General Supercharger Thread

No, it's 2WD.

 

Ewwww, not so easy. Nor inexpensive I imagine.

 

Ah. I thought that's what y'all were doing. Oh well. Back to saving for the motor build.

 

I believe @Wynnded is correct. Per @ViktorG you can use any transfer case from a sequoia 08-21 with an 07-13 tundra as long as you find one from a sequoia with the same engine; the 4.6 t case is different than the 5.7. The t case did not change for the sequoia. But I guess I will find out for sure as my T case came out of a 15 and my truck is a 13.

 

Your TC come from a Tundra or Sequoia?

 

You are correct, the Sequoia is Aisin right through the end. My suggestion is that Sequoia ECUs from the same model years would be a place to start checking for compatibility.

From what I recall, the BW transfer case series is used in other makes… there are likely many variants.

 

I've saw this referenced before, but the part # interchanges between 4.6 and 5.7L, at least in certain years that I checked before.

 

The input shaft is different/smaller for the A760F transmission that comes with the 4.6.

 

Ahh. I guess I should read for comprehension. Hahah.

 

My used T case for the awd swap came from a 15 sequoia. I think my 4wd computer for the swap is from a 12 or 13 sequoia, though. Might be wrong.

I really debated following Brian’s path and going with an LC case but the sequoia won out, partly due to availability.

 

I'll bet that you'll be fine then!

 

My neighbor had a wrecked sequoia. Thought I was getting a deal on a transfer case...damn its a 4.7 and a750 trans.

 

You could swap the input shaft.

 

Plug and play = Instant gratification

 

Very true!

 

@Jowett I think that if you were able to figure out a reasonable path to AWD conversion for the 14-21 trucks, champagne would fall from the heavens, doors would open, and velvet robes would part in the 2.5 gen forum... You, my friend, would be a connoisseur. Especially among the super charged crowd.

 

LOL! I purposely purchased 2nd gen so I wouldn’t have to go down that road should the decision be made to convert to AWD.

 

I didn't think of that thought they were different units and ecu.

 

Luckily, they all get the big Land Cruiser sized transfer case. Small input shaft to mate to the smaller transmission… if memory serves (lol) everything else after that shaft is the same.

 

I would think just the opposite for a y pipe; they should scavenge just as well at lower engine speeds (below the torque/HP crossover), if not better due to the added bonus of the Venturi effect creating a draw (vacuum) as well as the the friction between boundary layers. The first video partially demonstrates the venturi effect as is causes a vacuum at the second pipe. The headers on our truck us a tri-y configuration to optimize scavenging over a wider range (and packaging is better/easier) vs a long tube header that optimizes a large scavenging effect and torque boost at a specific RPM that is tuned by the length of the primaries and where the collector is placed. Most of the cylinder scavenging should be affected by the headers, and less so by the rest of the exhaust, but low end torque is affected more by the rest of the system. The engine is turning slower, so valves are open longer, meaning an exhaust pulse needs more time via a longer tube to travel down the system and back.


If you look at the second video, you can see the difference between low speed and high speed scavenging. The low speed x pipe has a trailing wave of lower pressure that helps pull the next pulse. This is a venturi type effect where you have a constriction (the exhaust traveling through the middle of the x pipe, which acts as a suction chamber, then is restricted again after traveling through x pipe to rear set of pipes. The suction in the suction chamber helps pull the wave from the other bank.

The high speed portion has a much smaller low pressure tail, but instead "rubs" next to the wave from the other bank. This the two boundary layers rubbing against each other, creating friction to, again, pull the trailing pulse forward. Both have high exhaust velocity, so there isn't much time for a vacuum to form. The X pipe still benefits from both, but more from one than the other depending on RPM. I believe power gains are realized throughout the RPM range on various Engine Masters dynos comparing x pipe to straight pipe, etc.

The H pipe still gains more on the low end in the dyno videos, but the dyno pull usually starts at 3500 RPM or so, so when we say "low end" we can only guess at the trend presented by data from 3500 to 5500 rpm, which suggests bigger gains from the H pipe down low. I suppose this is because the H pipe still benefits the venturi effect in the opposite tube (just as blowing air down one side of the x pipe does in the first video), but not so much from boundary layer interaction as illustrated in the high speed portion of the video.

Going from dual 2.25" factory pipes to a single 3" pipe is actually a small reduction in tube volume, but also a reduction in tube surface area. We should get better flow in the laminar stream (middle of the pipe) with less boundary lay friction on the inside skin of the pipe. Because it is a smaller tube volume, we are creating a small restriction in the exhaust, but not enough to create an obstruction.

Now, this is where some more magic should happen; once the exhaust travels through the y collector and down a small section of 3" pipe, it either enters a muffler, which has a larger volume than the 3" pipe, or exits to atmosphere. Both of those situations create another venture affect; it increases the exhaust velocity in the "restricted" 3" pipe, which comes with a decrease in pressure in that are. Coupled with the decrease in skin friction in the single pipe vs dual pipes, it should still flow very well - comparably to the dual 2.25" factory pipes or better. Dump the exhaust in to a muffler, then in to another 3" tailpipe section, then open to atmosphere, and you have several venturi traps to help increase exhaust velocity and flow.

In theory, anyways....

Edit: I should also add that the long run of the exhaust all they way to the tailpipe should create a wide RPM range of scavenging for the exhaust pulse as there are several points at which the negative pressure wave can travel back to the head to help with scavenging.

 

A quick search indicates that the planetary gear set are the same part number. Most don't want to take case apart but saving over a grand is nice! Ill have to see if he still has it...

 

@blenton don't forget about the inner 2 inch section of pipe inside the exhaust bend. Its there to help low end torque too.

 

New input shafts are relatively inexpensive when ordered direct from Japan.

 

I had no idea. The smaller v8 sequoia t cases go for half the price of the 5.7 cases.

@Mdl - swap input shafts and report back. Do it…

 

I'm a cheap SOB. If I can take my planetary gear set from the Tundra and disassemble the rear case, swap the gear set with input shaft to the 4.7 one, that would be great.
Of course the tolerances would have to be acceptable. Will see if he still has it.

**forgot about gear wear with different sets, so a bit more involved but still worth it.

 

A new input shaft is only $73 + the flight over the Pacific. No seal issues with a shiny new shaft. Input shafts are swapped all the time in the world of Tacomas…. Never heard of an issue with new vs old gears having wear in issues. They get to break in and know each other easily and w/o high loads because they rotate even in 2WD, additionally oil is always pumped through doing the good things it does.

 

Thanks for the info!

 

Stock system is so good I doubt a change to the exhaust system alone will make a huge difference without headers. What is left on the table is so small I doubt it will make a big difference where one design dramatically superior to another.

Based on the responses in the other thread it sounds like it is a wash as it all goes out the window on a supercharged truck (even though NA set ups benefit from headers and exhaust)

The Exhaust manifold article on wiki does state: "The lower pressure tail of an exhaust pulse then serves to create a greater pressure difference between the high pressure head of the next exhaust pulse, thus increasing the velocity of that exhaust pulse. In V6 and V8 engines where there is more than one exhaust bank, "Y-pipes" and "X-pipes" work on the same principle of using the low pressure component of an exhaust pulse to increase the velocity of the next exhaust pulse."

Further down the article also has a special uncited entry for "Why a cross plane V8 needs an H or X exhaust pipe". Tundra's firing order must have a way it resolves the stated issue since the TRD duals don't create this problem. Still looking more into crossovers on V8s just for my own edification.

https://en.wikipedia.org/wiki/Exhaust_manifold

This experiment here used a Y mid pipe design and states that no scavenging is possible after the Y pipe (on that setup).

https://motordyneengineering.com/scavenging-and-the-exhaust-backpressure-myth/

As far as the simulations in the video they do have a few problems in how they are set up. It is really only a good example of how the pressure drops affect the opposing bank. The velocities are too slow, the timing of the pulses are also too infrequent. The inlets and outlets aren't optimal for flow either. Doesn't mean observations from it are invalid but I would expect some behavior to be more noticeable with more realistic parameters.

 

@Saltyhero13 when I spoke with Keith he stated running the SC he would keep it close to stock for best power. I asked him that I was thinking if dumping it at the rear axle and with 3inch duals he said it would lose low end, drone and to just keep it as is.

 

My confirmation bias jumped all over this post.

here's why:

being the Forest Gump of Forced Induction, in the 2 instances my truck was on the Dyno getting tuned, I have not been told my exhaust has been an issue. it's always the intake. Even @~500whp.

I was told:
the injectors were @~85%.
MAF was maxing
Fueling was OK
Cats were probably taking a beating

but never "you need an exhaust."


However - My inquiry into straight pipes was/is purely adolescent. When I go thru the Washburn tunnel (6% grade) all the Mexican brethren sound off in the tunnel.

We grow old, we don't grow up.