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Discussion Starter #1
Hey guys,

I'm running an Explorer 5.0 in a '97 BMW M3 so I hope you won't run me out of here too quickly, but I ran into an issue while autocrossing yesterday and figured this would be the place to ask.

The engine's bottom end is totally stock Explorer with the exception of a generic Summit Fox body oil pan and pickup. The engine had 160k miles on it when I installed it and I've done about 3-4k on top of that. I'm running around 5.5 quarts of 5W-20 Motorcraft oil (dipstick shows a slight overfill, maybe 1/8").

I'm finally getting my brakes and my driving sorted and during yesterday's event I really got on the brakes hard in the braking zones. When I did that, I saw my low oil pressure light come on. I'm running a Megasquirt with a 0-100psi AEM oil pressure sensor.

What it comes down to is that I'm dropping to 10-15psi under hard braking. It recovers after a couple seconds, but obviously this is bad for the engine. I added an oil pressure gauge to my overlay so you can see what happens here:

https://youtu.be/b03EVsF9Gn8?t=1m2s

I know that hundreds of Fox bodies have raced with stock unbaffled pans and with stickier tires/better brakes than I have. Is this a common thing? Do I need to look at drainback or pickup issues? I'm seeing ~17psi at idle and 42+psi at high RPMs which isn't great but isn't too terrible. Thoughts? Suggestions?
 

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Add an Accusump. I blew a 302 in an E30 chassis (and that was with an Accusump, so...). It was the result of a couple things: severely cut down pan to fit the E30 chassis (I think the E36 is better about this), poor drain back out of the heads, and what I feel like was never enough oil pressure. Went dry sump and never looked back.

PS why such a thin oil?
 

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Discussion Starter #3
Thanks for the reply! I just stuck with the factory recommendation to start with. Obviously the factory cares more about emissions and fuel economy than performance, so I'm open to using something else. The oil analysis I did at the last change came back with high aluminum, iron, and copper.
 

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I'd try a 10w-30 and see if the hot oil pressures go up. 42# hot would make me nervous. Do you have an oil temp gauge?

Did you check the clearance of the oil pump pickup to the bottom of the pan?
 

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Discussion Starter #5
I'd try a 10w-30 and see if the hot oil pressures go up. 42# hot would make me nervous.
My peak RPM at the end of the long straightaway was 5250rpm and oil pressure was 47.2psi. After letting off, oil pressure spiked to 56psi then two seconds later bottomed out at 16psi.

Do you have an oil temp gauge?
I do not. Should I? I have a few spare inputs on the Megasquirt, it wouldn't be too hard to add oil temperature as well.

Did you check the clearance of the oil pump pickup to the bottom of the pan?
Nope.

I have this pickup: https://www.summitracing.com/parts/mel-247s

And this pan: https://www.summitracing.com/parts/sum-123458

I suppose during my next oil change I could pull the level sender plug and get the inspection camera in there to see what the clearance looks like.
 

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An oil temp gauge is a worth-while investment. That plus your pressure gauge will tell you a lot, and can help you settle on the oil weight your engine needs.

The pickup should be 3/8 - 1/2" off the bottom of the pan.

Are you running any remote oil filter(s) or oil cooler?

Stock oil pump?
 

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Discussion Starter #7
Stock oil pump, and the stock Explorer oil cooler:



It's a 90 degree adapter on the filter that engine coolant runs through.
 

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I had oil starvation as well, but when going around hard corners. I just replaced the stock pan with a canton road racing, baffled pan, Problem solved, i have plenty of oil pressure all the time now.
 

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To me the stock Fox body pan is a drag racers pan. Basically the opposite of what you want for autox or road course use.
 

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I run the FRPP pan/pickup. Much improved over my old Canton pan. Even now though with big brakes and race tires I still get pressure drops. I also have an accusump and it helps but even then it doesn't keep full pressure under those few seconds of oil starvation. Instead of 15psi, with the accusump help it will maintain around 25-30.

I run a HUGE oil cooler and even then I'm seeing 270+ oil temps. Your oil is definitely to thin IMO for race duty. I run 20w-50 redline on my car but it is built with race clearances. Minimum on your engine with 160k miles I would run 10w-30 and if it was mine I would be running a 10w-40 synthetic of the highest quality like Redline, Amsoil signature, Royal Purple. A good non-sheer synthetic oil will help during those few seconds of oil starvation.
 

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I run the FRPP pan/pickup. Much improved over my old Canton pan.
You said much improved. How much improved to be exact? Right now I'm running a high volume pump with a Canton pan and pickup. I have seen pressure drops to as low as 20-30 psi under hard braking. How well would you say that FRPP pan worked compared to that?
 

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Obviously I don't have scientific data for this but I'll tell you my experience.

Same situation as you with canton pan only with race rubber and race pads mine would occasionally go to 5-10 psi. Especially on any down hill braking zones. Also, I was getting low pressure on turns too. With the canton pan I would get pressure drops from 20-30 psi under brakes on the street with street tires and pads. 😳

Ordered the FRPP pan. Filled canton and FRPP pan with 7qts water. Turn at roughly 45 degrees and the FRPP pan has nearly 1/3 more water left in the sump than the canton.

On with the FRPP pan and test drive. Cannot get any pressure fluctuations whatsoever on street with street tires and pads.

To the track with FRPP pan. Race rubber & race pads. Still getting some pressure fluctuations with FRPP pan although not nearly as severe. Pressure drops to 30 on long hard braking zone only. Recovers immediately and never drops in turns.

I would get pressure fluctuations on nearly every braking zone with canton. At Putnam park for instance I got pressure drop on 8 out of the 10 braking zones. 2 of those would fall off the map at around 5psi. With FRPP I get pressure drop at the 2 turns where canton was at 5psi. With FRPP pan it's about 30psi. FRPP pan seems to also recover quicker. Where the canton was at pressure drop long into the turn, FRPP has recovered halfway through turn-in.
 

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If your serious about road racing, spring for the FRPP pan
 

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The FRPP pan is the best one that we have tested.

One important thing here to point out. It is very difficult to compare oil pressure readings from one car to another. This has to do with the amount of averaging (smoothing) built into the oil pressure gauge. Look at the link below for examples of different types of smoothing and averaging.

Signal Smoothing - MATLAB & Simulink Example

ALL gauges and the sensors, will smooth the measurements to some degree. OEM gauges tend to smooth the most as the manufacturer doesn't want someone to freak out when the oil pressure drops to 20psi for 0.5 seconds during a very hard stop. If you use the proper type of sending unit and sample it at 1kHz, you will be really surprised what the oil pressure really looks like. You can see the pressure pulses from the individual rotors in the oil pump.
 

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Ok im going to mess up a nice thread with a really dumb question.

Seems I remember reading in a magazine (i think it was MM&FF) a really long time ago, that over filling the stock pan by a quart during track days or autox events will help this problem to some degree. Is this true?

I understand not wanting to daily it like that, but seasions of sustained high rpm is it something worth entertaining?
 
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