I've got an ls vtec with forged rods/ pistons and a mildly built head. Running a borg warner .57 trim. Do I need to run an oil restrictor? Why or why not? Should I just find out what oil pressure this turbo likes to run on or is it more complicated than that?

 

Contact Borg Warner

 

You need an oil pressure gauge.

 

just run the restrictor. they are pretty cheap. off the top of my head i think many turbos only need like 20 psi or something low like that, im sure you motor is making above 80 when you are hammering on it.

 

You are absolutely right, although it's a little more than that. You need to know precisely what size turbo charger that you have, Oil pressure at cold start, and understand what size restrictor opening you using.

simply picking up one of the local restrictions on ebay may do more damage than it does good. You do not want the restrictor to be too small, or too large to use.

 

whats the result of running no oil restrictor. just a bit of burning oil in wot?

 

In my case a coked-up exhaust wheel and entire hot side, really.
Rebuilt the Holset but that stuff was a bitch to clean. Glass bead blaster got the parts back to new. That stuff was incredibly hard, exactly like what grows on exhaust valves. I think a less robust turbo would've self destructed by the time I finally addressed it, had to be out of balance with the massive deposits on the wheel.
I didnt get a restrictor tho, improved my drain. Maybe I should to be safe, i smell a little puff sometimes..it's hard to get everything optimum on the cheap and piecing together components catch-as-catch-can.
Hey, that was a FI pun. (catch can, get it?)

 

contact borg warner. period. I plan to run a -3an to my s363 with no restrictor. some people run -4an without restrictors too. just call BW, you can't go wrong.

 

Borg-Warner turbochargers of the sizes used by Hondas typically use larger turbine shafts and oil gallies than other makes, thereby less sensitive to oil pressure in oil splaying the shaft and journal bearings.

This means that more than likely you will not have to use an oil restrictor as you would a Turbonetics, Garrett or Precision. But it depends upon size of the turbocharger. Travisbiggie's example is a 62mm inducer with a larger 80mm wheel diameter exhaust wheel. So, he would likely not need one.

Its not a -3AN vs. -4AN, its the volume of oil (in correlation with its oil pressure) that determines the oil gallies's needs.