9krpmrx8's Boost Build Thread
10-21-2011, 09:52 PM
#1181
Super Moderator
Refresh me again 9K, just how did this Bolt become an issue in the first place???..again?
A cross-thread or over tightening..
A cross-thread or over tightening..
10-21-2011, 10:31 PM
#1182
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I was just putting everything back on the motor and I torqued all of the LIM bolts to spec and the last one just snapped off as the torque wrench clicked. A good piece of the the bolt was sticking out so i slotted and got a big flat head screwdriver on it and it would not budge. I used a impact screwdriver and still nothing. Then I drilled a hole and hammered in a torx bit head and attempted to remove it with a 1/4" ratchet and it still it would not budge. Then drilling began and it was all downhill from there.
10-22-2011, 03:50 AM
#1183
Super Moderator
Thanks 9K, I was just being lazy and not looking back...
I take it this is one of 3 Bolts which are the same for your LIM?..
I take it this is one of 3 Bolts which are the same for your LIM?..
10-23-2011, 12:18 AM
#1185
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What do you guys think of this paragraph. I have read some discussions about the oil return on the Greddy kit but I have been thinking if there is a better way to do it.
What can cause pressure to be greater in the center housing? Poor oil drainage and high crankcase pressure. Walk away from any turbo kit that drains the oil into the bottom of the oil pan as it can prevent proper oil drainage. What do you think happens if the oil can’t drain properly and oil is still being forced in by the oil feed line? Well, the oil has to go somewhere and that somewhere is usually past the piston rings into the compressor and turbine housings.
10-23-2011, 01:10 AM
#1186
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thats scares me a little because I was planning on doing this https://www.rx8club.com/showpost.php...7&postcount=25
10-23-2011, 02:55 AM
#1187
Ok so your stock oil pressure is say 60 psi. Just a figure folks. Anyway. You have 60 psi pushing "X gpm" of oil into a bearing/bushing. Well there's an outlet for that oil on the other side of the a fore mentioned bearing/bushing. Now on the outlet/return there is no restriction to the flow that has been pushed through the bearing/bushing.. Due to a larger hose used for return and an oil pan. Garden hose into a bucket.
So. What would cause the oil to back up into the turbo? Pressure/restriction. An equalizing or higher apposing pressure. (a slightly lower pressure can cause the same issue. But as restriction decreases so does the pressure.)
So to over come the gpm flow exiting the bearing/bushing your gonna need "back pressure". 60 psi will stop it. 50 psi will give it a hard time. And 70 psi will push back into the oil flow by 10psi. I'm just say'n. OK where does this 60 psi of apposing pressure come from?
Combustion pressure passes the side seals and corner seals and the compression ring and the oil control rings. Right into the oil pan through the irons.
So now we have pressure. Lets say we peak at 30psi. (has anybody ever measured the crankcase psi?) That just put a restriction on the flow from the turbo. What we just did was put 30 psi of back pressure into the bearing/bushing and it's seals. What might that do? Could cause some internal oil leakage/bypass in the turbo via the seals. Worn, weak seals will cause an exponential problem related to their actual wear.
Mazda already has a crankcase ventilation system installed on the stock engine. Which didn't work that great in the begining due to the foamy dipstick issue and the TSB for a fix.
But under some boosted applications when your running 12psi for about a mile. (just a number) Yes the increased combustion chamber pressures (from the turbo) lost through leakage past the seals on the rotor can increase the internal crankcase pressures.
How do you fix the issue? Or slow it down to where it is not an issue.
Vent the crankcase. It's been discussed in a thread somewhere.
So. What would cause the oil to back up into the turbo? Pressure/restriction. An equalizing or higher apposing pressure. (a slightly lower pressure can cause the same issue. But as restriction decreases so does the pressure.)
So to over come the gpm flow exiting the bearing/bushing your gonna need "back pressure". 60 psi will stop it. 50 psi will give it a hard time. And 70 psi will push back into the oil flow by 10psi. I'm just say'n. OK where does this 60 psi of apposing pressure come from?
Combustion pressure passes the side seals and corner seals and the compression ring and the oil control rings. Right into the oil pan through the irons.
So now we have pressure. Lets say we peak at 30psi. (has anybody ever measured the crankcase psi?) That just put a restriction on the flow from the turbo. What we just did was put 30 psi of back pressure into the bearing/bushing and it's seals. What might that do? Could cause some internal oil leakage/bypass in the turbo via the seals. Worn, weak seals will cause an exponential problem related to their actual wear.
Mazda already has a crankcase ventilation system installed on the stock engine. Which didn't work that great in the begining due to the foamy dipstick issue and the TSB for a fix.
But under some boosted applications when your running 12psi for about a mile. (just a number) Yes the increased combustion chamber pressures (from the turbo) lost through leakage past the seals on the rotor can increase the internal crankcase pressures.
How do you fix the issue? Or slow it down to where it is not an issue.
Vent the crankcase. It's been discussed in a thread somewhere.
Last edited by Easy_E1; 10-23-2011 at 02:57 AM.
10-23-2011, 03:17 AM
#1188
To me that makes no sense... why would the oil not be able to drain properly. Its just going through some cast iron just like the rotors and the oil coolers, etc etc...
The pressure is not going to change if you have it draining to the oil filter or the drain pan... IMO...
The pressure is not going to change if you have it draining to the oil filter or the drain pan... IMO...
10-23-2011, 07:50 AM
#1189
it would not probably be a constant issue in the rotary because we have a semi dry sump system?
Although the "crankcase" pressure in our engine can get extreme ( i have blown out a 1/2 quart of oil one time!) it usually is not.
I have had a uncapped dipstick to cause a little oil leakage while on track--i got the black flag
, but i have never noticed any problem on the street.
Although the "crankcase" pressure in our engine can get extreme ( i have blown out a 1/2 quart of oil one time!) it usually is not.
I have had a uncapped dipstick to cause a little oil leakage while on track--i got the black flag
, but i have never noticed any problem on the street.
10-23-2011, 05:23 PM
#1190
Some suggestions
*don't restrict the drain hose in any way
* Seeing as you have upped the oil pressure it might pay you to do a flow test from the turbo drain and compare with the video in Mad dog's restrictor thread .
*Use quality synthetic oil
10-23-2011, 09:02 PM
#1191
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I am just wondering if it has anything to do with why the stock Greddy dies so early. Obviously only being oil cooled and other issues help it to fail early but is there a better option?
This was his response
This was his response
Scott, the majority of kits that convert a non-turbo car into a turbo car probably drain into the bottom of the oil pan, through the drain plug location, to make the kit as simple and bolt-on as possible. For many people, that's probably okay. From a marketing standpoint, if kit A is a bolt-on affair and kit B requires you to drop the oil pans and drill out the block, a whole lot of people will go for kit A due to ease of install.
The best analogy I can think of is a slow draining sink. If the faucet is only turned on 50% and the drain can keep up, then it's fine. If the faucet is only cranked open 100% for short durations, it's fine. But when that faucet is open 100% for extended periods of time, that sink will overflow.
It's very much like the brakes and stock oil cooler system on the S2k (and pretty much any car sold). They're perfectly adequate for short durations of hard use. But they are inadequate for sustained hard use. Like the 370Z is perfectly fine to to drive around in and do the occasional WOT romp on the highway on-ramp. As soon as that car sees 3 laps on a road course in warm weather, it overheats the oil. What percentage of owners will drive the 370Z hard enough to cause a problem? Not many which is why the car doesn't come with a bigger oil cooler stock. But for those that do drive hard, the stock system is inadequate.
Anyways, the proper drain location for any turbo setup on any vehicle is above the oil level in the pan. That way, oil can not back up in the drain line.
The best analogy I can think of is a slow draining sink. If the faucet is only turned on 50% and the drain can keep up, then it's fine. If the faucet is only cranked open 100% for short durations, it's fine. But when that faucet is open 100% for extended periods of time, that sink will overflow.
It's very much like the brakes and stock oil cooler system on the S2k (and pretty much any car sold). They're perfectly adequate for short durations of hard use. But they are inadequate for sustained hard use. Like the 370Z is perfectly fine to to drive around in and do the occasional WOT romp on the highway on-ramp. As soon as that car sees 3 laps on a road course in warm weather, it overheats the oil. What percentage of owners will drive the 370Z hard enough to cause a problem? Not many which is why the car doesn't come with a bigger oil cooler stock. But for those that do drive hard, the stock system is inadequate.
Anyways, the proper drain location for any turbo setup on any vehicle is above the oil level in the pan. That way, oil can not back up in the drain line.
Last edited by 9krpmrx8; 10-23-2011 at 09:05 PM.
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10-23-2011, 09:35 PM
#1192
Stock greddy does not die early unless you did something wrong .
EG - no restrictor in supply , restricted drain tube , using cheap oil , no cool down after hard driving .
Mine is on 60,000 kms as we speak and i do know of others with similar mileage .
10-23-2011, 10:32 PM
#1194
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Thread Starter
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Yeah I have just not seen any T618Z's last all that long. They are used in the Greddy Skyline kit too and from what I have read they fail prematurely in that application as well.
I thought you were running a BNR Brett?
I thought you were running a BNR Brett?
