Which Porting Templates Are The Best?
10-03-2005, 09:57 AM
#11
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Join Date: Sep 2005
Posts: 67
Jep that's what I meant. I want to do this correct as I will open the engine. I just want to know what will work best with the fututre set up. How much will a large streetport move my powerband up the RPM line?
The reason i want to go non seq is pretty much contradictive as it's my opinion it will help you save fuel in the city. Slow traffic will force you to keep in low rpm's. The stock seq set up is very fast on the boost, and boost means a big fuel requirement with rotaries. I strongly believe that with a non seq set up you will see boost later UP the rpm and thus "normal" city driving/cruising will give you a better fuel consumption.
As for the non seg and GT35R setup, it will bring on boost by 3200 to 3500 rpm, which is fine to me (see above reason). I just wonder in what way opening up the ports will affect the point where it will have (full)boost. Like I said 3200-3500 will do for me, but I don't want it to be up in the 4500'ties liek a T78/T88 will do to your motor. (bad comparison I know, because we are comparing ports, not turbo's, but just to give you the idea)
The reason i want to go non seq is pretty much contradictive as it's my opinion it will help you save fuel in the city. Slow traffic will force you to keep in low rpm's. The stock seq set up is very fast on the boost, and boost means a big fuel requirement with rotaries. I strongly believe that with a non seq set up you will see boost later UP the rpm and thus "normal" city driving/cruising will give you a better fuel consumption.
As for the non seg and GT35R setup, it will bring on boost by 3200 to 3500 rpm, which is fine to me (see above reason). I just wonder in what way opening up the ports will affect the point where it will have (full)boost. Like I said 3200-3500 will do for me, but I don't want it to be up in the 4500'ties liek a T78/T88 will do to your motor. (bad comparison I know, because we are comparing ports, not turbo's, but just to give you the idea)
10-03-2005, 10:58 AM
#12
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Location: Savannah, Ga
Posts: 2,763
Originally Posted by l8t apex' post='765882' date='Oct 3 2005, 09:47 AM
I have had monster street ported motors. The question you ask is asked everytime a new owner wants to get HP out of the motor. The idea that porting will make your car stumble around and lope like a V8 with big *** valves and a ported head is not the case. Actual low end loss or street hassle on a street port is negligable to most any owner. I can say NA monstor bridge and PP are whole different matter.
Its my belief that since you going through the time and money to break apart the motor, buy templates go ahead and read alot and make them nice and big. Then support this with the proper set up.
This motor is not like a sick 10 second V8 at the light. the difference between 780 RPM and 1000 is nothing especially since you engage at a much higher RPM to engage the clutch.
Its my experience that the over all performance gains offset what you think could be a hassle when in reality afterwards you may say "**** this nothing , I should have done a nice large port."
However, the larger the more experience needed to design them correctly.
IMO
PS: pic is of my NA four port with a 50mm Haltech. This wasnt a hassle at all as a daily driver.
But just taking out a lot of material can hurt the low end more than it helps the top end. There is a balance between flow and velocity with the stock ports, and if you get a 5% increase in flow by increasing the port size by 10%, you havent done much good for the port. You may gain a little hp top end, but at the same time end up with less area under the hp curve, and a car that isnt any faster. And like its been said, port shape is only a small part of porting. The bowl(where the runner turns into the port) and the short side of the turn(the opening edge of the port) especially make all the difference in porting. Any seperation of the airflow on the short side of the turn will hurt the airflow a lot, so you want to avoid sharp edges there, and keeping it somewhat rough will help as well. You also want to keep the runner matched to the port shape. If you go big on the port without doing much on the runner, you will make the runner a restriction, which will hurt top end some, while the big port will hurt low end and low load performance.
Everything is a compromise with the ports and runners. By porting the engine, you will be shifting the compromises. Not all things will come out with a better overall end result. If you are wanting to do your own ports to save the money, remember that you get what you pay for. If you just want to experiment or whatever, then have a good time and do your research. If you want the best ports, youre best off leaving it to someone with good experience and proven work under their belt.
10-05-2005, 02:37 AM
#13
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Join Date: Dec 2002
Location: Bayou-self Louisiana
Posts: 947
Originally Posted by mazdaspeed7' post='765925' date='Oct 3 2005, 10:58 AM
But just taking out a lot of material can hurt the low end more than it helps the top end. There is a balance between flow and velocity with the stock ports, and if you get a 5% increase in flow by increasing the port size by 10%, you havent done much good for the port. You may gain a little hp top end, but at the same time end up with less area under the hp curve, and a car that isnt any faster. And like its been said, port shape is only a small part of porting. The bowl(where the runner turns into the port) and the short side of the turn(the opening edge of the port) especially make all the difference in porting. Any seperation of the airflow on the short side of the turn will hurt the airflow a lot, so you want to avoid sharp edges there, and keeping it somewhat rough will help as well. You also want to keep the runner matched to the port shape. If you go big on the port without doing much on the runner, you will make the runner a restriction, which will hurt top end some, while the big port will hurt low end and low load performance.
Everything is a compromise with the ports and runners. By porting the engine, you will be shifting the compromises. Not all things will come out with a better overall end result. If you are wanting to do your own ports to save the money, remember that you get what you pay for. If you just want to experiment or whatever, then have a good time and do your research. If you want the best ports, youre best off leaving it to someone with good experience and proven work under their belt.
I am taking the perspective of a laymen "as I am" and rememberd "I didnt want something that is of the wall and cant be driven".
Then after I paid for it and rode in a Johnson Racing Engine built motor I was like " damn this thing performs and I thought low end loss was something I would notice to be a pain".
In other words I mean to describe to a newbie that it not like gas to deisel engine performance difference.
How does 5% difference feel to a nonengine builder or your daily get in the car and hotrod it person.
your points are correct. I just hope that I can help because I believe understand what he is asking. Nothing too technical.
10-05-2005, 04:12 AM
#14
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Posts: 2,436
what does racing beat charge to do a port job now? It might be benificial to you to just have them do it instead of experimenting on it yourself.
10-05-2005, 06:29 PM
#15
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Join Date: Aug 2004
Location: Houston
Posts: 76
Originally Posted by banzaitoyota' post='765688' date='Oct 2 2005, 03:30 PM
SMART-*** REPLY: BUT Pineapple Racing sez a Flowbench is useless. :End uinsolicited sarcasm
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