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Discussion Starter #1 (Edited)
The guys who is doing my shortblock and rebuilding a head for me offered to do some slight porting of the head (mainly exhaust) and exhaust manifold for $100-$150. I told him I didnt want to affect the low end and he said what he'd do will just help in the mid range and up top but shouldnt affect low end torque. This guy builds race engines and really knows his shit so I trust him but I have a question for those who have done this...

Will the slightly ported exhaust manifold majorly affect the spoolup characteristics? I know when you increase the size of the runners you lose velocity of the exhaust gasses and therefore will have more lag but how much more lag? Do you think it will be extremely noticeable? BTW I will be running a 60-1 trim ct-26 w/ a 10 degree clip.

Thanks for your responses
-Zach
 
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Discussion Starter #2
anyone?
 

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ma70-7m=1JZ
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I think that the polishing of the ports would be the most benificial, by reducing turbulence alowing the gases to get in and out quicker. If you want that thing to spool up quick get a 3" turbo elbow or a full 3" elbow/downpipe.

Port matching the head/manifolds, and polishing the runners would be a good thing to do.

Using an ebc or a manual ball and spring type boost controller will also quicken spool up. The stock actuator starts to bleed off exhaust at 1psi and slowly opens up. With an ebc or ball/spring type it holds the boost signal back until the preset boost is reached , then the wastegate opens up. I can really feel a big difference in spool up when i turn the boost controller off.
 

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the clever guy
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I'm no expert and this is just my personal opinion:

I don't think opening the ports will have any negative effects, only positive. The inlet to the turbine wheel is basically a funnel, curved of course. Individual exhaust ports can only act as a restriction pre turbo so opening them up (within reason) should only provide gains. The size (area) of the nozzle at the end of the "funnel" is a static restriction. The velocity of the pre turbo gas is virtually irrelevant. Volume (amount) is the key here. The more gas you force through that restriction, the faster is comes out of it - until you start getting close to it's flow limit. Then you'll just be building more pressure and not any more velocity.

Of course this is a rough generalization but I think it's a fair illustration.
 
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Discussion Starter #5
Cool...thanks for the info guys.

I do have full exhaust, EBC and fuel upgrades so I'll be able to really push the turbo. I did have a problem though with boost spikes on the EBC at high boost :( Dont know why though...
 
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Discussion Starter #7 (Edited)
No shit :rolleyes:

Edit: Not to be a dick or anything but I know the internal wastegates suck and I know why I am getting spikes but I dont know how to fix it.
 

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Trev
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Port that mess! LOL...seriously...go with the 3 inch elbow...I can get you one made for 165....custom, complete 3"...port the manifold and the head...
 
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Discussion Starter #9
Already got a SS elbow but thanks :D
 

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Question to suit.
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Porting anything on the exhaust side will pretty much help you. You can port the exhaust ports, manifold, and probably even the inside of the exhaust housing, but you're still going to have to go through that hot wheel (turbo exhaust wheel). That turbine is the biggest restrictor. You will boost up faster with a gasket matched port on the exhaust side, though, it's not THAT much of a difference.


The velocity of the exhaust will not change much at all, but, you will flow more exhaust from the cylinder, and that will aid in the faster spool.
 
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Discussion Starter #11
Thanks :)
 
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