Snook

iTrader: (12)

How is your idle with such large primaries?
How much rwhp do you have?
What are the injector duty cycles?
Do you have a fuel pressure regulator?

I have a pfc with 1200s and 550s right now but I want to upgrade the 550s to 850s

I have a t66 running about 16psi and 380rwhp on a hot day without the water/alcohol injection on and my duty cycles are getting to 84 on cold nights

How much more power will I be able to get safely if I add 850s?

thanks!!

Snook

iTrader: (12)

?

SPOautos

Its going to depend on how much boost you have to run and what fuel pump you have. If you have a Walbro then when you get to about 18-20psi of boost the performance of the pump starts droping fast.

I was running 850/1200 injectors, Walbro pump, stock fpr with BNR stage 3 twins and making 412rwhp at about 80% inj duty cycle. I'd say that those injectors would be fine for up to 450rwhp, you could prob get 500rwhp from them if you want to be dangerous. I ran as much as 18psi of boost on pump gas. If you can make 450rwhp with less than 20psi of boost then the Walbro would be fine for it also, you get over 20psi of boost and the Walbro doesnt flow enough fuel

STEPHEN

Snook

iTrader: (12)

I have the boshe M2 pump

well it took 16psi to get 380rwhp im not sure what its going to take to get 450 anyone know?
I had 340 at 12psi can I assume that every 1psi is 10rwhp on my car?

stephen did you have the stock map sensor?? which 2 bar should I get?

artguy

no...you cant assume that. tuning is everything. also, some turbos will perform better at 17psi than they will at 18 or 20...which is what bryan at bnr has said about his sets. there will be a peak efficiency range depending on the turbo and you might find the biggest jump in power happens in that spot. you might find less power past that spot.

get either the gm 3bar map sensor or if you have a pfc you can get the boost control kit from xs engineering like i did.


jason

Snook

iTrader: (12)

I do have a pfc what does the boost controller do for me though? I want to run higher boost than 16 safely

Trout2

iTrader: (5)

I get a good idle with 850 primaries. I hear mixed reviews on this, it seems like those that have been tuned run good at idle.

I'm running 850/1300 with an RP/Nippondenso pump, SX regulator adjusted to 38 psi base pressure, and -6AN lines. At 327rwhp, I'm running 70% duty cycle.

When I had four 850's, I would hit about 84.5% duty cycle at 327rwhp.

Jack