HP limit on LLY injectors.

[McRat]

After looking more carefully at the factory MIPW table for a LLY, it seems the CP3 cannot keep up 100% after ~45mm of fuel, and slowly starts to lose efficiency for whatever reason. It also appears the "dwell time" that the injectors take before fuel starts to flow is 200msec. Using both those numbers, and assuming 250rwhp stock at 1500 msec/160mpa fuel shot, I come up with:

875rwhp at 3350 msec. While I hit about 800rwhp with stock injectors, it seems there was about 10% I left on the table. Probably because I had to reduce msec down to 2900 to get the engine to rev high enough. With twins, and peak HP at 3200, I think you could go 875rwhp on stock sticks.

 

[Max Power]

Ya but I hear you suck at math and LLY's will never be able to make the HP of the LB7's.

 

[paint94979]

Ya but I hear you suck at math and LLY's will never be able to make the HP of the LB7's.

bit your tongue

 

[Kat]

Ya but I hear you suck at math and LLY's will never be able to make the HP of the LB7's.

:hehe::hehe::hehe:

 

[TrentNell]

great info Pat thanks for sharing

 

[IOWA LLY]

How many motors have you melted?

 

[Kat]

How many motors have you melted?

2 First engine melted pistons after 100 plus passes more then 1/2 being nitrous passes. 2nd lasted 100 more plus passes with some nitrous being used, sled pull, and 3.75 Bonneville passes lasting 3 miles going 160 to 185 mph by GPS and melted more then pistons

So you are saying big injector trucks aren't melting pistons? Not what I hear

 

[Utahski]

2 First engine melted pistons after 100 plus passes more then 1/2 being nitrous passes. 2nd lasted 100 more plus passes with some nitrous being used, sled pull, and 3.75 Bonneville passes lasting 3 miles going 160 to 185 mph by GPS****** and melted more then pistons

So you are saying big injector trucks aren't melting pistons? Not what I hear

******Also Bonneville passes are 95-100* temperature and 4300' elevation. Not so easy on an engine running flatout over several miles.

 

[mytmousemalibu]

Melty pistons?

Maybe we should do like the import kids do......put bags of ice on the motor between runs

:rofl::rofl::rofl:


Great tech Pat :hug:

 

[juddski88]

Melty pistons?

Maybe we should do like the import kids do......put bags of ice on the motor between runs

:rofl::rofl::rofl:


Great tech Pat :hug:

i was at a pull in maine last fall were the cummins boys were doing this :spit:

at first i thought it was just for the W/A intercooler, but then they brought the whole cooler over and said F%$# it and dumped it all in!! it was only one pull, no pull off or nothing!!

and about the injectors, so say there are some of us who don't want to run ungodly amounts of timing and who are limited by a 1 CP3 rule, bigger injectors that are designed properly should, and usually do, make more power being easier on internals if tuned for them. i do not have any yet, i plan on getting some when my budget allows, but it just doesn't make sense to me to gamble with high timing on a stock motor.

 

[McRat]

How many motors have you melted?

Two sets of pistons were melted. Both from high boost + high EGT + nitrous.

This thread though is just a way for me to store my notes. When I originally did my math a couple years ago, I didn't look at the MIPW table close enough.

Try this, go to the 160mpa column. Subtract 200 from all the values. Divide msec by mm3 which gives you time per mm3 injected. Watch it climb after 40mm.

 

[paint94979]

i was at a pull in maine last fall were the cummins boys were doing this :spit:

at first i thought it was just for the W/A intercooler, but then they brought the whole cooler over and said F%$# it and dumped it all in!! it was only one pull, no pull off or nothing!!

and about the injectors, so say there are some of us who don't want to run ungodly amounts of timing and who are limited by a 1 CP3 rule, bigger injectors that are designed properly should, and usually do, make more power being easier on internals if tuned for them. i do not have any yet, i plan on getting some when my budget allows, but it just doesn't make sense to me to gamble with high timing on a stock motor.

why are all you guys so terified of timing...

 

[TrentNell]

why are all you guys so terified of timing...

cylinder pressure from starting the injection proscess ealrier and having more fuel to compress for the combustion on the compression stroke . i am no expert to say what is safe though ..................

 

[paint94979]

cylinder pressure from starting the injection proscess ealrier and having more fuel to compress for the combustion on the compression stroke . i am no expert to say what is safe though ..................

I still believe torque kills engines I am a good example of that and so is WolfLLY lots of timing and no torque

 

[TrentNell]

I still believe torque kills engines I am a good example of that and so is WolfLLY lots of timing and no torque

i totally agree with that statement but torque will kill rods , pistons are what worry me on timming . i have ran as high as 37 deg @ 3800 rpm with no knock............. but run a max of 30 now with the twins and dont rev that high .

 

[paint94979]

i totally agree with that statement but torque will kill rods , pistons are what worry me on timming . i have ran as high as 37 deg @ 3800 rpm with no knock............. but run a max of 30 now with the twins and dont rev that high .

that sounds like I good combination, I run 36* peak timing

 

[SIKDMAX]

My LMM was like 43º or something at WOT..... FAIL! :rofl:

 

[paint94979]

My LMM was like 43º or something at WOT..... FAIL! :rofl:

that is a lot lol

 

[slowlmm]

My LMM was like 43º or something at WOT..... FAIL! :rofl:

why so much ?

 

[[email protected]]

To me, timing seems like it does absolutely nothing when ever I change it. It is the same way with a gas engine too. The only thing I notice that does anything when I change it is fueling?