larry44

2007 AI 427

14 posts in this topic

2007 AI 427 . Who makes a bigger exhaust manifold for this motor ? 

If not aftermarket will any manifold fit if from say a e-7 ? 

My friend has an 1997? E7 350 and it looks like it'll bolt right up im just wondering if the ports on the backside are the same and the gaskets are the same ? 

 I think if I put a bigger manifold on it'll wake it up . Thanks . 

Edited by larry44
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Imma be watching this post, I've been wondering the same

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The AI/AMI engine has a small internal diameter exhaust manifold to create back pressure in the cylinders. The camshaft has two bumps on the exhaust lobe so that the exhaust valves open twice for every one time the intake valves open. This allows burnt exhaust gasses to be sucked back down and burned again  thanks to the exhaust back pressure created by the small exhaust manifolds. Its kinda like an internal EGR. Some guys on here have replaced the AI/AMI camshaft with a AC engine camshaft and had good results. I have run into a 427 HP  AI engine on a CV rolloff truck that had large ETECH exhaust manifold  installed on it. Every thing else was factory including turbo, it sure didnt  feel any stronger. 

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You have to do the cam swap to get the benefit power your doing away with the wasted fuel and some of the turbo lag ,the pre egr manifold will help a tad but not much

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Its a good truck , runs real good , but that lag has got to go , and needs a little more oompf . Does anyone know if the stock muffler has baffles in it ? I tried to pop cap off top its on there  real good . What about a more free flowing stack ? Little to no difference ? 

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If you put the AC cam in an AI engine will you have the same thing as a pre emission ETEC engine

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Also on most  CV trucks with AI/AMI engines . The exhaust starts out as 5" coming off the turbo then with in a few inches the turbo outlet pipe  necks down to 4" all the way to the muffler. Then the muffler is a 4" in and 5" outlet. On the very early CV with standard ETECH engines, the turbo outlet pipe stays 5" all the way till the last few inches of the pipe then necks down. Ive seen a few guys here use the older outlet pipe and cut off the necked down part and make there own 5" exhaust  and get a Walker high flow 5" in/5" out muffler. If I was gonna go the AC cam swap,  I'd do the full 5" exhaust too. 

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13 hours ago, larry44 said:

Its a good truck , runs real good , but that lag has got to go , and needs a little more oompf . Does anyone know if the stock muffler has baffles in it ? I tried to pop cap off top its on there  real good . What about a more free flowing stack ? Little to no difference ? 

Have you had any of the software updates done for poor throttle responce done at a dealer. If your unsure, I can pull it up and usually see. You got the last 6 of your Vin?

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well I'm floored ... i can't thank you enough 

2007 ct713 

006280      zero zero six two eight zero 

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i was looking at a walker 22970 hi flow 4 in 5 out 

does the stock exhaust have baffles ? what does it look like in there if you look down it ?

 

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13 hours ago, larry44 said:

well I'm floored ... i can't thank you enough 

2007 ct713 

006280      zero zero six two eight zero 

Yous has the newest "Step 12B" program in it . It was done in September of 2016. There are a few different engine files that Mack software guy ( not the dealer)  wont talk about that if the dealer begs enough they can get turned on and downloaded. These seem only for the AI 427 HP engine. And it will help. 

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tell ya what , i really can't thank you enough .

what manifold should i put on there thats bigger that will bolt right up with the same gaskets and turbo port ? 

can i get that file aftermarket or at the dealer ?

i don't really want to get into a cam job . thats gonna be $3-5000 no ?

Edited by larry44

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I put a walker megaflow on today . 

The old one had a full plate blocking it off in the center with a (X) sliced in it . 

I will see if it improves with a load on it . 

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