GREATWALLTA

I was just wondering how efficient are the stock 26 or 28 lb/hr fuel injectors Im not sure whick one. My car has developed a very lound tick lately, and its coming from the top back of the motor on the driver side. It makes the lound ticking noise for about 20 seconds and then goes away, no SES lights, car runs the same too. I was thinking maybe its one of my back injectors that has gone bad. My car has H/C and the sizes are in the sig. Do you guys think that it might be the fuel injectors thats going bad or something else? How long does the stock ones last with a moded car? How much HP can the stock injectors handle? And when will be the time for me to upgrade?

bshell

iTrader: (24)

Replied to your other thread in the Internal Engine section, but I'll post this here since it's fuel specific...
In order to calculate how much hp a set of injectors can handle you need to use the following equation:
fwhp = (injector rating)(idc)(#of cylinders)/(bsfc)

Injector rating (stock) is: 1998 - 28.8#/hr, 1999-2000 - 26.4#/hr, 2001-2002 - 28.6#/hr
IDC is Injector Duty Cycle - should be 80% max
BSFC stands for Brake Specific Fuel Consumption - this is a rating of the fuel needed per hp.

GREATWALLTA

Sorry, Im sure that what you listed should answer my questions. But I am very dense when it comes to the technical stuff like what you listed. So can you run that by me in plain english one more time please.

bshell

iTrader: (24)

No problem...what yr is your car?

bshell

iTrader: (24)

haha, just saw your title...02, so you have 28.4#/hr injectors. Doing some quick math I come up with them being able to support 363 fwhp. I used 80% duty cycle and 0.5 bsfc to get that. Now assuming you have about 15% drivetrain loss, they should support 316 rwhp. If you use 100% duty cycle for the injectors you get 454 fwhp and 395 rwhp. With your mods you are probably pushing pretty close to 100% on the stock injectors.

GREATWALLTA

So I guess that it might be a good idea to swap them out for some bigger ones then. Any idea what will be a good set of new bigger injectors for me, lb/hr and brand wise?

bshell

iTrader: (24)

The SVOs are pretty popular, either 30 or 42#ers. There are several different brands to choose from. Do a search on here and you should come up with some good threads. In my case, I went with a set of 36.5# Delphi injectors. I went from maxing out my old stock injectors to ~60% max duty cycle. If you do pick up some new injectors, you will need to get a tune for them.

ssfast99

iTrader: (3)

just to let people know my buddy's WS6 made 391 to the rear wheels with 28.6 injectors and i made 410 to the rear wheels with my SS with 24.7 injectors, both duty cycle at 97%. i say go bigger injectors like we will soon.

RDISADEIFAN

I have a chance of getting some 28lb injector cheap,is it worth it and would I need a tune for just 2lb diff?

bshell

iTrader: (24)

How cheap? You can get a set of 30#ers for around $180. Also be aware that with used injectors you never really know what you are getting. They could be clogged / dirty or close to worn out. It's also a good idea to have used injectors cleaned and flow tested to ensure they are working properly before you install them. This will undoubtedly drive up the cost to what a new set of injectors would run you. If the 28# injectors are in good shape, they will help you run a safer fueling margin with your existing mods. A 2# difference in injector rating corresponds to an 8-10% decrease in injector duty cycle. Every little bit helps.

As far as a tune goes...Yes you will need a tune for new injectors if they are a different rating than stock.

ls1408cp

iTrader: (37)

I have a friend with a 02ta h/c car it made over 440rwhp with stock injectors at 82% duty cycle.

V6 Bird

iTrader: (15)

I had that same noise on my 98 and it happens on cold temp cold start ups. Mine ended up being a noisy evap valve right there on the driver side even with the strut tower.

Mike

oange ss

iTrader: (50)

unless he's runnin 80 lbs of fuel pressure that impossible

ls1408cp

iTrader: (37)

car runs good factory fuel pump. The car only has 4k miles on it. The 02 cars have 28.6 injectors unless the dyno lied. The car made 390rwhp with just the cam and bolt ons. I was in the car when we raced my other friend real close side by side. The other car runs 11.5s so for a full weight ta with ac and all I think the numbers are a bought right. It was 92% duty cycle my fault come down.

Bombguy99z28

Over 400 at the wheels is possible with 28lb injectors, but it is really pushing the limits (especially since thats 28lbs @ 58psi). It wouldn't be unreasonable to assume that some factory engines will have a better bsfc than others, maybe even down to .45.

jimmyblue

iTrader: (11)

Back of the engine could be the AIR checkvalves
flapping. Injector would be a "lightweight" sewing
machine noise at worst. An exhaust leak is also a
possibility, maybe needing just a little heat to swell
shut. Go back to the basics and get yourself a bit
of vacuum / fuel hose for some stethoscope action.
"Turn your head and cough".

dgitchel

Does my 2002 Trans Am WS6 have the LS6 intake Manifold? What is the size of the intake? Also what is the part number for the 28 lb. Fuel Injectors?

Thanks,
DMG