VE table and timming tuning

[novaray64]

This is my first turbo car and could use some help with the VE table and timming. The car starts and cruises great, I just started tunning the VE table and havent got very far. As soon as I get above 115 kpa it goes way rich, so ive slowly been leaning out the ve table. Ive leaned out the ve table alot and its still rich so im thinking im not running enough timming. Will running not enough timming cause a rich afr? Is thers a cutoff point where running not enough timming will cause the engine to fall on its face and go way rich or do I need to keep leaning the VE table

My setup
1964 Nova
stock Lq4 with headstuds and mild cam
twin precision 6265 turbos
80lb injectors W boost reference FPR
pump gas
2 bar SD tune open loop

[ingsteve]

strange...have you inserted the right parameters for the injectors?

[novaray64]

ya I believe I have the correct inj info, Im using 80 lb siemens injectors and put 80 across the inj kpa/flow rate table since I have a boost reference FPR

[SultanHassanMasTuning]

if you are using a FPR, your injectors flow is going to be at a raising rate

[robbyredneck]

keep going your ve table is trending right in line with mine. you will definitaly throw a p0106 and get reduced power. so check that. your pe is set fatter than your be also. you could put more timing in after your ve is closer. are you running your injectors at 3 bar?

[bartender_77]

ya I believe I have the correct inj info, Im using 80 lb siemens injectors and put 80 across the inj kpa/flow rate table since I have a boost reference FPR

what your fuel pressure set at idle? those injectors flow 80lb at 42psi of pressure so if your FP its set at gm's 58psi those injectors are going to flow a lot more so you need to adjust the tune for that cause thats why you are rich

[novaray64]

what your fuel pressure set at idle? those injectors flow 80lb at 42psi of pressure so if your FP its set at gm's 58psi those injectors are going to flow a lot more so you need to adjust the tune for that cause thats why you are rich

My fuel pressure is set at 43 psi at idel with the reference line off.

[bartender_77]

My fuel pressure is set at 43 psi at idel with the reference line off.

ok, how much boost are your running? boost and octane will dictate how much timing you can run, also when you say really rich, how rich is it, like below 10A/F or just under 11?

[Blingole]

This is my first turbo car and could use some help with the VE table and timming. The car starts and cruises great, I just started tunning the VE table and havent got very far. As soon as I get above 115 kpa it goes way rich, so ive slowly been leaning out the ve table. Ive leaned out the ve table alot and its still rich so im thinking im not running enough timming. Will running not enough timming cause a rich afr? Is thers a cutoff point where running not enough timming will cause the engine to fall on its face and go way rich or do I need to keep leaning the VE table

My setup
1964 Nova
stock Lq4 with headstuds and mild cam
twin precision 6265 turbos
80lb injectors W boost reference FPR
pump gas

Fix your injector flow rate to the correct boost reference data. Then start all over.
and post a correct log.

[novaray64]

ok, how much boost are your running? boost and octane will dictate how much timing you can run, also when you say really rich, how rich is it, like below 10A/F or just under 11?

6 psi of boost , AFR goes below 10:1 but is getting better as I lean out the VE table, I understand the boost and octane determine how much timming I can run, I was wondering if running 13-14 degrees while tunning the ve table would cause unburnt fuel to go into the exhaust and show a rich AFR

[novaray64]

Fix your injector flow rate to the correct boost reference data. Then start all over.
and post a correct log.

Whats wrong with my injector flow rate?

[Blingole]

If your boost referenced at 1 to 1 (or 1 to 1.5 on some i think) your injectors flow rates will change with pressure and/or boost. As its typically more.


Use 43psi as your base, meaning while the engine is off.
then if you have 80lb injectors and your 1-1 reference your IFR vs KPA should look like this.

VAC (kPa) 0 5 10 15 20 25 30 35 40 45 50 55 60 65 70 75 80
Injector Flow (lb/hr) 79.81 80.48 81.14 81.80 82.46 83.11 83.75 84.39 85.02 85.65 86.28 86.90 87.5191238361 88.13 88.73 89.34 89.94

[Blingole]

And no, 14 degrees isnt to low.

[driver240]

80 lbs injector @ 43psi should be 92.9lbs at 58psi
58/43=1.3488 then take the square root = 1.161 x 80lbs = 92.911

i dont understand why you have 89 ...??

[Blingole]

80 lbs injector @ 43psi should be 92.9lbs at 58psi
58/43=1.3488 then take the square root = 1.161 x 80lbs = 92.911

i dont understand why you have 89 ...??

Your right, but the graph above is kpa vs. injector flow rate, not fuel rail pressure vs. injector flow rate.

[Its Bruce]

I apologize for asking a question and not offering an answer, but why would the injector flow rate change if the delta P on the injector is constant due to the boost referenced FPR?

[Beatdown Z]

It wouldn't. Blingole is wrong.

[Blingole]

It wouldn't. Blingole is wrong.

ok, elaborate for me just so i learn.

Are you meaning 1 pound extra manifold pressure with 1 extra pound of fuel pressure equals the same IFR?

Injector Flow Rate vs. KPA MAP: This value is the Injector Flow rate in g/sec. It is used to tell the VCM the size of the injectors and also how flow rate varies with manifold pressure (ie. varying pressure characteristics). On some vehicles this table references absolute pressure drop across the injectors (hence it includes the fuel rail pressure).

[Blingole]

Your Absolutley right and im sorry.

Ultimately, what we need to know is the effective fuel pressure in any given situation though. GM uses manifold pressure to subtract away from the rail pressure (which it always assumes is 58psi) to calculate pulsewidth. By referencing the flow rate table, in which the flow rate at various effective pressures is programmed in, the PCM knows what flow the injector is capable of at any given operating system. To convert a GM vehicle to work with a boost referenced return system, one must simply populate all of the various pressures with the same flow value, since the effective pressure (and consequently injector flow rate) will remain constant, regardless of manifold pressure. Word to the wise, when you see injectors advertised to flow X amount of fuel at a certain pressure, if you have a boosted vehicle, they will actually flow less while in boost unless you have a boost referenced system!

http://www.injectordynamics.com/Stec...reArticle.html

i learned something.

[robbyredneck]

way to be bling. i wish all forums had members like you who man up and admit when they learn something.