do I have enough injector?

[Tom Tom Turbo]

I'm guessing I already know the answer here, but are my 42# injectors enough for a 109 with 206/206 roller, ported irons and intake, 6262 journal turbo and 20 PSI with Razor's alky kit backing it up?

I know it isn't ideal, but so far it doesn't seem to be running too lean on quick hits. I haven't made a pass in it yet, as I'm still breaking in a few things.

 

[87GN_70GS]

I don't think you have enough. What are your AFR's and duty cycle?

 

[Tom Tom Turbo]

Those are good questions! My AFR is in the low 12's, but no idea on duty cycle. How do I calculate that?


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[Nigel]

PowerLogger will give you the duty cycle, you want your AFR with alky to be mid tens to start. If you keep your boost low to start and timing mild you can walk it up if you have a scanmaster, but I would want a powerlogger if I was trying to max my combo.

 

[Mr.Spool]

the 42's and alkycontrol with 2 m10 nozzles took my car into the 10's years ago but you should tune your combo on a rich afr and creep up on the boost.knowing what I know now I prefer a cushion when tuning

 

[Mr.Spool]

looking at your sig the injector will be the limiting part if you want to go above 20 psi.

 

[Tom Tom Turbo]

Thanks guys, now the question is 60's or 85's


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[kandc7]

Go with the 80s same price and you have room to grow with them. 80s and alky is more than enough for what you want to do with that turbo. As long as you have a good fuel pump.. If you go e85 than you will want 120s.

 

[Tom Tom Turbo]

I think the 80's would give me room to grow as well. I think I probably should replace the fuel pump, I have a Racetronix 340 that put in in 2002, that has maybe 5,000 miles on it, but I'm guessing due to age it might be cheap insurance to throw a new pump in.

 

[87GN_70GS]

A 340 (255 lph) will not supply 80's safely. Need a little bit more pump for those

 

[kandc7]

I would replace that pump not worth the chance of hurting your motor.. Replace it with the newer better flowing pump's and make sure you have a hit wire kit and alky you will be fine.

 

[TTA308]

A 340 (255 lph) will not supply 80's safely. Need a little bit more pump for those

Please elaborate ... on a single pump.

 

[Mr.Spool]

Thanks guys, now the question is 60's or 85's

depends on the amount of power you want to make,regardless you wont use up a 60lb injector and alky with a 62/62 turbo.

 

[Jerryl]

Please elaborate ... on a single pump.

For gasoline;
80 lb/hr × 6 injectors = 480 lb/hr
480 lb/hr × 0.63 = 302 ltr/hr

The std. target is 80% inj. dc. or
302 ltr/hr × 80%= 241 ltr/ hr.

The math says that a 255 pump should be enough . . . But . . Key is we want enough fuel volume at the pressure the pump will operate at.

Estimated crank HP = 0.55-0.60 BSFC or . .
480/0.6 = 800 crank hp

 

[87GN_70GS]

To explain it, need to understand what is going on in the attached chart. This is a plot of flow vs pressure for both the injectors and fuel pump for flow rate in gph versus a range of rail pressure. The injector curves are all plotted at 25 psi boost and 100% duty cycle. Pumps are plotted against rail pressure, not a static rating.

6 of 80#/hr injectors at 25 psi boost and 45 psi base fpr (70 psi rail total) require about 80 gph of fuel. At a max safe dc of 90% (or pick another one) that's about 72 gph. A 255 lph pump (it's not shown on this particular chart) operating against 70 psi rail pressure, supplies about 50 gph, not enough.

You could either drop your airflow so that injector dc needs to only be 62% to provide a safe AFR, or use alky to cover additional fueling or get a bigger pump. But you couldn't do it on pump gas alone and with enough airflow to require above 62% dc.

 

[usetaboost]

Go bigger injector Tom. Might not be a bad idea to switch to low impedance injectors either. If the fuel pump can't keep up, deal with it when you get a chance to log it or at least see what the pressure is doing with a guage tapped to the windshield. I'm running a what is close to a 6176 at 25psi, ported heads, cam, single reds xp pump, all the other same old shit with single alky and front mount and my injectors are at 93% at top of 3rd barely making 10.8 afr and no KR on 57lb injectors. Pump pressure was 77lbs at 5800 rpm if I remember correctly.

 

[usetaboost]

For gasoline;
80 lb/hr × 6 injectors = 480 lb/hr
480 lb/hr × 0.63 = 302 ltr/hr

The std. target is 80% inj. dc. or
302 ltr/hr × 80%= 241 ltr/ hr.

The math says that a 255 pump should be enough . . . But . . Key is we want enough fuel volume at the pressure the pump will operate at.

Estimated crank HP = 0.55-0.60 BSFC or . .
480/0.6 = 800 crank hp

Jerryl wasn't there a big thread with a chart showing a few different pumps comparing the volume and pressure? I remember the reds xp was one of the better ones and maybe the douchebag pump?

 

[SloGN]

Just go with the 80s. Its better to have to much fuel than not enough..

Also a double pumper would be needed for max effort....


I put a set of 72lb inj in the high nines with a single nozzle and a double pumper using red xp pumps..

 

[TurboTnZ06]

80's idle like a stocker. Need double pumper or one massive pump, a single walbro can't feed 80's if you want to go stupid fast. FWIW, I ran 10's at 127 mph on 48# injectors back in the day.

 

[turbo89]

I'm guessing I already know the answer here, but are my 42# injectors enough for a 109 with 206/206 roller, ported irons and intake, 6262 journal turbo and 20 PSI with Razor's alky kit backing it up?

I know it isn't ideal, but so far it doesn't seem to be running too lean on quick hits. I haven't made a pass in it yet, as I'm still breaking in a few things.

80's and a DW301 pump .. feed the pump good power and never look back .. proven mid 10 second setup with excellent street manners