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What turbo belongs on a AI-460 and an AI-427? S300 or S400? My research says an etech should have a S300 on a 350-400hp and a S400 on a 427-460. That is all I know. I realize the AI is not an etech but similar. My engine is an AC-427 converted to either an AI or etech engine. I'm not sure which. Its a very long story. I appreciate the help in advance and love the site. This site helps the working class diagnose our truck troubles and keep us earning the money to feed our familes.

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You need to put an etech exhaust manifold on it with an s400. But, there are a lot of setups/options with the s400.  Best thing is to find a good turbo shop and have them set it up for what you are trying to accomplish.

Edited by OldRedMack

Both AI are S300 series center bearing, stock. Don't install a S300 for any reason. If you really want one though I have one listed for sale, dirt cheap, in good condition, off an AI-460.

 

Gotta believe no practical chap would ever convert to an AI engine?

 

E-tech 427 & 460 is a 631GC5145M Turbo

 

 

 

 

Edited by Mack Technician

Thanks for the help from you guys in advance. I'm going to try and make a long story short the best I can even though I will end up leaving out some details. Have 04' Vision with an AC-427. That motor was a pile, as most would agree. Got tired of dumping oil in it at 697,000 and decided to get it deleted and overhauled. I was told at the time the motor was converted to an E-tech and had 460 injectors. Imediatly after the work was done I gained .8-1.0 mpg, coolant and oil temps went down 10-15 degrees, and a lot more power. A puff of black smoke when shifting and away I went while still being light weight.  The shop we are unfortunatly dealing with, fired the mechanic who did most of the work during the overhaul. The truck has 870,000 on now. Recently we took the truck in to have some simple things repaired including replacing the exhaust manifold gaskets. While doing that job they ran into a crack on the exhaust housing of the turbo. The existing S300 turbo was replaced with another S300. I went through 3 of those S300's. They all lasted a week. The bearing goes out and starts shredding the housing. YES, the truck has good oil pressure. The intercooler was replaced in January before we had all this trouble recently. The intercooler was pressure checked and cleaned. Nobody at the shop can figure out the problem. My EGT's were never got above 1050 degrees on a long hard pull and the boost was 32 psi. So the other day we stopped at the shop to see how things were going. Noticed a 2000 Vision 460 sitting next to ours with a S400 turbo on it. My research and your verifications have told me our truck needs a S400. I thought I hit a home run and figured it out. Now the owner of the shop tells me I have an AC427 converted to an AI460. All of the parts to do the conversion were off a AI motor using the S300.

Some things I do know for sure are:

1. my ecm says 12MS530M (pretty sure thats an AI ecm)

2. I have an S300 turbo currently and he switched my injectors to 427 thinking that will magically solve the problem. He tells me I am getting it too hot at 1050 degrees. I think that is B.S. I am extremely disappointed with the power. The truck won't pull a drunk hooker off a barstool.

3.Intercooler is still the same p/n as the ac motor had, just has modified plumbing to it.

4. The exhaust pipe right after the turbo has a hose going to intake side of engine. I was told by mechanic to limit the boost so it doesn't get too high.

Conclusion- I think I need an S400 with 460 injectors and the thing should run fine. Why the orginal S300 lasted as long as it did for two years is unknown. The company has done what he wants without permission and the total situation is a nightmare. I know I left out some details. Thanks again for listening to my incoherant rambling. Oh, and the shop still hasn't fixed the hard miss under load or the hard starting. We left the shop worse than when we came in by far.

Edited by blackmack460
forgot something

Think you need to get hold of your now missing mechanic and figure out what is inside your ECM. Then you will have the answer for all the questions. 

Take pics of your turbo and exhaust manifold and upload them. 

Change your turbo feed no matter what.

if it really is an AI-460 conversion you are ahead of the game since your camshaft is ideal and has no scavenging bump. 

Edited by Mack Technician

Anyways....tried uploading the photos I took of the truck. That went over like a fart in church. However I have some part numbers to share. Exhaust manifold   104GC5164M. (just realized that is the P/N for only the front third of the manifold) I'll get the other to tomorrow.                S300 turbo  631GC5172BM8X. Thats what my pictures show.

S300 model number S300A113. My ECM has "Advanced" wrote on it in white paint pen. I will try and get more info on the emissions swap Friday.

Old Red Mack, I immediatly thought the same thing about the miss I have. An EUP problem. As far as the hard staring goes, they told me it has 80psi fuel pressure. So, they don't know the answer. The hard starting and miss problems started happened all at once. That was actually what I originally went to shop for. Now that you mentioned it, I do remember hearing the injectors are the same except for different cups.

Mack Technician, Finally on the 4th turbo(S300) they changed the oil feed line. A little late in my opinion. The rest of the work will be done at home.

Thanks again guys.

 

Edited by blackmack460
brain fart

The good fuel pressure doesn't mean that there is not a problem with an eup.  I had a loader that was hard starting, replaced batteries, tried priming it, did everything I could think of, nothing helped.  Then the starter went out, the bearing on the gear on the flywheel side was worn slap out.  Causing it to bind and drag just enough to slow it down, but not enough to make an audible difference.  Replaced the starter and it fires off fast now.   We have never had that problem with a truck, but you never know.

Edited by OldRedMack

I tend to think the turbo problem may be someone not cleaning the intake system out and your digesting aluminum turbo compressor-side metal back into the new turbos. That’s generally why you see that kind of short, repetitious failure of turbos. You have to remove the intake tubes, disasssemble, clean, remove air cleaner house, clean and install a new air filter. The problem compounds as you eat turbos and release more garbage. Mack’s policy is to remove all pipes and cooler, basically everything all the way to the engine intake manifold.

You may want to take the mechanics advice on heat. If you're cracking exhaust manifolds or turbo housings it may well be the case. When you modify the injection on a Stock AI engine you automatically have a heat management challenge on your hands. Pressure = Heat, in hydraulics or pneumatics. If you modify an engine with a restriction system you will create a heat issue. After you modify it you need to open up the sinuses of the engine a bit so you don't run too high on pyro.

Since you Frankenstein'ed the truck your going to need to make sure guys aren't putting on the wrong turbos. Obviously they won't be installing a VGT accidentally, but what numbers are they working with or referencing for the parts they are installing? If you put an AI-427 turbo on a modified AI-460 you may be eating those all-ready-undersized S300's.  

You can diagnose your miss with a 3" piece of wire. Short out the two connections at the EUP. It will not harm your ECM. The reason the connections are not insulated is because it will not hurt it. If it would wreck the ECM you would need a new computer every time a magnet coil shorted itself out. I did it last week on a 934D Liehberr with a miss, only because I don't like to hook-up laptop to cut cylinders, wire is quick and easy. If the lights are low you will see a little spark and also know the ECM is driving that EUP.

Edited by Mack Technician
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Use the pictures in the attached thread to identify your manifold set-up. Your mechanic must have been sharp, so I wonder if he would have swapped manifolds, knowing what he knew about the conversion process? This will also have the 5" exhaust listed.

If you use this recipe you need to know what engine HP and injector part numbers you have when you call Mike. Assuming this is now an AI460 ECM you will need to tell Mike at K & S....

"I have an AI460 and need a S400 to replace my 631GC5172M3 turbo which is currently a S300"

"I need upgraded injectors to replace my 419M3 stock injectors that currently have the stock tip #1868"

Edited by Mack Technician

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