Alex Trebek

iTrader: (2)

I finally installed all my turbo components and now my oil pressure is much lower than it was prior to install. I was expecting a small drop since another part has to be fed oil, but not as big of a drop as I saw.

The engine is a D16Z6. 50k on rebuild. I have an HX35/H1C being fed with a -4AN SS line, and a -12AN SS return. I arrived at these sizes by measuring the stock feed and drain sizes that came on the turbo from the Cummins engine. And also lots of reading on the Holset thread on the DSM boards.

I'm running Amsoil Z-Rod 10W-30. Before the turbo I had about 80-90psi on cold start, and when warm it would sit at about 15psi idle, and around 40psi at 3k rpm. I'm not sure the redline pressure. Now on cold start I get 40psi, and at idle it is sitting around 12psi. And when I rev the engine it seems to hit a wall at 40psi.

The min spec is 10psi at idle, so I'm bareeeeely above that, which is slightly worrisome, but not the biggest concern of mine. What I'm concerned about is that I'm not getting enough pressure up top. The min spec in the manual is 50psi at 3k. I'm never seeing above 40psi, even when the oil is cold. I'm assuming this is because the oil pump cannot flow enough volume to keep the pressure up because of the size line that is on the turbo.

The whole, "holset blowing seal thing" seemed, to me, to originate from drain lines that were too small, that is why I went with a -12AN return line. So I figured I should stick with a -4AN feed. But now I'm worried that it is too big. Should I be worried? Should I switch to a -3AN feed? Could there be not enough oil to sustain a higher pressure at higher RPM's due to the increased volume necessary due to the turbo? I have it filled up to the second dot...Thoughts?

I have a dyno appointment on the 24th of June (12 days from now) and I'd like to get it sorted out by then.

Willy Wiskers

Out of curiosity what oil filter are you running?

Alexslow1k

Where are you getting your oil pressure reading from?
Is the turbo tapped to the same plug as pressure sensor?

Alex Trebek

iTrader: (2)

OEM S2000 Oil filter. Fits the D block perfect and has higher capacity.

Yes, it is. Which I know, means I'm actually reading the turbo feed line pressure. But isn't this the same pressure as the whole system is seeing? Or are the pressures different at that location vs. say the vtec solenoid? Is there a better place to measure the system oil pressure at?

scottdh20

I have a d16y7 with z6 head and an hx35

-3an feed off a tuner toys tee fitting, and 5/8ths return iirc

cold start is 75-80psi, normal idle is 10-12psi....hot idle after highway driving, boost or racing is 3-5psi at idle. per several competent engine builders whom you all know, they all said the same thing, at idle 1psi is enough to lube things up.

I generally keep about 10psi per 1k rpms except for when I road race and after about 10miles im hitting a wall at 45-50psi at 7k, this worries me and I plan to add a oil cooler to bring that up a bit...but honestly a lot of the guys there said that after a few laps 40-50psi at readline is fine....still worries me

I also have a fairly loose built motor for higher hp

Alex Trebek

iTrader: (2)

Where are you feeding your oil from? And where are you measuring your oil pressure at?

5/8" seems a bit small. Holset recommends a minimum of ~20mm or 19.25mm or something along those lines 5/8" would be just under 16mm. Have you had any problems with seals?

I'm wondering if I should drop down to a -3AN feed....

scottdh20

its been on there for 3 years without a problem...and my drain has all of a 1-2" drop ....and the line droops down....no way around it, not an ideal drain but again never had any issues...yet

oil pressure and turbo are fed off the tuner toys block fitting....aka a tee off the stock oil pressure sensor port...but a properly threaded and quality unit vs. the ebay junk that breaks

scottdh20

here is a super old pic, the oil pressure line comes off that also

E_F_9

iTrader: (1)

Are there advantages to running it from there rather than from a sandwich plate?

Alex Trebek

iTrader: (2)

Yeah, we are sensing from the same spot. I have the Go-Autoworks firewall kit. So I have a fitting in the stock oil pressure sensor/switch port coupled to a SS line that goes to the firewall tee. At the tee I have my turbo feed and gauge line. Sounds like dropping to a -3 might be necessary to keep my pressures up.

The only reason I'm running -4AN is because the stock feed from the Cummins was roughly -4AN. But I'm thinking that pump can probably flow more volume than the D series pump, therefore keeping the pressure up.

I'd be curious to hear what TheShodan has to say, but I'm not sure if he will reply after our last disagreement.

Alex Trebek

iTrader: (2)

It depends. That spot on the block is after the filter, so it's *clean* oil. It was cheaper to do it this way than run a Golden Eagle sandwich plate, which AFAIK is the only one that provides post-filter clean oil. The other cheaper ones do not. There is some debate on whether or not this matters, but to me it did. So that's why I went with this.

Alexslow1k

I know many people have done the oil feed this way for some time now.
Personally I would do a sandwich and thrown an inline filter before the oil gets to the turbo.
if I remember correctly some sandwich plates provide unfiltered oil.

tasco

Are you running a oil restrictor going to the turbo? If not I would install one before going to a smaller feed line.

Alex Trebek

iTrader: (2)

No, I'm not. The general consensus and data from Holset is that Holset's need big drain lines, and no restrictors. Now, my -4AN may be overkill, and a -3AN might provide enough restriction to get my oil pressure up to where it should be. From what people are saying a -3 seems to do the trick. But I'm not going to run anything smaller than a -3AN sized hole. Unless someone has some really convincing evidence otherwise regarding a Holset H1C. But thank you for the suggestion. I know it does the trick and/or is necessary for a lot of other turbos.

Turbo-LS

iTrader: (4)

.060-.065 restrictor on -4 feed

mar778c

iTrader: (1)

Holsets do not need a restrictor.

OP, I feed oil to my H1C with the GE sandwich plate.

Alex Trebek

iTrader: (2)

What size line? What are your oil pressures like, cold, idle, wot, etc. D or B? I would expect to see similar pressure to you. Same chra, feed location, etc. Well lower than you if you use a -3.

mar778c

iTrader: (1)

My line size was -4AN. I never checked oil pressure. This on a B series.

Pro-SeriesFab

Personally, I would run a -3 regardless . . .

I've run a -3 on a H1C/HX35 and a H1E/HX40 with zero problems AND a 5/8" hose drain.

If its a straight shot or a slight downhill bend the drain is fine.

Alex Trebek

iTrader: (2)

I ended up buying a -3AN to -4AN adapter and running that. It bumped my oil pressure up by about 10psi. I'm just gonna leave it in and run it.

wantboost

iTrader: (2)

Oil feed diameter doesn't really matter because the oil passage diameter in the CHRA limits oil flow.

Alex Trebek

iTrader: (2)

Unless the feed diameter is smaller than the passage in the CHRA, no? I would think which ever one is the smallest would dictate the flow.

wantboost

iTrader: (2)

Oil passage diameter in the CHRA for the bearing feeds is no larger than 2mm

the thrust bearing gets the largest feed at a little over 3mm but it's feeding a large area so pressure to the thrust bearing isn't important, flow is, since the thrust bearing collar is what absorbs most of the heat from the CHRA. the bearings need pressure and minimal flow to maintain an oil film between shaft and bearing for obvious reasons.

restrictors only limit pressure really, Holsets can handle higher pressures by design since they use much lager shafts, bearings, and a seriously beefy thrust bearing system, after all they were designed for a 500,000 mile service life on diesel engines (same service life as the motor itself). I've literally seen people run Holsets dry and never have an issue. the only problem with their design is you don't get any early warnings signs of a failure... once you know it, it's already too late.

Slacker93eg

I'm having the EXACT same problem, however I am running a -3 feed from a GE sandwich plate. I would love to hear if you find the problem. If I can figure mine out as well, I will let you know. I haven't had the time lately to get to the car. I actually had my car ON the dyno and had to bring it home only base tuned because the oil pressure dropped to exactly what you mentioned. So I had to pay full price for the dynotune that I didn't actually receive. I'm really hoping they don't charge full price to finish it once I bring it back.