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Carrera RSR
Joined: 08 Jan 2010
Posts: 2309
Location: Somerset, UK
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 Posted: Mon Sep 25, 2017 5:49 pm Post subject: |
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Can you remove the USA strangulation parts and update to RoW? More potential on boost and power. Simpler fuel and ignition? You will end up with a car closer to 200bhp than 150bhp.
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1980 931 - forged pistons, Piper cam, K27/26 3257 6.10 hybrid turbo, 951 FMIC, custom intake, Mittelmotor dizzy & cam pulley, H&S exhaust, GAZ Gold, Fuch'ed, Quaife
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924-76
Joined: 05 Jun 2006
Posts: 1475
Location: Ontario, Canada
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| Posted: Mon Sep 25, 2017 7:21 pm Post subject: |
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| Carrera RSR wrote: | | Can you remove the USA strangulation parts and update to RoW? |
Yes, but I have few questions first,
-What are those parts?
-What are the difference between those parts?
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1976 924 N/A ROW SOLD
1980 931S
1981 931 Part car RIP |
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Carrera RSR
Joined: 08 Jan 2010
Posts: 2309
Location: Somerset, UK
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| Posted: Mon Sep 25, 2017 7:57 pm Post subject: |
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I'm not the expert here on USA emissions parts and if/how they can be deleted and the potential impacts and opportunities
I do know with the RoW spec cars we have, a small tweak of ignition, fuelling and boost with a charge cooler, FMIC or TMIC will see you easily nearer, if not over 200bhp. But we started with 20+bhp more than the USA spec cars in the first place
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1980 931 - forged pistons, Piper cam, K27/26 3257 6.10 hybrid turbo, 951 FMIC, custom intake, Mittelmotor dizzy & cam pulley, H&S exhaust, GAZ Gold, Fuch'ed, Quaife
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morghen
Joined: 21 Jan 2005
Posts: 8879
Location: Romania
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| Posted: Tue Sep 26, 2017 12:02 am Post subject: |
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lambda "enrichment" system must be gutted.
The way I see it that's no enrichment over the ROW cars but a system that leans out the mixture in certain conditions to improve overall fuel efficiency and statistically reduce emissions.
So, I would make sure the lambda mixture system is gutted and locked on maximum rich..then go about your normal life and enjoy your 924.
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morghen
Joined: 21 Jan 2005
Posts: 8879
Location: Romania
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| Posted: Sat Sep 30, 2017 6:42 am Post subject: |
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Had a lovely evening drive today and checked some numbers for you.
Cruising at around 3500rpm gets me 13.7 afr and i'm not on boost yet.
In fact it will go about 100mph without boost past atmosferic pressure and keep the afr values around 13.X
And at about 3500rpm in 5th it does approx 90mph.
http://www.youtube.com/watch?v=Luiff-THaAM
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Last edited by morghen on Sat Sep 30, 2017 3:34 pm; edited 1 time in total |
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924-76
Joined: 05 Jun 2006
Posts: 1475
Location: Ontario, Canada
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| Posted: Sat Sep 30, 2017 9:34 am Post subject: |
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Thank you very much morghen, what is your idle A/F ratio?
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1976 924 N/A ROW SOLD
1980 931S
1981 931 Part car RIP |
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morghen
Joined: 21 Jan 2005
Posts: 8879
Location: Romania
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| Posted: Sat Sep 30, 2017 3:33 pm Post subject: |
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Cold is like 10.X and warm low 12s
I can set it to 13.7 when warm and then it will be 11.X when cold but i need this additional fueling for higher rpm fuel amounts otherwise it goes lean over (13.7) above 5000rpm and also with this extra fueling the car is overall more responsive at mid and liw range.
I have no idea what the box does for you, maybe see what is connected to.
That frequency valve maybe?
If so, just disconnect it.
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Carrera RSR
Joined: 08 Jan 2010
Posts: 2309
Location: Somerset, UK
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| Posted: Sat Sep 30, 2017 5:57 pm Post subject: |
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Morghen, you should be aiming for 14.7 stoichiometric AFR. 13.7 is a lttle rich for warm idle and off boost cruising? It’s not lean until heading into the over 14.7 and into 15’s
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1980 931 - forged pistons, Piper cam, K27/26 3257 6.10 hybrid turbo, 951 FMIC, custom intake, Mittelmotor dizzy & cam pulley, H&S exhaust, GAZ Gold, Fuch'ed, Quaife
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morghen
Joined: 21 Jan 2005
Posts: 8879
Location: Romania
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| Posted: Sat Sep 30, 2017 8:49 pm Post subject: |
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I'm extra cautious since the k27 does not joke around I guess.
And there is the whole debate over what to aim for really...yes the optimum burning of gasoline is at 14.7 but that's in lab conditions.
In our engines this may be different especially today with additivated fuels...I think today most gasoline fuels are at least 5-10% ethanol.
And I still get 30 mpg (US) or 35mpg (UK) with that mixture setting on a longer trip...which is ok for me.
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924-76
Joined: 05 Jun 2006
Posts: 1475
Location: Ontario, Canada
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| Posted: Sat Sep 30, 2017 11:35 pm Post subject: |
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30 mpg is pretty good for a performance oriented car.
Below info is from Automotive Engine Management Systems by Jeff Hartman:
-9.0 Black smoke, low power
-11.5 Approximate rich best torque at WOT
-12.2 Safe best power at WOT
-13.3 Approximate lean best torque
-14.64 Stoichiometric (chemically ideal)
-15.5 Lean cruise
-16.5 Usual best economy
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1976 924 N/A ROW SOLD
1980 931S
1981 931 Part car RIP |
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morghen
Joined: 21 Jan 2005
Posts: 8879
Location: Romania
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| Posted: Sun Oct 01, 2017 1:19 am Post subject: |
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Yepp, that sounds about what i know from my drag racing buddies.
When in doubt low 12s..when sure, high 12s for max power, good torque and good responsivness.
My only problem is it goes to high 13s at wot over 4500-5000 rpm and when it does that, the power delivery drops and the engine shakes a bit like its not running round. I'm going to try to test the injectors pattern and delivery at wot.
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Cedric
Joined: 27 Aug 2004
Posts: 2608
Location: Sweden
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| Posted: Sun Oct 01, 2017 3:50 am Post subject: |
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High 12s are lean, dont forget EGTs, especially if you don't measure it. Optimum afr is not the same for all engines, it depends on what the limiting factor is. But in general i those guidelines are reasonable, be aware that n/a and turbo engines are very different when you look at guidelines.
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1980 924 Turbo
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Carrera RSR
Joined: 08 Jan 2010
Posts: 2309
Location: Somerset, UK
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| Posted: Sun Oct 01, 2017 4:09 am Post subject: |
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High 12’s lean for off boost Cedric? I would say that is lean for on boost.
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1980 931 - forged pistons, Piper cam, K27/26 3257 6.10 hybrid turbo, 951 FMIC, custom intake, Mittelmotor dizzy & cam pulley, H&S exhaust, GAZ Gold, Fuch'ed, Quaife
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Cedric
Joined: 27 Aug 2004
Posts: 2608
Location: Sweden
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| Posted: Sun Oct 01, 2017 5:51 am Post subject: |
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| Carrera RSR wrote: | | High 12’s lean for off boost Cedric? I would say that is lean for on boost. |
Morghen was talking high 12s for max power, that's why i mentioned it. Of boost and low load is more of an emissions issue with low afrs 
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morghen
Joined: 21 Jan 2005
Posts: 8879
Location: Romania
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| Posted: Sat Oct 07, 2017 8:40 pm Post subject: |
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Just drove the GTS wannabe and though not enough straight road but it seems like it wil do like 125mph off boost 
Off boost meaning under atmospheric
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