Stock Injectors??

[bigdoug3022]

i have a 1990 gsx and plan on running a big 16g....i will be running bc 280's and an evo 3 manifold and o2 housing...do i need bigger injectors or will i be ok wit a afpr and a walbro 255?? and i was also wondering what to do about a computer since it is a 90...as of right now i have a wideband and an afc2 will this be fine??...any help would be great thanks guys

 

[DSMTriad]

i have a 1990 gsx and plan on running a big 16g....i will be running bc 280's and an evo 3 manifold and o2 housing...do i need bigger injectors or will i be ok wit a afpr and a walbro 255?? and i was also wondering what to do about a computer since it is a 90...as of right now i have a wideband and an afc2 will this be fine??...any help would be great thanks guys

For a big 16g you would want at least 550cc. The wideband and afc2 will be fine.

 

[bigdoug3022]

allright cool thanks man

 

[aaronhawk60]

You will be fine with the wideband and afcs2 will work though some prefer to run dsm link

 

[jrohner]

I really don't see the point of upgrading the FPR & pump without changing injectors. I would do the injectors first if anything.

Look into EPROM tuning.

 

[->PrOjEcTGS<-]

Why such a large cam? STM made more power with a good set of 272's than they did on the BC 280's on on the same car. I just hope you haven't bought them yet.

 

[spitefire1]

i would change out the injectors to at least 550's but if you can 650's and mayb eget a chip from jeff at dsm chips. it will help you an dyou tunning!

 

[bigdoug3022]

yea i no i saw that test they did right aftr i bought the cams hahahah shouldve got some kelfords but yea i got em from a friend brand new for cheap.....im not sure ### to do about the computer since its not an since its a non eprom any suggestions would be great

 

[dsm-onster]

A little trick. The walbro fuel pump flows enough at 85psi (base plus boost) for anything a big 16g can throw at it. 60psi base + 25psi boost = 85psi in the fuel line. 60psi base fuel pressure with 450s is about 530cc of fuel flow, with less deadtime than larger injectors.

 

[toofast82]

A little trick. The walbro fuel pump flows enough at 85psi (base plus boost) for anything a big 16g can throw at it. 60psi base + 25psi boost = 85psi in the fuel line. 60psi base fuel pressure with 450s is about 530cc of fuel flow, with less deadtime than larger injectors.

will he be safe with his injector duty?

 

[dsm-onster]

He will have the injector duty cycle of 530cc injectors. However lower his %DC ends up swapping in 550s, things will be nearly the same as just raising the base fuel pressure to 60psi with the 450s. Duty cycle is dependent on final fuel injector flow.

. . . I hope the OP has a logger.

 

[bigdoug3022]

ok coool thanks

 

[oldman420]

dsm-onster, you strike again. I will be trying this when my trans. gets done as i don't want to install my injectors untill I get dsmlink later this summer.

 

[Lonewolf64]

i have a 1990 gsx and plan on running a big 16g....i will be running bc 280's and an evo 3 manifold and o2 housing...do i need bigger injectors or will i be ok wit a afpr and a walbro 255?? and i was also wondering what to do about a computer since it is a 90...as of right now i have a wideband and an afc2 will this be fine??...any help would be great thanks guys

Running BC 280 cams is stupid with a 16g, even if you got them cheaply. The car will run worse than with stock cams, because your power curve will be moved up to 7000-9000 rpm, coincidentally an RPM range past your motor's redline.

I recommend selling off the cams for more than you bought them for and either retaining stock cams or swapping out to HKS 264/264 cams (if you aren't planning on a larger turbo any time in the future, this is probably the best cam setup for 16g).

75 percent of people getting upgraded cams for their oversize them for their application and lose performance or do not gain as much as they could.

 

[toofast82]

You should sell those cams for a nice set of injectors and something else for your setup. 280s are a little big for the 16g, i wouldnt go bigger than 272s. My friend has a set of 292s in his garage. I laugh my ass off every time i see them! I've never even heard of anyone running them. Shep ran 8s on 272s

 

[habitatguy187]

A little trick. The walbro fuel pump flows enough at 85psi (base plus boost) for anything a big 16g can throw at it. 60psi base + 25psi boost = 85psi in the fuel line. 60psi base fuel pressure with 450s is about 530cc of fuel flow, with less deadtime than larger injectors.

Can you explain this to the slow-learning like myself?

 

[JEFFREYCASTGSX]

Why such a large cam? STM made more power with a good set of 272's than they did on the BC 280's on on the same car. I just hope you haven't bought them yet.

But they weren't degreed, which plays a big role on 280's from bc

 

[dsm-onster]

Typical 272s have an effective valve close angle that resonates at a 2nd order harmonic with the stock intake manifold at about 7000rpms. The stock cam has a 3rd order harmonic (weaker) at 7000rpms. And a 2nd MUCH higher than that. Yes, the larger the duration the higher the momentum of the aircharge must be to get the most out of the cams, thus the higher in the rpm range such cams push 100% VE. But also, the larger the duration the lower the resonating rpm for a given intake manifold length. This will certainly restore some lost VE due to a high duration. I doubt the 280s, once degreed, would be so much less effective than 272s.

Just because a ported 2g exhaust manifold went into the 9s doesn't mean that an 11second car couldnt greatly benefit from an exhaust manifold upgrade. I never did get the "shep/rau/brown/etc. went _._seconds with X part so don't bother with Y part" arguement. If 272s flow enough to max out a 16g, then how to 280s hurt. They flow even more. You're still maxing out the 16g. ???

Habitatguy187, running that 60psi base pressure makes your stock 450s become 530cc injectors. And the walbro pump can handle that base pressure just fine for any thing the OP's turbo could throw at it. Even at that base fuel pressure, he'll run out of injector long before his fuel pump won't be able to flow enough to keep up.

 

[oldman420]

Base pressure is with or without vacuum?

 

[snowborder714]

Without. You have to remove the vacuum line to an AFPR to properly set the pressure while the car is running.

 

[oldman420]

Don't want to jack this guys thread but i don't want to start a new one for this question. My roomate has an evo1. I have no clue what they have in them for a fuel system but theoretically could we do the same thing to his car, and if it runs rich do i just lower the base fuel pressure?

 

[DSMTriad]

Don't want to jack this guys thread but i don't want to start a new one for this question. My roomate has an evo1. I have no clue what they have in them for a fuel system but theoretically could we do the same thing to his car, and if it runs rich do i just lower the base fuel pressure?

C'mon dog start a new thread. The OP is trying to get some understanding.

 

[habitatguy187]

C'mon dog start a new thread. The OP is trying to get some understanding.

This would be helping the op if he accidently runs it too rich, or changes injectors in the future.

Oldman; The way I understand it yes, if you drop the base pressure it would lean it out a little, just be careful not to lower it too much.