IH 466 is boost to high??? May 01, 2016 12:58AM
Ok, so let me put this out there for anyone who has some input on this. I have a 466 (468) engine in my hot farm tractor(IH) with a 13mm A-pump on it, ive had the head ported to the max and the cam is also been re-ground, also my pistons have been decompressed some and fly-cut also running an S400 charger with the smaller S300 compressor housing(72mm comp wheel and 76 turbine wheel) no matter what timing changes i make or fuel amount i consistently run 82PSI for boost and 55 for drive PSI. So i guess my real question is why is my boost and drive PSI so far off?
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Re: IH 466 is boost to high??? May 01, 2016 01:09AM
Are you happy with the way it runs?? Are you failing the turbocharger because of this difference?? Where do you think the numbers should be?? same- same??
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Re: IH 466 is boost to high??? May 01, 2016 01:14AM
To be honest it runs ok.. but still not happy with it completely, it will run strong the entire way down the track but at the end when it starts to get more load on the engine it just pukes out. even in lower gears....
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Re: IH 466 is boost to high??? May 01, 2016 01:45AM
You said that you had the head ported to the max. That could very well be your problem right there. With the charger you are running there is only so much air that you are shoving through that head and if the ports are too big there is probably a lot of dead air in there. Especially on the exhaust since your boost is lower on that side. I have heard of a lot of 466 hot farms performing better with a + head with little to no work done on porting vs one that's had extensive work done on it.
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Re: IH 466 is boost to high??? May 01, 2016 02:37AM
JL IS 100% CORRECT!! put a factory plus head on it with the valve springs u run and see how that works
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Re: IH 466 is boost to high??? May 01, 2016 02:50AM
Ok, to answer back to both I ran the tractor all last season with a factory + head and heavy valve springs and the boost and drive PSI was the exact same... so after talking with the guy who built my charger and then talking to riverside they both said the head needed ported because the engine wasnt eating up enough air. But tell me if this sounds right or not had buddy of mine who pulls say it may be to much charger for 466CI???
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Re: IH 466 is boost to high??? May 01, 2016 03:33AM
I'm gonna go out on a limb here and assume you used the same cam with both heads. I'd say it's ground wrong for what you are doing
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Re: IH 466 is boost to high??? May 01, 2016 04:57AM
Yes, my cam was ground before i had the head ported and before i put the bigger A-pump on. But the engine still did the same thing as far as building lots of boost PSI and less drive PSI with the original set-up, which is what riverside used in order to grind my cam
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Re: IH 466 is boost to high??? May 01, 2016 06:23AM
An S400 style charger should be perfect for what you are doing. Do you know what size exhaust housing you are running now? The easiest and cheapest route would be to drop down 1 size and see how it performs and what the psi numbers look like. One other suggestion I would make is to check your cam to make sure it matches up to what your card says it is. Our tractor fell on its face at the end of the track for half a season, we tried everything and finally measured the cam and found that the intake side was right but the exhaust side had not been ground correctly. The cam came from a VERY VERY reputable shop. They made it right for us. Just saying that slip ups can happen in even the best of shops.
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Re: IH 466 is boost to high??? May 01, 2016 10:18AM
Not to be a wise guy, but are you sure you really have 82 psi of boost? Are you going by a tattle tale, watching the gauge, or data acquisition? You could be getting a pressure wave back that makes the tattle tale show high.

Are you sure the gauges/sensors read the same? Check by putting regulated shop air to both at the same time and verifying they read the same.

How is the boost line plumbed into the manifold? If the flow velocity is pointed towards the fitting you could be getting some velocity head bumping the number up, but I doubt that's accounting for all of the difference.
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Re: IH 466 is boost to high??? May 01, 2016 11:09AM
Using a gauge and watching it and it also has the recall which shows me max psi when I'm done and its pretty much away from the air coming into the intake manifold
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Re: IH 466 is boost to high??? May 02, 2016 01:07PM
Remember to "keep it simple". An engine is just an air pump and that does seem like a high number when comparing head etc. to charger capability. Old textbooks call the cam the "brain" so is it moving the right amount of air at the right time? Good luck.
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Re: IH 466 is boost to high??? May 03, 2016 06:10AM
I would agree bad things happen but if you step back and look at the picture you said that the driving psi is 55 and boost is 82 is the driving psi is that high there is a
blockage or restriction in the exhaust , (turbo head or cam ) . I have had a cam sent to me that was indexed and sent and found out after install that number one and six
were the only correct lobes. it is very possible that the cam is the trouble due to lobe lift duration and overlap. it could also be a turbo issue with a restriction in wheel and
housing ect.
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Re: IH 466 is boost to high??? May 03, 2016 03:40PM
Try changing cams if you had the same cam stock head or ported it may be the wrong combo it could be closing your intake sooner which will back up into the intake creating the 80 pounds of boost air needs to be faster then the cam operation opening to quick on the ex side you aren't letting any pressure build in the cylinder before it opens thus creating a slower air speed on the ex side. Kinda like kinking a garden hose when you start to kink it the pressure builds shooting the water farther which makes it faster. There's 4 points to figure out on a cam how quickly your intake and ex opens an how quickly they close (io-ic-eo-ec) which is the main effect of the duration if it closes faster that air that should be getting into the cylinder can't an gets backed up you want your air speed to control the rest of the engine the quicker everything goes in an out the better you are like changing injector lines the shorter the better with the cam the lift is okay but it's how fast you can move the air in and out.
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