Sorry they took so long to design -- I have been very busy over the past several months.
http://www.crank-scrapers.com/prod01.html Scroll down to Datsun/Nissan for extensive description and more pics.
Kevin Johnson
Sorry they took so long to design -- I have been very busy over the past several months.
http://www.crank-scrapers.com/prod01.html Scroll down to Datsun/Nissan for extensive description and more pics.
Crank scraper and windage tray for SR20
Sorry they took so long to design -- I have been very busy over the past several months.
http://www.crank-scrapers.com/prod01.html Scroll down to Datsun/Nissan for extensive description and more pics.
The website home page has some info on this: http://www.crank-scrapers.comiNGEN said:
Older Datsun/Nissan engine designs did not have as much attention to windage control but in designs starting from the mid to late 1980s one can see this trend emerge strongly. The SR20 is very advanced in this respect, for example. The stock louvered tray used in the SR20 in the girdle valley and the tray over the opening to the steel lower sump can be described as windage trays with crank scraper louvers.
I received your email and will disassemble the scraper and take some pics of the parts.
This was made on the engine that your forum member Jeff gave to me and it has a fully counterweighted crank. That design should work with partially counterweighted cranks as well so long as they use the same girdle structure. As an aside, I am working on the designs for the KA24 -- some versions have a girdle and some don't. The SR20 design here presumes the presence of a girdle.
This was made on the engine that your forum member Jeff gave to me and it has a fully counterweighted crank. That design should work with partially counterweighted cranks as well so long as they use the same girdle structure. As an aside, I am working on the designs for the KA24 -- some versions have a girdle and some don't. The SR20 design here presumes the presence of a girdle.
bigtoe said:
There is still plenty of oil that is ejected from the rod journals that lands on the underside of the pistons (I have not looked to see if the SR20 has dedicated jets for this as well).downunderNX said:
There are far more extreme methods of extracting as much windage as possible from engines (see Formula One engines, for example, which use as many as 12 suction ports in their dry sump systems).
Also, modern positive pressure lubrication engine designs do not rely on oil splashing but rather ejected oil landing on the respective surfaces. This is a very important distinction and in these more modern designs any "splashing" is deleterious to both the oil and the engine. Many enthusiasts remember pre-war designs that relied on the rotating assembly passing directly through the sump oil for lubrication.
For example, the two-stage compressor I use in the shop relies on splash lubrication but it was designed in the 1930s. (Automobile engines are in a sense just a powerful air pump.)
Lastly, the engineers at Nissan have themselves made great efforts to reduce windage losses in their engines -- very notably the SR20 -- and use both windage trays and crank scraper technology. It is my understanding that the SR20 has one of the best reputations for longevity and power.
I'm still not understanding this exactly. Speaking of the mods that reduce the rotational mass of the crank:
Lightweight Underdrive pulley is good for about 3-4hp, I would say
Flywheel, I would assume is a little more due to the reduced mass at a further radius from the center of rotation.
Lightweight crank, is only about 3hp or so due to the fact that all the mass is concentrated in a much smaller radius.
So anyway, how would scraping off a little excess oil produce any readable gains?
I agree with the piston lubrication, not all SR20s came w/ piston oil squirters, particularly the USDM engines. Even though you say it is enough, I'm still more concerned about proper engine lubrication than gaining 1 horse from a mod that would prolly take me half a day to install.
Correct me if I have ventured too far away from the apple tree.
Lightweight Underdrive pulley is good for about 3-4hp, I would say
Flywheel, I would assume is a little more due to the reduced mass at a further radius from the center of rotation.
Lightweight crank, is only about 3hp or so due to the fact that all the mass is concentrated in a much smaller radius.
So anyway, how would scraping off a little excess oil produce any readable gains?
I agree with the piston lubrication, not all SR20s came w/ piston oil squirters, particularly the USDM engines. Even though you say it is enough, I'm still more concerned about proper engine lubrication than gaining 1 horse from a mod that would prolly take me half a day to install.
Correct me if I have ventured too far away from the apple tree.
Before I forget, I have the pics of the disassembled scraper. I use several different computers and for some reason the USB link to the camera has decided to act up on the computer I have linked to the internet. Makes me do an extended song and dance to get the images ready. I fit this in while still doing the normal production and R&D. Anyway....
Oil serves multiple functions in an engine: primarily lubrication and cooling. The oil jets that spray on the pistons are usually for cooling purposes rather than lubrication. The USDM models often have lower compression ratios and are not quite so tweaked (speaking generally here about engines rather than Nissan specifically) which lessens the need for such cooling mods.
Because the oil is used for cooling it is advantageous to transfer heat to it and then return it to the sump for cooling as soon as possible. If you allow superheated oil to be recirculated in the windage cloud (roughly what people seem to be thinking is a good thing) that is actually bad for the engine. The oil will be heated up even more as the rotating assembly passes through it at high speed. Remember, the energy used to create this additional heat is subtracted from the energy available to make your car move faster. Hence another advantage of an efficient oil management system.
Sure, you will pick up additional power from removing the mass of the oil that is adhering to the rotating assembly and entrained in the windage cloud (two different phenomena/things). That can easily be one to two quarts of oil (even more if your engine is in a cascade failure mode where the oil is foaming). Weigh a quart of oil sometime. More importantly, though, making the oil system more efficient allows you to push the whole engine system further in power output and stability during extreme movement (turns, braking, accelerating etc.). This is also why oil coolers are so important in high performance engines -- "think systems."
Gotta get back to work...
Oil serves multiple functions in an engine: primarily lubrication and cooling. The oil jets that spray on the pistons are usually for cooling purposes rather than lubrication. The USDM models often have lower compression ratios and are not quite so tweaked (speaking generally here about engines rather than Nissan specifically) which lessens the need for such cooling mods.
Because the oil is used for cooling it is advantageous to transfer heat to it and then return it to the sump for cooling as soon as possible. If you allow superheated oil to be recirculated in the windage cloud (roughly what people seem to be thinking is a good thing) that is actually bad for the engine. The oil will be heated up even more as the rotating assembly passes through it at high speed. Remember, the energy used to create this additional heat is subtracted from the energy available to make your car move faster. Hence another advantage of an efficient oil management system.
Sure, you will pick up additional power from removing the mass of the oil that is adhering to the rotating assembly and entrained in the windage cloud (two different phenomena/things). That can easily be one to two quarts of oil (even more if your engine is in a cascade failure mode where the oil is foaming). Weigh a quart of oil sometime. More importantly, though, making the oil system more efficient allows you to push the whole engine system further in power output and stability during extreme movement (turns, braking, accelerating etc.). This is also why oil coolers are so important in high performance engines -- "think systems."
Gotta get back to work...
Ninety-Nine SE-L said:
Think of it like this;
Stand in a pool with you hand facing front and the palm facing down, now quickly pull yor hand to your hip, throught the water it's harder and slows down right?
Same thing in the crankcase. The oil moves and does come into contact with the counterweights and rods. The windage tray also helps to keep the oil at a consistent level to prevent surge etc.
The oil scraper is an old American V8 trick.
It reduces inertia by wiping excess mass, oil, off the crank, it also reduces windage because the crank does a good job of atomising the oil it throws off. So if you can remove it by wiping it off, then it helps the situation.......big time.
This is not a mod for the bolt on guys.
Every little bit counts and this is truly intended for the racer types.
As far as piston oiling from oil thrown from the crank.............not realy.
The rod journals traverse a sector in their path that takes them almost into the bore with the piston at TDC. The oil leaving the rod journal is slung upwards to the bore, more than sufficient oil.
You also have a thrust face lubrication port in the rod that keeps the bore wall lubricated. Also the Oil control ring pack takes oil into the underside of the piston where it can drain to the wrist pin and the eye at the top of the rod.
Nissan did not intend for a random uncontrolled "windage" to lubricate the pistons or bore.
Again, good product. I want one for my Dry Sump system, I can do with the 1hp gain.
Stand in a pool with you hand facing front and the palm facing down, now quickly pull yor hand to your hip, throught the water it's harder and slows down right?
Same thing in the crankcase. The oil moves and does come into contact with the counterweights and rods. The windage tray also helps to keep the oil at a consistent level to prevent surge etc.
The oil scraper is an old American V8 trick.
It reduces inertia by wiping excess mass, oil, off the crank, it also reduces windage because the crank does a good job of atomising the oil it throws off. So if you can remove it by wiping it off, then it helps the situation.......big time.
This is not a mod for the bolt on guys.
Every little bit counts and this is truly intended for the racer types.
As far as piston oiling from oil thrown from the crank.............not realy.
The rod journals traverse a sector in their path that takes them almost into the bore with the piston at TDC. The oil leaving the rod journal is slung upwards to the bore, more than sufficient oil.
You also have a thrust face lubrication port in the rod that keeps the bore wall lubricated. Also the Oil control ring pack takes oil into the underside of the piston where it can drain to the wrist pin and the eye at the top of the rod.
Nissan did not intend for a random uncontrolled "windage" to lubricate the pistons or bore.
Again, good product. I want one for my Dry Sump system, I can do with the 1hp gain.
A Roadster enthusiast (Sid -- you probably know him) lent me several engines. The earliest one had an empty pan and then a tray/surge baffle was added in the later ones -- probably have a pic somewhere. People were telling me there are some similarities between those blocks and the MGA/MGB engines of the same vintage -- that's true.
Slartibartfast said:
My father (when he was a very young man, and still is, only 47 this year) had a top notch engine builder show him what a crank scrapper can do on a dyno. Back to back runs, one without and then one with a crank scrapper, and the second run netted a 12hp gain. I won't ever forget that story.
Now I'm not saying that you will get that, but they do work. NASCAR uses them I believe.
Now I'm not saying that you will get that, but they do work. NASCAR uses them I believe.
Here are some pics of the separated pieces...
The last baffle that is bolted on the prototype is made of 16 gauge (easier to work with in prototype stage). I will be making that baffle out of 12 gauge in the production ones.
You can see how closely the rotating assembly passes by the scraper -- ~1mm clearance. BTW, it's nice when manufacturers use machined constant diameter counterweights -- makes my life easier and the scraper more efficient.
If you get the scraper alone the studs will not be there, of course.
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The last baffle that is bolted on the prototype is made of 16 gauge (easier to work with in prototype stage). I will be making that baffle out of 12 gauge in the production ones.
You can see how closely the rotating assembly passes by the scraper -- ~1mm clearance. BTW, it's nice when manufacturers use machined constant diameter counterweights -- makes my life easier and the scraper more efficient.
If you get the scraper alone the studs will not be there, of course.
bigtoe said:
A few people have said they saw films of an engine with and without a scraper/windage tray in tech school. It would be nice to be able to track that down.
Yes, they really do work. They work so well that many circle tracks have banned them because they are an unfair advantage.
Yes, they really do work. They work so well that many circle tracks have banned them because they are an unfair advantage.
Peanuthead said:
I was reading about the hassle you got at the border -- I will send you one for no charge (need a mailing address in Canada). Good luck in your classes as well.FastNX said:
This design only approaches the outer face of the counterweights due to the constraints of the girdle -- if you have mods that affect that let me know and I should be able to add extra metal so you can grind it in to fit.
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