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Discussion Starter · #1 ·
Gents,
New to posting in the forum but have been reading for a while now.

Could someone please explain the LTFT acronym to me. I believe the FT is fuel trim, the LT still evades me.

BTW, I just bought an 02 EB Z, picking it up in a week and I'm so excited I've nearly peed myself a couple of times already. I have also got the CAGS defeat, Column lock bypass, frame savers from A&A and B&B Quad tip Bullets already on the way. Can anyone with the B&B exhaust give me an idea how loud it is? I want the dead making noise complaints.

Thanks for the info, Noel.
 

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Long term fuel trims. You'll love the Bullets, and welcome.
 

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You've opened the box. ;)

It means Long Term Fuel Trim. The cars PCM or Powertrain Control Module is the cars primary onboard computer and is responsible for engine fuel delivery, as well as just about every other function. Within the PCM is a matrix of "cells" or registers arranged in tables, much like those of a spreadsheet. This matrix of cells is arranged by RPM and MAP (Manifold Absolute Pressure) As engine operating conditions change, the PCM will switch from cell to cell to determine what LTFT factor to use in the base injector pulse width equation. To put it as simply as possible, it determines how long to pulse (open) each fuel injector so as to deliver the correct amount of fuel to each cylinder. A value of 0% indicates that fuel delivery requires no compensation in order to maintain the PCM commanded air/fuel ratio. A negative value significantly below 0% indicates the air/fuel ratio is rich and the PCM is reducing the fuel delivery (or decreasing injector pulse width in order to reduce the amount of fuel). On the other hand a positive value significantly above 0% indicates that a lean condition exists and the PCM is compensating by adding fuel (increasing the injector pulse widths in order to increase the amount of fuel).

These LTFT values are derived from the Short Term Fuel Trims (STFT) which are instantaneous fuel trend indicators and are given a numeric value with (-) being rich and (+) being lean. Any deviation from 0% indicates the STFT is changing the injector pulse width. The amount of pulse width change depends on how far the STFT value is from 0%. Over time the LTFT averages are computed by the PCM and stored in the LTFT tables.
 

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Discussion Starter · #4 ·
damn

Ok, that was an excellent explanation. Sounds like I have some more investigating to do.

Thanks.
 

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I was talking to HP Tuners at the fest and they recomended keeping the LTFT in the slightly negative.

Now you got to get some LG Headers to really hear your car scream :sneaky:
 

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Welcome to the Family!
 

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Discussion Starter · #8 ·
thanks

Really, thanks. Glad to be a part of this place and I look forward to learning a pile.

As for the LG headers, I was just at the A&A site...those headers are porn. Absolutely gorgeous. I need them. hahahaha.

Just out of curiousity, woulod I hear a big difference using those or the Kooks for that matter, with the B&B Bullets?

Thanks again guys, Noel
 

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Discussion Starter · #11 ·
the new Z

I'm still at work in West Africa...offshore...about as far away from my new Z as I can get. I'm about ready to burst. Reading this forum hasn't helped any either, it's just made me want to be driving even more!

Thanks for the welcome though guys, I'll let you know how the 1300+ mile drive home goes!

Noel.
 

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When I first got the Z I thought that it was an amazing machine but it made me angry that V6 mustangs had more of a muscle car growl. So I got some borla stingers which made it louder but was a little to high pitched. When I got the LG headers (even witht the cats) it really opens things up. The car rumbles at idle and when you get WOT it screams. The headers made a big difference in performance (HP) and sound. I couldn't be happier witht he LG, worth every penny.
 

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You will love the B&B, i do. It's not to loud at all to me.
 
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