As in the post, high duty cycles is not the most important part of the equation.

The margin of error doesn't have as much to do with duty cycle as it does ECU programming. You can certainly have a bad map with low injector duty verses a good map at high duty.

 

but if u have a good tune, a high duty cycle can mean u are running out of room or running out of your safety margin. That is my point and the reason why i spent a few hundred on upgrading my fuel system.

LEts get back onto the bnrs.....i want to see a dyno chart. Goodfellas how come bnr doesnt have any dyno sheets? i thought he used to post on here.. whats his thoughts on power? he seemed like a reasonable guy.

edit: i am stuck at work today and there is nothign going on so we can debate this all day if you like....i have afeelin your bored of it though.;

 

It's not really a safety margin, it's a "room to grow" thing. If your are programmed for 12 PSI and you hit a spike of 17 PSI, it doesn't matter whether your injector duty is low or high; you simply aren't programmed for it.

Tuning is the key (timing, charge temp, a/f, etc), not the injector duty. Injector duty cycle only becomes a problem if/when you need more fuel for the a/f ratio and you are already out of room with your current injectors. However, one again, that comes back to tuning.

The stock injectors can and have safely done 15 PSI (and in some cases higher) without exploding. It's just another myth of the FD saying that it can't be done.

 

It is a myth like Mahjik said. If you're tuned correctly it can be done.
Most everyone I talk to looks at me like I'm insane for running 14-15psi on stock injectors and stock twins. All I did was upgrade my fuel pump and my duty cycle's are just fine.

 

i dont know much about timing. perhaps thats why my duty cycles were so high with a 11.2afr when i had the stock injectors at 12-13psi. i dont know the realtionship. Somethign soewhere is up b/c all the "myths" with my car are true. i needed to upgrade the fuel system early and also the ignition. Nowa dayswhen i run 15psi i get break up in the upper rpms but like i said my afrs are solid. i am planning to get an amp soon.

 

i am tuned to 11.2 afr and i still had high duty cycles..

my arguement is that cars vary and so do their owners...some are comfortable with high duty and some arent. ita all about margin of safety and where u are taking the car (what your goals are)...

i am not some FD newbie.

 

Well, that also comes into what "safe" means with looking at AFR's. I've seen dyno's of people using Pettit ECU's running upper 11's and low 12's for AFR's above 12 PSI. To some people anything in the upper 11's is unsafe, to others it's just fine. It works the same as duty cycle, what some people think is fine others think is unsafe.

The bottom line is that you need to modify your car in a way you feel secure about what you are doing. While I'm not suggesting every run out and run 15 PSI on the stock fuel system, I'm just stating that it can and has been done without issues.

Keep in mind that programmable ECU's like the PFC haven't been around as long as the FD. People were pushing the limits of the stock components years ago before the better technology like the PFC came about.

 

I am planing to keep my stock turbos but get the maximum potential out of them. I haven't decided if I whant upgrade them (say BNR's or pettit). I have about 30000 miles on whole car (motor, turbo's, trans, chassis). I have the pettit ecu, full 3'' exhoust, hks intake, pettit pulleys, 10.5 plug wires. But I haven't touch the fuel system yet. My plans were to get a larger fuel pump, relocate fuel filter, add a FPR, and have my stock injectors sent to rc engineering for cleaning and blue printing. after reading this thread and some of the other threads linked from this thread it looks like I should be fine , and might not need the FPR?


And here is my dyno graph from this summer. and to say i was suprised with th HP figure would be an understatment.

I do understand that the spike in the graph is a boost spike, but my AFR seemed rich threwout the run.

and the smoothing was on 0.

 

350 with no ic ? what boost level?
that is awesome power.

 

At the track with 103 to 112 unleaded race gas I get 17-18 lbs of boost, air fuel ratios in the low 12s, not a hint of pinging, and frequent 100% on my duty cycles. Ported motor, stock turbos with 80,000 miles on them, upgraded fuel pump & a high flow cat.

No spikes, no pinging, still in one piece after 3 years of pushing my luck. Mahjik has it right. Tuning, tuning, tuning.

 

oorx7,

If you get a RRFPR (Rising Rate), it's basically an older way of adding more fuel. It will allow you to increase fuel without increasing your injector size. You'll still need tuning to know how much you are adding (i.e. dialing the RRFPR, not the ECU). It would probably work well if you also used one of the standalone fuel systems that HKS and Greddy offer. However, after you spend the money and time for that setup, you will most likely have been better of going with a PFC and larger injectors.

Using just a standard 1:1 FPR won't get you anything with the stock injectors (unless you added a large fuel pump that was overrunning the stock FPR).

 

yes it was the stock IC. the psi was steady @ 14.5 to15 but @ the spike it got to 16.

 

Damn! what else can i say.
have u ran the 1/4 yet? curious to know your traps.

 

i would say u are at risk and certainly damaging your turbos at that boost. God u are creating some heat. But for three yrs....wow. PFS can build a motor. thats obvious.

 

A larger fuel pump is going to be my next upgrade( with the rest of the fuel system) I dont really whant to get a stand alone ecu BUT ,and it is a big but, I would get the hks fcon. Were I work part time is a autherized fcon pro dealer and we also have a dyno. With the pettit ecu, a RRFPR , and a lager fuel pump vould I get 400 WHP (also probebly would need a new intercooler setup and mabey ingniton upgade), on say just cleaned and blue printed stock injectors.

I type pretty slow so I didn't see matty's Q. 12.7 @ 114. with terrible 60' 2.2's 2.3's.

 

I don't see why you couldn't get 400rwhp with a RRFPR and something to fine tune the Pettit maps after increasing fuel. Yep, you will definitly want an aftermarket IC to make sure to keep the charge temps down.

When I was talking about fuel pumps overrunning the stock FPR, not all aftermarket fuel pumps will do that. Most of the in-tank stock replacements don't have a problem with the stock FPR. Unless you are looking for some mega-flow pump, you most likely won't run into a problem like that. However, I would recommend getting the IC before the fuel pump. The IC will be a better upgrade first even though it's more expensive.

 

I have access to welding and maching ( I work full time @ a injection platsics molder). I am looking for just a core to weld custome endtanks and piping too. I think I have a line on a used aluminum radiater. I am going to do a custome V-mount this year (2005). do you know of a place to get a core for a reasonable price, doesn't have to be the cheapest because I cant sacrafice quality fo price. Any one could PM me about this because I know this is of topic (bnr's).

mahjik would the stock supra pump out flow the stock FPR?

 

I don't think the stock FPR will be outflowed by the Supra Pump. I have been running that pump for a little over a year and a half with no prob. I am however running stock injectors and I know I am not taxing the Supra pump like most applications might. I only run about 12 psi but it flows by far enough fuel for the injectors.

 

The old sets smoked b/c of the dynamic seals. The new ones do not have dynamic seals.

 

I talk to Bryan pretty often. Some of the info I post comes from him. As I have already posted, he feels that the stock turbine housing will limit the power to ~420 rwhp.

 

No. I have been running the supra tt pump with stock fuel rails and fpr (850s/1300s) for over 2 years now, making ~375-400 whp the whole time.

 

sounds like what I needed to know but should fresh stock injecters be good for 400 whp or do I need (850s/1300s) for this goal. I believe from what mahjik posted, that the stock ones will work but be near max duty cycle

 

You're going to want to upgrade you injectors if you want that much power. I don't feel comfortable pushing the stockers over 340-350 rwhp as at that point they will be pushing high duty cycles.

 

SINGLE!!!

 

too much money...i have a baby coming and just upgraded to a bigger house. Spending 6k for a single turbo set up might get me hung by the wife. And i dont want to port the engine.