997gt3north

- first of all it has been a few months, 5 track events and the car is bone dry
- as a reminder, the factory seal lasted 9,000kms and the first OE replacement also lasted 9,000kms (raceshop did this when I did the 4:1 r&p and the guard lsd)
- the next 2 seals (done by the dealer) each lasted about 48 hours and were gushers (the first one on removeal they said the old tool must have nicked but the next one they ordered a new tool and it was a gusher also)

- lets just say, somehow a 996TT seal apparantly ended up being installed

- as i said above, car is totally bone dry

- now here is the "observation" that i just noticed it this morning
- the oil pressure guage, which if i remember correctly pre the TT seal install, would bounce around from almost zero to about 3 when the car was at rest in neutral, is now much more pegged at around 3 1/2

So, here are my questions for all of you engine experts:

1)
- when the engine is ON, but in Neutral with NO gas being applied, does this observation (if true) likely imply that a gt3 engine with a "better" seal imply that only low rpm oil pressure is increased OR is it likely that the entire oil pressure curve has been shifted up by a 1 to 2 bar
- my initial thought is that it is only at very low rpms where there is a big difference because if the literature is to be believed, the OE seal "activates" with engine vacuum and then "seals" under load
- that said, i would also guess that there must be some smaller effect at very high rpms

2)
- for anyone that owns a TT (993,996,997) is there an oil pressure guage and what does it read at idle and does it also rise like the gt3 as soon as rpms rise

3)
- can someone explain why a gt3 engine operates are very high oil pressure (is it higher than a TT engine? is it to handle the 8400rpms and potentially high lateral loads)
- can anyone speculate IF the TT seal raises the high rpm oil pressure, if something were to happen, where it would be noticed first (so i can monitor the situation)

4)
- if high rpm oil pressure has been raised with a TT seal, would his affect high rpm HP/TQ (might get a dyno to test it out)


paul

sjgreco

I'm clearly no engine expert but I read that the original seal was designed so that there is about an 8 horse power gain at high RPM's. Personally, I would gladly sacrafice 8HP for a seal that is proven to be dry provided it does not cause some other issue with the internals over time and is factory sponsored. I don't remember if you mentioned if the TT seal was installed by a factory authorized dealer. Happy Thanksgiving.

997gt3north

Can't comment about the dealer install thing but let's just say I have a tt seal and the car is under warranty

Paul

fc-racer

Paul, the higher oil pressure may be due to our low ambient temps now vs. when you had the normal seal. When the temps are low, my car has high oil pressure, and probably due to the excellent cooling systems in this car, it rarely goes down to what I see after a track session.

997gt3north

Farz

Are you talking about pressure or temperature

When I first got my car in December I also noticed the bouncing pressure and it was colder then then this morning so I don't think that is it but I could be wrong

Paul

eclou

I honestly cannot see how a RMS would affect the dry sump oil pressure, unless you had oil spewing out the car when your pressure wavered

997gt3north

- all gt3s, to my understanding, have a somewhat bouncing oil pressure when in neutral
- at minimum, on the guage it is "low" i.e. around 1 to 2bar, and then rapidly rises as you get on the throttle
- this has been discussed before, but i think for most cars when the car gets to around 3000-4000rpms it is then and only then pegged at the 5bar upper level on the guage

- what i noticed this morning, and then tested it continuously as stop signs, was that even in neutral, my oil pressure guage is now holding 3 1/2bar stopped in neutral

- from your picture poster, it looks like you have a 997tt, does the TT hve a oil pressure guage? if it does, what goes the oil pressure guage read when the car is in neutral?

- car never had spewing oil

paul

eclou

Paul,

on both my 997tt and 997Gt3, idle oil pressure would read about 3-3.5 bar when cold, and 1.5-2 bar when hot. This is in Texas where it never gets below 50F. My oil temps never ran over 200 on the street, and 220 max on track. You might just have a sending unit problem

997gt3north

Thanks
I will monitor it closely to see if it is just a temp thing
I don't think so but maybe I never noticed it before

Paul

todinlaw

Paul I echo what ecolu said, I am No Expert, but I can't come up with how a RMS could impact oil pressure. Oil pressure is made by the restriction of the flow of oil thought the motor's oiling system. The RMS may have a lubrication point just behind it on the crank bearings but I can't see that making fundamental changes. Truly, I don't now crap about the P motor, all my motor rebuilding experience is with 70's era US V8"s. I am sure interested in you continued outcome. sounds like this will be the seal I put in when I am on the 47th month of ownership.