Hi, I was told by my tuner that the injectors in my 2001 coupe are now running at 100% capacity (406rwhp). Is this something that can hurt the car? I would assume that if I put larger injectors in that peak power would increase a bit, is that good logic? And finally, can someone recommend a decent set of higher flowing injectors that are drop in replacements? I would like to keep the set under $300 if they exist for that price. I do plan on adding another 20-30hp to the car over the next year so the injectors would have to be able to handle the extra fuel.

Thanks!

Jeff R.

 

Larger injectors won't give your car more peak power. What happens when the injectors go 'static' (100% duty cycle) is they stop clamping shut and just spray continuously. This isn't where the problem lies. The problem is the coils that move the pintle are recieiving current continuously which causes them to overheat eventually. If they overheat they could sieze and that piston will either get too much or too little fuel causing either a burned piston or a hydrolocked cylinder. When the duty cycle approaches 100% the metering gets flakey too. With a lot of fuel going through it and the closed cycle approaching 0% it acts like it does when it gets a very short pulse. Because of inertia it starts to get non-linear.

A good rule of thumb is to try to keep the injector duty cycle below 80%. You can get away with 100% or more duty cycle if you drag race. The injector isn't at 100% for very long. But road racing can have it there or close to it for long periods of time.

When selecting a new size injector you also have to keep in mind the type of injector you're replacing. There are pintle and disc, high and low impedence, and there is also the spray pattern to consider. Also, obviously, the physical size has to be accounted for.

What a lot of guys have done, me included, is to go to an SVO 30 lb/hr injector when going bigger. They posses a lot of the same characteristics of the stock injectors, which makes them easier to tune, they fit without any modification and they will go to about 80% dc at about 450rwhp. The 30 lb/hr rating is at 2 bar (43.5psi), the vette has a 3 bar regulator so they rate ~35.4 lb/hr at that pressure.

Check out New Era Performance, a sponser here. They have some good deals and will flow-match them for you if you want. You won't need to flow match the SVO's though.

If I am not mistaken the SVO 30lb/hr 'Red Top' injectors are no longer being made. SVO has introduced a new injector as a replacement and it's supposed to be better than the old version. It's supposed to flow the same, be closer in tolerance between units, and be a little quicker in response time, so it will improve the idle.

 

Thanks for all of the great information! If it poses a risk then I think I'll order them right away, I'll give NE performance a call. Are the SVO injectors easy to install? Will I have to have the car retuned or can I run them as is?

Thanks.

Jeff R.

 

Are these the injectors that you are talking about?

http://www.neweraperformanceparts.co...E&PKV=c5bo30|0

If these will work then I'll order them right away, thanks again for the help!

 

It doesn't necessarily have to be re-tuned, but you will have to get your tuner to change the injector settings in the PCM to reflect the new size. If you don't, the computer will send out the injector pulse width to the new injectors based on them being stock sized. Since the new ones are much bigger, you will get a lot more fuel than needed. If done correctly, rest of the tune should be ok.

 

Ah, that makes sense, thanks. Can a chevy dealership handle that type of update? My tuner is over three hours away so I'd rather not make the trip for a simple update.

 

Ya what ArK said

At WOT, I was hitting 120+ % with the stock injectors. I switched to SVO and hang around 75-83% at WOT.

It wont hurt you to switch

 

I doubt it. I don't think that a Tech II has that ability. I don't know what to tell you, because even if you find a fellow member that has tuning software (HP Tuners, EFI Live) and would do it for just the licensing, it would still cost you $100 for the licensing.

 

Yes, those are the ones. Wow, that's a great deal too! Sorry I didn't get back to you on this sooner, I was out of the house all day today.

 

So what you are saying is that I now have an excuse to get a new intake manifold and a re-tune. I like your logic .

 

Awesome, I'll order the set on Monday, they are right in the price range that I wanted to pay!

 

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