 Oil Pressure???, What is the max? |
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 Dec 8 2004, 10:55 AM
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#1
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DSMCentral Freak  Group: Members Posts: 328 Joined: 21-October 03 Member No.: 189  |
The book says oil pressure at 750 rpm for the 1st Gen Turbo is suppose to be 11 psi. Thats nice, but what is the WOT peak oil pressure? I'm not saying there is a limit or its bad if its over a certain amount, but what is the peak oil pressure the 4G63T motor usually makes? I ask because Garner is running 20 something at idle (but he has the balance shafts removed so that could be why). But when he gets on it, it goes to 100 psi right away and maxes out the gauge so it could be more. I want to make sure something isn't messed up and there isn't an oil passage clogged and making it run higher oil pressure. This would explain why the external oil cooler lines popped off and split open in the past.
WOT @ 6-7K rpm oil pressure anyone? -------------------- |
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Dec 8 2004, 11:47 AM
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#2
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 Zen Master DSM Group: Moderators Posts: 3,008 Joined: 10-January 01 From: in front of you Member No.: 5 |
I'm not sure what the recommended peak oil pressure is, but I have had a problem similar to this. My oil pressure would get high enough to blow the oil filter gasket on my car at WOT. I attributed it to either blow-by past the rings (which I kinda doubt now after a few compression tests that show good compression) or pressure seeping past the oil seals on the turbo and raising my overall crankcase pressure.
I cured this problem on my car with an electric vacuum pump sucking from the pcv location, breather location, and balance shaft stop-plug in the back of the block during WOT. But I'm still not absolutely sure of the real root of this problem. Considering I'd probably have to take the engine apart again to find it, I'll stick with my vacuum pump band-aid for now. Though I may need a winter project soon anyway... |
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Dec 8 2004, 03:01 PM
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#3
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DSMCentral Freak Group: Members Posts: 328 Joined: 21-October 03 Member No.: 189 |
Intersting.
His head is new and should be free of blockage. The block was bored, honed, and clean and washed so it should als obe free of blockage. You'd think if the turbo line was blocked it would have seased up within 50 miles of Garner style driving (similar to Spy). Maybe the oil cooler is very restrictive? We could bypass it temporarily and check I guess. -------------------- |
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Dec 8 2004, 03:08 PM
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#4
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 Eats and sleeps DSM jargin. Group: Moderators Posts: 1,156 Joined: 23-September 02 Member No.: 16 |
The problem is that he's got a brand new oil pump and no balance shafts. This will naturally raise his oil pressure. Is it too high? Probably. I'd put a straight fitting on his valve cover and a vent on the block like nate described (minus the vacuum pump) and see if he gets any excess oil spray issues that way. Seems to have fixed the problem for me. As it was, everytime I hit full boost, I'd get some spray around the front case seals.
To confirm the oil pressure gauge readings, I get similar readings from my autometer oil pressure gauge on the evo. At normal 3K rpm driving in 5th, my pressure would seem to be off the chart. But the car is perfectly stock so I'm not going to tear into it just jet 
-------------------- my cars breath smells like car food
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Dec 8 2004, 03:51 PM
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#5
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DSMCentral Freak Group: Members Posts: 328 Joined: 21-October 03 Member No.: 189 |
What kind of oil pressure does your GSX run? Have you seen the way some of the turbo Hondo guys vent? They run valve cover breathers but also run 2 lines from the back of the block to a Moroso catch can with a breather on top. Then there is a drain so it the caught oil is returned back to the engine. Brad from Bloomington has this setup. Its nice.
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Dec 8 2004, 04:52 PM
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#6
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Zen Master DSM Group: Moderators Posts: 3,008 Joined: 10-January 01 From: in front of you Member No.: 5 |
I built something similar. A boost switch and relay activates the vacuum pump at 10 psi and closes a solenoid valve at the bottom of my catch can. Off boost the pump turns off, the solenoid opens and any oil caught in the catch can is allowed to drain back to the oil pan.
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Dec 8 2004, 06:07 PM
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#7
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DSM Tech Wizard Group: Members Posts: 2,404 Joined: 16-December 03 From: Fletcher/Bloomington Member No.: 214 |
Very interesting topic. I'm sure my oil pressure is probably off the charts as well. When my motor was rebuilt the guy put a shim in the oil pump which gives it a little higher oil pressure. It doesn't get into the red on the stock gauge but it comes close when I'm driving when it's cold out.
-------------------- "I hear he tunes the space shuttle also...and that thing is fast"
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Dec 8 2004, 08:12 PM
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#8
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DSMCentral Freak Group: Members Posts: 328 Joined: 21-October 03 Member No.: 189 |
Dam Nate, thats one tricky setup. Cool.
No one knows the factory spec for peak psi at WOT? -------------------- |
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Dec 9 2004, 04:56 AM
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#9
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 Post Master Group: Members Posts: 810 Joined: 9-July 03 From: Bloomington, IL Member No.: 151 |
you guys are silly. no car needs that. all it needs it that new v-attack and a backwards/upsidedown dragon visor. it makes 150whp and makes you run 6s. screw that engine bullshiet.
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Dec 9 2004, 03:53 PM
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#10
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DSMCentral Freak Group: Members Posts: 328 Joined: 21-October 03 Member No.: 189 |
You mean none of you DSM freaks know what your oil pressure should be at WOT? What if your car is to low and you're screwing up your engine? I'd want to know. I know what my engine spec is. Help a fellow DSM'er out.
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Dec 9 2004, 06:39 PM
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#11
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DSMCentral Godfather Group: Admin Posts: 3,823 Joined: 10-January 01 From: Washburn Member No.: 26 |
I don't know the exact oil pressure reading above idle either, but I do know that every DSM I've ever heard readings on have been the rediculously low 10-11psi at idle and off the charts as the RPM's go up. We scratched our heads over this at SloPny before but seems to be the way the 4G63 runs.
Except for Garner, and Nate I have not personally heard of the oil pressure being a problem. And even with Nate's I'm not sure we could rule out excessive boost in the crank case yet. -------------------- In Loving memory of David T Crebo
Greatness comes from the most unexpected places!  |
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Dec 9 2004, 07:02 PM
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#12
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Zen Master DSM Group: Moderators Posts: 3,008 Joined: 10-January 01 From: in front of you Member No.: 5 |
QUOTE (awd4kicks @ Dec 9 2004, 06:39 PM) And even with Nate's I'm not sure we could rule out excessive boost in the crank case yet. Yeah, that's still what I suspect. Excessive boost...hmmm...I like the sound of that! |
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Dec 9 2004, 07:22 PM
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#13
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DSM Tech Wizard Group: Members Posts: 2,404 Joined: 16-December 03 From: Fletcher/Bloomington Member No.: 214 |
Stop drooling on the keyboard Nate!
-------------------- "I hear he tunes the space shuttle also...and that thing is fast"
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