General Supercharger Thread

Agreed, I tried to get the right (correct) rotor. The world conspired against me.

 

*too OCD . . .

 

Yeah, no shit. Seems they dont want you to install that BBK.

 

OK grammer police. Not "too" OCD when it comes to grammar. I is a high school graduate though.

 

How many of you have cat-backs on your trucks? Debating a DD 12 that's near me. As I get older I am not a fan of drone or loud systems. But have been reading up and the DD 12 seems to be as quite as OEM until you get on it.

 

I only deal with stuff that goes up, so convection has never once been mentioned for anything

 

I have a DD catback. Keith is great to deal with.

 

I have this exact system on a regular cab, with Helmholtz resonator there is no drone at any rpm range. Sound is objective right, but to me it's a good blend of you know it's there cruising around town, but without being obnoxious/loud, and yes when you put your foot into it you get the great V8 sound. This coming from a RCSB, so depending on your truck cab it will be even more quiet.

 

next month im gonna do a dual 3" , x pipe and carven R from first cat back. second cats are already gone. want that rumble in the jungle

 

You may lose a little low end torque but the SC will flow a bit more air.

 

Had carvens before but with 2.5 “to a single exit. sounds like this

https://www.instagram.com/reel/CwJ-GOBvhND/?igsh=dGFreXFnY2ZlaDlo

 

i thought you gain when you open the exahust?

 

Depends. The engine needs back pressure, depending on exhaust flow.

 

well itll be stock from engine to first cat.

 

True, but apparently it matters through the whole system. There's plenty of people that have said, going to a cat back system with a bigger diameter pipe has cost them low end TQ. Me personally, I would like to keep all HP/TQ and not lose any. This is why if I do a cat back it will be a DD. You actually gain HP/TQ according to Keith.

 

looking at their exhaust system it doesnt look any different honestly

 

Whos? DD exhaust.

 

yes

 

Much more free-flowing is DD, yes.

 

Well, according to everything I have read, he spent the time to actually dyno his exhausts to get the best possible outcome. He didn't just slap together some pipes and 2 muffler cans and call it a day. This is also a reason why he went with the dual muffler setup, better for HP/TQ. He also took the time to figure out how to completely get rid of the drone. Me personally after having multiple cat back exhausts, I cant stand drone anymore. So this is a big plus for me.

 

I’ve been driving around on this DD replacement TRD dual with an X pipe. Ironically it feels like it lost gear holding torque compared to my true dual TRD duals. I notice it unlocking the TC sooner. I think I’ll be switching back to TRD both for sound and torque. It sometimes feels more responsive in the 2-3k range, but not always. WOT seems to be about the same, may even give the nod to the TRD. I think the SPD midpipes and TRD catback will be just right for me, if I ever get them installed.

 

You could call Keith and talk to him. Since 2010 his research has changed a little bit. Especially concerning exhaust with supercharger and added modifications. To keep velocity and scavenging in check he likes the 2.5 inch exhaust with a pretty much stock system. Open up the airbox to 4.5 or 5 inch then that will support the air pump(SC) flowing more for a 3 inch exhaust.
His posts on exhaust in tundratalk from 2012 has changed a little bit with more info. https://www.tundratalk.net/threads/...61632&nested_view=1&sortby=oldest#post-961632
But I'm rambling trying to remember when I spoke to him a few months ago.

 

i need to up my fuel parts before i open up the intake as im already pushing the limits of my injectors.
most my exhaust, as i measured, is still the stock piping 2 1/4 into a single in 2 out muffler. i removed the rear cats.
i was liking the sound of the 3" and carven r.
maybe others can chime in and input on a a 3" or 2.5

 

Best thing is to call. Even if you don't buy he will answer your questions and steer you in a informed direction. He likes talking Tundra.

 

yeah i dont like the phone lol. im not buying a kit. im gonna get universal piping and add the x and mufflers. be putting it together myself. "budget guy" lol

 

from everything im reading the power our trucks make with the SC, the 3" would be best.
where NA engines need that BP more than forced induction

 

When I was talking about BP, I meant it NA. You probably are correct on that the SC would probably benefit more form a larger diameter pipe.

Edit. I was just looking into this and apparently SC engine suffer the same fate as NA engine. If you dont have enough BP the you lose HP/TQ. So maybe 3" might be an over kill.

 

I think the answer to a full header exhaust setup and loosing low end power is just a smaller s/c pulley

 

Maybe the best bet would be to split the difference and do dual 2.75” exhaust, or 3” for a single exit.

 

As I understand it, back pressure is not helpful to any motor. What is often attributed to back pressure is actually scavenging and exhaust velocity; a smaller diameter pipe creates higher exhaust velocity at low speeds (fixed exhaust passing through a smaller opening means the exhaust must flow faster; put your thumb over a garden hose and the water sprays out faster), which contributes to better scavenging and exhaust evacuation, increasing torque at lower RPMs. Scavenging is the effect of one exhaust pulse pushing through the tube at a positive pressure, creating a negative pressure wave behind it; that negative pressure wave pulses back to the cylinder head in either constructive or destructive interference. Pulse timing is affected by both tube diameter and length. X pipes and H pipes work on the same principle in a constructive manner; helmholtz resonators do the same thing but as a closed ended tube create destructive interference to larger specific exhaust frequencies without interfering with flow.

The reason Keith recommends leaving the stock mid pipes, which are smaller than optimal for exhaust flow, is because they are tuned well for scavenging pulse as well as keeping up velocity at low speeds due to the smaller surface area and insulated double wall exhaust pipe in the mid pipes. The double wall increases heat retention of the exhaust to prolong exhaust velocity along the exhaust track. As exhaust cools, it loses energy and slows down. The smaller mid pipes and overall system tubing retains the factory engineering, despite being undersized for the horsepower output fo the motor, and thus retains torque. *ASTERISK*

At higher RPM, the exhaust pulses are stacked on top of each other since there are 10 times the number of combustion events per second at redline than at idle, so scavenging is less important - almost irrelevant. So higher RPM exhaust flow is just about that - flow. Bigger tubing makes better flow, more power, and more efficient operation. A free flowing muffler contributes to better flow than the restrictive, stock unit, so you can get better power delivery in the midrange with a free flowing muffler and factory mid pipes. But you don't get much on the top end. Look at the dyno graphs of most cat back exhausts and you will see midrange gains with very little low end or top end gain.

So why did I put a large *ASTERISK* at the end of the paragraph earlier? Because you rarely loose torque on the low end with a larger exhaust; you just shift the power band up in the RPM range. It creates a bit of lump in the power delivery, making the lower RPM's "feel" like you lost power since you gained more power right above it. Engine masters, for example has show this time and time and again with exhaust dyno comparisons. Yes, their motors and usually cammed and tuned for top end power, but the results are typically the same: low RPM power doesn't change much, mid RPM or high RPM will change more-so. A DD system retains factory low end with factory mid pipes for scavenging, gives a little more mid-range from a free-er flowing muffler, but doesn't do much of anything for the top end because the exhaust is still undersized for a supercharged motor (and borderline/considered undersized for the displacement/horsepower of the factory 5.7L).

A larger diameter exhaust will flow more exhaust, make more power, and increase engine efficiency at most RPM. You may feel a loss in low end due to the increase in mid/higher RPM flow. Larger exhausts will typically create more noise, as well, which is the only reason I haven't made the jump to change up the mid-pipes yet. Not that I am the expert on the matter, but that's what I have garnered from an... EXHAUSTIVE... deep dive in to the subject.