I ported and polished the exhaust side of my head....Truck last year would go past 60lbs of boost. This year its only making only 50 with a lot more performance parts put on....Anybody else experience less boost with a ported head?

 

how much material did you take off?

possibly, just thinking out loud, but boost is a measure of restriction. since the air flowing into your motor is 'smoothed' out, you have less boost, because it is flowing more freely into your motor

just my opinion

 

Yeah, the Cam as well as your ported head will lower boost pressures.

Does the truck run better or worse?

 

Well it runs good same as before with the leak...Changed that gasket on the head out and it doesn't make anymore boost after we found that leak...I'd say we took about 1/8's inch out of the exhaust ports...It makes right at 50psi the guage...We are going to go ahead and check it again this week to make sure its not leaking anymore....

 

Boost is a measurement of restriction not airflow.
If you have 10psi less boost you did a good job.

If your egt's were fairly high before the port job your egt's will be down and power will be up slightly. Max turbo rpm's will be down.

When you port a head by guess and by golly you need to be careful when running competition level egt's.
If the ports are not flowing the same it is possible that you could have one or more super hot cylinders.

 

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Coal Train:

The Members are giving you good advice/input on the ported head and boost.

I just saw the same thing happen on my 1996 Dodge CTD 12 valve. Scheid Diesel put a new cylinder head on my truck with much more porting that I had with the old head. My peak boost has gone down from 75lbs. before to about 68lbs. now with the new head. With EVERYTHING else being the same,
(fuel settings on P-Pump, Injectors, Timing etc.) I have cut 3/100ths of a second off my 1/4 mile times going from 11.52 before to 11.49 with this new cylinder head and added porting. Power on the dyno is up some too.

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John_P

 

After porting and a cam job my boost dropped a good 11-12 psi, but It pulled way harder. The lower boost just mean your engine is more efficient and moving more air. Enjoy!

 

Well we checked for boost leaks yesterday because I felt I had a leak....And sure enough it was leaking between the aluminum plate that bolts on the intake...When I did all the work I didn't have a gasket so I just reused the old one...I replaced that today and felt like it might make more but its still about the same.. Truck seems to run real good....I'll update everyone when we check it again....Again I feel a lot better after talking to you guys...Thanks once again...

 

You get better flow and lower egts from your port job. As stated,.. you also get lower psi of boost resistance. Much better for your head gasket.

 

Guys he said he ported and polished the exhaust side and that should not affect the boost downward on the intake side. A freer flowing exhaust between the head and turbo can increase drive pressure/flow and could result in more boost due to a faster turning turbo.

Someone said you put a cam in, that can have a major impact on the boost.

On edit I see you found a leak, makes a lot more sense then the exhaust port job.

 

Glad to see someone is paying attention!
I missed that minor point!

 

Yes we are going to put pressure on the system and check it again since I replaced the gasket.

 

[QUOTE=Coal Train;2116997]I ported and polished the exhaust side of my head....[QUOTE]

Oh i see, YOU did it huh?! How long did it take YOU?!

 

mason my boost is about the same as what you have most of the time. ive seen 60psi out of my truck but only about one time. most of the time on the street mine is 50-55 I hope that helps somehow. I dont have a tst or mp8 either so if you have that off it might be correct. I think pourin diesel has stated his will make 65psi around in there.

 

We put pressure on the system today and couldn't find any leaks...It appears ok its making right at about 50psi on the road. I guess we will see at tampico, hope to see you there Jesse