Major timing corrections, super knock & misfires

V8bait

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Did any of those motors with bent rods have stock turbos?

Mauricio's did if I recall, he blew up going for stock turbo records though and was pretty much running 100% duty cycle with aggressive timing, I forget who was tuning him, Ken maybe at the time?
 
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SlowE93

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Every motor I've seen with bent rods was torn down for a build and had been driving fine previously, some had blown with cracked pistons/rings, some were just building for more power. A lot of them had random misfires that never showed up in logs, or consistently bad timing corrections that influenced building for safety. Power was usually fine as was drivability and fuel economy etc. Alex at ABR or Tony's builder could probably comment more, if I had to put a number I'd say 10 out of the 15 or so I've seen before/after of in Houston and Florida have had bent anywhere from one to 3 rods. Nobody really talks much about it.

Any of the actual engine builders would have better numbers probably but I think it's pretty common. I will add that building the motor won't fix corrections, it always makes them worse with false knock. Good times lol.

Edit- it can be subtle, like here:
Crazy how its BARELY bent, but, it IS bent
 

martymil

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My stock motor was making 400rwk with a cracked ring land, if I kept going it would have been disastrous but otherwise the car ran fine.

The only way to tell was to do a leak down test.
 

Jeffman

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Mauricio's did if I recall, he blew up going for stock turbo records though and was pretty much running 100% duty cycle with aggressive timing, I forget who was tuning him, Ken maybe at the time?
Doh! I better adjust my home-brew Flexfuel map!
 

Msport335

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Assuming there wouldn't be any tell tale signs of a bent rod during a leak down test would there be?
 

E92-Ghandi

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I have been through this awhile ago and it drove me crazy, changed everything as you did @Msport335. i got really frustrated and came up with a solution, yes it's not the perfect solution but it helped and i finished tuning the car and dyno'd 710WHP on 27 PSI and 652TQ.

I added a spacer between the knock sensors and the block and desensitized the knock sensors from MHD. BUT, i aded up a knock detection device (or whatever it's called) so i can hear knock next to bank 1 knock sensor and started gradually adding boost, started from WG pressure until i reached 27 PSI, engine didn't knock and everything went smooth. Again, i know it's the proper way to do it but i had too, now i'm enjoying the car and racing it almost twice a week and this engine is still holding all the beating and asking for more lol.

Of course i keep checking and doing maintenance and running a look on everything just to be cautious.
 
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Torgus

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+about 25% for dynojet so around 630whp

That is not how it works and you know it. You can't just say let's add on 25% if it is a dynojet or any other brand. There is no % that is accurate between dynos be it a mustang, dynodynamics, etc. If you made 400 kW measured at the wheels then you multiply by 1.34 as said above. That would give you your HP that would be measured at the wheels on that dyno which is 535whp. One kilowatt of power equals ~1.34 horsepower.

There is a reason why all the records that matter have to be done on a dynojet. https://www.spoolstreet.com/threads/700-hp-club-n54-dynojet-only.4608/ They are the most consistent and repeatable in various parts of the world and allows for actual comparisons to be done correctly. None of this add 25% bullshit or any other percentage. That is literally ricer math.
 
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martymil

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yes you multiply 1 kw by 1.34 to get hp then you add 25% for dynojet it's been well documented across many platforms.

Dynojet is a very happy reading dyno.

One of the tafe schools has one in Australia and they confirmed it dynoing an evo but like all the doubting Thomas's you have to see it to believe it.

The only consistent thing about dyno jet it will constantly give you extremely happy bloated results

On shootout mode using dyno dynamics the difference becomes smaller like 10 to 12 %

They don't call the dyno dynamics dyno the heart breaker dyno for nothing.
 
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martymil

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Any dyno will give you a good base line for your car and in the end of the day you should always use the
same one to see the difference in the car setup or tuning changes as its only a tool that gives you a number.

A true indicator of power is your mph at the drag strip that's why I was there often when tuning as that's the
only real way to tell if the changes you done made any difference.
 

martymil

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Assuming there wouldn't be any tell tale signs of a bent rod during a leak down test would there be?
leak down test wont but a compression test will as the comp will be down

A leak down test will show bent valves, cracked rings or ringlands or any defects in the combustion chamber like a cracked bore and such.

Sometimes the damage can be so small and only a teardown will reveal whats going on.

So if the tuning hasn't changed there is something mechanical going on and you have to keep looking to find it or it could be just the fuel supplier.
 

Msport335

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leak down test wont but a compression test will as the comp will be down

A leak down test will show bent valves, cracked rings or ringlands or any defects in the combustion chamber like a cracked bore and such.

Sometimes the damage can be so small and only a teardown will reveal whats going on.

So if the tuning hasn't changed there is something mechanical going on and you have to keep looking to find it or it could be just the fuel supplier.
Well that's a good sign i guess...compression test results were
1, 180
2, 180
3, 172
4, 178
5, 180
6, 180
 
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martymil

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Not quite whilst they are close cylinder 3 is not happy for some reason, mine where closer with a cracked ringland.

You need to do a leak down test now.
 

martymil

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Get a leak down test done to rule things out and go from there, you been chasing this for months so why haven't you done this.

There is no magic cure you have to rule out things one by one.
 

Msport335

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Tuner turned the tune way down and way less timing advance as well. Pulled a few logs and still get pretty bad correction.
Noticing that I'm having to top up oil and valve cover is a bit oily on the outside but don't notice any cracks....maybe VCG?
would a leaky VCG or cracked valve cover cause timing correction? don't notice any oil on plug threads or electrode.

 

martymil

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If your sucking oil into the intake that would not foul your plugs but will cause major corrections