LQ9 bent rods at 16psi/12*/11.5AFR
10-28-2014, 12:33 PM
#101
10-28-2014, 01:15 PM
#102
I looked all over for where the noise was coming from and couldnt find it...all the pistons looked perfect. I didnt drive it long at all though and just brought it home apprx 1.5 miles away so it didnt have a whole lotta time to self-clearance lol. I'm sure it was hitting somewhere though - something was making noise.
10-28-2014, 02:39 PM
#103
I looked all over for where the noise was coming from and couldnt find it...all the pistons looked perfect. I didnt drive it long at all though and just brought it home apprx 1.5 miles away so it didnt have a whole lotta time to self-clearance lol. I'm sure it was hitting somewhere though - something was making noise.
10-28-2014, 04:42 PM
#105
Sux Vince,..
At this point, why not buy a set of $300 aftermarket rods and throw in it and not worry about it?
The stock rods and pistons are always gonna be a concern when making 600+..
Fix it once and be done with it. Personally, I think your tune, boost level and setup was fine...just stock parts giving up.. Sometimes they last, sometimes they don't.
Only on ls1tech do people make 800-1000rwhp on stock motors and have them "last forever".
At this point, why not buy a set of $300 aftermarket rods and throw in it and not worry about it?
The stock rods and pistons are always gonna be a concern when making 600+..
Fix it once and be done with it. Personally, I think your tune, boost level and setup was fine...just stock parts giving up.. Sometimes they last, sometimes they don't.
Only on ls1tech do people make 800-1000rwhp on stock motors and have them "last forever".
key is to bring in torque later to help keep rods alive. bringing in torque to early will only **** the rods up in a hurry
if going to hit the limiter you should set the recovery rpm a good bit lower then limiter so its not banging and becomes a soft limit
his timing isnt that bad but also dont know the actual cylinder pressure of his setup. Timing can be up there if has weak dynamic compression
hitting limiter on meth will bend them alot, did it on a 5.3...hit the 7700 limiter and meth was still spraying as motor still sees X amount of flow from the map sensor so the Meth controller still is dumping fuel
10-28-2014, 05:07 PM
#106
we just made 1053rwhp on 23 psi on a SBE, been running same setup all season with countless 8s passes 160-164 mph
key is to bring in torque later to help keep rods alive. bringing in torque to early will only **** the rods up in a hurry
if going to hit the limiter you should set the recovery rpm a good bit lower then limiter so its not banging and becomes a soft limit
his timing isnt that bad but also dont know the actual cylinder pressure of his setup. Timing can be up there if has weak dynamic compression
hitting limiter on meth will bend them alot, did it on a 5.3...hit the 7700 limiter and meth was still spraying as motor still sees X amount of flow from the map sensor so the Meth controller still is dumping fuel
key is to bring in torque later to help keep rods alive. bringing in torque to early will only **** the rods up in a hurry
if going to hit the limiter you should set the recovery rpm a good bit lower then limiter so its not banging and becomes a soft limit
his timing isnt that bad but also dont know the actual cylinder pressure of his setup. Timing can be up there if has weak dynamic compression
hitting limiter on meth will bend them alot, did it on a 5.3...hit the 7700 limiter and meth was still spraying as motor still sees X amount of flow from the map sensor so the Meth controller still is dumping fuel
I know my ls6 cam tq pks somewhere around ~4500 rpms, maybe less in a 6.0 like I have. At that point I make 5psi and timing is 21*. I could u/s if max boost was in effect but is 5psi enough to bend rods and 21*?
10-28-2014, 09:23 PM
#107
ScreamingL, can you give me an idea as to what your timing table looks like? Trying to see how much it would dip around pk tq. Does your table have a dip around pk tq?
I know my ls6 cam tq pks somewhere around ~4500 rpms, maybe less in a 6.0 like I have. At that point I make 5psi and timing is 21*. I could u/s if max boost was in effect but is 5psi enough to bend rods and 21*?
I know my ls6 cam tq pks somewhere around ~4500 rpms, maybe less in a 6.0 like I have. At that point I make 5psi and timing is 21*. I could u/s if max boost was in effect but is 5psi enough to bend rods and 21*?
E85
.86 26----------------------------------------carries to 8000
.92 24-------------------------------------------carries ti 8000
1.0 i think car is at 24*----------------------carries to 8000
1.12 .......22*-----------------------------carries to 8000
1.20 ......20*----------------------------------carries to 8000
less boost i have more aggressive ramp
limiter with meth is what bent them IMHO or possibly the early Lq9 rods were just weaker then the strong rods or later yrs
also ran 26* on a 5.3 yrs ago with 12.5 psi...made over 700 rwhp with about 35% of fuel being 100% meth and yes it picked up mph with each degree i added. started with 21 and vehicle kept picking up mph as i richened the afr up. 10.8 with 26* with 35% meth made the most power based off trap speed
so some saying timing this and timing that......afr and octane used play more role then many think.
10-28-2014, 09:34 PM
#108
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His were (more) random.
And I can't explain why water/meth injection and spark cut rev limiters don't play well. I have suspicions, but nothing concrete. There seems to be a pattern emerging within the same/similar conditions, which is, in my mind, suspicious and worth looking into. But, I also am aware it could simply be just as random as 4 bent rods that happen to be on one side of an engine... Could be it's just a fluke too.
Good luck and keep us posted. If you're feeling really ballsy, put that thing on the rev limiter again in the name of science and see if ya bend some more and where they are... lol Kidding, I don't recommend that.
10-29-2014, 06:59 AM
#109
Who knew a rev limiter could cause damage when its whole purpose was to prevent it.
10-31-2014, 06:00 AM
#112
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the only explanation I have it that those rods didn't bend "all at once" and maybe with ignition problems on one side it has been detonating at the torq peak
doubt butted rings could bend the rods as it would have occurred on all 8
quite a mystery! but the bottom line is that you got it all together
I'd check on the bring the timing in a bit less aggressively as you can back the timing down and probably not lose much power at all and it will live
keep us posted, this is really interesting!
doubt butted rings could bend the rods as it would have occurred on all 8
quite a mystery! but the bottom line is that you got it all together
I'd check on the bring the timing in a bit less aggressively as you can back the timing down and probably not lose much power at all and it will live
keep us posted, this is really interesting!
10-31-2014, 02:06 PM
#113
Interesting thing I noticed while putting things back together is the need for a good grd path for the coils. The coils are sitting on the valve cover which is sealed with o-ring-style gaskets - no real metal to metal contact. Grounding is imperative here and somthing I need to pay more attention to.
11-08-2014, 05:37 PM
#114
Just an update - I kicked its *** all day to day at 16 psi w/92 octane and a bit of water/meth...almost burned a full tank of gas just farting around and she didn't miss a beat. Took a bit of timing out in the midrange but don't think that really was the issue as mentioned. Going to back the boost down to about 12psi and that's still too much almost for the street. 16psi I'd really like some race fuel I think.
Thanks all!!!!
Thanks all!!!!
11-09-2014, 01:00 AM
#115
Just an update - I kicked its *** all day to day at 16 psi w/92 octane and a bit of water/meth...almost burned a full tank of gas just farting around and she didn't miss a beat. Took a bit of timing out in the midrange but don't think that really was the issue as mentioned. Going to back the boost down to about 12psi and that's still too much almost for the street. 16psi I'd really like some race fuel I think.
Thanks all!!!!
Thanks all!!!!
11-09-2014, 08:22 AM
#118
Is there no... Interesting thing I noticed while putting things back together is the need for a good grd path for the coils. The coils are sitting on the valve cover which is sealed with o-ring-style gaskets - no real metal to metal contact. Grounding is imperative here and somthing I need to pay more attention to.
11-09-2014, 09:15 AM
#119
The Holley wiring harness has two separate ground wires, one to each head that provides the grd path for the ignition coils. The heads need a good ground for all this to work right, which I didn't have on the driver's head (untightened bolt).
I think a stock LS motor has a braided ground wire to each head doesn't it for adequate grounding?
I think a stock LS motor has a braided ground wire to each head doesn't it for adequate grounding?
11-10-2014, 09:25 AM
#120
Yep.. The Holley wiring harness has two separate ground wires, one to each head that provides the grd path for the ignition coils. The heads need a good ground for all this to work right, which I didn't have on the driver's head (untightened bolt).
I think a stock LS motor has a braided ground wire to each head doesn't it for adequate grounding?
I think a stock LS motor has a braided ground wire to each head doesn't it for adequate grounding?
Glad you found it....Even if it was a bit of a PITA to do so....
