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Average AFR for FD Stock Twins

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Old Jul 8, 2007 | 02:32 PM
  #1  
Monsterbox's Avatar
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Mazzei Formula
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From: Birmingham, Al
Average AFR for FD Stock Twins

Im on the stock twins with full bolt-ons and stock fuel system with fuel pump rewire. I am going to tune the car myself.

What is the best AFR to tune for..allowing decent power with a good bit of safety..Ive searched and cant find this anywhere on the club

last week at dyno

10psi = 247RWHP @ 10.5, 256RWHP @ 11, and 274RWHP @ 11.5...i decided to go with an 11 tune...is it safe to do 11.5 at those stock boost levels on 93 octane?

15psi = 322RWHP @ 10.8 AFR...I figured keep it really rich when running higher boost?

I want 3 maps 10,12.5, and 15...what afrs should i tune too and the dyno tuner was telling me its fine to have 12.5 and 13 afrs in the beginning on ur curve like btw 2k-4k rpms!???!?

Please help me out guys...I think this should be a sticky for all twin turbo owners as we all know you cant follow piston engine AFR
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Old Jul 9, 2007 | 01:16 PM
  #2  
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From: Midland Texas
Originally Posted by Monsterbox
Im on the stock twins with full bolt-ons and stock fuel system with fuel pump rewire. I am going to tune the car myself.

What is the best AFR to tune for..allowing decent power with a good bit of safety..Ive searched and cant find this anywhere on the club

last week at dyno

10psi = 247RWHP @ 10.5, 256RWHP @ 11, and 274RWHP @ 11.5...i decided to go with an 11 tune...is it safe to do 11.5 at those stock boost levels on 93 octane?

15psi = 322RWHP @ 10.8 AFR...I figured keep it really rich when running higher boost?

I want 3 maps 10,12.5, and 15...what afrs should i tune too and the dyno tuner was telling me its fine to have 12.5 and 13 afrs in the beginning on ur curve like btw 2k-4k rpms!???!?

Please help me out guys...I think this should be a sticky for all twin turbo owners as we all know you cant follow piston engine AFR


You should be ok. Keep in mind that timing is also important. Your tuner is right about the A/F in the 2k-4k range. Reason is the engine's not making much power in that range. Detonation from a leaner mixture is more apparent in the upper rpm range and under more engine load. Look at any dyno chart here to compare. The stock twins Give full boost on the primary at 2,400 rpms and don't even go full rich (10.0 ratios) till near the transistion point.
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Old Jul 9, 2007 | 03:43 PM
  #3  
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From: Birmingham, Al
i just dont understand the general aim for afr....where do i want the 11...from 6k up...what boost levels do i need to lower the afr....how is it safe to run 13.5 at 3500rpms at 15psi of boost up hill!?

I cant find a dyno chart with afr's attached showing stock twins
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Old Jul 9, 2007 | 04:21 PM
  #4  
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7 Rx-7s since 1980
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From: oHIo
Wow. I would not use 12.5 to 13 afr in 2-4Krpm. Not for a client car. But I am more conservative. Maybe up to 3Krpm and 12afr with some retarded timing. That would help spool up. Once you start getting into the sweet spot (let's say 3500rpm with twins) you want to get timing back to "normal" levels for your car and then start advancing after your torque peak.

Tony
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