General New motor Injector duty cycle

[SasaniFab]

Hey guys, I was driving the car today with the new motor and I'm currently at 22 psi give or take, I am running a walbro 450 with pte 1000cc injectors 6an lines tank back. I happened to look at my idc and its now over 100% in wot. Is this because I'm out of injector or could it be something else? I was at 70% on my stock motor with a little higher boost. Any info would be appreciated

 

[Vegas Smith]

I think @Kapok6 reported higher fuel requirements on his new engine.

 

[SasaniFab]

Ok, so this is probably normal. I have a set of highz 1650s sitting in my closet ready to go in

 

[boostdawd]

Just curious as to what fuel pressure your running? What is the compression on this new engine?

 

[SasaniFab]

8.5:1 , 1g base fuel pressure

 

[donniekak]

Are you running e85, what is your wideband reading wot?

 

[Kapok6]

On my 8.3 comp hks 272 motor, e85, walbro 450, e85, stock lines and filter, 30psi+, never saw above high 60% idc in my 1550's. 3395lb car trapping 130.75. Afrs 11.3-12

Switch to a 10.5:1 motor, GSC S2 cams, I have to have afrs 9.2-9.5 @ peak torque and about 10-10.5 up from there to keep knock at bay. This took my idcs up to over 100%.

Every motor is different, including fuel needs and ability to flow air. This is why I had to switch to some 2000's (2160 actual flow).

 

[94awdcoupe]

On my 8.3 comp hks 272 motor, e85, walbro 450, e85, stock lines and filter, 30psi+, never saw above high 60% idc in my 1550's. 3395lb car trapping 130.75. Afrs 11.3-12

Switch to a 10.5:1 motor, GSC S2 cams, I have to have afrs 9.2-9.5 @ peak torque and about 10-10.5 up from there to keep knock at bay. This took my idcs up to over 100%.

Every motor is different, including fuel needs and ability to flow air. This is why I had to switch to some 2000's (2160 actual flow).

seems more like a "dont run high compression " post more than anything. wow

 

[SasaniFab]

Are you running e85, what is your wideband reading wot?

Ok guys so I took the car out again, wot I'm seeing 11:1 give or take , this is on 98 octane race gas....I'm also spraying methanol 50/50. I turned up the fuel pressure but the idc remain the same

 

[SasaniFab]

I guess I should be asking how dsm link figures out the idc. The car has a base tune and I'm just breaking in the motor. I am on prob mile 30, third filter, first two were clean. The compression is 155 on each cylinder, dead even. Been testing the radiator for combustion gases periodically. Like I said I have a set of high z 1650s but I'm starting to think there might be another issue.

 

[gsxeclipse102]

Theres no way you should be at 100% with 1000cc injectors on 98 octane gas with meth injection

 

[gsxeclipse102]

Fuel pressure rising with boost 1:1?

 

[donniekak]

Something is very wrong, no way you should be hitting those idc's with gas at 22psi.

 

[gsxeclipse102]

Maybe boost gauge is off and your running 30+ psi

 

[SasaniFab]

Could my tune just be messed up, throwing off the readings?

 

[SasaniFab]

Like I was saying, what are the causes of an elevated idc?

 

[91talonts1]

I think the highest I ever saw with 93 and 850s on my bolt on HX35 was mid 80s and that would've been up around 30psi.

If you increase fuel pressure but IDC doesn't go down that suggests there ain't enough fuel to the rail.
Are you logging fuel pressure? Pump getting enough voltage at wot? Can you post a log?

 

[SasaniFab]

Boost verified through link via map and boost gauge . The car is on speed density

 

[gsxeclipse102]

Fuel pressure 1:1 with boost?

 

[SasaniFab]

I'm thinking this is a delivery issue, so when I adjust my fuel pressure I pull off the vacuum line, screw in the Allen stud and the number rises but asa I put the vacuum line back on it drops back to 43 if that makes sense

 

[SasaniFab]

Fuel pressure 1:1 with boost?

Can you explain this statement, are u saying that per 1 psi I am getting 1 psi of fuel pressure.

 

[SasaniFab]

The strange thing guys is that this only started when I installed the walbro 450, the 255 didn't give me these problems

 

[91talonts1]

Fuel pressure should rise 1psi for every 1psi of boost. That's why I was asking if you log fuel pressure. It's a great tool to have for these situations.

 

[SasaniFab]

Could it be my 6an lines with the walbro 450 is to much?

 

[SasaniFab]

I just looked through my logs , all I have is fuel flow, I don't see fuel pressure