Talking with Vortech the only info that they gave me was that the Injectors where pretty much maxed out with the pulley that comes in the kit. I have seen cars with stock injectors making 420hp with a good tune and not have a problem. Sorry that I do not have anymore info than that.

 

Appreciate the data. Sounds like a safe way to go particularly if using the smaller pulleys would be to upgrade the injectors as well as a larger fuel pump...To rely on stock injectors one should find out what the duty cycle is and if close to 80% your probably max'd out in terms of fuel flow..

 

It is always good to go with a a larger injector if you are close to maxing out your current ones, I can get you a good deal on some RC injectors and the pulley if interested.

 

Im not surprised on thier reply . Although it isnt good to run that high a fuel preasure [ 135psi ] when running the 2.87 pulley . Several people are doing it and the injectors are holding up and giving them enough fuel for a good tune

 

You are maxing out the stock injectors, which will eventually cause them to fail. The jet will get stuck open and if that happens bye bye fuel for that cyl. then bye bye motor.

Is it really worth it? At least find a nice set of used Power Enterprise as they use the same harness as the stock bosch ones. Either do a reflash of the ECU or get some sort of piggyback. Actually, the splitsecond can handle larger injectors.

 

I've only had my Vortech on for about 2k miles on an engine with 3k miles, but am looking for more power. I really want to increase the torque, and was following this thread for the past week.

I'm waiting for 'thebigsadler' to post the dyno results with the new pulley, but I'm not 100% sure how it was already tuned without using a dyno.

Also, like jpc350z, I'm very interested in the duty cycle during the dyno to see if new injectors are a must.

One half of me wants to do only the pulley and fuel upgrade, the other thinks it's probably much better (safer) to do the full forged piston, rods, bearing upgrade before increasing the boost.

Ideally I'd like to get close to the 450hp/400 ft*lb range (on a 'safe' engine), but don't know it that's achievable using the Vortech anyway.

Anyone see a Vortech do numbers in that range lately?

 

To get them numbers with a Vortech . You will need to build the block . Upgrade the blower to a T-trim or better , return fuel system and bigger injectors. Im running 13.5psi for now [plans to go more ] and making 400whp and 319trq on a mustang dyno....convert to Dynojet # is 448whp & 357trq.

 

so with my 3.12 pulley i've overmaxed the injectors ? also, if i end up going with larger injectors do i still use the aux fuel pump that comes with vortech and will a retune be needed. i think i would need to retune but not 100 % sure.

 

SO much miss information . Ok the stock Vortech, fuel preasure in the fuel rails at 8psi is 64psi higher than stock and that adds up to around 115psi . If Vortech didnt think the fuel injectors couldnt handle it . They wouldnt have done it that way . Adding 1 to 1 1/2 psi with a 3.12 pulley would put your fuel preasure in the fuel rail at 123 to 127 psi . Others have been running the 2.87 pulley for a while with no ill efects @ over 130psi in the fuel rails . And Ive read on other Nissan forums of guys running Vortech SC 's and the same injectors at the same psi for 2 or 3 year with no problems . That doesnt mean it couldnt happen and isnt the safest way to go . But it doesnt mean you absolutely need to go bigger injectors and return fuel system. This forum has sponsors and they are here doing thier job of trying to make money buy selling as much as they can . Its thier job and you cant fault them for doing it

 

I will on 9/8 have the 3.12 pulley installed as well as RC440 injectors a Walbo fuel pump and a dyno tune to compare against the last tune which yielded the #'s in the signature.
I for one am a very conservative engineer and whenever I have an opportunity to add some conservatism in something that is important to me and does not come at an exhorbitant price I will do so..I like margin!! Don't wanna worry that the next time I floor it it will go "BOOM"...

 

Do you have the dyno results. Would really like to see the data...Thanks

 

You have to think about it this way, everyone here has seen the stock Vortech tune correct? It is way rich, Vortech tunes safe, they want the safest setup for these cars while the extra injector is safer but not needed, which we have seen on Ray's car, Andy's and Jeremy neither all these cars have smaller pulleys yet still have stock injectors none of those cars showed any sign of going lean even on the top end. With a safe tune stock injectors are fine, Vortech is not going to say that because it does not allow that car as much of a cushion, with Vortech’s tune I would not suggest it with a custom tune on the dyno it is a fine setup to run

 

You may be right but how close to the edge of safe limit(s) are these cars? Without data we are just speculating and guessing. Need some real data (injector duty) while tuning to judge how safe they are..imho

 

I can tell you for a fact, that if you do the pulley swap and a tune on the dyno the tuner will be able to tell by the a/fs, I had a supercharged 05 mustang on the dyno last week and you could just tell that the fuel system was on the edge, the car was making 525hp and it was deff pushing the fuel system and you could tell because the air fuel cure started to rise towards the end of the run. It never got to dangerous a/fs but at that point we knew that was all the car could handle there was no more pulling power out of it, every 350z with the pulley swap on the dyno has had a fairly flat even on the top.

 

What is the difference between the psi in the fuel rails versus the psi listed at the regulator? I have the AAM return and was currious to know what my fuel gauge should be showing for 3.33 vs 3.12?

 

I don't doubt a good dyno tune can tell if you are within the fuel delivery's capability , my concern is how close is the stock fuel system to saturation(injectors/fuel delivery). Can you tell from a dyno tune how much margin the system has? After spending kilo bucks for the system and protecting an investment in the car's engine I believe it prudent to have margin in the system.. My opinion..

 

I would honestly would say if you want to be extra safe step it up to 440cc injectors

 

Do the 440 injectors just drop in, like plug and play?

 

I would characterize the situation a little differently than wanting to be extra safe. The question is how unsafe would I be with the stock fuel system. An A/F curve from a dyno does not provide any indication of injector duty cycle.. A duty cycle approaching 80% is unsafe. Quoting Jeff Hantman's book Engine Management Systems... "Maxcycle is the maximum duty-cycle of the injector.(Above 80% , some injectors could begin to fibrilate or overheat, which leads to eventually causing them to lose consistency or even fail completely". Stock injectors designed for around 230 Hp to the wheels are now having to meet close to 400 Hp to the wheels.. Seems like a high risk to me and I for one want to be safe.. Not extra safe..Great discussion..

 

FWIW...

RC Engineering has a nice little calculator and formulas to help chose the right size injectors. You could also use this to estimate the duty cycle given you know (or estimate) the other parameters.

Link

For my vortech I was estimating

Crankshaft Horsepower = 450 (dynoed and tuned to 400hp)
# of injectors = 6
BSFC = 0.6 (worst case for supercharger?)
Fuel pressure = 130 psi (max for 2.87 pulley?)

It seems like a RC440 would have a duty cycle or 0.62.