Good thread.

My numbers say the 97 and 98 LS1 had 28.6 lbs/hr@58 psi fuel injectors and 99-00 had 26.4 lbs/hr@58 psi injectors.

I think either the Ling Viper or the Hennessy twin turbo Viper used GTP injectors, 20 of them.

 

It maybe obvious but for the sake of being thorough I will also mention that as you run down the 1/4 mile track your are not constantly at peak RWHP and a fixed RPM. As you shift the gears and accelerate you are not only placing increasingly greater loads on the engine, but also may only be running dangerously lean for a small amount of time before you lift off the nitrous and drop it into another gear, giving the fuel system enough time to catch up, the cylinder pressure to come down some and the AFR's to drop back down.

[ November 27, 2001: Message edited by: Godspeed ]</p>

 

[quote]98 LS1 had 28.6 lbs/hr@58 psi fuel injectors <hr></blockquote>

I had RC Engineering flow and balance a set of 1998's and they did flow 28.6p lbs/hr. They were also balanced withint 1% of each and adjusted for "excellent" rated fuel pattern which is a good idea for anyone considering serious power. The set of 8 I had balanced had only 10k miles on them and were -+ 5% from each other and had spray patterns of poor to good prior to being flowed/balanced.

-Jeremy

 

Thanks for the replies Jeremy, they make a ton of sense. So, how much are the SV0 30# injectors? I wonder if I could sell my '01 injectors since they only have 2K miles on them.

/NineBall smacks Jeremy's hand for giving him more ideas on money to spend.

Tony

 

[quote]Thanks for the replies Jeremy, they make a ton of sense. So, how much are the SV0 30# injectors? I wonder if I could sell my '01 injectors since they only have 2K miles on them.
/NineBall smacks Jeremy's hand for giving him more ideas on money to spend.<hr></blockquote>

I haven't priced them lately. I picked up my SVO 42's for 399.00.

The SVO 30's are a good step up from the GM 28's, but like I said before I would consider them a minimum. One of the reasons I think they were so popular was the relative ease they could be installed with using a MAFT. As mentioned previously the SVO 42's are actually very good at idle and low RPM - they ran just fine in my car in and out of boost. If you have access to LS1 Edit changing injectors will be much simpler since it's just a single parameter you can alter in the PCM. So the question that comes to mind is that you can spend all day long calculating which injector size is the minimum you could get away with, but why not just buy the largest one, have the PCM calibrated, and not have to worry about max'ing them out?

Just thought I would throw that one out for you to think about.

Also one other point worth mentioning in the discussion of the limitation of the LS1 stock fuel system is the bottleneck in the fuel rail. For those that are unaware behind the factory noise suppressor at the junction in the fuel rail there is a significant restriction. You need to remove the clip that holds in the suppressor, pull it out, and then open it up with a dremel.

[ November 27, 2001: Message edited by: Godspeed ]</p>

 

[quote]Originally posted by Godspeed:
<strong>Also one other points worth mentioning in the discussion of the limitation of the LS1 stock fuel system is the bottleneck in the fuel rail. For those that are unaware behind the factory noise suppressor at the junction in the fuel rail there is a significant restriction. You need to remove the clip that holds in the suppressor, pull it out, and then open it up with a dremel.</strong><hr></blockquote>


w/o the damper setup, the fuel system can do wonders.

I run a LS1 rail, but from a 97 vette. So my damper is replaced w/ a regulator. Stock sized rails, 3/8 factory feed line, 5/16 factory (V6) return line, AC delco filter, 255 lph intank, SVO 42's (base pressure of 4 BAR). I put down 573 RWHP mustang dyno at 95% DC on the injectors at 70 PSI when the pump started to run out.

FWIW, industry standard flow ratings are at 3 BAR (~43 psi) LS1 system is at 4 BAR (~58 psi), GTP injectors are rated at 3.5 BAR <img src="images/icons/rolleyes.gif" border="0">

Do not forget your pump <img src="images/icons/smile.gif" border="0">

BIG, don't forget..... If you're spinning the hell out of your motor you may need bigger injectors even though they may flow the numbers. The faster you spin it then less time you get. DC goes up for a constant pulsewidth as engine speed goes up. just another piece to think about

 

and another tidbit...

factory enrichment under WOT is like mid 11's

You may go static on the injectors and begin to lean out, but how "lean" you go all depends. is 12.5 too lean?? is 13??

more to think about <img src="graemlins/fluffy.gif" border="0" alt="[Fluffy]" />

and even more, BSFC goes up on a FI car <img src="images/icons/smile.gif" border="0">

more like .55 to .6

[ November 27, 2001: Message edited by: y2khawk ]</p>

 

[quote]and even more, BSFC goes up on a FI car

more like .55 to .6
<hr></blockquote>

Don't forget what Dave used to preach to us:

"Modern efficient turbos have a BSFC of 0.50 or less. "

 

Should you use a BSFC higher than .50 for dry nitrous setups?

 

[quote]Should you use a BSFC higher than .50 for dry nitrous setups? <hr></blockquote>

Increasing the BSFC in your calculations certainly couldn't hurt. If anything they will help pad your numbers on the safe side.

Numbers and calculations are fine and dandy. They give you a good indication of what the car should do and how to go about supplying adequate fuel. The best approach is to to choose an injector that may be slight overkill. There really isn't that many choices for them - 28, 30, 36, 42 (although different vendors.) Once you choose an injector before running maximum nitrous or boost on your engine, it is critical to monitor what the car is doing. This can only accurately be accomplished using widebands on a dynojet.

Once your PCM has been calibrated for the larger injectors, head over to your favorite dyno shop. Do a few pulls and check out the A/F ratio. Use a Tech2 or autotap and monitor what the car is actually doing and then begin to gradually increase the amount of nitrous and/or boost being used. This process may seem slow and laborious, but it is really the best way to make good power safely. The key is making changes slowly and incrementally, monitoring the differences, and adjusting accordingly.

Through personal experience I found what it takes to blow up a stock 1999 LS1. Repeated use of very large 150-200 shots of dry nitrous on pump 93 octane gas for extended periods of time. Eventually the motor turned into a pile of broken pieces, but the point isn't to worry you but show you the extremes that the engine can take. If a little time goes into planning your setup, a little self restraint is exercised when using the nitrous, and you do a good monitoring what the engine is actually doing, it will enjoy a long and happy life. <img src="graemlins/burnout.gif" border="0" alt="[Burnout]" />

[ November 27, 2001: Message edited by: Godspeed ]</p>

 

I have a couple of questions in this thread...

https://ls1tech.com/ubb/cgi-bin/ulti...c&f=1&t=000468

 

Tony...I installed the 30# SVO's in mine. So far so good...Will prob. have to upgrade fuel pump some day soon though...TNT here I come !! Got mine at Tommy Vaughn Ford for $214.54 out the door. Hope that helps. Oh yeh, congrats on the awesome pass sun. Wish I was there...

 

[quote]Originally posted by Godspeed:
<strong>

Don't forget what Dave used to preach to us:

"Modern efficient turbos have a BSFC of 0.50 or less. "</strong><hr></blockquote>

LOL

is it really a function of the turbos or the motor/injection system. Your fuel consumption has alot of variables.

I'm showing close to .55 at 12:1, go figure <img src="images/icons/smile.gif" border="0">

 

Is there a downside (other than cost) to doing what was suggested earlier in this thread and just going overboard and putting bigger than needed injectors in to stay on the safe side?
Matt

 

Formulas are great to find out what you may need, but you have to go get it all tested and running correctly.
MMS has a dyno with Wide band. It actually prints out on the bottom of the dynosheet the A/F ratio of the entire run. From those WOT runs, will find out if my '98 stock fuel system is up to par or I will need to stick the 3800 SC'd Monte Carlo part # 24508208 in there, and upgrade the pump. Probably will be in the 450 rwhp range or better, I hope. Ls6 intake, MMS ported throttle body, Mild MMS cam, MMS stage 2 heads, stock headers y pipe, Corsa Exhaust.
Then the harder part will be the custom tuning for cold start and what not to get it running just like stock and pass emissions.

Leo with 427MMS coming soon!

[ November 27, 2001: Message edited by: pedaltothemetal ]</p>

 

Most injectors will max out at 80% duty cycle and this is the accepted industry standard.
B.S.F.C is brake specific fuel consumption - How much fuel you are using per horsepower per hour.

Formula:

.50 = B.S.F.C (Brake Specific Fuel Consumption)
In most cases a naturally aspirated engine will have a B.S.F.C of .50. This means that the engine will use .50 lbs. of fuel per hour for each horsepower it produces. Turbocharged engines will want to be at .60 lbs. per hour or higher.

(Inj. Size lb/hr) x (Duty Cycle) / .50 = HP rating per injector


C5 Corvette:

97-98 = 28.4 lbs/hr
80% duty cycle rating: 45.44 Crank HP x 8 = 363.52 Crank HP
100% duty cycle rating: 56.8 Crank HP x 8 = 454.4 Crank HP

99-2001 = 26.4 lbs/hr
80% duty cycle rating: 42.24 Crank HP x 8 = 337.92 Crank HP
100% duty cycle rating: 52.8 Crank HP x 8 = 422.4 Crank HP

Z06 = 28.2 lbs/hr
80% duty cycle rating: 45.12 Crank HP x 8 = 360.96 Crank HP
100% duty cycle rating: 56.4 Crank HP x 8 = 451.2 Crank HP

30 lbs/hr SVO = 36.12 lbs/hr (LS1 at 58psi)
80% duty cycle rating: 57.79 Crank HP x 8 = 462.33 Crank HP
100% duty cycle rating: 72.24 Crank HP x 8 = 577.92 Crank HP

Note:

(While .50 is used as the industry standard for calculating and determining an injectors HP ability. High Performance Engines and Racing engines begin to use less than .50

.48, or even .40 in extremely high output.

So with the LS1, there is a margin there below .50

It's difficult to determine precise BSFC needs on an individual basis, because the process involves extensive dyno testing, and the use of lambda meters to observe and log specific air fuel ratios under all conditions.

Also to note, an engine will be most efficient at peak torque.

 

Also the 80 percent value is a good figure to use when *sizing* injectors, but as to actual application unless you are running something like silver state where you will see sustained 5000+ rpm usage possibly 90-93 percent is really about where the limit is with most injectors. Even if your computer reports more than that you probably aren't seeing it, but I would have no problem running 90% duty cycle for short (< 1-3 minute) stints in order to avoid a new injector purchase.


Chris

 

[quote]Originally posted by Nine Ball:
<strong>Excellent thread guys! I've never done any research on my fuel system. What are the current stock injectors values? If I am not mistaken, they are:

1998 = 28 lb
1999-2000 = 26 lb
2001-2001 = 28 lb

I currently have '01 injectors in my car. By looking at these formulas and doing calculations, I should have a minimum of 33.4 lb injectors. But, that is for the current power. If I am realistically looking for 460 rwhp, I need some 36 lb injectors.

NOW, the question is, will larger injectors improve my performance at the drag strip, or just make my injectors work easier? If there is no gains to be found, then why bother? FYI, I pulled over 500 rwhp with a completely stock fuel system (98 injectors) on a dry nitrous shot in the past:

So, how come I could make so much power on stock injectors on nitrous? If I could make that power back then, then why can't my stock injectors handle "only" 450-460 rwhp on motor now?

Tony</strong><hr></blockquote>

Hi Tony,
The formula above is using a 12:1 A/F ratio as the basis of the calculation. If you are doing over 500 rwhp, then this would result in an A/F ratio of approximately 15:1. The injectors are maxed out and therefore running very lean. If you were running sustained WOT, then you will definitely blow your engine. But you can get away with it for a the short time down the drag strip, and you are running a very short time. haha
On a side note you have to have a fuel pump and to support bigger injectors too.
Also you need to know this when changing injectors. Not all injectors are rated at 80% and 42 or 43 psi. That is just the standard. A large company like GM or Ford can have specs for theirs anyway they want it. As is the case with the LS1 pressure was increased to 58 psi. Most injector manufactures wiil rate injectors at 80%(the standard) and static flow which means 100%. When they tell you the size they will also tell you at 80% or static so you will know how it is rated. But you need to do a lot of testing with a wide band on the dyno, and as noted here some are not flowing in our engines as speced.
How about injector tips. Well some are different. Some injectors will spray a cone patteren and some spray in a steady stream. Two injectors can have the same flow but the stream injectors can't work in our LS1 engines. That's why I chose the GM Gran Prix injectors cause of the correct spray pattern, and HP rating for my very conservative 427 stroker. Although I do believe I can get by with my stock '98 injectors. Will put in on the dyno with wide band o2 recording to see if the A/F ratio goes lean at the upper hp levels with the stock '98 injectors.

Leo

[ November 27, 2001: Message edited by: pedaltothemetal ]</p>

 

just a note , the viper uses a different kind of injector. the injectors on a viper won't interchange with anything i've seen. have you noticed that the viper has no fule rail? the fule flows through a hole in the cast manifold and through the sides of the injectors, the top is where the plug goes. and i doubt ( no flame intended) the used two injectors per cylinder, cause there isn't enough space.

 

[quote]just a note , the viper uses a different kind of injector. the injectors on a viper won't interchange with anything i've seen. have you noticed that the viper has no fule rail? the fule flows through a hole in the cast manifold and through the sides of the injectors, the top is where the plug goes. and i doubt ( no flame intended) the used two injectors per cylinder, cause there isn't enough space. <hr></blockquote>

Is Kyle Kent on here yet? If not let's get him...he's the one that tuned the TT Viper, so I'm sure he can answer that question.