Hey I had a question: which is better for oil flow on ls vtec turbo, sandwich adapter,or t off the oil pressure sending unit? I have both t'd off the oil pressure sending unit.and under full boost at high rpm's the vtec starves for oil....then throws a vtec system malfunction cell.then redlines at about 6000 rpm's .....ever since I boosted the motor the vtec don't kick in as hard....I do have vtec set to engage at 5000 rpm's .....i have a sandwich adapter. For the head external oil line....would it hurt to run both off the adapter? Or one t'd off the block,and the head off the adapter? Which would be better? Will there be enough oil pressure at the adapter? Any suggestions?

 

off of the sending unit is horrible... a 4an line will not feed enough oil to the head.feeding the head and the turbo off of one port is bad... I wouldn't be surprised if you've damaged the bearings in the turbo because of pressure and flow fluctuations... also check your head, you might have cam journal/cam damage.

you need a sandwich plate... and one line to the back of the head. you cannot run both... that would serve no purpose and you really dont have a way to run 2 lines into one port without some clever adapter work...


just get a sandwich plate and a vtec oil line kit.... works fine for lots of people and the sandwich plates have an extra port for an oil feed line. you'll still have plenty of flow and pressure and won't have oil starvation problems. also check your vtec solenoid screen, it could have debris in it, possibly metal flakes if you've done damage to the turbo/head

 

Thanks for the good advice....I've only had it boosted for about about 2 months,and I change my oil religiously...never had any shavings...thank god.I have a morosso oil pan with a magnetic drain plug,so that has helped.I built the motor about 10k miles ago un- boosted and I did all the necessary. Steps in the break in period .....but I actually. Have a 8 an line off the sending unit,then I have a 4an line for the Turbo t'd Off the head..it worked...I thought it wouldn't affect my oil getting to the head for vtec.but I guess I was wrong.thanks for your help.

 

That's your problem

 

the problem here isnt the size of the oil feed line to the head, its the size of the sending unit port in the block... Its only 1/8bspt so youre limited by how much oil the port can flow... which isnt enough.. Its simple fluid dynamics.... youre flow limited by the smallest point in the system.... especially when you have this small port trying to feed two different things. and you should never tee off of the vtec oil feed in the head, it only has a small reservoir in the head for system fluctuations.

you need a sandwich plate, feed the head off of the large port and feed the turbo off of the smaller one and put the oil sending unit back in the stock port..

Imagine it this way. You have a 3" exhaust but a 2" downpipe. yea the 3" will flow a lot and support a lot of power but you're ultimately limited by how much the downpipe flows.

I'm still worried you've done damage to the turbo or severely limited its service life.

 

Oh I see exactly why....makes perfect sense.....hey ya learn something new everyday.I'm gonna run a 8an line out of the big port on the sandwich adapter I got and run the Turbo off the small port.I bet it'll run a hell of a lot better then.plus save my motor and Turbo from some serious failure.thank for the insight ......

 

no problem, im just hear to help and give back.
if you ahve any more questions or issues feel free to pm me. I can answer you more directly there and people wont bash you lol