General Supercharger Thread

On 34.5” tires and stock gears I find my truck shifting into 6th even at 50mph going up hills on the back roads in my area. I’ve found all my gears to be fully usable at the speeds you would expect to be using them.

 

I'd agree with that use case, but where I live most of the driving I do is either 80mph speed limit interstates with lots of elevation change, or the slower roads are still 55-65mph speed limits going through the mountains (Utah has an obsession with high speed limits, a nice perk of living here ). Certainly the elevation change isn't helping, but that combined with the high speed is the real issue. That's one of the motivating factors to figure out supercharging the wife's GX460, the "big hill" between us and our friends the GX can only do the speed limit if it's in 4th gear screaming, where as the Tundra can do it in 6th gear without boost usually. Obviously the 4.6 is a far cry from the 5.7, but point being that trying to maintain 80mph over mountain passes is my baseline and brings vehicles to their knees. Hell on 4th of July there were three vehicle's that caught fire on/near that grade

 

In my experience the faster I go the higher the RPMs are in 6th and the more cruising and gear holding power I have. If I’m doing 80 unloaded then I’d probably be near at least 2200-2300rpm in 6th (I’ll have to check) and mine will pull hard at light throttle at that RPM. For example when I’m towing the camper (usually in S5 on the highway) I always wish it were safe to pull at 70-75 for prolonged periods. When I sneak up to those speeds to pass other vehicles, the gear holding power is immense in that 2300-2800 rpm range in S5 with the converter locked. It may grab a couple lbs of boost on hills but it just wants to go, and that’s towing a 7500lb 32’ wind sail.

 

The elevation definitely makes gears make sense. When we came thru south Utah into SLC towing our little teardrop trailer, it was all over gears to maintain speed (wasn't SC then)

Flat land in TX and around OR: SC, 34's, doesn't need gears and just hums around locked in 6th.

 

Damn I was doung 70 sometimes 70+ pulling my camper. Im still stock gears (as far as I know lol bought the truck lifted)

 

N/A these trucks definitely don’t have great gear holding power. Maybe it can be improved with tuning the shift points in relation to throttle angle somehow, but I’m also not sure if the power is there or not, or if it’s mostly trans tuning related.

You “can” tow at 70+ but it’s usually not considered the safest practice especially with a half ton. A tire blowout or something could result in it being tough to control. A lot of trailer tires are barely rated for that fast also. Some are rated at only 65mph, some at 75.

 

I was surprised that using HPT tire wizard for shift points really smoothed out the shifting. But I also haven't been plagued with the wandering some people complain about. Could have been the programming in my '07.

As to towing, the Tundra SC'd with a 2,500# teardrop loves 85 across TX.

 

I played around with different shift points and torque converter settings. Especially when trying to get the 95mm TB setup. After @snivilous setup the airload and torque levels. I kept some of the settings especially the torque lockup release and some shift points by 100-200 rpm.

 

You should def hit me up if you're ever up this way. Happy to meet you along your way so you aren't losing too much time, but you def should experience the 5.29s.

 

Don’t get me wrong I love my super charger but I still think the 5.29s was definitely the best upgrade for my truck.

 

It’s more likely just a matter of time until my tundra goes from the tow rig to the fun toy/dirt drag truck if I keep it around. With this in mind I can’t see dumping a couple more grand into gears at this point, but maybe I’ll dive in at some point anyway if I have cash laying around. It already tows better than I could imagine any gas truck towing. Unloaded acceleration wise, there appears to be no advantage to 5.29s based on our dragy data.

 

I was thinking 5.29s with my 35s because of the mountains etc we travel through going to oregon and back but also read a lot that 4.88s would be better.
In not trying to make a drag truck neither lol

 

There are some nice factory gears that will help that GX, too.

 

Well I just had my 2nd serpentine belt eaten by my AC pulley clutch with 90 deg weather. Not sure if it's my belt tensioner causing slack when I get on it. Luckily I was 5 miles from home and had my e-fan on. But...it boiled right when I pulled in my driveway.
Hopefully its ok. Temp came down right after I shut down and kept fan on.
Ordered another HD Gates and tensioner...freaking uncool!

 

I need a bit of clarification.

The temps came down after you shut off the engine, but continued to rent the electric fan?

Isn't the temp sensor in or near the radiator hose inlet connector?

If so, the only thing you cooled was to the radiator? The engine was only able to cool very slowly because no coolant was flowing thru it because the water pump was not circulating.

Please educate me, I'm here to learn.

 

Yeah you are right. Having the fan run on high speed was cooling the radiator and external front of engine. So she was still pretty hot. The engine oil didn't go over 180 from my oil cooler.

 

So the

$38 Gates k081124HD FleetRunner Micro-V Serpentine Drive Belt

Gates k081124HD is not reinforced like the Dayco 5081125 or the TRD PTR belt, same company? The Dayco is reinforced with wire radial wound type... Looks like is just separated under load?

 

I've seen 235 water temp on my SGII while pulling the RV up a loooong mountain pass, yet the dash gauge to showed normal, so I'm thinking our 5.7's can take an extra 50* north of the 200 normal temps.

I'll admit I was very unhappy seeing those temps and the wife was well aware how upset I was...hence she asked what could be done to help.

My comment: we need another 100 HP via a supercharger or we sppending 80 grand for a 3/4 ton truck.

Hence, the supercharger sourcing project had began.

 

Are you running a small pulley? I don't know if I've ever seen such a clean belt failure. Is the smaller radius causing premature failure?

Again here to learn.

 

I don't think the smaller radius is causing it. @snivilous and @Fastlane47 are running the smaller pulleys without incident. My first failure was an older Dayco with the cable reinforced belt. It was wrapped up inside my AC clutch.
I ordered another Gates and New Old Stock Dayco. Will run the Dayco with Gates as a backup.

 

I run the TRD pressure cap, 18psi. Toyota red coolant with water wetter and have an engine oil cooler. Just to keep things on the cool side. I like serpentine belts but there is no backup when it let's go!

 

Check all your pulleys to make sure you dont have any burs. If youve got through a few belts already something may be cutting into them forcing them to snap

 

I looked them over and didnt see anything that stood out. The only thing I can think of is under hard acceleration the tensioner could be giving slack or?
The first one was from a seized idler pulley bearing.

 

Did it ever do this before the small pulley? Is this the first belt to shred on the small pulley? Have you ever replaced the tensioner?

 

The first belt, Dayco, was on the 2.3 pulley. I had the SC idler pulley seize up and belt shredded.
This Gates HD belt on the 2.0 pulley snapped after I went about 50% throttle. The belt was 6 mos old. No...tensioner had 130k on it! New one is on order with another belt.
I believe it may be the tensioner.
The belt is smooth and has a pretty clean break. Defect with tensioner?

 

Hopefully! I always tell people to run a new belt if stepping down pulley sizes just to remove any stretch from a large pulley. Would make sense that a tensioner that has been worked hard with a tight belt could have issues keeping up when there's less tension on the belt. Plus couple that with the small pulley loading up the belt harder from driving the blower so fast. Seems plausible it's making the tensioner slap and shock load the belt.

 

Thanks! The belt was about 4 mos old going to the 2.0. I'll check out the condition of all the pulleys and swap out the tensioner!

 

You may have said this, how many miles on the idler pulley?

 

At the time about 125k. I'm slowly replacing hoses, etc.
After seeing @e30cabrio post about replacing hoses etc. I started to think about high mileage parts to replace. Ordered up some silicone hoses and other consumables.

 

Hopefully when you check pulleys and accessories tomorrow something will turn up. If not a stethoscope or long acetate handle screwdriver may help you hear a bearing starting to go.