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Oil pressure drop at Track

Old 12-03-13, 03:36 AM
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Oil pressure drop at Track

my car is 13B PP 290WHP at 8500 RPM . with Comp oil pump n comp regulator

one thing really bother me is

althought i shim my regulator on 130PSI at idle

but after few lap on track the pressure will drop between 95-105 on main straigh way

that really bother me a bit i know one reason is oil foaming on high speed

but i already have oil pan plate n accusump(100 psi)

any suggestion on how to keep my oil psi above 120 at WOT ?

btw i am using liqu molly 10-60w( sponser) i am thinking to change to different type of oil next time like 20-50

thanks for your time
J
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Old 12-03-13, 05:22 AM
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here are my lastest pic of my race car

thing to do at off season better aero balance

cover up front wheel more

solve my oil pressure problem n my tri link suspension

https://www.rx7club.com/attachment.p...1&d=1386069652
Attached Thumbnails Oil pressure drop at Track-1462571_433941300062195_554722715_o.jpg  
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Old 12-03-13, 08:14 AM
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I use Redline 50w racing synthetic in mine and maintain 120+ even when it's hot. This is the recommendation from my engine builder, Jesse Prather.
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Old 12-03-13, 10:35 AM
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i'm a bit curious is oil pressure that high really bad ? I thought anything about above 60 is good.

Why do you guys run somuch more ?? sorry I know this is off topic but just curious .

And does this happen in every track is your engine temps going up

have you checked for excessive fuel dilution ?
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Old 12-03-13, 11:46 AM
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Originally Posted by Don49 View Post
I use Redline 50w racing synthetic in mine and maintain 120+ even when it's hot. This is the recommendation from my engine builder, Jesse Prather.
+1, try a straight weight oil, 50w is a good choice. 40w is the minimum
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Old 12-03-13, 05:21 PM
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TEM120,
This is a motor that runs to 9K on track and is seldom below 6K. My understanding is that 120PSI is the standard for a high revving race motor.
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Old 12-03-13, 09:12 PM
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Originally Posted by j9fd3s View Post
+1, try a straight weight oil, 50w is a good choice. 40w is the minimum
^^ Agreed!!
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Old 12-03-13, 11:57 PM
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Dont think i can get REdline 50WT in my area

might need to custom order from state

will try it at next year race


what is every one PSI on track ?

J
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Old 12-04-13, 11:41 AM
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Originally Posted by diyman25 View Post
Dont think i can get REdline 50WT in my area

might need to custom order from state

will try it at next year race


what is every one PSI on track ?

J
Originally Posted by Don49 View Post
TEM120,
This is a motor that runs to 9K on track and is seldom below 6K. My understanding is that 120PSI is the standard for a high revving race motor.

Oh I see thanks..

i'd also be interested in knowing what most people run PSI wise , and what RPM.

say my motor is balanced and rotated to run to 9000 ,

But I set the limit at 8600 for safety margin .

but now with the whole PSI question I wonder if my Oil pressure is up to snuff at those levels .

Also I do know that the centrifugal forces push oil out of the Eshaft at such high rpms . but I didn't know people ran that much oil pressure.

Last edited by Tem120; 12-04-13 at 11:45 AM.
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Old 12-04-13, 07:20 PM
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Originally Posted by Tem120 View Post
Oh I see thanks..

i'd also be interested in knowing what most people run PSI wise , and what RPM.

say my motor is balanced and rotated to run to 9000 ,

But I set the limit at 8600 for safety margin .

but now with the whole PSI question I wonder if my Oil pressure is up to snuff at those levels .

Also I do know that the centrifugal forces push oil out of the Eshaft at such high rpms . but I didn't know people ran that much oil pressure.
Well the last RX-8 Oil pressure set at 115 psi
Then u know in order to safely rev pass 8000
For extended of time
That is oil psi u need
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Old 12-04-13, 07:57 PM
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Originally Posted by Tem120 View Post
Oh I see thanks..

i'd also be interested in knowing what most people run PSI wise , and what RPM.

say my motor is balanced and rotated to run to 9000 ,

But I set the limit at 8600 for safety margin .

but now with the whole PSI question I wonder if my Oil pressure is up to snuff at those levels .

Also I do know that the centrifugal forces push oil out of the Eshaft at such high rpms . but I didn't know people ran that much oil pressure.
Well the last RX-8 Oil pressure set at 115 psi
Then u know in order to safely rev pass 8000
For extended of time
That is oil psi u need
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Old 12-05-13, 08:42 AM
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Originally Posted by diyman25 View Post
Well the last RX-8 Oil pressure set at 115 psi
Then u know in order to safely rev pass 8000
For extended of time
That is oil psi u need

oh i see, whats the downside of running somuch oil pressure ???

on a regular car , running such higher oil pressure doesn't that put stress on the oil seals ?

my builder did do some oil pressure mods so I believe my oilpressure is at like 90psi . but thats at around 3000 rpms I havent had a chance to abuse the motor since it was getting broken in still .

And again , I feel like I'm hijacking your thread so I apologize.
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Old 12-05-13, 01:47 PM
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This is very interesting as I confirmed the same thing myself without even knowing this. When my engine was brand new it would pull 130+psi at idle and cold. When hot it would drop to about 80 psi at idle using 10-40 any brand. After about 20 hours of running time the engine would still pull 120 at idle cold but hot (900 to 1000 rpm) the idle pressure would be about 40 psi and jump to 100+ when I picked up the rpm a bit. On track with the 10-40 the oil pressures would fluctuate a fair bit when temps got up higher, so I swapped to 20-50 Q Racing oil. That would work great for the first weekend, but for the second weekend pressures would drop again.

For my last race this past fall, I changed back to the Redline straight 40w again and bingo all pressures were like it originally was when the engine was first built and I didn't see a pressure drop even when oil temps got above 240 degrees (drafting too close for too long).

The only downside is the oil warm up does take longer in the morning.

Eric
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Old 12-05-13, 10:12 PM
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Originally Posted by 23Racer View Post

The only downside is the oil warm up does take longer in the morning.

Eric
You can always run an oil heat like this for improved cold start;

https://www.wolverineheater.com/Engi...ars-s/1814.htm
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Old 12-05-13, 10:14 PM
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Originally Posted by 23Racer View Post
This is very interesting as I confirmed the same thing myself without even knowing this. When my engine was brand new it would pull 130+psi at idle and cold. When hot it would drop to about 80 psi at idle using 10-40 any brand. After about 20 hours of running time the engine would still pull 120 at idle cold but hot (900 to 1000 rpm) the idle pressure would be about 40 psi and jump to 100+ when I picked up the rpm a bit. On track with the 10-40 the oil pressures would fluctuate a fair bit when temps got up higher, so I swapped to 20-50 Q Racing oil. That would work great for the first weekend, but for the second weekend pressures would drop again.

For my last race this past fall, I changed back to the Redline straight 40w again and bingo all pressures were like it originally was when the engine was first built and I didn't see a pressure drop even when oil temps got above 240 degrees (drafting too close for too long).

The only downside is the oil warm up does take longer in the morning.

Eric
Sounds Great !! I will try to use redline next season. during this year the Liqui moly guy from german told me there is really no Replacement for Straight race oil like 50WT compare to 10-60
this mean from next year on i will be import my oil from state............. the only car use 20-50 here is the disel truck..............
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Old 12-05-13, 10:16 PM
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Originally Posted by Tem120 View Post
oh i see, whats the downside of running somuch oil pressure ???

on a regular car , running such higher oil pressure doesn't that put stress on the oil seals ?

my builder did do some oil pressure mods so I believe my oilpressure is at like 90psi . but thats at around 3000 rpms I havent had a chance to abuse the motor since it was getting broken in still .

And again , I feel like I'm hijacking your thread so I apologize.
The downside would be your oil pump wear out quicker

What kind of engine u have u what hp n rpm u rev ?
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Old 12-05-13, 10:36 PM
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Originally Posted by diyman25 View Post
The downside would be your oil pump wear out quicker

What kind of engine u have u what hp n rpm u rev ?
13b REW , recently rebuilt balanced and rotated till 9300 rpms ,

But I set my limit at 8600 for a safe margin of error , but now I'm wondering if i have enough oil pressure for that . I have a soft limiter at 8600 timing retard and then a hard fuel cut at 9k

power should end up being somewhere between 330-350

medium street port

new oil pump , since a bad oil pump and low oil pressure is what caused my motor to blow in the first place .

my oil reads about 90 while cruising at 3k , I haven't revd past 6k yet .

Last edited by Tem120; 12-05-13 at 10:42 PM.
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Old 12-05-13, 11:56 PM
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Originally Posted by Tem120 View Post
13b REW , recently rebuilt balanced and rotated till 9300 rpms ,

But I set my limit at 8600 for a safe margin of error , but now I'm wondering if i have enough oil pressure for that . I have a soft limiter at 8600 timing retard and then a hard fuel cut at 9k

power should end up being somewhere between 330-350

medium street port

new oil pump , since a bad oil pump and low oil pressure is what caused my motor to blow in the first place .

my oil reads about 90 while cruising at 3k , I haven't revd past 6k yet .


Rotary Tech Tips: Oil Cooling Tips


If stock FD have 115 PSI at WOT

so i suggest to shim it to get higher oil pressure
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Old 12-06-13, 09:40 AM
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Originally Posted by diyman25 View Post
Rotary Tech Tips: Oil Cooling Tips


If stock FD have 115 PSI at WOT

so i suggest to shim it to get higher oil pressure

thank you , and I believe it was shimmed

But my car had such terrible oil pressure before that I dont know if its higher then stock or normal LOL

I used to have 30 psi at WOT till 8k

And 10 psi at idle
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Old 12-08-13, 05:58 AM
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Originally Posted by Tem120 View Post
thank you , and I believe it was shimmed

But my car had such terrible oil pressure before that I dont know if its higher then stock or normal LOL

I used to have 30 psi at WOT till 8k

And 10 psi at idle
The engine won't last at this kind of psi

Put a know good mechanical gauge to confirm ur oil psi
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Old 12-08-13, 06:37 AM
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Originally Posted by diyman25 View Post
The engine won't last at this kind of psi

Put a know good mechanical gauge to confirm ur oil psi
that engine went boom new engine has a new oil pump the old pump was toast i thought it was just a bad sensor but i was wrong
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Old 12-10-13, 03:21 AM
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Originally Posted by Tem120 View Post
that engine went boom new engine has a new oil pump the old pump was toast i thought it was just a bad sensor but i was wrong
Could be ur front oil pressure regulator did not set it rights
It happend to my friended motor once
So all the oil let go to front
Cause engine seeze at the Raer
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Old 12-10-13, 08:41 AM
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Originally Posted by diyman25 View Post
Could be ur front oil pressure regulator did not set it rights
It happend to my friended motor once
So all the oil let go to front
Cause engine seeze at the Raer
Front stationary bearing was what spun ever since I bought the engine it had low oil pressure. I figured it was a bad sensor

maybe I hoped thats what it was . it lasted like that for a year . But eventually gave out

it was 100% my fault . ignorance caused the blow .
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Old 12-15-13, 04:43 PM
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Originally Posted by j9fd3s View Post
+1, try a straight weight oil, 50w is a good choice. 40w is the minimum
Redline racing 50wt is actually a 15w50 oil.
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