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Displaces 500cc so has to turn 2 times every turn of the engine just to stay even at 2 liters. That would be 12K when at 6K so if you want 7PSI or about 50% more air that's 18K???? Am I thinking this right?

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Mike is that at 1:1 with the drive pulley?  I think you have to take into account the pulley size of the crank pulley driving the blower. 

Edited by obrut
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Yes the output is changed by spinning the supercharger faster or slower by changing the pulley size. Two to one turn of the crank would be zero and supplying 2 liters for a 2 liter engine. To add 50% more air it would have to spin 50% faster or three to one turn of the crankshaft. Fifty % more air should be (theoretically) around 7.5 PSI which is safe on an unmodified engine with hypereutectic pistons.

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10 hours ago, datzenmike said:

Yes the output is changed by spinning the supercharger faster or slower by changing the pulley size. Two to one turn of the crank would be zero and supplying 2 liters for a 2 liter engine. To add 50% more air it would have to spin 50% faster or three to one turn of the crankshaft. Fifty % more air should be (theoretically) around 7.5 PSI which is safe on an unmodified engine with hypereutectic pistons.

Ill be the first to admit, i know half of all that which is to say nothing. I do get how they work. I have read several threads from other datsun forums on supercharging. But i am super obsessed with the idea of running a supercharger on my l20b. And id like to do it with low boost numbers to keep everything as reliable as possible. I figured these brand/models were probably cheap. Im sure id probably need a more efficient blower to make some decent numbers...

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Arm yourself with this knowledge http://www.roadkill.com/supercharge-everything-cheap-blower-shopping-local-u-wrench

 

and couple it with http://datsun1200.com/modules/mediawiki/index.php?title=Supercharger

 

keeping in mind the ability and cost to rebuild a unit (which is recommended for any junkyard forced induction unit) and your on the way.

 

 

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45 minutes ago, 510revisited said:

Ill be the first to admit, i know half of all that which is to say nothing. I do get how they work. I have read several threads from other datsun forums on supercharging. But i am super obsessed with the idea of running a supercharger on my l20b. And id like to do it with low boost numbers to keep everything as reliable as possible. I figured these brand/models were probably cheap. Im sure id probably need a more efficient blower to make some decent numbers...

 

The great thing is there is no turbo lag and boost is as fast as you can step on the gas. There are parasitic losses turning everything even when not using it.  If a blow through set up you can run an inter cooler. 

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So heres a couple questions. If the a12 or 14 can handle reliably 10 psi, can the same be assumed for a bone stock (not mine) "brand new" l20b? Also, why do so many people boost 1200s, and not the l's. Ive read a lot over the past few years on supercharging l's and it seems like one: not many do it, two: theres only two types of people. Nay sayers and yay sayers. Basically you love it or hate it. I want to be different. Plus i just like superchargers more than turbos. And im curious how it would work with the holley sniper. Im not trying to get crazy numbers, and high psi.

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Ive never heard of this about the A series. Continuous 12-14? Possibly with ignition retard, fuel management, knock sensors and methanol injection but I wouldn't run 10 on anything with stock pistons. Most turbo Datsuns were 7 PSI and they can live forever. Chrysler 2,2 Daytona, Ford 2300 all were 6-8 psi.

 

I would get the block O ringed and the ring end gap opened up if going that high. When the pistins melt or break switch to forged ones.

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It does say that, but to get that reliably you'll have to go back and read everything specially spark control and that's just one thing. There's a lot involved in keeping an engine alive as the boost goes up. Maybe someone got away with it but I'm not convinced. A quick zip to 10 the pistons can absorb the heat but running at 10 for any time? Not on a stock engine I wouldn't. That's just me though.

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I was drawn to the IHI twin screw supercharger (in the first link) for lower boost to increase engine efficiency. As said by DatzenMike with boost "ignition retard, fuel management, knock sensors..." are helpful and some of those sensors are also junkyard findable, along with adapting a Ford EDIS. To use this option, I believe you must install a crank trigger ignition. Info on this site on how to run EDIS with L20B. Here as example of what you would need (example is for a 280Z, so not exact match)http://datsunworks.com/page3/page4/

If you use the Ford EDIS it is easiest to use this https://www.autosportlabs.com/product/megajolte-mk2_crank_fired_ignition/

In my weak understanding of these concepts, I believe you would need a MAP sensor integrated into the manifold to monitor and adjust boost, fuel, efficiency

 

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On 5/7/2020 at 8:09 PM, frankendat said:

Here is a guy making a crank trigger wheel out of a Ford and adding it to an L-series pulley to use the Ford EDIS on a Datsun L-series https://www.youtube.com/watch?v=nKD9OeTkFVA

Ive read up on the edis stuff. I was tempted to go that way. I ended up buying a 123 ignition distributor. I can control my timing on a tablet.  I toyes with the idea kf a mini cooper supercharger,  but heard they have a bad design flaw. Some gear, or bearing or something. 

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Forced air edis stuff is intriguing.  There is suggestion of getting something for nothing by adding air and leaning out the mix.(better mpg without sacrifice of power) Of course, there is that nagging voice in the back of my head ...."You can't get something for nothing." 

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On 5/8/2020 at 12:58 PM, frankendat said:

I was drawn to the IHI twin screw supercharger (in the first link) for lower boost to increase engine efficiency. As said by DatzenMike with boost "ignition retard, fuel management, knock sensors..." are helpful and some of those sensors are also junkyard findable, along with adapting a Ford EDIS. To use this option, I believe you must install a crank trigger ignition. Info on this site on how to run EDIS with L20B. Here as example of what you would need (example is for a 280Z, so not exact match)http://datsunworks.com/page3/page4/

If you use the Ford EDIS it is easiest to use this https://www.autosportlabs.com/product/megajolte-mk2_crank_fired_ignition/

In my weak understanding of these concepts, I believe you would need a MAP sensor integrated into the manifold to monitor and adjust boost, fuel, efficiency

 

 

For all the effort you're going to with a megajolt, may as well use one of these instead...

 

https://www.diyautotune.com/product/microsquirt-engine-management-system-ecu-only/

 

You could use it as an ignition only module, add EFI later. It would also allow; boost control; Water injection pump switching; over-boost and lean-out protection, 2 step, etc.

 

BTW, with intercoolers as cheap as they are these days, surely it's common sense to install one at the same time.

 

Re boost and stock pistons. A lot of stock pistons will cope with more than 8psi. It's all in the tune. If you get that right, most pistons will cope with life up to 14psi, but you could do even better. Just make sure, as you said, your mixtures aren't too lean. EFI would help ensure the tune consistently. I watched a heap of guys install "cheap and cheerful" blowthrough carb systems on their ACVW motors only to give up and put EFI on. It's just so much easier to get right. 😉 

Edited by slowlearner
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Slowlearner, much like your handle, I am a confirmed and certified slow learner. Sometimes my refusal to bite the bullet and pay retail has ended in more money and more aggravation, but other times it has worked out well, and so I scrap on. The only reason I have for entertaining forced induction is increased fuel efficiency, and if paying more than salvage yard prices, the dollars saved in fuel are less than the cost of parts. 

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You won't save any fuel with a supercharger. Even driving around slowly on the highway you can't help getting less mileage because it takes engine power to turn it even if not using it. If not using it there's free 14.7 pounds of atmospheric boost so??? A supercharger is simply a mechanical way to ram more gas and air into an engine to increase power. There is nothing for free. Under boost if you gain another 35 horse power there was another 15 horse power robbed from you that you never saw or got to use but had to pay for just to run the compressor. It would be less at lower boost but still a loss you pay for.

 

The closest thing to free is a turbo that uses waste exhaust energy. Same boost as a supercharger will give you 50 horsepower.

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