What are FIC 850's capable of?

[90 GSX]

I bought them because I figured it was a good round number. I'm going to be using an HX-35 with a bullseye housing at about 20 to 25 psi on the street w/ alcohol injection. I didn't want 1000cc because they just seem too big to use without the capabilities of DSMlink. I'm curious to know what my limits are with these injectors.

 

[TurboAnything]

On 100 octane i hit 95% DC at 489hp thats 26psi on a 3065. On a DynoJet at AMS you should be fine more then enough injector for you.

 

[MrBoxx]

What are you going to use to tune? An SAFC won't be enough to handle 850's.

 

[Spidey]

850s will be plenty for an HX35 assuming the car is tuned properly and your fuel pump can keep up.

 

[2gGSX]

5.69 lbs/min of fuel at 100% IDC, or 4.84 lbs/min at 85% IDC. That's good for 55.6 lbs/min of airflow at 85% IDC and 11.5:1 AFR, so you should be fine.

 

[Boost92awd]

What are you going to use to tune? An SAFC won't be enough to handle 850's.

With a MAFT and a SAFC though it would work.

 

[2gGSX]

With a MAFT and a SAFC though it would work.

The ECU losing out on 47% of the airflow would shift you down a few timing maps though.

 

[wret]

http://www.dsmtuners.com/forums/fre...questions/277747-fuel-injector-questions.html

 

[90 GSX]

I have a keydiver chip for the injectors and an afpr. I thought that 850cc injectors would do a little more than just 400 horses. I'm running 43 psi fuel pressure as well.

So you are telling me if I wanted to upgrade later to something like a gt30 maybe I would need new injectors again? The guy above is at 95% dc with a 3065 at 26 psi which is pushing more air than my hx35. What A/F ratio are you running?

 

[Spidey]

Wret's article is meant as a guideline, not solid fact, as we all know every car(and tune) is different. You can surely make more than 400 with 850s, though. ~55lb/min of airflow should certainly make more than 400 crank horsepower on a dyno.

 

[biglady112]

As much as the AFC is a thing of the past, a local made 503whp on E85 with 1000cc injectors and an AFC.

He is now on a 1G AWD with dsmlink. He made 20whp less at 7 less psi. But the torque was like 70lb/ft more.

Rocky Mountain DSM Forums - 500hp club finally...

Steven

 

[kelvinb]

AFC and what?

 

[wret]

Wret's article is meant as a guideline, not solid fact, as we all know every car(and tune) is different. You can surely make more than 400 with 850s, though. ~55lb/min of airflow should certainly make more than 400 crank horsepower on a dyno.

True, it's a guideline. If you're starting out with a goal no higher than 400 hp, 850 cc injectors will get you there but not a lot more. Even the best tuners are bound by the laws of math and physics. Look at our dyno list and you'll find that most of the guys making around 400 hp are using 850's or higher.

 

[kelvinb]

If there are upgrades past an HX35 then I would just wait that much longer to get it over with and just get the largest injectors you can coupled with the proper controller.

 

[sbiggi]

As much as the AFC is a thing of the past, a local made 503whp on E85 with 1000cc injectors and an AFC.

He is now on a 1G AWD with dsmlink. He made 20whp less at 7 less psi. But the torque was like 70lb/ft more.

Rocky Mountain DSM Forums - 500hp club finally...

Steven

500... corrected, with a ~1.25 CF? So thats 400hp, thats a big difference in HP.

 

[biglady112]

What does it matter seth? I was just stating a PROVEN number from an AFC and 1000's. No one cares that you have to be right. I was just giving a reference to something I have seen and heard about.

Steven

 

[sbiggi]

What does it matter seth? I was just stating a PROVEN number from an AFC and 1000's. No one cares that you have to be right. I was just giving a reference to something I have seen and heard about.

Steven

For accuracy of info. Its not really a proven number, being that he only made 400, not 500.

 

[Black95TSIawd]

I find this very interesting. Back in the day, Dre made 500whp on pumpgas with 720cc injectors. Albeit they were maxed, 850's would not have been. 55lbs/min is a lot more than 400whp.

 

[Black95TSIawd]

Here is a chart that was derived on the dsmlink boards. Assuming the tuning is well, you should make 10 crank horsepower per 1lb/min. Please note, these are gasoline numbers. Not E85.






FPR = 43psi and Fuel = 93 Octane and Target AFR = 11:1
550cc = 40.5lbs/min
650cc = 47.8lbs/min
660cc = 48.6lbs/min
680cc = 50lbs/min
720cc = 53lbs/min
750cc = 55.2lbs/min
780cc = 57.4lbs/min
850cc = 62.5lbs/min
880cc = 64.8lbs/min
950cc = 69.9lbs/min
1000cc = 73.6lbs/min
1600cc = 117.7lbs/min

FPR = 43psi and Fuel = Race Gas and Target AFR = 12.5:1
550cc = 43.8lbs/min
650cc = 51.8lbs/min
660cc = 52.6lbs/min
680cc = 54.2lbs/min
720cc = 57.4lbs/min
750cc = 59.7lbs/min
780cc = 62.1lbs/min
850cc = 67.7lbs/min
880cc = 70.1lbs/min
950cc = 75.7lbs/min
1000cc = 79.7lbs/min
1600cc = 127.5lbs/min

 

[90 GSX]

The HX-35 according to the cummins website flows .46kg/s at 3.0:1 pressure ratio which is like 42 psi right? That equates to about 1 lb/s which is 60lb/min. I am running 43 psi fuel pressure and 10.5:1 a/f ratio (I can't believe stock is even richer!!!! I run 12.0:1 on my trans am but anyway)... I think I'll be good with this turbo and injector combo. I will only be running 25 psi or less. If I can keep it under 85% IDC I will be a happy camper.

Is my math right?

EDIT: Wow, I can't believe I just compared airflow to fuel flow. Duhhhh. I don't think a 3:1 pressure ratio is 42 psi either.