Discuss this absurd bullshit (serious input sought, vendors?)

[86GT351]

I had VMP retune my 2010 GT with the Roush M90 blower and tuned for 94 octane ( and no ethanol in it). Other mods at the time were the FRPP twin 62mm TB and the K+N panel filter...and FRPP FRS-500 mufflers. Car ran good.

Fast forward, and in went the JBA LT's with the mating hi-flow catted H section. These are the titanium ceramic coated LT's..... with 1 5/8" primaries and 2.5" collector....and 2.5" for everything else down stream. Car again retuned by Justin at VMP....and again tuned for Chevron 94 (and no ethanol).

Any idiot could easily tell the difference, it was blatantly obvious. This is on my 2010 GT with 5r55s automatic.

Before LT's ( measured on local dyno). 350 rwhp / 320 rwtq
After LT's ( measured on same local dyno) 386.3 rwhp / 376 rwtq

That's an increase of 36.3 rwhp. And an increase of 56 rwtq. The JBA LT's are a lot longer vs kooks etc, so the increase in TQ is shifted further down the rpm scale...which is where I wanted it. 5 psi boost before and after the LT install. The LT's provided for a LOT more TQ, from Idle to redline.

I also looked at FRPP shorties, and IMO, for the expense + labour, the gains were minimal.

That is the general consensus with mod motor cars. The effort and gain don't just fiy themselves with shorty headers.

 

[Dino Dino Bambino]

Guess nobody seen Engine Masters' header length test.
There is way more advertising jargon in here than actual data.

This header test on a 6.0L Chevy engine was very useful though:

Cast iron log manifolds: 474.2hp & 453.2lbft
Mid length headers: 488.2hp & 464.3lbft (3.0% & 2.4% gain respectively)
Full length headers: 494.5hp & 474.3lbft (4.3% & 4.7% gain over cast iron manifolds respectively)

The torque gains from full length headers were particularly impressive from 2900-4500rpm.

 

[JC SSP]

Not sure why this 10 year old thread got resurrected??? But I have been putting on headers on all my cars for over 30+ years.

Regardless if they are shorties, mid/quarter length, or long tubes… for me they always provided some performance increase. Long tubes being the best!

True some vehicles have factory style headers and/or less restrictive exhaust but for me they always provide some power with more pronounced exhaust.

I have said it before. An engine is an “air pump” the more air in and the more air out faster it will generate more power.

 

[Pentalab]

With ceramic coated LT's....(ceramic coated both inside + outside), I'm 90% convinced that since the internal exhaust gas temps are a lot hotter..... they will also flow faster.
After taking the car for a romp, including turning on the blower a block from home, I get out in the driveway, and push down hard on any of the 8 x primaries with my fingers...and don't burn em. They glopped the ceramic coating on good and thick. The hi-flow cats reside directly below the front seats, unlike the oem cats, that reside at the base of the eng bay. Touch any other part of the eng and fingers are burnt asap.

With the oem log / cast iron junk, and oem cats at base of eng bay, the under hood temps were pretty hot to say the least. With the ceramic LT's, and hi-flow cats residing way further back, the under hood temps dropped 40-45 F. ( I measured all of this very carefully years ago).

 

[GlassTop09]

With the oem log / cast iron junk, and oem cats at base of eng bay, the under hood temps were pretty hot to say the least. With the ceramic LT's, and hi-flow cats residing way further back, the under hood temps dropped 40-45 F. ( I measured all of this very carefully years ago).

As did Steve Dulcich in the Engine Masters video that was referenced to by Juice some 10+ yrs ago when he measured the EGT's off a set of ceramic coated headers vs a set of non-coated headers (this video is still available to see thru YouTube......I have it saved in my favorite linked videos on my YouTube channel).

With ceramic coated LT's....(ceramic coated both inside + outside), I'm 90% convinced that since the internal exhaust gas temps are a lot hotter..... they will also flow faster.

+1.........this is basic laws of physics concerning gas modeling dynamics..........why were folks using header wrapping back in the day? This property is what makes using properly sized primary tubed LTH's scavenging capabilities......thus max intake airmass cyl filling using valve OL, max intake airmass charge velocities possible--the supercharging effect & what makes the difference of spooling up a turbo's exhaust turbine faster thus faster boost response or helping a PD blower to load even more airmass charge into a cyl w\o creating higher intake boost pressures (the resistance that is measured during boost).

Was true some 10+ yrs ago as it is still true today...............even though the advent of VCT\VVT has somewhat widened the range of effectiveness but didn't change the general scope of the physics involved.

This same Engine Masters video also came to the same conclusive results found in the Engine Masters video Dino provided using a GM LS 6.0L engine as well.............also some 10+ yrs ago.............using a late 60's\early 70's GM Corvette 427 ci L78 carbed engine.

Now in the video that Dino provided, how many caught what Freiburger said about how the cam timing profile of a cam used in an engine will determine how effective\ineffective a set of LTH's will be...............? Also, that the larger consideration for the vast majority that influences choice is due to fitment, ground clearance & costs criteria & not so much actual engine HP\TQ output............just as was made in the other Engine Masters video put out some 10+ yrs ago as well.

Really depends on how the engine is primarily going to be used & how much of a premium a person is placing on the actual HP\TQ output gains from using LTH's to justify the costs of & installation of LTH's along w\ the issue of EPA emissions compliance when street use is warranted. Also, the actual camshafts cam timing profiles being used should also be factored into this as well..............no sense of installing a set of LTH's on a Ford Mod Motor\Coyote engine that is still using the OEM VCT\Tri-VCT cam timing settings w\ the OEM cams as set by Ford that were tuned to work w\ the OEM exhaust manifolds designed scavenging capabilities the engine was fitted w\ during production. In this case you'd be better off installing a set of shorty headers......outside of costs & installation that is.

This is the main reason why a Ford Mod Motor\Coyote engine needs to be retuned when a set of LTH's are installed.........to redo the VCT\Tri-VCT cam timing settings to take full advantage of the better scavenging capabilities that LTH's provide.......w\ the 4.6L 3V engine this also can mean a necessity to change out the OEM camshafts being used as well & installing cams that their GI cam timing profile is ground\tuned to take full advantage of a LTH's tuned\improved scavenging capabilities thus make more potential peak HP\TQ output w\o sacrificing at all or excessively sacrificing off idle\low RPM available under the curve HP\TQ outputs.....this part is where the use of VCT\Tri-VCT thru TM can make or break this......thus is also where the tuner's knowledge\understanding of engine operational dynamics\capabilities doing the tuning will come into play as the cam manuf's can only do so much w\ their cam grinds........the tuners need to know how to use\input this cam timing into VCT\Tri-VCT to get the most out of them in an engine......across the board, not just during WOT.

I'd post this video but from the last time I tried to do this I seem to have had some issues doing this so someone else should do it in order to bring the right context to this reopened thread...................

My 2 cents.............................FWIW.

 

[Dino Dino Bambino]

Now in the video that Dino provided, how many caught what Freiburger said about how the cam timing profile of a cam used in an engine will determine how effective\ineffective a set of LTH's will be...............? Also, that the larger consideration for the vast majority that influences choice is due to fitment, ground clearance & costs criteria & not so much actual engine HP\TQ output............just as was made in the other Engine Masters video put out some 10+ yrs ago as well.

A set of full length LT headers on an internally stock 4.6 3V with only a CAI, CMDPs, underdrive pulleys, and tune will produce almost identical peak to peak HP/TQ gains in percentage terms to the LT headers in the video I posted.
The stock cams and VCT were already optimized by Ford to maximize torque from idle to 4400rpm. No aftermarket cams, even when optimally tuned, can beat the stock cams in that rev range.
In order to optimize the wave scavenging effect from the exhaust, selecting the correct header primary diameter and length is important. The stock exhaust manifolds on the 3V have runners that are far too short to produce any wave scavenging effect whatsoever. Mid-length "shorty" headers such as the JBA Cat4ward and BBK "tuned length" offer some increase in exhaust gas flow but the primaries are still too short to offer any wave scavenging effect. Three quarter length headers such as the Kooks, Pypes, and MAC offer some wave scavenging effect but the rpm window where that's effective is fairly narrow. Full length headers such as the JBA, BBK, Stainless Works, and American Racing have primary lengths that allow wave scavenging over a broader rpm window and fatten up the torque curve.
That said, none of the aftermarket header designs are fully optimized simply due to space constraints. Our cross plane crank V8s have uneven firing intervals on each cylinder bank and would require unequal length 180 degree headers to optimize exhaust gas flow over the broadest possible rpm range. That simply isn't possible in an S197 chassis, therefore header manufacturers are forced to make compromises.
No such compromises are necessary when it comes to primary pipe diameter though. The stock intake manifold and cams on the 4.6 3V were designed to produce maximum torque at ~4400rpm. If your intention is to retain those items and the 4.6L displacement, you'd need headers that also enhance that torque peak. As it happens, an internal diameter of ~1.50" is required for each primary. The wall thickness is typically 0.060" and therefore 1-5/8" headers would be optimum for a 4400rpm torque peak on a 4.6L. A set of 1-3/4" headers would be tuned for a ~5100rpm torque peak, and that's typically where many of the aftermarket cams (except for the Hot Rods, Detroit Rockers, and Comp stage 1) also produce peak torque.
Your header selection will come down to whether you want a broader, flatter torque curve or a narrower, peakier torque curve. The former would be more suitable for the street while the latter would be more suitable for the strip.