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With soo much going on lately with personal health issues I got anxious to head out for the opening day at the track and see what the car would run.The car feels totally different with the roll cage,sfcs and fresh nittos outback.
Long story short..I buttoned the car up and did some street testing sat night.Now before everyone kills me..the audio in the vids suck.Im having issues with the mic so don't bark up my tree.
The next morning went from a very nice scenic drive...to 1 pass wonder.This is lq4 #3 Ive pushed too hard.I got greedy with boost and meth thinking it wold hold over 700whp for the full 1/4.
I'm pretty sure from looking at the video a few times about half track it appears I started losing oil pressure and at 3/4 track or so the motor shut off.I think I spun a bearing and then maybe the rods bent or lifter failed.Im hoping to maybe pull the motor in a week or so and see what was the failure point.But I had the boost and meth up past the point of what it was tuned safely on.I will say the car was moving.I came out soft(stock diff) spun 1st,bit of 2nd,chirpped 3rd,hooked 4th and then bam.
So Ive already prepped to either take the motor apart and throw in gen 4 rods/pistons,new bearings,lifters and hopefully the block isn't hurt.The oil looks mint..no material,no window in the block..but sounds like marbles when you start it. Time will tell how bad things are lol
Last edited by Redbull87; May 31, 2018 at 01:16 AM.
First off I will say its truly amazing the abuse these cylinder walls can take.This was a much higher mileage motor than my previous lq4 but the main reason Im not going to put fresh parts in it is because the crank itself got chewed up slightly on 7 & 8 from chunks of pistons..ringlands and connecting rod. Plus #8 cylinder at the very bottom tip of the bored had a chunk broken off.Would it affect anything..most likely not but i wasnt going to chance it.
So I pulled my engine out from last year that i was in a rush to get up and running..didnt open it up..just swapped in another junker.This block was mint! All the bearings were in spec etc.When i tore it down I found what my failure was.#8 bent a rod and a lifter failed.So Im going to put my gen 4 parts in this block..replace all the bearings anyways,gap the rings for boost this time and put it back in the car. Look at the pics,I died laughing when i pulled the pan and #8 dropped down. Really glad my old motor wasnt as bad as I thought and can be put to use.Gave it a quick cylinder cross hatch clean,fresh paint.
Cant really hear you over the music need to soften that up or just take it out man. I am really surprised what happen do you happen to have a log of the run?
I would think it's tune related also. Timing and AFR @ WOT? I'm running 14 lbs on a stock gen 4 6.0 with no problems and mines a Whipple . The boost hits like s hammer. Turbos are a little easier on things since they roll in to the boost.
Once its back up im going to revisit the tune and verify nothing is funky there. I dont have the tune file but i have the dyno sheet. Timing is at 15* and Im at about 16psi boost on 94 octane pump gas and afr was 11.2ish
no methanol injection? That is right on the jagged edge for pump gas .... All gas mixes aren't created equal and you could get some slightly lower quality mix and blow your stuff up lol.
I am at 12* 14psi pump 94 meth/water injection AFR in the 10.5 rangeish
Updating the thread.Ive got the new Dssracing forged pistons and rods installed and they are very nice pieces.I almost wish i opted to have the skirts coated but I was fairly tapped out in the budget.The precision of machining was very apparent when as i was putting this together.I also choose for the upgraded ap steel top ring and moly 2nd rings.I set the gaps at 30 now instead of 28 I had last time.Trying to play it safe as much as possible.I dont want to be tearing this motor down a 3rd time in 3 months lol. Anyways as for the damage was minimal. #7and 8 both broke n 2nd rings and lands,#3 had just broke the 2nd ring only,no bent rods. Thankfully the metal debris didnt get into much aside from the pickup tube and oil filter.I pulled the mains off and they were not phased. The rod bearings had extremely fine lines of debris and cleaned up with a leather belt and slight polish compound.Put new rod bearings and everything measured out perfect.
I flushed the block,the heads,turbo etc and will slap it all back together tomorrow.Hopefully have the car running and break in Tuesday night.Friday will be dyno tune and varify everything is truly happy.I will try to get or record as much info during tuning to relay back here. My goal isnt to make more power at this point.I want it to be reliable power,making more from it being 100% healthy would be a bonus. Ill have my cage mounted camera recording every pull inside the car and another camera as i watch from outside.Should be interesting to see if it makes the same power or not and what timing..afr etc it actually ends up being.
Your timing is high for 94 pump and meth. I'm at 10psi and 17* timing. at 12psi I'm in the 15* range. I run the cheapest 93 pump and wiper fluid at 750cc/min progressive (comes in low boost and ramps up).
Once its back up im going to revisit the tune and verify nothing is funky there. I dont have the tune file but i have the dyno sheet. Timing is at 15* and Im at about 16psi boost on 94 octane pump gas and afr was 11.2ish
Whats going on with this dyno pull? Peak power at 4750rpm and then it drops like a rock. Did you let out of it? Or was that a normal pull?
Shes back on the road making steam. So learned a few things.1. the timing was high...we last tuned my car more than 2 yrs when I was not running half as much boost and it was set 18* timing 2. my backpressure is very high,dangerously high with 8psi of pressure. 3.this combo is capable of so much more that is going to hurt feelings again since its a ratty fbody.
You keep timing it like that and you'll blow up the forged pistons, it'll just take a little longer.
Its certainly not at that now.Running 14* on meth currently.Seems much happier driving around,but the backpressure needs to be addressed asap before I run full boost again.not taking chances blowing it anytime soon.
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Up goes another lq4 *video* 
