A GRANNY????? *****?????? Should i step it up to 11.5 or 11.6


Mod are
ported heads
Fully ported blower and snout/TB 90M
Custom cam (between the BTR stage 2 and 3 cam)
9.1 and 2,55
D3 and stock HX installed
AR Headers
id850
Alky meth pre
ALL OF THESE MODS EQUAL USELESS POWER WITHOUT DR. For the street i use 335/25/20 with no grip before 70MPH (BUT I LOVE IT) And my experience with these 335 tires add much better grip that the super sports 305/30/19
I will be unplugging the meth for a test to see how much of the meth get into the cylinders affecting AFR. I think unplugging the meth is important test to see how much does the AFR drop. Has anyone ever done this test. Of course i will be careful
Here a sample of the first start-up http://www.youtube.com/watch?v=BUfp-3xsOTI&feature=youtu.be

V locity
04-08-13, 11:18 PM
I'm commanding 11.8 with 15gph pre boost.

What tuning software are you using?

Chrispy
04-09-13, 02:54 PM
It sounds like your tune is bang on. I would not run it without meth.

Do you have the tune setup to drop timing if the IATs shoot up from a meth mafunction?

obd2
04-09-13, 05:36 PM
It sounds like your tune is bang on. I would not run it without meth.

Do you have the tune setup to drop timing if the IATs shoot up from a meth mafunction?

Vlocity. I use HPT. I am worried about your 11.8

Chris
The meth is a cheap way of added octane when needed. i use 91 octane from Costco (esso) love it due to no ethonal added.
As for the IAT i use both the stock HX and D3 HX in series VERY AFFECTIVE AT LOWERING IAT. I keep the stock IAT retard and the knock sensor setting (have seen many tunes with tweaked knock sensor setting.

I have posted the following thread in CTSV Owner forum and thought it would be a good idea here also. Please read

this article confirm the variation in AFR's sensor. I use an AFX NGK windband because i believe this to be the best for the money. i am anal about my tune and have swap the Bosch sensor to a NTK making it more accurate. Please read the following i hope this article can save someone from burning down. I do not tune cars for a living/by no means call myself a professional tuner, but i do try to be informed as possible.

Air Fuel Ratio Reference Information: Posted 9/25/08

There appears to be a great amount of confusion in the area of air fuel ratio (AFR) meter readings and accuracy. This issue is very simple and straight forward when facts are presented and opinions are not used. Hello to all who read this post as this is David Darge from Powertrain Electronics. My experience and background started in 1985 with being the only USA technical engineer for Horiba Instruments. Horiba held the first UEGO sensor patent (1978) and manufactured the world’s first AFR analyzer called MEXA-101 in 1985. This analyzer being the only solution and early on as over 500 units were purchased by GM, Ford and Chrysler for $10,300 each. I also worked at Whipple Industries and with Kenny-Bell for the past 16 years and have experience using AFR data for well over 6000 hours. In 1998 we decided to market the AFM1000 which is AFR analyzer that is OEM industry tested and recommend by Kenne-Bell and considered a standard by many professionals.

Last year we helped with a test of many AFR meters/analyzers at Westec Performance engine dyno where 10-sensors were installed into a single exhaust collector. All of the data was recorded by Opto-22 (a world leader in data acquisition systems) on a 16-bit DAQ system with isolated channels to prevent any possible offsets caused by ground loops. The reference analyzer selected was the ECM Model 4800 manufactured and supplied by the world wide leader of analyzers. The Model 4800 ($12,000) is used and certified by GM, Ford, Chrysler, EPA and validated by NGK the sensor manufacturer. In fact GM high performance engine assembly plant uses 12 of the 4800’s to test every LS7 or now the LS9 engines everyday. The below test data shows to be very interesting as each meter was tested at various AFR’s while monitoring the EGT and battery voltage throughout each test. The complete test data to be posted soon as below is listed a single test at 12.30 AFR. When tested at 10.50 AFR some of the meters showed richer not leaner as indicated by the data below.

Data averaged (200 samples)

Delta from master
AFR Analyzer AFR
12.30 ECM4800 0.00

12.27 AFM1000 -0.02
13.05 PLX M300 +0.75

13.02 Innovate LC1 +0.72
13.34 DynoJet Commander +1.05

12.80 FAST A/F Meter +0.50
12.74 PLX R500 +0.44

1097 EGT (deg F)
13.81 Battery (volts)

FAST is a trademark of Competition Performance
Dynojet Commander is a trademark of Dynojet

As you can see most of the meters show an AFR leaner from the reference analyzer. The values range from 1.05 AFR leaner to 0.02 AFR richer. The data was averaged to take out any single sample error. In fact in the past we experienced more than one AFR meter reading drifted from 1.0 to 2.0 AFR’s plus or minus over time. This makes it impossible for anyone to predict the actual AFR error based on time or previous experience. Some dyno operators claim they can calculate the AFR error and make a correction factor based on time but this is not feasible. One of the AFR meter company warns to not use when the EGT is above 1330 deg F and then sometimes shuts down where the AFM1000 functions well to 1643 deg F. The AFM1000 will provide repeatability of 0.5% over the life time of the sensor with accuracy of better than 1.5% when the air calibration procedure is performed.

The AFR Meter Shootout article in Ford Muscle Magazine is not a true test because a reference analyzer was not used and errors could be caused when a common ground 8-bit data logger was used. Also it is not a proper procedure to hold a sensor near a calibration gas and expect to obtain a reference AFR. You may ask, How would I know that? Well while working at Horiba I wrote the calibration test procedure the automobile OEMs preformed on the MEXA101 and this procedure was not used for this AFR comparison test. Did you ever think, What if poorly rated analyzers were the most accurate and the best rated analyzers were the least accurate? How would you know if this was a valid test unless one included a reference analyzer that is certified in the USA and Europe such as the ECM 4800?

There are many professionals such as Jim Bell at Kenne-Bell and many other professional Ford tuners or engine builders that recommend and trust AFR data provided the AFM1000 when the fuel is gasoline, ethanol or methanol. The AFM1000 uses the best NGK sensor, is validated, well engineered, manufactured and tested by the world wide leader in air fuel ratio analyzers. In fact the AFM1000 uses the same NGK laboratory grade UEGO sensor as the Horiba Mexa110 and the ECM 4800. If you depend on accurate AFR for your business or performance engine then I would recommend using the AFM1000 and trust the data from now on.
As an addendum to this post, Mr. Darge has privately communicated that for the budget minded consumer and performance enthusiast, the NGK AFX (which is nothing more than an AFM-1600 with a modified display), tho not as accurate as an AFM-1000, is the best and most reliable of the "budget widebands" on the market. Although the AFX comes with a Bosch sensor by default, it is recommend to upgrade to the NTK sensor (approx. $150).

V locity
04-09-13, 10:28 PM
Vlocity. I use HPT. I am worried about your 11.8

This would be plus the meth...

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It sounds like your tune is bang on. I would not run it without meth.
Do you have the tune setup to drop timing if the IATs shoot up from a meth mafunction?

It's basically the stock table except it starts pulling timing at 140* rather than 149*

http://i1358.photobucket.com/albums/q776/pollackk/IAT2SparkTable_zps22d1e54d.jpg

obd2
04-09-13, 11:24 PM
This would be plus the meth...

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It's basically the stock table except it starts pulling timing at 140* rather than 149*

http://i1358.photobucket.com/albums/q776/pollackk/IAT2SparkTable_zps22d1e54d.jpg


I never tought about that option, i really like it. Thanks for sharing

Chrispy
04-10-13, 09:47 AM
This would be plus the meth...

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It's basically the stock table except it starts pulling timing at 140* rather than 149*

http://i1358.photobucket.com/albums/q776/pollackk/IAT2SparkTable_zps22d1e54d.jpg

Good stuff, you can test fairly safely then. I know the intercooler setup is solid on your car, was just curious if the IAT / timing safety net was programmed in giving timing at WOT.

In my old supercharged car that I ran cats on I had a wideband before the cats on each bank. It was the only way to be absolutely sure of true AFR. What you have done above is a great but I didn't have access to that sort of data in the old days :)