Dry Sump 2wd Rb.. Cradle Plate & Pickups

[GDZ1LA]

my s15 rb30 keeps having issues when braking at high speed with oil pressure. it drops right off after a few laps with heavy braking. i tried doing a simple mod with a brake bafffle in front of pickup but cant be bothered p1ssing around every month re modifing it till it wourks 100%.. i still havnt used slicks which would really upset it..

ive decided to do a simple dry sump setup with a few additions..

i was thinking of blanking off oil pump with a 10mm plate with oil seal, (std seal with machined crank to sut it 30mm further back... this would give a perfect place to run my 5" 60-2 trigger wheel.behind cambelt. as i wont have much room on crank pully as of ps alt and oil pump.

and making a simple but stong and thick 6-10mm scavange /sump tray it would be spaced perfecly to clear cradle..

and machining flat 14mm seats to cradle with 5mm spacers, so oil can pass under. and tapping some 8-10mmcap bolt holes in cradle to strengthent the bottom end they would be attached to the thick sump plate and into cradle this will streghtent the bottom end from twist and serve as a scavange sump. and would be cheaper than a custom cradle.

i want to run higher hp 700+ one day and have heard the block can get weak at this level. i will also lower engine.. and maybe look at mid mounting engine some day as would have virtually a flat bottom

does this sound doable? how many holes should i drill and where are the safe places in cradle to drill and tap? gtrs have a good 30 6mm holes std whoch dont strenghten so a few "helpfull" holes woulnd hurt would it?

i will use a simple 3 stage pump with twin sump scav.. prob just 50mm from front and 50mm from rear of sump? is that the normal?

any suggestions. is drilling into the cradle worth trying or could i go backwards in strengh?

[R31Nismoid]

What sump do you currently have on there?

[shanef]

if ur going the dry sump route, better to do it properly and run a tank in the boot/engine bay

[r33_racer]

seems like your going to a whole lot of trouble for a whole lot of complication.

What were you planning for the scraper, if any at all?

[1400r]

hyperdrive run a dry sump in there cefiro so they would probably be good people to contact

[r33_racer]

bloudy cefiros and their stupid lower crossmember. So much more room under there for a nice sump pan.

[shanef]

is there any real reason in having a 'nice' sump in a dry sump setup with a tank carrying most the oil, and jsut having the sump with scavange/s so it dont lap on the crank?

[r33_racer]

allows you to run a proper scraper, and a sump designed to catch the oil in the right places to get sucked out with room for inline filters and fittings. Dont know about gtr sumps, but std gtst ones arent too friendly in regards to those things. Plus a new ally one looks the piece

[GDZ1LA]

im replacing modified 2wd one.. i know dry is what i want its just hiw and if i make it attached to cradle is what im consorned about.. and is making a flat bottom (but slightly sloping to exh side) is practical, do i scavange from exhaust side? the natural 5 deg engine lean would help it. and all head and turbo returns are on that side, i would make simple scraper attached to cradle.. therfore very little oil would return on intake side of sump

Edited June 19, 2007 by GDZ1LA

[Fitzpatrick Speed Works]

You definately dont scrap from the exhaust side, that would be a fatal mistake for your engine.... YOur engine spins clockwise spitting oil off the crank into the right side of the sump not the left (exhaust) you would have bigger probs than you have now.

Not trying to be rude or having a go but the way you have explained things sounds like you need alot more knowledge before attempting a dry sump setup, I can appreciate thats why you are here asking questions but to do a proper dry sump setup requires a fair bit of understandin especially relating to RB's. There are many things you can do to make it work better than you have proposed like secondar oil feed to ensure even dispersion of oil pressure to all 6 main bearings, and also ensure even scavenging. As mentioned there is scraper design, quite cruicial, also vacuum can be achieved. I would recommend highly a 4 stage as to scavenge out of the head. THe tank design and placement are important, you cant beat a moroso or peterson tank as they de-airate the oil as well. Crank case ventilation needs to be more than adequate especially if running vacuum. I dont recommend your idea of running the belt behind the balancer either as the pump will sit too rear wards and foul on the engine mounts.

A good 10 litre sump and proper trap doors will fix you problems I can assure you, maybe an option as the dry sump route is definately an involved one to do correctly.

Edited June 19, 2007 by Fitzpatrick Speed Works

[EVILS13]

hyperdrive run a dry sump in there cefiro so they would probably be good people to contact

Just to let you know its not Hyperdrives car its Borneo and all work was done by Lumpy (Glenn Campbell) in our workshop in Wanagara

bloudy cefiros and their stupid lower crossmember. So much more room under there for a nice sump pan.

The Cross member in the ceffy is an R33 crossmember the dry sump pan is pretty much flat across the bottom of the block except for 3 suction pick ups. The Tank and system and sump hold about 15 litres of oil.

[T04GTR]

yeah someone just pm me the technical drawings kthanx

[r33_racer]

really...i didnt know it was changed to an r33 crossmember, glenn never mentioned that to me last time we spoke. But i know about the sump. There are many photos on my comp of it. Only thing about glenn's setup that i didnt like too much was his lazy attempt at a scraper, not being rude its more in jest but a proper plate with louvered wings facing towards to the exhaust side would have been better to break the vaccum, think i mentioned it to him at somestage. Doesnt matter anyway, but he did a good job setting it all up, and its a nice sump and the car is nice also...i could sure steal that motec dash he put in along with that strain gauge he was talking about for the flat shift......*drools*

Edited June 19, 2007 by r33_racer

[Chris Wilson]

I'd run a scavenge section for the head, too, myself, and get around the lack of drain back the RB engines suffer from.

Let us know how you get on, I too am considering dry sumping a 2WD car with RB26 engine. I came to the same conclusion re blanking the front of the engine off, although I believe you could use the tomei pump as the pressure side, and belt drive just the scavenge sections. I think I'd go for remote pressure and scavenge sections though at the end of the day, so pump overhaul isn't a sump off jobbie.

[Sydneykid]

I will go with what Michael and Fitz have said. Dry sumping is good, but it COSTS and requires some knowledge and considerable fabrication skills. I have been involved in several dry sump set ups for GTR's over the years, due to the design of the 4wd sump, they really need it. But not so much so in a 2wd application. For example, in my own R32GTST I run a High Energy 8 litre wet sump on the RB31DET and I have never had a problem with oil surge.

I would like to comment on this;

braking at high speed with oil pressure. it drops right off after a few laps with heavy braking

That doesn't sound like oil surge to me, more like you haven't sufficiently limited the amount of oil getting to the cylinder head and/or improved the oil return to the sump. On the straights, the high rpm is pumping too much oil upwards and it isn't returning to the sump fast enough, this lack of oil in the sump manifests itself under brakes. That is where I would start looking, limit the flow and improve the return.

cheers

[GDZ1LA]

I would like to comment on this;

That doesn't sound like oil surge to me, more like you haven't sufficiently limited the amount of oil getting to the cylinder head and/or improved the oil return to the sump. On the straights, the high rpm is pumping too much oil upwards and it isn't returning to the sump fast enough, this lack of oil in the sump manifests itself under brakes. That is where I would start looking, limit the flow and improve the return.

cheers

i have a 1.3 mm restrictor on a std gtr pump with collar.. with std oil returns

ill try add a larger sump with gate for braking.. as soon as i accel it returns stright to normal.

next time i rebuild ill overside the 6 oil returns to say 9mm.. i dont want a external return if i can help it

[r33_racer]

you really should have the external return. Why would you want a dry sump setup, yet not one external return. You do realise with the setup there will be quite a few lines running everywhere?