Should I get bigger injectors?
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Should I get bigger injectors? I have a 2000 WS6, which seems to have the smaller injectors out of all the years...
I currently have Lid, ported TB, Hotcam, Macs w/ORP, and MagnaFlow all tuned with LS1Edit.
I will soon be adding a LS6 intake as soon as the damn thing arrives in the mail.
Am I at the edge for these injectors? I know, I know, log it and figure it out, but I just wanted some opinions... Thanks.
Tommy
I currently have Lid, ported TB, Hotcam, Macs w/ORP, and MagnaFlow all tuned with LS1Edit.
I will soon be adding a LS6 intake as soon as the damn thing arrives in the mail.
Am I at the edge for these injectors? I know, I know, log it and figure it out, but I just wanted some opinions... Thanks.
Tommy
Re: Should I get bigger injectors? Shouldn't need new injectors with your mods. Most people don't seem to need new injectors till 500 RWHP. Its usualy the fuel pump that gets changed first.
Chris
Chris
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Re: Should I get bigger injectors? Well, I logged some data today and figured out where my injector's duty cycle. This is without the LS6 manifold (which is still on back order) 
The max duty cycle it hit was about 83% so I guess I'm going to need new injectors since I assume the LS6 manifold will demand more fuel...
In any case, I am no where near 500rwhp, and my tiny 26lb stock injectors are just out of the "safe zone"
Tommy
The max duty cycle it hit was about 83% so I guess I'm going to need new injectors since I assume the LS6 manifold will demand more fuel...
In any case, I am no where near 500rwhp, and my tiny 26lb stock injectors are just out of the "safe zone"
Tommy
Re: Should I get bigger injectors? my cam only car was maxing out my small stock 26 lb. injectors too. 114% at times on the track. i switched to 1998 stock 28 pounders and now my duty cycle is much better (in the 80's).
hope that helps. start looking for injectors
hope that helps. start looking for injectors
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Re: Should I get bigger injectors? Stock injectors are maxed out at around 350 flywheel HP as to staying within the proper 80% duty cycle. Pushing them above that is only asking for higher amount of knock and lower timing plus once the injectors fall behind the engine load demand the fuel trims suffer from leaner averages which then have an impact on low engine output conditions since PCM has to resolve the LTFTs that were sent way lean.
If you see over 18 mSecs pulse width over 5,000 RPMs then the injectors are above the 80% duty cycle.
It is always better to have injectors that have the ability to meet high engine loads then to be handycapped with smaller ones that limit performance due to being max'd out.
Sure if the engine is always cruising around then a stock injector would be fine even with a 500 HP engine but not when the engine is running at it's max output so it is better to have a injector that has reserve of fuel flow ability it can flow then one that is beyond its limits.
Smaller injectors were used by GM because of the slow CPU of the PCM, the longer the injector pulse width is the more control the PCM has but as performance is increased and fuel demand also increases a larger injector works just fine.
I use 44 lb injectors at around 500 FWHP so clearly a stock injector of around 26 lbs was too small, esp when like drag racing.
The SVO 30 injector of 36 lbs works nicely even with a stock engine for injectors then never fall behind and keeps the fuel trims around zero where a stock injector at high load causes high lean conditions so the PCM is forced to bounce around from lean to rich pulse widths where with a larger injector and proper tuning the fuel trims are always within the operating window of the STFTs.
If you see over 18 mSecs pulse width over 5,000 RPMs then the injectors are above the 80% duty cycle.
It is always better to have injectors that have the ability to meet high engine loads then to be handycapped with smaller ones that limit performance due to being max'd out.
Sure if the engine is always cruising around then a stock injector would be fine even with a 500 HP engine but not when the engine is running at it's max output so it is better to have a injector that has reserve of fuel flow ability it can flow then one that is beyond its limits.
Smaller injectors were used by GM because of the slow CPU of the PCM, the longer the injector pulse width is the more control the PCM has but as performance is increased and fuel demand also increases a larger injector works just fine.
I use 44 lb injectors at around 500 FWHP so clearly a stock injector of around 26 lbs was too small, esp when like drag racing.
The SVO 30 injector of 36 lbs works nicely even with a stock engine for injectors then never fall behind and keeps the fuel trims around zero where a stock injector at high load causes high lean conditions so the PCM is forced to bounce around from lean to rich pulse widths where with a larger injector and proper tuning the fuel trims are always within the operating window of the STFTs.
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Re: Should I get bigger injectors? Well, I just ordered a set of OEM 28.6lb (1998) injectors off someone from this board for $85. This should be good for now. I don't really have any BIG mods in my future... but who knows 
Anyways, for $85 I might as well put these in with the new (LS6) intake.
So since my LTFTs are slightly negative can I just divide 28.6 by 26.4 and mutiply that by my current injector flow rate to get a good estimate of where I need to be?
Thanks!
Tommy
PS I must be doing OK in the horsepower department, because I took out a Z06 today on the highway!!!! First time I had a good race since I installed my cam...
Anyways, for $85 I might as well put these in with the new (LS6) intake.
So since my LTFTs are slightly negative can I just divide 28.6 by 26.4 and mutiply that by my current injector flow rate to get a good estimate of where I need to be?
Thanks!
Tommy
PS I must be doing OK in the horsepower department, because I took out a Z06 today on the highway!!!! First time I had a good race since I installed my cam...
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Re: Should I get bigger injectors? oh...I take that back....since you have the 26lb injectors, you will need to upgrade to really do anything.
I actually have the factory 2001 28lb injectors that came out of my car (10k miles on them). If you want them, I can make you a really good deal on them (think I'm asking $150 shipped for the set).
If your buying NEW injectors, get BIG (I went with 36lb SVOs) and tune for them (LS1Edit). That way you won't have to buy them again for a long time (lots of mods).
Chris
I actually have the factory 2001 28lb injectors that came out of my car (10k miles on them). If you want them, I can make you a really good deal on them (think I'm asking $150 shipped for the set).
If your buying NEW injectors, get BIG (I went with 36lb SVOs) and tune for them (LS1Edit). That way you won't have to buy them again for a long time (lots of mods).
Chris
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Re: Should I get bigger injectors? Thanks CamaroGuy,
Unfortunately I already ordered a set for $85. They have 30k on them (less then mine do now...) I'll see how these work out.
Thanks for all the advice.
Tommy
Unfortunately I already ordered a set for $85. They have 30k on them (less then mine do now...) I'll see how these work out.
Thanks for all the advice.
Tommy
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Re: Should I get bigger injectors? I needed bigger injectors with just my bolt-ons (see sig.). My duty cycle was near 100% (at higher rpms as TeamZR1 mentioned). Just scan your car using the info John provided, and I think it will show that you need at least SVO 30s.