General Supercharger Thread

Groovy.

My TRD blower with the URD +2psi pulley, kit supplied airbox/intake with an AFE dry filter will sometimes flash a max of 10psi when the boost gauge is zeroed to whatever elevation I'm at. This changes slightly with all the predictable variables of air temperature, humidity, etc.

 

What gauge do you use? I guess I assumed the boost gauge is measuring in gauge (relative) pressure, so it shouldn't need to be zero'd since it's comparing to the outside. I'm also amazed you've seen 10psi in the Rockies, I got flashed 10psi too but I was in California at sea level.

 

10psi is huge in the Rockies and this excites me!!

 

I'm using the gauge that you recommended, and that I assume you're using as well. I haven't messed with it in quite a while, but I'll try to find a little time to make note of what/how/where/etc. But let me ask you this first. Before you start the engine, turn the key to RUN so the gauge fires up. It indicates zero at your home elevation, right?

 

That's what I thought and why I'm confused/surprised I've never really paid attention to what it said when it wasn't running, but it'd make sense it's reading 0 which is the gauge pressure. I don't think it's calibrating anything, it just isn't seeing a pressure differential between the manifold and atmospheric. If you were at 10000ft and drove to sea level without turning it off, it'd still read correctly since it's just looking at pressure delta, it doesn't know what elevation it boots up at or cares.

I'm more intrigued that you've hit 10psi. What elevation and psi do you normally see? I'm usually lucky to get over 5psi at 5500ft which is why I'm surprised.

 

More IAT crap….

So Houston is at a frigid 50 degrees.

Driving to work I saw the SAME 25-27 degree delta that I see when we are averaging 93 degrees.



I was expecting something different. Dunno what.



Some observations:

When I stopped the IAT rose the same as when it’s 90 degrees outside.

When I got back up to speed it settled down to the 25-27 degree delta.



See, my cranial system would have thought there would be a smaller delta….but, noooooo



It’s as if the I/C system keeps the delta about the same no matter what.



Does this mean the heat of the motor has little effect on the IAT? And the heat is coming from the rotors – as many of y’all have professed.

It’s just fascinating that the delta remains 25-27 degrees no matter what the ambient.

Are these numbers the same for you cold weather fellas?

 

I'm at 8,000ft a vast majority of the time and I'll easily see gauge displays of over 5psi getting onto the Interstate. I have to run to Denver some time in November (probably around Thanksgiving). I'll play around with the gauge more and get some more information on this specifically as I'll be driving at elevations ranging from 5,280 to 11,400. I'll stop and "reset/zero/calibrate" the gauge at these and other elevations to try to determine what I'm actually seeing displayed. I don't recall if there's anything specifically about this in the literature that was included with the gauge. I likely still have it, I just don't know where I stuffed it...

 

I just ordered the Prospeed intake, 2.3 pulley, 750cc injectors and a RCF throttle body. I will be tuning next month, I will let you know what boost number I hit.

 

Interesting. If I drive through Eisenhower I can't even make any boost at all (apparently). I can't imagine why mine makes less boost since I have brand new rotors too. I'll have to inspect the lines and bolts and valve and see if I'm leaking somewhere.

 

In regards to the IATs, I was pulling my 7500lb. camper last weekend in a very mountainous area. 62 degree ambient and going up some very long and relatively steep grades I watched my IATs. It hit 109 part way up the hill and held that steady all the way to the top. This was very long hills, and running 4-5psi of boost at 3-3500 RPMs. Pulled like a champ, but it did reach the point where it didnt get any higher despite the load. 47 degree delta from the ambient, not bad!

 

I think that once I recall what it is I'm changing in regards to the gauge we'll have a better idea why there's such a discrepancy in what we're seeing. I may have the chance to get over to Vail Pass this weekend rather than waiting til November. Then maybe we'll understand more, or at least be on the same wavelength when talking psi readings.

 

that supports the premise that the heat comes "mostly" from the rotors & compression function. good stuff.

I will now stop belaboring the IAT issue.

I will now consider myself learned.

 

heart-on

 

Do you monitor engine temps? I see the engine temperature climb with prolonged boost, only talking a couple degrees but if I get out of boost it drops back down to ~200.

 

Yes I do monitor the coolant temp, but i wasn’t looking at that as closely this past weekend unfortunately. I did glimpse at it on the hills and remember seeing it at its hottest at 206. Even unloaded daily driving though it does seem to hover around 200 like you said. Even at 206 degrees, that’s a 3% increase in temps. That seems pretty minimal I think, considering the extra load.

 

Awesome! The hottest mine gets on a regular basis is 203, and I'll see 206-208 if I stay under boost going up a hill.

 

did they recommend 750cc with the 2.3" pulley? I was under impression 650cc is the good compromise.

I've been debating getting CSF rad for next season, I noticed when towing at max during Summer up a hill it gets near 96c/205, I wonder if changing out our heat exchanger would help too.

 

96C I wouldn't worry about. Where I've had issues (and still do) is the fucking drive through at In N Out sitting for 20 minutes when it's 40C+ in the summer. Unless I turn the AC off the engine temp will climb, and I now have a new fan clutch and a relatively new radiator. With how much shit is packed in the engine bay and having four heat exchangers stacked on top of each other, I can't say I'm surprised, but it'd be nice to get the temps under control. If there's any ram air at all then the truck is fine though.

 

I think it’s not really about 750s being necessary for adequate fuel. Prospeed basically exclusively uses 750cc injectors, they seem to have a particular kind they like. If you want it tuned by them especially remotely, they basically say using their 750s are required. I think part of that is it removes a lot of variables for them, and they have data and experience tuning those injectors so it’s probably easier to get it dialed in faster on multiple trucks. They may also figure if you decide to run E85 then you have more cushion with the 750cc injectors.

 

Worst case scenario you just a smaller pulley from @snivilous

Well....worst case scenario we call up the yeehaa boost exploding engine vid lol

 

Just Lee Roy Jenkins the motor lol

 

Just landed

 

If you could take note of, and even better a picture of the oil drain plug before you put it on if you don’t mind. I forgot to look for that on mine, not sure where it’s located and I’m curious. Lol

 

I don't know where it's located either.. It's gonna be in my garage for a week before it gets dropped off for install. Hopefully someone will chime in and I'll take care of ya!

 

What’s in the Bosch box?

 

Gonna say i/c pump?

 

Got a late start so only got everything torn down and got the new hub pressed on! This was the biggest risk imo since if the hub works I can swap pulleys out and improve them with very little effort, and it pressed on great! The shaft is 0.663" so I think it's good I went with 0.662" (some quick napkin math puts that at ~5600lbf of shaft compression, which would be like 900ft-lbf of torque at 0.5 coefficient of friction, so that sounds like plenty?) I am slightly worried about spinning the hub, but if that's the case I can drill and key it which isn't uncommon on other superchargers. Now would be the time to do that, but I'd like to run it how I'd sell it so hopefully that isn't needed!







I forgot how much of an absolute bitch it is to swap pulleys, if I knew that when I got the URD I probably would've designed my own a long time ago so I would never have to go through this process again. The URD fought me to the end to come off, and then of course you have to pull the blower housing to pull the snout off since the crossover pipe is in the way I swear when I did the URD I didn't have to pull the whole blower but that was awhile ago. Either way, at least the hub is on so (knock on wood) I never have to Jerry rig a harmonic balancer again and worst case it's just unbolting some things! With some luck tomorrow will be the beginning of testing

 

Ah yes. I never go the chance to see my Harrop crate before install as it was shipped directly to the installer.

 

Did you use the urd press on tool to install? I think I still have mine. Also did you need to heat up your pulley to press on? Heated the URD in a toaster oven in my garage for like an hour and it made the press on a lot smoother, on the taco