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Mack AI460 AI427 AMI low torque low horsepower poor fuel mileage granite , dead dog , remediation

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Posted (edited)

Can you tell me 

years and size of engine with non restrictive manifold, just to be sure and buy the right piece 

to fit on mack CT 713 2007 AI 460

thanks 

 

Edited by Sparksracing

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Posted (edited)
16 minutes ago, Sparksracing said:

Can you tell me 

years and size of engine with non restrictive manifold, just to be sure and buy the right piece 

to fit on mack CT 713 2007 AI 460

thanks 

 

The part numbers are one page back...…..

Ends are 21090679 (104GC5164M-old number) $284.06, of which you need 2.

Center is a 21090730, $203.99 (Both 104GC5165M3 (high temp center) and 104GC5165M (regular application) supersede to same number.... 21090730).

 

If you use PAI the end pieces are  EEX-2054   Quantity 2  (ends)

                                                             EEX-1848   Quantity 1 (center)

Edited by Mack Technician
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Isn't the center section where turbo bolts on slanted on the CL's if so you will need a different part number

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Never mind I see he asked about CT not CL

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Posted (edited)

 

This is a CL713, W/Slant turbo (flash back to how trucks use to be built for accessibility...…). 

 

2000 MACK CL713 at TruckPaper.com

 

 

 

This is a CT713, no slant.

2006 MACK GRANITE CT713 at TruckPaper.com

 

2006 MACK GRANITE CT713 at TruckPaper.com

Edited by Mack Technician

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I wanted to list Sparksracing's (above) comments. He burned out an AI manifold and needed to replace it so he put the E-Tech manifold on his Aset and ran all original parts in tandem with a Programmer (he said Pittsburgh brand). The transition of surface mates can't be smooth, but its a mate.  Right off the line he blew his tube boot off and the thing went to smoke, hence the black tar seeping out the gasket. He got things straightened out and from his observation it sounds like the manifold turned him from a 460 Econodyne into a 460 Maxidyne.  :loldude:     First AMI460?

 01F217B1-0924-4626-8796-5B30590ED14A.jpeg

 

Ok 

i have re-tested and all looks ok. No more slobber and normal black smoke, but more than before. The truck runs good for the moment, the only difference. I think is the turbo boosts a little bit slower than before. Before i would boost up to 32 psi now it takes longer to get it, but the truck has more power, it’s strange. I think all is ok. I think when the boot kicked off the engine was not breathing and a little bit of engine oil was go into the exhaust and caused slobber, cause now all is ok . Today it’s too hot 42 degrees outside and the pyro looks like normal, temps 8-900f, but when I let off the fuel pedal the pyros going down more fast than before. I found it more normal, it’s like my Peterbilt.

thank you so much 

 

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Swapping thoughts with a well established heavy haul member today about adding an AI460 to his fleet of pavement crackers. Looking forward...He wants to camshaft swap up front. Jump in anyone who has cam swapped a 460, but I’m advising him there’s no great advantage. 

Mack didn’t/couldn’t afford to/ failed to build a variable exhaust restriction to make the AI engine NOx reduction work at all RPM’s. Instead they built a simple, logic free, fixed restriction that works in one RPM range. At low RPM and low fuel delivery rate there isn’t enough flow back pressure to make the AI fixed restriction work properly, so Mack lowered fuel delivery to lower exhaust ppm at low RPM. Low end torque disappeared. If Mack had designed a variable restriction exhaust they could have choked the flow at low RPM, created back pressure, cooled the burn and reduced NOx @ low RPM. They could have delivered more fuel on low end with a variable restriction and built torque.

Any fixed restriction has a pressure delta curve, IOW the more you try to force through a fixed restriction the higher the back pressure.

Low RPM, Low flow volume, low back pressure, higher NOx, reduced fuel delivery. No torque and horsepower.

High RPM, high exhaust flow, high back pressure, lower NOx, increased fuel delivery. Enough horsepower and torque but overconsumption of fuel due to inefficient, uncooled, EGR back flow. The stock granites get 4 MPG, so plenty of fuel is flowing out at working RPM range, but with a poor return.

With nothing else considered......you have a fuel system that delivers too little fuel at low RPM and too much at high RPM. The product of catering fuel delivery to match a fixed restriction rather than varying the restriction to cater to the needed fuel delivery.

Once modified.......Too much fuel is making lots of heat and lots of power when running more clean air and less scavenged EGR gas. Everybody notices the pyro operating range is elevated after the upgrades. Flow injectors fix the low RPM (low fuel) delivery issue. Flow injectors also increase an already high output of fuel at full governed RPM. That generates your higher torque/HP return, higher NOx and higher pyro. You can back off the accelerator now since your fuel is giving a power return and MPG increases. You can use the extra top end when needed as long as you manage the pyro.

Disclaimer....

With the current arrangement you have sufficient power and a manageable creep on the pyro. Some bump scavenging is likely still occurring (impossible to know how much) and lowering the combustion temp. If the residual scavenge is completely eliminated (by AC cam swap) with this set-up it’s possible to see a rise in pyro beyond the common, manageable, 900F. If little or no bump scavenging is occurring(with the original camshaft),  because of our restriction elimination, a bump-less AC cam wouldn’t add performance and could drive more pyro temp....with this set-up. There could be a combination of air and fuel that favors the AC camshaft plus manages heat, however I’m not convinced it would deliver more to the wheels. 

 

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