Guys what are you opinions on removing the under piston oil sprays and blanking them off? My engine builder has removed them and fitted a higher pressure spring in the oil relief valve.

This is to keep the oil pressure around 6-7 bar at high rev's while the car is hot. 100 C + oil temps.

The only problem now is the car idles at 50psi hot and is pulling 90psi at 3K rpm and pegs the OEM gauge at 120psi + at 4K and over.

Ive been told that this will not damage anything and will help keep the cams and bearings in better condition due to the higher oil pressure.

Any views on this ? Im not sure if the under piston sprays being removed was the way to go?

Thanks.

 

You must be kidding!

That is way too much pressure It will cost you your bearings
50 lbs hot is the most you would want.at 120 lbs you start to ping the bearings.

2nd Why close off the sprat to the top of the piston as it does two things 1st it is really for lubing your wrist pins
and cool the top of your pistons,

As with all things too much oil shooting up their is not good but none is detrimental. When I would build some racing motors I would have to chamfer the bottom of the piston to pick up oil from the cylinder wall and shoot it at the top of the piston to keep the wrist pin oiled.

If I was worried about it more volume of oil not pressure
is what you need. I feel if this is his concern open up the oil passage to the cams to achieve it.

 

^^ The OEM gauge is not accurate.

 

I really would not have suggested doing this. First, install a dedicated oil pressure gauge, if you haven't done so already. Then report back with your observed pressure. Pressure is inverse to flow (volume), so too high an oil pressure can be just as bad as too low (within reason). 6-7 BAR of oil pressure is really the max I would want to see once the engine is under load, and oil up to normal operating temp

 

To be honest I did not even know they were doing this, I had a small oil leak to the upper oil pan had to come off so they did the work while the oil pan was off.

I'm running 15w-50 oil so I'm swappin this out to a 10w-40. If the pressure is still too high a lower oil releif valve spring may need to be fitted.

Does any one know where this valve is on the VQ ?? Around the oil filter I would guess?

 

OOPs

 

I dont think bearing or cam issues due to low oil pressure are common on VQ's. We already have a good amount of pressure to begin with. The squirters are there to cool down the pistons from what I understand, and also something that you might want to think about now is, your providing a crap load of more oil pressure to your turbo(s), which might eventually cause them leaks, unless you change or put a restrictor. just my thoughts, im no expert.

 

Guys does any one have a picture of the oem oil relief valve? I'm not sure where this is located?

 

Guys I just took the car out to do some testing. When the car is at 80 degrees oil temp it will peg the the pressure gauge after 4.5k rpm. I blocked off my oil cooler holes in my bumper and got the oil temp to 105 degrees and the idle pressure dropped to 40 psi and would just hit 120psi at max revs. This sounds more like what it should be.

Do you think by dropping down to a 40 weight oil I'll have better pressure while the motors cooler?

I may block off some oil cooler holes and run the oil temp at 90-100degrees instead of the 75-85 it normal runs at the moment??

 

Anything you do at this point would likely just be band-aiding a bad situation. Not only is your pressure too high, but they removed your piston squirters? Thats just bad news. I would just have them put it back the way it was.

 

You need to use an aftermarket oil gauge. The oem one is not accurate at all.

 

Guys I have spoken to my engine builder who has stated the oem oil pump has not been modified. It has just had the oil releif spring replaced with a new oem item. The increased oil pressure is just down to the removal of the oil sprays. If the 10w 40 oil does not make much difference then the car will have the oil sprays refitted but with a smaller spray hole to keep the oil pressure a little higher than stock.

 

Why do you still want to have your oil pressure higher than stock?

 

To keep the pressure around 6-7bar at redline when the cars real hot on track. The engine builder said the car will run/last better with an increase in oil pressure at high temps/load.

 

if i had a builder tell me that i would walk out his shop right away. With more pressure comes more heat, in addition by removing the squirters you now dont have that cooling for the pistons. So now you have more heat, less piston cooling and possibly provoke detonation. I would put everything back.