Titans need backpressure my A##

14672 Views 221 Replies 33 Participants Last post by DRTYAZN, Jun 3, 2011

deerslayer

Discussion Starter · May 16, 2011

Here is a video from a member on CT. He was running 14.0X forever with 07+ exhaust with 2 spintec mufflers. Now he's running just straight pipe after the headers with 2 14" magnaflows and ran a 13.7. He has NO X pipe or Y pipe on his truck. We argue on here about the X or the Y being better and now we have a member running this....LOL

141 - 160 of 222 Posts

titanss

· #141 · May 26, 2011

giimmelub said:
sooooo if i'm reading your preliminary results correctly.... the scavenging theories and balancing/equalizing exhaust gas theories go out the window when it comes to our trucks??

i was given the advice one time to NOT go the true duals route when i asked about it. found the quote:

would love to know what everyone's thoughts are on that.

the fear, as i understood it, is that our trucks would lose our low end torque w/ true duals. i'm definitely eager to see you prove them wrong! definitely want a report on how the power band shifts.
thanks for guinea pigging, DS! PM me your paypal so i can buy ya a beer :cheers: haha

Pipe size is what kills the low end, no bigger than 2 1/4", any bigger you will defiantly loose low end with duel pipes. The Nismo exhaust is true duel with no X or H pipe. My set up is true duels with a X-Pipe, just look at my numbers, best of 1.81 60' times.

w00t692

· #142 · May 26, 2011

1.81 60'? no wonder you ran a 13.66. My buddy ran a 13.77 w/ a 2.05 60 ft lol.

deerslayer

Discussion Starter · #143 · May 26, 2011

titanss said:
Pipe size is what kills the low end, no bigger than 2 1/4", any bigger you will defiantly loose low end with duel pipes. The Nismo exhaust is true duel with no X or H pipe. My set up is true duels with a X-Pipe, just look at my numbers, best of 1.81 60' times.

Whats your race weight? Idk why everyone doesnt run your set up or a similar setup like I did. You are the fastest n/a non cammed T on earth

Reactions: 1

deerslayer

Discussion Starter · #144 · May 26, 2011

w00t692 said:
1.81 60'? no wonder you ran a 13.66. My buddy ran a 13.77 w/ a 2.05 60 ft lol.

With a titan? What mods does he have?

08crewcab

· #145 · May 26, 2011

no i bet its with a honda si

GTGallop

· #146 · May 26, 2011

I hate to be the proverbial "Turd in the punch bowl" here and I do mean it with all sincerity when I ask this question:

If more/less back pressure (or insert other mod here) improved performance, then wouldn't it be in Nissan's best interest to do that at the factory? Wouldn't they compete better sales wise and move more product? There may be a really good answer here. Thats why I throw it out there. I'm sure cost and ease of manufacture area an answer to some mods, but overall I would expect a Titan to roll off the assembly line and be at its peak performance.

Example - Throttle Body Spacers... If they worked all that well, then why doesn't Nissan make them standard?

08crewcab

· #147 · May 26, 2011

^ well a good performing exhaust works the best with no cats(as we are finding thanks to DS and a few others on our Ts)...so as far as nissan doing that no way it will pass emissions testing. the dealership wants to MASS produce so every corner that they can cut they do...

w00t692

· #148 · May 26, 2011

The way an engines intake and exhaust is tuned is 2 reasons.

1.) movement of torque: The manufacturer will tune intake runner length and exhaust size for moving torque around the rev range
2.) emissions: The manufacturer will add multiple catalytic converters and tune piping size to force the engine to run cleaner to pass emissions standards

It's almost never about maximum power.

deerslayer

Discussion Starter · #149 · May 26, 2011

GTGallop said:
I hate to be the proverbial "Turd in the punch bowl" here and I do mean it with all sincerity when I ask this question:

If more/less back pressure (or insert other mod here) improved performance, then wouldn't it be in Nissan's best interest to do that at the factory? Wouldn't they compete better sales wise and move more product? There may be a really good answer here. Thats why I throw it out there. I'm sure cost and ease of manufacture area an answer to some mods, but overall I would expect a Titan to roll off the assembly line and be at its peak performance.

Example - Throttle Body Spacers... If they worked all that well, then why doesn't Nissan make them standard?

You ever seen the 04-06 stock y pipe???

titanss

· #150 · May 26, 2011

deerslayer said:
Whats your race weight?

IDK, Never had it scaled, Drop the spare and tailgate with 1/2-1/4 tank of gas.

I know there is a set of Cat scales about 20 miles from me, may ride up there on my next set of off days.

O-FiveCC

· #151 · May 26, 2011

I'd say if mine in a CC XE with no spare was 4840, then you would probably be around 4700. Nut sure how much lighter your wheels are

760 Titan

· #152 · May 27, 2011 (Edited)

Gene 5.6 said:
Any backpressure isn't good for an engine. But remember that an exhaust setup is only as good as the other modifications before it. The intake, throttle body, intake manifold, heads and cams all dictate where the power will be made. I thought about doing a 3" true-dual setup on the Titan. But without any other options for an intake manifold/throttle-body the VK56DE is strictly a low-end/mid-range motor. It's not made for high-end performance where a true-dual or any extreme flow system would shine. I also have speculations that the VK56DEK (07+ up motor) might have more then just IVTC in comparison to the earlier VK. Why stick an entirely different cam control system and intake manifold on a VK without opening up the head up a bit? I'll be finding that out soon enough.

So for the VK56DE, I think a 2.25" true-dual (ie. NISMO) would be an ideal setup to retain most of the low-end/mid-range but also gains some ponies in the higher end.

Backpressure is ABSOLUTELY necessary for an engine unless your valves are set up properly to run without it. It's not about how large the ports on the head are, it's about how well the head flows. Look at ANY honda head. the ports are tiny, but they flow stupid amounts of air through them due to the way its channeled through the head. Basically backpressure is needed to help maintain pressure in the combustion chamber. Unbolting your exhaust still wouldn't give you zero backpressure. You'd have to let it come straight out of the ports for that, and I promise you it will run like 10lbs of **** in a 5lb bag. Additionally, saying that "the intake, throttle body, intake manifold, heads and cams all dictate where the power will be made" isn't really accurate. You basically named all the parts of an engine, without the crank and pistons, which are the base of power production. They determine the displacement, strength, and compression ratio of the engine. Internal combustion effeciency and power production revolves around air. Exhaust will shift your power curve, and MIGHT get you as much as 15 ponies, but your real gains will come from finding ways for more air to get in, rather than out.

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08crewcab

· #153 · May 27, 2011

What's your name 760?

760 Titan

· #154 · May 27, 2011

08crewcab said:
What's your name 760?

Dan Waddingham.

ViperPowa

· #155 · May 27, 2011

760 Titan said:
Backpressure is ABSOLUTELY necessary for an engine unless your valves are set up properly to run without it. It's not about how large the ports on the head are, it's about how well the head flows. Look at ANY honda head. the ports are tiny, but they flow stupid amounts of air through them due to the way its channeled through the head. Basically backpressure is needed to help maintain pressure in the combustion chamber. Unbolting your exhaust still wouldn't give you zero backpressure. You'd have to let it come straight out of the ports for that, and I promise you it will run like 10lbs of **** in a 5lb bag. Additionally, saying that "the intake, throttle body, intake manifold, heads and cams all dictate where the power will be made" isn't really accurate. You basically named all the parts of an engine, without the crank and pistons, which are the base of power production. They determine the displacement, strength, and compression ratio of the engine. Internal combustion effeciency and power production revolves around air. Exhaust will shift your power curve, and MIGHT get you as much as 15 ponies, but your real gains will come from finding ways for more air to get in, rather than out.

Nope, your wrong, infact your whole post had so much misinformation I'd have to disect every sentence in order to straighten it all out. Like you saying port size doesn't affect flow. Are you kidding me? That's why nobody ports/polishes thier heads to make it flow more in order to make more power right? You also clearly have no clue what the scavenging effect is and where & how it takes place.

So just to stay strictly on the whole backpressure topic, backpressure is needed in a two stroke engine to prevent unburnt mix from getting into the exhaust. It's detrimental to exhaust velocity in a four stroke engine. Though a certain amount is to be expected, but contrary to popular belief not needed to "make power". You ever hear of the scavenging effect helping pull the intake charge in during the small window of OVERLAP? You think backpressure isn't going to negatively affect that? Backpressure is the bane of the scavenging effect's existence, it has a direct negative affect on exhaust velocity. You should read up on the matter of exhaust velocity before posting in an exhaust thread.

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GregK

· #156 · May 27, 2011

Not to mention exhaust valves burning up.

2011 Titan SV 4x4 in Galaxy black
Added: heated seats, Advent bluetooth, Advent 10" overhead DVD system, PolarStart remote starter, Impulse brake controller, LLumar tinted windows, DiamondKote rust module, graphics, U-Guard SS nerf bars, TrailFX SS rails, Aries SS grille guard, Access rollup cover, Bushwacker Extend-A-Fender flares, Flo-Pro MAX full dual exhaust, factory fogs, air box mod, K&N filter, Bully Dog Triple Dog GT, JVC KW-NT300, MB QUart Reference Seires amps, JL C3 components, Polk subs, Dynamat loaded, PAC steering wheel control interface, tailgate reverse camera, tailgate power lock actuator, hood deflector, in-channel vent visors, KC Daylighters, Rough Country 6" lift kit, D(ick) Cepek 18x8.5 Torque wheels, Hankook 35/12.5/18 tires, Galaxy DX959 AM/SSB CB radio with dual antennas, Reese 16K Pro 5th wheel hitch, True dual exhaust with Flo-Pro mufflers and SS tips, AEM Brute Force CAI and more to come.

GTGallop

· #157 · May 27, 2011

deerslayer said:
You ever seen the 04-06 stock y pipe???

Nope... but I have an 06 so I'll go look tomorrow.

w00t692

· #158 · May 27, 2011 (Edited)

ViperPowa said:
Nope, your wrong, infact your whole post had so much misinformation I'd have to disect every sentence in order to straighten it all out. Like you saying port size doesn't affect flow. Are you kidding me? That's why nobody ports/polishes thier heads to make it flow more in order to make more power right? You also clearly have no clue what the scavenging effect is and where & how it takes place.

So just to stay strictly on the whole backpressure topic, backpressure is needed in a two stroke engine to prevent unburnt mix from getting into the exhaust. It's detrimental to exhaust velocity in a four stroke engine. Though a certain amount is to be expected, but contrary to popular belief not needed to "make power". You ever hear of the scavenging effect helping pull the intake charge in during the small window of OVERLAP? You think backpressure isn't going to negatively affect that? Backpressure is the bane of the scavenging effect's existence, it has a direct negative affect on exhaust velocity. You should read up on the matter of exhaust velocity before posting in an exhaust thread.

True story, scavenging effect is THE sole reason a header gains so much power on my car. The exhaust pulses causing MORE air to be sucked into the combustion chamber with negative pressure causes a good header to be VERY effective.

And also what the hell is he talking about the ports on a honda head being small. I hope he's joking, the ports on the head are quite large actually.

and almost all additional flow through a cylinder head port is not from enlarging the size of the port, but enlarging and improving the area where air comes down the back of the valves.

deerslayer

Discussion Starter · #159 · May 27, 2011

w00t692 said:
True story, scavenging effect is THE sole reason a header gains so much power on my car. The exhaust pulses causing MORE air to be sucked into the combustion chamber with negative pressure causes a good header to be VERY effective.

And also what the hell is he talking about the ports on a honda head being small. I hope he's joking, the ports on the head are quite large actually.

and almost all additional flow through a cylinder head port is not from enlarging the size of the port, but enlarging and improving the area where air comes down the back of the valves.

Track times for straight pipe with dual borlas in just a few hrs

w00t692

· #160 · May 27, 2011

You better run a good time you mother****er.

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