General Supercharger Thread

What kind of boost would you expect from those sizes?

 

The DW have had zero issues on the old man’s rig.

Also boost update here in Vegas. Seeing 8.5-8.7.

 

DW's here.

flawless @ 9.5psi

 

I had posted something and it was totally wrong I realized, so if you saw that post ignore it! This one should be "closer" to real.

This is an extremely preliminary extrapolation I did based on @Wynnded saying he made ~4psi at ~7000ft (bottom right yellow cell), this also projects close to what @carn_dogg said about making ~9psi at ~sea level, so I think the 86mm (stock) size is pretty close. Up and down (altitude) on the chart is pretty consistent with air pressure. Where it gets more complicated is pulley size isn't linear to boost in my experience. For example, my 2.0" pulley which is ~13% smaller than a 2.3" pulley, generates ~48% more boost. Using numbers I measured before and assuming the 2650 has a similar efficiency curve, I came up with the orange cells on the left. The 77.5mm is ~10% smaller, but generates ~32% more boost, and the 70mm is 19% smaller and generates ~50% more boost. Both of those assumptions are loosely based on the Magnuson 1900 data I've compiled, but without someone actually testing one of those pullies and giving me numbers, it's all a guess.

With that said, I would think these are pretty close within a psi or two. The values on the left (Raw Output) is how much boost is the blower actually creating, the values on the right (Sea Level Equivalent) is taking the Raw Output and subtracting the boost used to make up for elevation loss. How I think of it is Raw Output = supercharger stress, Sea Level Equivalent = engine stress (and is what your boost gauge actually reads).

 

Im anxious to see the results I'll have with the lighter pulleys going in if this will effect boost at all. Less engine rotational mass less boost?

 

So is magnuson under-rating the 2650 when they say it makes 7psi or is there that much variation between individual setups?

 

I never saw over 7psi on my 2650 with the 85mm, granted I live at 800’ and my boost gauge only reads in whole numbers. Don’t know if it shows 7 if it’s 6.5 or greater, or if it actually needs to hit 7 to show 7. 9 psi sounds high to me unless it was an exceptionally low DA when that was seen, perhaps combined with terrible flowing exhaust.

 

How are you liking the 77.5 pulley when towing,I have not installed Mine yet just waiting to get it back from the body shop after the deer strike.......did you returned or just slapped it on

 

I like it a lot, not that different than the 80. It’s more of a difference you notice more at WOT without a trailer hooked up. Every time I try WOT lately with it installed and this cooler weather it feels like it pulls noticeably harder than it did with the 80. Takes me by surprise sometimes. I didn’t do anything with my tune, I just put it on and monitored my LTFTs, AFR, and Knock. I’d like to get a proper log to see the MAF readings and injector duty cycle still.

 

Funny you guys talking about 9psi, boost I'm an old guy haven't seen over 6 yet...trying to knock Nobodyintexas out of the slow man spot....haven't even done WOT run knowing my luck I'll break something.

 

Oh man, you have to even if only for a few seconds (that’s typically all I ever do).

 

Maybe I'll man up soon but if I break something gonna wine like a little girl

 

You won’t break anything lol. But look at it this way, if something was on the verge of breaking wouldn’t you rather find out now instead of when you’re towing your camper 500 miles from home? Don’t forget, Toyota used to offer the tundra with a dealer installed and factory warranted supercharger. It’s not like you’re operating far out of the engines design criteria if you’re properly tuned and providing enough fuel.

 

it won’t break

it sounds glorious

85mm was good
80 was better
77.5 appears ideal

 

and sea level with soupy ass humid cool air is the cherry on top

 

On the matter of bypass valve controllers, another find:
https://impulsetuning.com/supercharger-bypass-controller

Instructions:
https://pettysgarage.com/pdf/308046

 

I'm being told by my tuner that I should be running E85 based on my desired pulley combo.... im looking for some feedback.. its a built motor and fuel system with new 2650 harrop. thanks

 

its not a FFV truck

 

If you tune for it to take advantage of the higher average octane, you could do an E30 mix.

Run a tank of straight 91 or 93 every 3mo or 3k miles or so, to clean the fuel system.

 

This is interesting

what controls the actuator?

 

Being not FFV, unless you're running a Motec or something else that has an ethanol sensor and adjustable maps, that's a horrible idea. I've heard that pump e85 is all over the board as well for ethanol content.

How small of pulley are you planning?

 

70 upper

 

xat harmonic balancer with their 7" overdrive diameter pulley on bottom

 

Are they seeing something that they are basing that on (needing E85)? Are the IATs on the high side with the smaller blower pulley and 7" crank?

 

I reached out to these guys to see if they have an ETA on these:

https://www.aesinnovate.com/product-page/3ur-runner-kits-v8-5-7l

 

Looks like boost and pedal.

 

pedal would be awesome

I’m not remotely smart enough to make that work.


I have my parts ready to make a small light come on when the bypass closes.

I just need to save up some cuss words to do it.

 

the tuner i think is thinking because I'm running stock compression (should have led with that) that it would burn cooler. less potential harm on motor

 

Pulleys ordered for Magnuson 2650, 6x of both sizes. They'll cost $100 a piece I'm thinking.

 

Nice find. Bookmarked.