Oil pressure rise time at start

MoparMap

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So I recently finished my rebuild after shattering a rod in my 04 at my last track outing and this time around I went full in on the oil system upgrades. I've got a gen 4 pan with swinging pickup, the Prefix oil pump upgrade (30% more flow), the gen 4/5 style PRV that Prefix also sells as a drop in for the gen 3, and some block mods Prefix does to add oiling holes to the crank mains and grooves to the cam journal surfaces. That being said, I've noticed on cold starts that the oil pressure takes a while to register on the gauge. It's been 6+ months since I drove it with the old gen 3 setup, so I can't recall how quickly the pressure used to rise after start on it, but can anyone confirm if this is typical operation? I didn't know if the swinging pickup might have something to do with it as I'm not sure exactly how it seals around the swinging part. It's definitely a loose fit so it can freely swing, so guessing maybe it just needs a little oil around it to "seal up"? If so I would expect this to be typical to stock gen 4/5 cars as well. Currently running the standard Mobil 1 10W-30 full synthetic "factory fill" oil. Pressure is great once it's running, but the 5-10 seconds it takes for the gauge to register has me worried that I might be accumulating damage over the long term. Cold pressure is around maybe 90 regardless of rpm. Hot pressure idles around 25 and goes up to 75 or maybe a little more when over 1750 rpm or something like that. I know the factory gauge is fairly heavily damped from what I've read, so maybe the lag time isn't quite as bad as it seems, but it still feels longer than I remember.
 

Steve-Indy

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Our stock 03 does not take that long to register oil pressure upon startup...whether using the old 10W-30 Mobil 1 or the newer factory fill (2005) Mobil 1 0W-40. I am not in the habit of driving (therefore not starting) Vipers in ambient temps below 50°F...which posdibly could affect your readings at much lower temps. On startup, it reads 80 psi...and when fully up to temp on 90° F days, it settles down to 45 psi at idle.

If you are concerned, check with a real pressure guage...as maybe your sensor is "lazy".

P.S. On a 50°F day, the water temp rises to 185-190° within a very few minutes of driving at around 1400 rpm in 1st gear in the neighborhood. However, the oil temp has always lagged way behind...up to 15 minutes plus of real driving to see an oil temp of 185°. The oil temp in our Gen IV's rises as a faster rate then the Gen III...for whatever reason.
 
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MoparMap

MoparMap

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How long does it take your gen 4 to register oil pressure on a cold start? I'm wondering if it's just a swinging pickup thing, or maybe the new pump I put in.
 

Steve-Indy

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Sorry that I cannot supply a stop watch answer...but, my impression is 2-3 seconds for both Gen III and IV.

Since I do not start these cars without the ability to do a full drive cycle, I will have to wait for Spring to give a more accurate answer.

Hopefully, someone is a warmer climate will jump in here and give a timed answer.
 
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All good, I appreciate any data points and feedback I can get. Thanks! I'll have to see about getting a mechanical gauge on it one of these days.
 

BYAIC

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So I recently finished my rebuild after shattering a rod in my 04 at my last track outing and this time around I went full in on the oil system upgrades. I've got a gen 4 pan with swinging pickup, the Prefix oil pump upgrade (30% more flow), the gen 4/5 style PRV that Prefix also sells as a drop in for the gen 3, and some block mods Prefix does to add oiling holes to the crank mains and grooves to the cam journal surfaces. That being said, I've noticed on cold starts that the oil pressure takes a while to register on the gauge. It's been 6+ months since I drove it with the old gen 3 setup, so I can't recall how quickly the pressure used to rise after start on it, but can anyone confirm if this is typical operation? I didn't know if the swinging pickup might have something to do with it as I'm not sure exactly how it seals around the swinging part. It's definitely a loose fit so it can freely swing, so guessing maybe it just needs a little oil around it to "seal up"? If so I would expect this to be typical to stock gen 4/5 cars as well. Currently running the standard Mobil 1 10W-30 full synthetic "factory fill" oil. Pressure is great once it's running, but the 5-10 seconds it takes for the gauge to register has me worried that I might be accumulating damage over the long term. Cold pressure is around maybe 90 regardless of rpm. Hot pressure idles around 25 and goes up to 75 or maybe a little more when over 1750 rpm or something like that. I know the factory gauge is fairly heavily damped from what I've read, so maybe the lag time isn't quite as bad as it seems, but it still feels longer than I remember.
Whenever you try something new you become more alert to the mundane. Had the same observation when I switched to 0-40. I recently switched back to 10-30 and there is still a lag of that red light going off; it was probably there with both oils but I freaked out because it seemed to be taking longer with the new 0-40, it wasn’t.
 
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MoparMap

MoparMap

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Whenever you try something new you become more alert to the mundane. Had the same observation when I switched to 0-40. I recently switched back to 10-30 and there is still a lag of that red light going off; it was probably there with both oils but I freaked out because it seemed to be taking longer with the new 0-40, it wasn’t.

Lol, this is too true. I joke now that the only thing louder than my exhaust is my imagination. Every little tick or rattle has me second guessing things and wondering if something is going to **** up. Once I get a few oil changes and oil reports I'll hopefully be able to be more at ease again.
 

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