General Supercharger Thread

This is what I've already towed from 5500 to 10k ft. It did struggle up parts of I70 in the mountains with the RPM's pinned at 4k on some steeper grades. But no overheating or anything on stock engine. *neither vehicles look like the picture anymore either lol

 

imo, at altitude it's not really a battle of superchargers but a battle of aftermarket support. You might be making 7psi with any supercharger, but after making up for elevation really only have 3psi over stock horsepower. You are still making way more power than you're used to, but compared to a sea level truck you're hardly making any power. That might be fine for you, but if you want to actually get the most performance out of your truck regardless of the elevation then you need to look at how to modify the supercharger to move more air and compensate for the altitude deficit. The issue with all the superchargers (besides the Magnuson in the "near" future arguably ) is there's minimal pulley options. A turbocharger has comparatively a lot more boost potential since you can easily (and cheaply) just swap the turbo out, but at this instant that's not an option at all.

Below is my boost chart I made, which so far has been accurate for a Magnuson and otherwise stock system.



As you can see, a stock Magnuson (bottom line) is making the same horsepower at 10,000ft as a stock truck at sea level. Is that a lot more horsepower than a stock truck at 10,000ft? Sure! But there's still a lot on the table as far as what the engine can handle. Is the Harrop a more powerful option or the Whipple? Sure. But right now they have very limited pulley options. You only have the 85mm/80mm/75mm options, and I'd wager the 75mm pulley is still making less power at elevation than a 85mm pulley at sea level.

So I would consider that, my friend is someday (right @M3Tundra-JK and @reywcms ) making a pulley option primarily meant to make up for elevation. Right now I have a 2.0 pulley on my Magnuson, which even at 5500ft where I live is making horsepower barely higher than a stock Magnuson at sea level, and at 10,000ft is making like 4.4psi--but that's a considerable increase over a stock supercharger at those elevations all while the truck is being stressed the same or less than a stock supercharger at sea level.

With all that said, if I was buying a new supercharger I would buy a Harrop, but I'd also end up building smaller pulley options for it with what I know now. Instead, the Magnuson is currently (or will be soon) the only option that allows that much adjustability of the boost level and allows such a large degree of compensation at altitude. But you aren't getting the increased cooling and maximum potential performance of the Harrop or Whipple, and are pushing the Magnuson a lot harder. Food for thought.

 

You can get as small as a 65mm pulley for the Harrop at this moment.

 

Link? I've found a 65mm but it was for the LSA application and the hub is different

 

I would have to find the link myself, although maybe you’re right that’s where I saw a 65mm in use, different application? Not sure, don’t have time right now to look. Maybe later.

 

If that's the case then ignore my huge post and buy the Harrop and slap a tiny pulley on it!

 

I searched high and low! I've found a 65mm with the correct hub that's a 6pk, but we need an 8pk.

 

What is pk? Ribs? Sounds like it could potentially be modified on a lathe easily.

 

That's my understanding. 6pk pulleys are advertised for the BRZ/FRS cars.

 

did you post something?

It was very good info, as I was thinking to put 80mm and otherwise treat it like stage 1, but apparently that's something that could likely happen even with a 75.

And I think I still lean toward the harrop, was just the lowend torque that seemed more tow-handy, thus the blip in my thinking and plea for guidance!

Now, anybody write a book on how to convince wives?

 

Ok...let's expound on this 75mm pulley thing.

with my stock intake, it would probably work fine up until ~4500rpms? then, I would be > 5volts on the MAF. right?

Presently, I don't hit 5 volts till ~5800rpms or thereabouts. and I never go that high.

am i thinking right?

 

I'm just extrapolating based on the graph and thoughts from @snivilous and considering I reside at about 5-6k ft above sea level, I simply won't be pulling as much air (ie boost) unless I rotate the blower faster at a given engine RPM. Therefore , I won't have the same feuling demand until I am producing about the same airflow/boost as stock, which at my altitude is easily 40% less, meaning the smaller 75mm pulley would still not match boost at MSL from a stage 1 blower. So the altitude provides the safety.




Now, should I do nothing else and go nuts with a tiny pulley, of course not, but in theory there is less demand for the feuling at my elevation and associated upgrades. right along the lines as snivelous' post. I will surely get flamed for the thought, and if I blow up my motor on a trip to sea level, clearly that would be on me.

I simply think I could discuss bigger injectors and a 75mm pulley to gain some deficit from my elevation and that would also help my initial thoughts about getting torque earlier.

But, no blower in hand, so for now I just blow!

FYI, don't take my post as advice, and aplogies in advance, lol

 

guess you'd have to test and record what happens at your given situation/elevation and map out what you're getting at WOT like that graph, boost and MAF voltage to really answer your question. But I think we're saying the same thing in different ways.

 

All this talk about elevation. I'm glad to be at sea level with a drag strip a few miles away.

 

Is your motor built?

 

No sir. Factory manifolds and the trd exhaust too.

 

Yes, everything you said is correct. Less air, means the blower has to spin faster and there is less fueling needed since fueling is proportionate to airflow. This is why when I made my smaller pulleys, I made sure I could easily swap them out for a larger pulley in the event I go to sea level. Also keep in mind the supercharger has a bypass valve, so the engine isn't actually experiencing boost until you get into the throttle.

 

I think you can still be happy at 5,000’ with a 75mm on a Harrop. This guy doesn’t seem to be suffering too terribly at 6,000’. I think 538whp 566wtq should suffice.

 

As for the pulleys smaller than 75, you can probably get a 65 somewhere. This guy has a 70 on his. I would try superchargersonline. Just for reference, by the math the 70mm on a 2650 moves 1.2% more air than a 2.0 pulley on a 1900. A 65mm pulley moves 8.9% more. That is per engine revolution. Good way to blow some stuff up!

 

Oh, how he suffers. . . lol

Have you swapped them for a dip down to sea level? No weirdness if so?

 

I have not actually, it's sitting in my glovebox with the allen wrench and breaker bar so I can change it in a parking lot though

But out of coincidence, I am driving to LA this weekend which will be my first foray to sea level since the smaller pulley. If I need to swap to the 2.3" pulley, we'll see! When I went to the 2.0" pulley there wasn't much change that occurred in the tune, since it just flows more air but otherwise is fairly consistent. I'll have my laptop with me, so if I need to go to the 2.3" pulley I'll be able to datalog how it's going, but my gut tells me it'd be fine (maybe not as optimized, but fine) since the truck will effectively just make 80% of the power--similar to driving up to high elevation actually, truck is fine, just less air.

 

Badass! I'm interested to read about your successful findings!

 

So guys with the Prospeed intake, you really gain 2psi of boost with it? I was thinking about that and it’s surprising to me and doesn’t make total sense. If true that alone is a good mod for high elevation guys. If it’s true, in theory I should see an extra .5 to 1psi by going from the stock intake to the Maggie box I would think…

 

I 'm running a 2.3 pulley with the PS Intake, on the highway it holds at 10.5 psi, spikes to 11.3. That has gone down a bit, after my tune the first few test drives spiked at 12.3 and held at 11.

 

What were you seeing prior to the PS intake, 8-9?

 

That's the bad part, I didn't install the a/f and boost gauge until after putting the pulley on.

 

Decent read on this topic actually. https://www.motortrend.com/how-to/1306-boosting-your-horsepower-gettin-air

 

Makes me wonder at level does the Lexus TB become a constraint?

Edit: NM article talks to calculating this.

 

I wish there was an easy way to know the CFM that each intake/TB combo is capable of flowing other than a flow bench. From there it could be determined what sizes are actually needed for a particular HP goal. A 2650 on an 80mm pulley at 6,000 engine RPM moves about 1,088 CFM if I calculated that right.
6.1” crank/3.149” pulley x 2650 = 5,133 cc/rev x 6,000 RPM = 30,800,254 CCM = 1,088 CFM.

 

Harrop stage 1 people please read: I am going to tune @ZPhilip truck, and this morning he sent me a datalog of his Stage 1 Harrop which is stock intake, stock injectors, stock tune, and the 85mm pulley, and he is at sea level.



The first thing to note is at 4000rpm and above the truck is seeing a LOT of knock. It is comparable to the Magnuson, stealing this picture from Viktor's thread of a TRD/Magnuson tune on a Magnuson:


There is more data from the Magnuson test, but the point is that both "stage 1" setups have similar knock issues.

Back to the Harrop:



This is at WOT in 4th. As you can see, the MAF is completely maxed out (stock 3.5" intake). But more concerning is the injectors are maxed out. In this instance the truck is reading 12.2 AFR and the Innovate gauge is reading 12.5 AFR---so not only are the injectors maxed out and the truck is still revving up, but the truck has started to lean out.


This is the first time I've seen logging of a stage 1 Harrop. I'm not an expert, but my advice is do not consider "stage 1" to be a thing. The Tundra at a minimum needs more injector to keep up with the base supercharger. The MAF maxing out, that isn't ideal but can be tolerated. The high rpm knock may be a side effect of lack of fueling, or may be unavoidable with the stock tune.

Luckily ZPhilip has 650cc injectors and a 4" Magnuson intake laying around ready to install. In the mean time I've made a bunch of changes to his tune, and will try to get the knock under control until he can install his injectors---but regardless there's no way to get around that the truck cannot flow enough fuel to keep up with the stock supercharger and that is not something that tuning can fix. With all of that said, the truck is fine before it gets heavily into boost, and I suspect up to 4psi it is perfectly fine, but it clearly cannot safely handle WOT. The stock tune is arguably as bad as the stock TRD/Magnuson tune, with the caveat the Magnuson comes with injectors so isn't as limited in that regard.