what happens if you run past 10psi on ghettodyne?
 

so the original chip only reads to 9.5 psi. what happens if you go past that, say 10-12 psi?

what do the ignition maps and fuel tables do? im starting to think this is why my engine blew up...help me clear things up.

Re:what happens if you run past 10psi on ghettodyne?
 

im un-fimiliar w/ ghetto dyne but if the fuel map is only for 9.5 psi and you are boosting 11psi the car wont have the right fuel so i would imagine it would stick w/ that 9.5psi fuel column and that would be way to lean. If you richen up the 9.5psi column and run 10psi...you would be fine...but 11 or 12 psi...it would be terrible.

Thats the way i understand it atleast. im probably wrong. but i know that if you are boosting 11-12psi you are going to be very lean

-bignig

Re:what happens if you run past 10psi on ghettodyne?
 

11-12psi looks like 9.5 psi on the stock MAP sensor. Even more than ghettodyne it is your MAP SENSOR!!! that is the problem.

as bigwig said, go past the limit of the stock MAP sensor and you will go lean. The ECU can't detect any changes past the limit of the sensor so it provides fuel and timing for less boost than is there.

If you don't richen / retard your last column for the overboost condition, you're going to blow ---- up sooner or later.

Re:what happens if you run past 10psi on ghettodyne?
 

so that would explain why my engine lasted 2 days...? i blew all the ringlands. im guessing it got pretty hot and detonated quite a bit?

Re:what happens if you run past 10psi on ghettodyne?
 

How long were the pulls you were doing? I still find it hard to believe that this happened. You say you went to 10 maybe 11? Unless you were boosting 11psi for a long period of time this should not have happened, especialy if the map was rich at 9.5psi. It might have leaned out a bit over the safe zone, but to blow the ringlands is just crazy. Doesn't the stock sensor read to around 11.xxpsi? Wouldn't that allow the GD to compensate for fuel up to 11.xxpsi?
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Re:what happens if you run past 10psi on ghettodyne?
 

i was hardly in 10 or 11psi. as soon as i saw it i left off or shifted. the engine was strong, very strong, when it was not turbo, hell it was strong when it was turbo.

during the turbo install, i poped the vavle cover to tighted the head bolts a bit tighter than stock. i found some didnt seem to be torqued to proper stock specs and one rocker arm bolt was loose (the bolts that hold down the assembly)

and it's not like i just cracked the ringlands, i cracked peices of them from the piston. but the rings themselves looked perfect!

maybe i got a shitty batch of pistons or something?

Re:what happens if you run past 10psi on ghettodyne?
 

That would be my guess.

You got any pics of the damage?
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Re:what happens if you run past 10psi on ghettodyne?
 

http://www.imagestation.com/picture/...3.jpg.orig.jpg
http://www.imagestation.com/picture/...a/fa247f23.jpg

might be easier to view in the large version in the link above the picture.

that was #4 piston. im 80 miles away from my car/pistons/camera right now, so i cant do any better at the moment.

Re:what happens if you run past 10psi on ghettodyne?
 

stock OBD0 reads to 9.5psi or so.
stock OBD1 sensor might read 0.5 psi higher.
past the max reading, no more fuel.
no more fuel + much more boost = lean
lean = boom
the end.

Re:what happens if you run past 10psi on ghettodyne?
 

so, my engine blew because it went lean and got too hot, and the ringlands went?


i just want to make sure i know exactly why the engine blew before i try this again.

alot of people say ringlands = detonation. which would be ignition related. but the lean condition makes more sence to me. if it gets too hot in the cylinders the ringlands will break?

Re:what happens if you run past 10psi on ghettodyne?
 

p.s. keep in mind, my engine might have been in boost for a maxium of 20 minutes, not even 10 mintues at a time. the car ran no longer than 20 min with the turbo on, thats counting idle time to warm up and cool down, etc...

i can probably count on my hand how many time the engine went into boost.

Re:what happens if you run past 10psi on ghettodyne?
 

That's why I can't understand why it blew. I ran a motor one time with NO fuel management. It didn't produce much boost, but it boosted and it would just fall on it's face. Yes, this was stupid, but I was waiting on parts and was just to stupid to keep off the gas. I ran it like that for a few days entering boost very frequently engaging a cel every time. The motor was fine after all of this. No smoke, no loss of compression. I never made it to anywhere near 10psi, but still........ ??? :-\
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Re:what happens if you run past 10psi on ghettodyne?
 

OK! This has got to be it.


I finally got the clutch working correctly after dropping the tranny this weekend. I also examined the pistons more.

On the #1 piston (which had the lowest compression after the calamity) there was a piece of the ringland which broke out, after i wiggled it off the piston. i was looking at the piston, the groove the ringland had left and there was a clean part (fresh break) and the rest of the broken out section had some carbon build up on it, and when i looked straigh up on the piston, to the edge of the top it was a darkened black color there also.

I've also notices this sohc zc pulls a lot harder at top end than my other one, and the engine, cranking it by hand feels like it has way more compression that my old engine had, before i blew it up.

so im thinking that the pistons were cracked before and the boost with the lean condition just put it over the top and cracked the ringlands a little worse than they were already.

moral of the story, compression test an engine before you put a turbo on it. oh well, live and learn.

Re:what happens if you run past 10psi on ghettodyne?
 

detonation is not only caused by ignition, but lean too. running lean means the cyl (and exh) temps are hotter. a hotter mix of fuel/air will ignite easier. compression also plays a factor here. sounds like the combination of 11psi w/ a maz 9.5psi fuel table w/ high compression casued detonation and broke ring lands.

Re:what happens if you run past 10psi on ghettodyne?
 

This fall I implemented boost cut routines for the PM6 map. They were posted up on PGMFI and the maps were sent around to the ghettodyne guys and a few others. I'm not sure if they were ever merged into support with these programs but I deem that feature as being absolutely necessary for anyone running a turbo car. They can and have saved a number of engines.

-Michael

Re:what happens if you run past 10psi on ghettodyne?
 

as implemented, they aren't useful for the HMT crowd pushing the edge of their MAP sensors to start with.

You can say "boosting more than 9.5psi on a stock MAP sensor is BAD" a thousand times and most kids aren't going to listen because they want more boost. If the target boost level exceeds the maximum boost able to be read by the sensor, there is no value to set the boost cut to that will protect the motor while at the same time allowing the target boost level.

The solution to this problem is obvious - MAP sensors that can read more boost than is desired used in conjunction with code that can support the different resolution of the sensor. If the MAP sensor can register more boost than is desired, the boost cut code can (and will) save motors. The boost cut code is active and live in the TE2 ROMs, although I think it may need to be modified slightly to account for the new code handling the MAP sensor.