fr0st
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Posts posted by fr0st
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Using cheap fittings is asking for trouble. Same goes for hose. It will end in tears.
There is only one line under pressure, the rest are in vaccuum. The one pressure line only needs to take 150 psi max which isn't really that high for 750psi rated -12 hose.
I'm taking plenty of pics during my build so I should be able to write it all up in a few weeks. If the engine runs for a week and dies then I'm willing to learn from my mistakes and rebuild.
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bare in mind the price of hose and fittings. eg -12's and -16's range from $50-$100 per fitting for anything other than a straight.
hose -12 $40-150 a meter and -16 $50-230 a meter
As much as I want to support local business, these fittings are available at less than half the price on eBay. Considering the local stuff is likely to be made in China/Taiwan anyway the quality is exactly the same. The -12 fittings and hose for my 4 stage come to around $300, I have to get a 2 meter -16 made locally which is going to break my wallet.
Overall my dry sump will probably end up costing around $1500 inc. pump, tank, fittings and hose. The sump I'm fabricating myself. It's not bad when you consider a Nitto pump + collar is around $1500 and you still need a high capacity sump to be completely safe.
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What if it were backward mounted it on a transverse fwd motor?
I was just talking RB's. Dry sumping a FWD just seems... sad
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From what I've learnt lately (I'm building a dry sump setup now) -
- The pump is normally run at half crank speed. This is because normally can only turn up to 5000-6000 rpm.
- The gears in a usual pump are much larger than the stock pump, so flow is not really much of an issue. You will normally get excess flow (which causes increased pressure) and the pressure regulator in the pump will bleed it back into the scavenge stages.
- Stages depends on what you are trying to achieve. More stages means more even oil collection accross the entire engine and more vaccum, it also means more complexity. You can run a two stage pump if you want but you may not achieve the vaccuum or oil pickup evenness you want (because you can't scavenge the head)
- It doesn't matter which side of the engine the pump is mounted.... it will turn the same direction regardless (clockwise)
So yeh, it depends a lot on your wallet and what you're trying to do.
- The pump is normally run at half crank speed. This is because normally can only turn up to 5000-6000 rpm.
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From that thread -
I'm with you, IMO, having a rear scavenge without the factory oil returns is not a good idea and as someone else said earlier, having a rear scavenge WITH the factory returns might not be such a good idea either as you would run the risk of that set of pump gears running with very little oil going through them possibly causing damage to the gears but with the block returns blocked off and a manifold collection of an external "top end" scavenge is a good idea for spacer plate motors.RIPS has a good point here... even the stock external drain is in now way in a position where the oil can pool. If the standard block drains work well enough the head scavenge will get no oil and will eventually wear out the pump.
What's everyones opinion on having 3x sump scavenge instead of 2x sump and 1x head?
R33_racer, do you run a head scavenge?
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Will be very interesting to see the T67 on an RB30 - what fuel? Should be brutal!!
Just 98 octane, it's a regular street car with a touch of insanity
Fairly sure there are no E-85 pumps in Perth... I might have to steal some off Simon once the engine is run in and do a dual map.
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Ordered the T67 for my dry sumped RB25/30. My dry sump pump also arrived today so I'm getting a bit happy in the pants thinking about how nuts the car will be when its done.
Spec's so far are -
RB25DET head
RB30 block
CP Pistons (8.5:1)
Spool rods
Raceline 4 stage dry sump pump
Shortened sump and head scavenge
Greddy inlet
Reinforced/modded china manifold
44mm ext gate
All showhorned into a little R32 GTS-T... should be mental
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Is the standard scraper good enough for use with a dry sump pan? Could you re-fit the same scraper with some perferated mesh underneath and then just modify the sump so it is shallower with pick ups for scavange in the right places?
I was considering doing something custom but there isn't a whole lot of room between sump and girdle to put a proper scraper. The stock windage tray is probably about as good as you can get unless you have a custom girdle with an inbuild windage tray (if anyone wants to give me a massive piece of billet I'll happily CAD one up in Solidworks). I'll have another look at my block tonight but I'm fairly sure it won't work well unless you angle it between the block and girdle somehow.
Something like this would be awesome - http://www.crank-scrapers.com/BMW-M30-DUAL-TEFLON-B.jpg
Who wants to bank roll my CNC machine build?
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I wouldnt run it back to the sump, I would run to to a catch can.
I think you would find the catch can will fill up very fast. There is a heap of oil vapour in a wet sumped engine and the vacuum pump would pretty much suck it all in. It may be good for a few laps around a track but I think it might fill the can too quickly to be viable.
Happy to be proven wrong though, have you got a link to a wet sumped car running a vac pump?
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This is kinda off topic, but has anyone thought about or tried something like a Moroso vacuum pump on an RB?
Not needed on a dry sump setup though.
I was actually under the impression that were used with dry sumps for the sole purpose of pulling more vacuum than a regular dry sump setup (without having a 6 stage pump). I'm not sure how it would work in a wet sump since you are extracting air/oil vapour from the engine then piping it back into the sump, the net effect would be zero.
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I've just found this old thread - http://www.gtr.co.uk/forum/121558-dry-sump-13.html
The conclusion they came to is that the oil draining system in an RB is sufficient once you remove the positive crank pressure and windage by running a dry sump. In a wet sump the crank is normally positivly pressured whilst the head is low so the direction of airflow is to the top of the engine, stopping the oil from coming down into the sump. The reverse is true on a dry sump due to the scavenge pumps, asumming there is some sort of leak/breather in the head, the oil will flow freely or even sucked down into the sump using the stock drains.
I'll be putting the 3rd scavenge on the stock head drain for good measure. If you take into account the above the oil level will probably not get high enough to even hit the return so it will usually just suck oil vapour. In the event of high speed corning or sustained high revs it's there as an overflow/safety measure.
... now I just need to finish building the f#$%ing thing
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So you are isolating the oil return from the head/turbo to the block... why?
It doesn't seem like a bad idea, but it also doesn't seem like it accomplishes anything?
If you went this direction, I assume you would have to drain from the rear of the head all of the oil out as opposed to some oil through the stock external drain?
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Hey all,
I'm putting together a dry sump for my RB25/30 build and had a few questions for the more experience builders.
At the moment I have a 4 stage pump and the plan is cut the stock sump off below the windage tray and weld it up to make it look like this -
http://www.hioctanedirect.com/index.php?main_page=product_info&cPath=67_74&products_id=1828
The only mods I was going to make was using 2 scavange instead of three and to move the oil catch further to the drivers side of the engine. Does anyone have any other suggestions for the sump?
The third scavenge is going to the head, is it best to use the stock oil drain on the side or block the front, remove the big welsh plug and drain from the back?
The head will have VVT, front restrictor blocked and 1.5mm rear restrictor.
The tank will be ~6.5 liters (1.5 gallons). Should be plenty overkill.
If anyone has done this before that can drop some wisdom it would be most appeciated.
Thanks
-Matt
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My head and block is getting machined up at the moment. Apparently my pistons were missing there spec sheet so I did a search and came up with 3 thou piston to bore... thought I just read another thread that said 3.5 thou is the standard. Should 3 thou be fine for CP flat tops?
Cheers
-Matt
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Hey Guys,
I recently cooked my RB20 after my bottom coolant pipe came off during a country trip. The engine got baked hard as I didn't catch it until I could smell it, because it dumped all the coolant the needle stayed at the normal level
At the moment the car is blowing steam out the exhaust and in general running like shit... but its still running. The turbo is starting to squeal so its definately on its way out so I'm a bit unsure if the steam is coming from the turbo or head gasket. Is there any way to tell before I start pulling things apart?
The oil definately has no water in it and the steam seems to be fairly regular and doesn't rise too much with the revs. The car misses a bit but it could also be due to baking the stock coils which were already on thier way out. The engine only has to last another month (or atleast a few weeks till I can ride again) so hopefully some SilverSeal will sort the HG.
Cheers
-Matt
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Is the HX35 easy to obtain in Australia?
I skimmed the thead but couldn't find where you sourced it from. I'm very keen on following your footsteps with my RB30 build.
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Any updates? Should look sweet with some paint
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Hey all,
On the subject of wasted spark ignition I am thinking about making my own ignitor (I have an R33 S2 with inbuilt ignitors)...
I was gonna use 3 N-ch power MOSFETs as the power stage..Each of the 6 ECU ignition inputs would be coupled with small signal diodes...
Has anyone done this before????
Ignitor outputs will be pull downs, so they pull down to ground to charge the coil and then float again to trigger the spark.
To trigger the Fets reliably your going to have to pull the gates to 5v to charge and then ground them to float the coils and trigger the spark.
My advice is make an inverting buffer using discrete BJT's, use this to pull up and down the fets as fast as you can. You will probably only need a single FET, they'll be running at very low duty and will barely make any heat if switched fully on.
Keep in mind if your using aftermarket coils they will probably have a higher inductance than stock so they take longer to charge. Only way to really solve this is to raise the input voltage to the coil when its charging or by increasing the charging time. If your using the stock ECU you can't so the latter, but pulling off the former is feasible with a bit of DC-DC conversion.
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The hard thing is getting the flame holder right, you want it to burn all the fuel before the turbo but not blow out the flame when giving it some throttle.
Here's a good link for a really basic one - http://www.junkyardjet.com/primitive.html
And finally, a good use for a spare set of N1's
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I have a generic engine building question, probably easy an one for you guys but it's my first engine build so I'm trying to get my research done.
I've got a standard 30 block, crank and rods, all are in good condition and don't require grinding. I also have a full set of standard size ACL race bearings.
Questions is, if I simply put them in and torque to spec the clearances will most likely be all over the place and no good?
And, if the clearances aren't right do I have to get the crank ground to match the bearings?
I'm more than likely just going to hand the bottom end components to an engine builder and have them do it, I'd just like to know the process.
Cheers all
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I love the high and mighty "We saved his life tonight by getting him home", "We got rid of a dangerous driver tonight"
Top notch police form!
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I'm on a mission to replace engine and gearbox mounts as a part of a religious experience also known as removing a yellow sticker.
The engine should be easy...
Undo engine mount bolts
Attach engine crane to engine to take the weight
Lower cross member and replace mounts
The gearbox I'm not 100% on and it's also an RB25 box. I was thinking of whilst I have the engine mounts out, undo the gearbox mount and lower the engine slightly with the crane so the gearbox mount can be removed.
Does that sound right or is there a better way?
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Check the #6 injector. Does it tick? Is there 12v present when the ignition is on (and engine not running)?
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Is it a megasquirt with some electronics to suit skylines attached?
Thats how I planned on adding all the features you mentioned to my car using as little money and R&D time as possible, I got majority of the way there too. Open source that bad boy and make all your money on hardware & tuning, people will join you in making it truly competitive to motec and autronic.
Dry Sump System
in Engines & Forced Induction
Posted
You need a motorbike to go with the car. If at least one of them is one the road then I'm a happy man
Well I had 3 options -
Stock/N1 oil pump
Nitto oil pump + extended sump
Dry Sump
The stock and N1 pump sucks. It's pot luck whether they live 10+ years or crack within 2 weeks, I didn't want to risk forged rods and pistons on a $400 oil pump.
The dry sump has every advantage over the Nitto + extended sump. It costs less, it's a more stable oil supply, I can rev higher and I get to learn about designing and fabricating a dry sump. Seemed like an easy decision for me. I don't see how it could be a waste of time, once it's setup it's done. Just stick to regular belt and oil changes it should look after itself and the motor.
In a decent 4 stage setup the sump pressure is a fair bit lower than slightly negative. It's enough to eliminate the head -> sump oil flow issues and the majority of the vapour trail behind the crank. General opinion (from what I've read) is that dry sumped cars rev easier and have better fuel economy due to the lower windage losses. I haven't experienced this first hand as this is my first dry sumped car but I'm looking forward to finding out how the engine feels.