350 Vortec with Cam Tune problems

[lazydogtuning]

I'm pretty new to tuning and I am doing my best over here not to blow up my engine, lol. Not funny tho!

I put a 5.7 vortec in my 99 GMC Jimmy and did the 0411 swap as well. I got that all installed, slapped a stock Express Van tune on it and everything was great for about 30k. The junk yard engine decided it needed rebuilt so that's what I did.


Specs
Bored .30 over
Flat top pistons (7cc relief for the valves.)
Summit Racing heads (flow a little better but nothing major)
Mellings 22280 cam (283 int./287 exh.)
Headman short headers
rebuild 4l60e /w corvette servos and shift kit

For some reason I just cant get this tune right. I have made few adjustments to get it running but it runs rough and has no power. below are my notes on what I've done and Ive attached my tune file. If anyone can help me out I'd greatly appreciate it. My goal is horse power or course but I also want to see if I can get a tune that still keeps a decent MPG. Thank you guy

Jimerra Tune 1

Temp Control
COT: Disabled

Tach Output: +1

VATS: Disabled
--------------------------------------------------------------------------------------

Jimerra Tune 2

Idle-RPM
Base Setpoint: Multiplied by 1.35 (35%)

Idle-Airflow
Base Running Airflow: Multiplied from 68/deg up 1.50 (50%) Interpolated from 25Deg up

Spark-Advanced
Idle Spark Advance: set to 28 deg in idle range(1200 and below) for both Park and Drive.

Spark-Advanced
Idle ADAPTIVE Spark control :Adjusted to put smalles value at 50 rpm

[5FDP]

That's a ton of base running airflow to add, I probably wouldn't have done that much.

You're going to need a wideband oxygen sensor for tuning, the entire MAF and VE table will need to be gone over.

Also you are going to need larger injectors. A cammed 5.7 with headers and way better flow cylinder heads is going to need a lot more fuel under heavy throttle. Those stock 23lb/hr injectors aren't going to cut it.

[lazydogtuning]

If I remember correctly the engine is demanding more airflow than I have added, see log file.

I do have a wide band but my dumb ass didn't pay attention to compatibility so I have the AEM 30-4110 that only allows you to log thru analog and I have that hooked up thru my EGR signal wire and logging correctly. As far as I can tell anyway. The readings in my log do not respond as fast as the AFR gauge tho. I've done a ton of research and I'm using the videos from GoatRope Garage to try to tune me MAF and VE tables is just alot to take in and I guess I'm just looking for a little more guidance.

I've read that the spider injection system is good for 400hp but either way the stock injectors should still work for a mild tune at least and its only a 2 bolt so I wouldn't even aim for more than the stock injectors allegedly can produce.
I do have a Pro-Flo XT intake I want to install in the future but I'm hoping to get it tuned and have a little power with the stock fuel system at the moment.

I added the one MAF log I was able to make, I probably need to reset my channels some aren't there but maybe this will give you an idea of how the truck is running. This was set for MAF tuning to everything not needed was disabled, I think.

[5FDP]

No way it'll have enough injector, you already reached like 60% injector duty cycle not even dipping into power enrichment. Stock 5.3 injectors are only 25lb/hr and those need larger injectors with a camshaft.

That log is 20% lean per the fuel trims. Make sure that both the long term and short term trims are disabled if you are using the wideband to tune the MAF and VE tables.

[lazydogtuning]

LTFT should be disabled. I never cleared the memory on the ecu when I replaced the 02's so that's why the LTFT are still so lean. Please take a look at my MAF tune file and let me know if there would be anything else I need to adjust to disable them.

I do plan on upgrading the Intake and injectors but I've seen on this forum where guys have got basically the same engine set up and have tuned it to the 'Black box' ecu so I should be able to get this ecu tuned to run this combo. I haven't taken a look at any of those files because they are for a different ecu but maybe the setting are similar. I'll have to go look.

[Oleblu]

Tried years ago to tune my truck after the intake swap with 25lb injectors and a touch bigger cam than listed above. I agree they are maxed out above 5k. Switched to flex fuel injectors quickly. I also tuned a truck recently with a similar setup to mine. But with factory intake & mpfi upgraded injectors. and it was definitely out of fuel above 4800rpm. It's a bummer to see a decent sbc build with poor fuel management.

[lazydogtuning]

Guys, I'm not building a race truck I was just trying to build something reliable that would pull my jeep, yes its a fat cam. Maybe not the best choice but here we are. I just want to get the engine tuned right. There is no reason the mpfi spider injectors I have can run this engine to 300hp. that 50 hp over stock. I'm not advance with tuning but I just find if hard to believe I cant get 50hp out of the stock injectors but I'm listening. I will keep at it and let you guys know my results.

If anyone thats done this before sees this please give me hand. Thank you.

[Shrek]

Guys, I'm not building a race truck I was just trying to build something reliable that would pull my jeep, yes its a fat cam. Maybe not the best choice but here we are. I just want to get the engine tuned right. There is no reason the mpfi spider injectors I have can run this engine to 300hp. that 50 hp over stock. I'm not advance with tuning but I just find if hard to believe I cant get 50hp out of the stock injectors but I'm listening. I will keep at it and let you guys know my results.

If anyone thats done this before sees this please give me hand. Thank you.

Getting upset with people, who offer you valid advice, won't change anything.

GM tended to use fuel injectors in the 1999 to 2006 Gen 3 LS engine truck platforms, with absolutely no additional capacity available. Anyone who has data logged their stock LQ4 or LQ9 6.0L truck under heavy load, will have noticed that the fuel injector duty cycle can easily reach 100%.

Your Vortec engine with the spider fuel injector setup is similar - there is no additional capacity.

So, could you "half way" tune the engine with the existing fuel injectors - Yes you could.

However, you would likely need to set the Rev Limiter to around 4500 RPMs - which would essentially negate some of the benefit of the camshaft upgrade.

You can do this correctly, or you can do this your own way.

[lazydogtuning]

I'm not upset at all just trying to clarify what my goal was this time around.

I was just trying to get it tuned to run good, I'm not looking for huge HP gains. This will be my road trip/pulling vehicle.

Like I said maybe this cam was the wrong choice but I still find it hard to believe that I can't get this combo tuned to run correctly but as I stated I'm new to tuning and I'm listening.

This is the info I've come up with.

.5LB of fuel = 1HP
1Lb of fuel is good for 2HP

23*2=46HP If this is correct then one 23lb inj will produce 46HP each.
8*46=368HP
If this is correct my 23LB injectors will handle 368HP at 100% duty cycle. Why can I not make this engine run well and procedure 300 HP with the stock injectors?

[Shrek]

I'm not upset at all just trying to clarify what my goal was this time around.

I was just trying to get it tuned to run good, I'm not looking for huge HP gains. This will be my road trip/pulling vehicle.

Like I said maybe this cam was the wrong choice but I still find it hard to believe that I can't get this combo tuned to run correctly but as I stated I'm new to tuning and I'm listening.

This is the info I've come up with.

.5LB of fuel = 1HP
1Lb of fuel is good for 2HP

23*2=46HP If this is correct then one 23lb inj will produce 46HP each.
8*46=368HP
If this is correct my 23LB injectors will handle 368HP at 100% duty cycle. Why can I not make this engine run well and procedure 300 HP with the stock injectors?

The LQ4 and LQ9 6.0L truck engines used 25 Lb / Hr fuel injectors - slightly more fuel flow (about 9% more) than your spider style fuel injectors.

Stock the LQ4 was rated between 300 HP to 330HP, while the LQ9 was rated at 345HP.

Both of the above engines, in completely stock configurations, will reach 100% fuel injector duty cycle when under heavy load.

A camshaft upgrade, in either of the above engines, will often cause them to run lean on the top end - as they have ran out of fuel injector capacity.

Once again, you argue with all advice given - so why ask for any advice in the first place ?

Just do it your way, and see what happens.

[gtstorey]

I'm not upset at all just trying to clarify what my goal was this time around.

I was just trying to get it tuned to run good, I'm not looking for huge HP gains. This will be my road trip/pulling vehicle.

Like I said maybe this cam was the wrong choice but I still find it hard to believe that I can't get this combo tuned to run correctly but as I stated I'm new to tuning and I'm listening.

This is the info I've come up with.

.5LB of fuel = 1HP
1Lb of fuel is good for 2HP

23*2=46HP If this is correct then one 23lb inj will produce 46HP each.
8*46=368HP
If this is correct my 23LB injectors will handle 368HP at 100% duty cycle. Why can I not make this engine run well and procedure 300 HP with the stock injectors?

"Yes you could.

However, you would likely need to set the Rev Limiter to around 4500 RPMs - which would essentially negate some of the benefit of the camshaft upgrade."

[Fast4.7]

My ~500 hp 383 ran out of injector at about 450 hp with the MPFI spider at 75 psi. 75 psi makes them about 25 lb/hr. The 383 hit 100% duty cycle at 410 gms/sec airflow at 5,000ish rpm. Whoever decided that 0.5 bsfc was the number is flat wrong on a naturally aspirated sequentially injected small block with decent heads. They are more around 0.45 and even as good as 0.40 in some cases. 25 lb/hr each is good for 444 hp at 0.45 and 500 at 0.40.

I have run 24 lb/hr LT1 injectors on a 450 hp setup as well and had enough fuel.

[Fast4.7]

Also many operating systems have just flat wrong duty cycle. I have added fuel well past an indicated 100% duty cycle and the mixture richens. I have observed richer mixtures as much as 115-120% duty cycle.

[TheMechanic]

Goal=400hp
Injectors=300 hp
Goal not achievable under current equipped vehicle.

[Fast4.7]

Goal=400hp
Injectors=300 hp
Goal not achievable under current equipped vehicle.

His current injectors are capable of ~450 hp at the crank and about 400 at stock fuel pressure.

[lazydogtuning]

300 was my goal here, not sure where you picked up 400.

[lazydogtuning]

My ~500 hp 383 ran out of injector at about 450 hp with the MPFI spider at 75 psi. 75 psi makes them about 25 lb/hr. The 383 hit 100% duty cycle at 410 gms/sec airflow at 5,000ish rpm. Whoever decided that 0.5 bsfc was the number is flat wrong on a naturally aspirated sequentially injected small block with decent heads. They are more around 0.45 and even as good as 0.40 in some cases. 25 lb/hr each is good for 444 hp at 0.45 and 500 at 0.40.

I have run 24 lb/hr LT1 injectors on a 450 hp setup as well and had enough fuel.

I was just going off info I found. There was an explanation of how they could be more efficient but for a quick understanding 0.5 bsfc was used so I just based my calculation off that. Thank you for the info, Ill look into finding a higher fuel pressure regulator.

[Fast4.7]

I was just going off info I found. There was an explanation of how they could be more efficient but for a quick understanding 0.5 bsfc was used so I just based my calculation off that. Thank you for the info, Ill look into finding a higher fuel pressure regulator.

My MFI upgrade spider had an adjustable regulatpr already on it. While I had the plastic plenum up, I hooked the fuel lines up to the spider, hooked a pressure gauge to it, then ran power to the fuel pump priming terminal, I then adjusted the torx screw on the regulator to 75 psi.

I later swapped my spider to a 48 lb/hr spider. I need to do the pump but I will be feeding the ~500 hp 383 on E85. On E10 93 octane the stock replacement Express van bucket pump with a Racetronix hotwire setup is feeding the 383 adequately. I can tell the pump is near its limit as the pressure drops 2-3 psi at 6,000 rpm.

[lazydogtuning]

Goal=400hp
Injectors=300 hp
Goal not achievable under current equipped vehicle.

My goal was 300 maybe 350, not sure where you picked up 400.

[Fast4.7]

My goal was 300 maybe 350, not sure where you picked up 400.

300-310 gross at the crank is what the factory L31 makes before the accessory load is removed for net rating.