F.A.S.T B2B and Big injectors

[Ed95Pont]

I just put together a Big inch (396)small block nitrous moter.It will be a dry shot with fuel enrichment through the injector.

The moter will make around 700 hp at 8000 rpm with up to a 500- 600 horse shot.Though I will start out with a smaller shot I want to size the injectors for the biggest I will give it.

Using a b.s.f.c. of .6 a duty cycle of .8 fuel presusre of 43 and a very optamistic 1300 h.p I come up with an injector of 122.58 lbs.
I have a set of 160lbs that I would like to use.

I have put my heart and soul into this car and the money tree is dead.I had every intention of running a sequential system with e-dist but Just ran into a b2b system that would save me over 1.5k.That is the difference in possible running this car this year or maybe having to wait until next year.I dont want to wait.

My question is will the car idle?It can be at 1500 -2000 rpm I dont care.It wont see the street.What does it cost to send it back to fast and have it updated to sequential.

Plus the part number indicates that it has aic control not n.o.s.Fast website says that it does not need to be sent to them for the uprgrade for the nitrous.What is the cost involved with that.

Thanks ED

 

[TurboTR]

Well Ed you might be ok. You can hedge your bet a bit by turning down the inj to like 35 psi static fuel press, which would make them about 145 lb/hr.

Lessee, if you want 1300 hp with 8 inj and go with 0.55 bsfc and a max duty of ~ 90% you could get away with the 96 lb/hr inj. That would be the "right" size inj for your app. You could always sell the 160's and recover much of the cost for the 96's I guess.

FWIW I have 160's in my 274" v6 too, toned down to about 145 lb/hr as above. With the inj on/off time set to 1 ms it will idle pretty well at about 850 rpm with a mild solid roller (224). But I'm told that the b2b ecu for the Buick v6's actually fires the inj once every 720, basically as a random sync version of a sefi, but also with grouped injectors I'd guess that with a much larger mill you might be able to make it ok.

TurboTR

 

[TwinTurboIroc]

Ed, i know someone who has a sequential system for sale that just needs to be converted to work with a LT1 which i think is only around $100 for the change

otherwise the system is CHEAP

email me for specifics

 

[Ed95Pont]

TwinTurboIroc You have mail.

 

[quickstrike]

Although my experience here is limited as I am a fairly new FAST user. During alot of my research into the system I have learned of many people using the B2B system with 150 and 160lb inj. No problems with idle quality as long as you make sure it is open loop idle, and not closed loop. I would not downgrade the injector if not needed(especially your HP level). I believe your 160s will work fine.

As far as the upgrades to the system for later down the road, I would have to refer that question to some of the more experienced fellows here.

Good luck

Randy

 

[Craig Smith]

As I see the numbers, you need 97.5 lb/hr injectors to support 1300 hp @ 100% duty cycle. I would probably find a set of 100 lb/hr injectors, or 96, or whatever value is available in that range, and turn up the fuel pressure a bit to give yourself some margin. With the 160s your duty cycle will be a lot lower, and I think that keeping the duty cycle up will help the car run better. The more time you give the fuel to mix with the incoming air charge, the better off you will be IMO.

 

[vtec4gs]

.... what Craig said plus higher fuel pressure will also allow better fuel atomization... IMO
I must have seen a good 6-8 lb-ft from a 150 lb-ft 4-cyl motor, mostly in the midrange, from redoing the entire fuel map to raise the fuel pressure form 35psi to 50psi. these were with peak & hold injectors. I wouldnt; go over 60psi either.

Greg