357 Rwhp tune 2008 2500hd 6.0L

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Originally Posted by Area47

look at the dyno chart. granted there are exceptions to every rule. however, saying there is only a 28hp loss in the drivetrain is a bit out there.

which leads me to believe someone found a really happy dyno. not saying you're wrong, not saying you're right. im just going off the info in front of me.

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I'm not saying there is only 28 hp of loss, you are.

I'm saying that 30 lb injectors are good for ~385hp. You can spin it anyway you want. A certain amount of gasoline can only make a certain BTU which can only make a certain HP. That is fact.

Here's some valid numbers...

Injector size (lb/hr) = (horsepower x BSFC)/(no.of cylinders x duty cycle)
30 (lb/hr) = (385 x .5)/(8 x 80%)

Even if you up the duty cycle to 85% it's still only 400 hp....

Either the formula is wrong or the dyno. You decide, since according to you, there is no way in hell he can only have 28 hp in loss....

there are other factors in there at play that also skew numbers on total supporting horsepower levels.

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Originally Posted by Area47

there are other factors in there at play that also skew numbers on total supporting horsepower levels.

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Correct. On the dyno side as well... But my point is no matter what, 240lbs of fuel per hour is good for about 385 hp. And 336 lbs per hour is worth about 540 hp.

A motor is only about 28% efficient. A lb of gasoline will produce about 19,000 BTU. ....and 2,545 BTU = 1 HP.....

Injectors are unpredictable over 80% duty cyle. It could be less, could be more than 80% of the rating. When they rate injectors, they are shorted open and not pulsed. So a 30 lb injector in a car, most likely will not provide 30 lbs of fuel...Ever.


Bottom line, I would bet a buck that bigger injectors on this rig will provide better results :)

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Originally Posted by waynehartwig

Correct. On the dyno side as well... But my point is no matter what, 240lbs of fuel per hour is good for about 385 hp. And 336 lbs per hour is worth about 540 hp.

A motor is only about 28% efficient. A lb of gasoline will produce about 19,000 BTU. ....and 2,545 BTU = 1 HP.....

Injectors are unpredictable over 80% duty cyle. It could be less, could be more than 80% of the rating. When they rate injectors, they are shorted open and not pulsed. So a 30 lb injector in a car, most likely will not provide 30 lbs of fuel...Ever.


Bottom line, I would bet a buck that bigger injectors on this rig will provide better results :)

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Derp.

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Originally Posted by snowvette

I was wondering, what is going on in the Idle>Airflow>Throttle follower>Torque table? I have not seen a table that looked like yours. How did you get those values?

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It's stock, i didn't touch it, I recently ported the throttle body and im in the process of redoing those tables.

and I definitely need injectors, in seeing 84% duty cycle at WOT

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Originally Posted by 08RED2500HD

It's stock, i didn't touch it, I recently ported the throttle body and im in the process of redoing those tables.

and I definitely need injectors, in seeing 84% duty cycle at WOT

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I plan on doing the same thing. My IDC is up in the 80s also. Good luck, your truck makes good power.

I'll say it, 30lb injectors are good for more than 385fwhp.

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Originally Posted by zippy performance

I'll say it, 30lb injectors are good for more than 385fwhp.

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Yeah, agreed. Once upon a time in ABQ, they were running a 402 LS2 on the dyno with 30#ers at 58psi rail pressure which produced 447 horsepower, and 424 ft. Lbs of torque. 95% IJDC at 6500 rpm though.

Stock LS3 heads, a very mild cam, FAST Intake, and 1 7/8" headers.

I've made over 400rwhp with 30lb hr injectors many times. Someone needs to stop reading info on the the internet about injectors, injector power capabilities, efficiency numbers, etc and actually work on them. I work roughly 50 hours a week where dyno tuning is pretty much my only job. There are some crap injectors that can't handle spray efficiently, but the newer injectors, especially Siemens Deka, Delphi, and Bosch really don't have much issue with that. Many, many, many times I've replaced injectors because they were up in the 95%+ duty cycle range and unless you were unable to get the desired afr or they were crap injectors you will not pick up more power. If you build something and your injectors are spraying in the mid 80's for duty cycle and you don't plan to add any more power from there out just leave them be. I can tell you that all of the injectors we've tested at work on the ANSU machine certainly shows which injectors are worth a damn. This machine is fantastic in every way and really shows you spray pattern differences overall as well as differences in injector control at low pulse and heavy spray. Engine design, fuel spray, ignition system, etc all have an effect on how much fuel it takes to make xxx amount of power. An LSx type motor with it's efficient chambers, higher compression, individual coils, higher fuel pressures, better design injectors, etc, will make more power on the same amount of fuel as an old design v8. Efficiency can't just be calculated so easily as well as b.s.f.c.. If that was the case engineers would be able to write ecm calibrations without ever firing up an engine.

good numbers!

My LS2 GTO made 430rwhp with the stock injectors (32#) at 95% IDC, 228/288 cam, full exhaust and tune, 12.2-12.5 AFR and conservative timing. from the GTO's i've tuned, i had one with AFR 225 heads, 232/236 cam and Fast intake, full exhaust and stock injectors at 98% IDC, that one made 487rwhp.

Food for thought.... Brian Tooley's all motor 454 made 705hp at the crank with 42lb green top injectors and on a dynojet 248x I squeezed 599rwhp out if it. IDC was 77% @6500rpm

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Originally Posted by LSxpwrdZ

Food for thought.... Brian Tooley's all motor 454 made 705hp at the crank with 42lb green top injectors and on a dynojet 248x I squeezed 599rwhp out if it. IDC was 77% @6500rpm

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Rail pressure?

What transmission is in the truck. My 6.2 didn't even dyno at your base line with a tune. Am I doing something wrong?????

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Originally Posted by Pickupguy226

What transmission is in the truck. My 6.2 didn't even dyno at your base line with a tune. Am I doing something wrong?????

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It's got the 6L90E.

Any chance I can see this tune?

I've mad 500+ rwhp on stock gto fuel system. 33~ lb/hr injectors

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Originally Posted by jakesz28

Any chance I can see this tune?

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It's a 3 year old thread, so I doubt it.