Whats makes a street port mild, aggresive, extended etc?
09-17-03, 07:49 AM
#26
Airflow is my life
Originally posted by peejay
The secondaries already are the same size as the runners in the block. Well, slightly smaller, which is what you want... you want *some* step. How much bigger do they need to be? I don't realistically see them needing to be larger because the port window is so necessarily small... in effect the port window is a choke point. Which is why you can't make it too big.
And why I see a benefit in making the runners *smaller*... since the large area isn't doing anything, let's get rid of it to increase velocity.
The secondaries already are the same size as the runners in the block. Well, slightly smaller, which is what you want... you want *some* step. How much bigger do they need to be? I don't realistically see them needing to be larger because the port window is so necessarily small... in effect the port window is a choke point. Which is why you can't make it too big.
And why I see a benefit in making the runners *smaller*... since the large area isn't doing anything, let's get rid of it to increase velocity.
09-17-03, 11:38 AM
#27
Old [Sch|F]ool
I don't believe you will physically be able to *get* to that point, unless maybe you have a J-bridge.
Look at the port area on a 300+ HP peripheral port engine, then look at how much area combined is in the two port runners, then get back to me. You'll find they are about the same.
Look at the port area on a 300+ HP peripheral port engine, then look at how much area combined is in the two port runners, then get back to me.
You'll find they are about the same.
09-17-03, 12:30 PM
#28
Haltech Dealer
Originally posted by silverrotor
Don't you hate finding out after everything Is all said and done?
I spoke to 20B-3Rotor and he had said the Intake Is of Racing Beat but the Exhaust Ports are considerably bigger.
Perhaps he can chime In and give me an exact description Junior.
Don't you hate finding out after everything Is all said and done?
I spoke to 20B-3Rotor and he had said the Intake Is of Racing Beat but the Exhaust Ports are considerably bigger.
Perhaps he can chime In and give me an exact description Junior.
09-17-03, 02:44 PM
#29
on the normally aspirated engine with the intake manifold ported no low end was lost (some gain), midrange and upper range definite improvement (big gain).
on turbo motor gain in the mid and high. low rpm no loss of hp (how low is low?)don't be afraid to port big. if you don't port big now you will just want to do it later. port big or you will regret it. on the INTAKE. too big on the exhaust and you will have zero low end and mid range.
on turbo exhaust applications i just remove the top lip,and make it open earlier. you don't need to make the exhaust close later on turbo. you don't want too much overlap.
on turbo motor gain in the mid and high. low rpm no loss of hp (how low is low?)don't be afraid to port big. if you don't port big now you will just want to do it later. port big or you will regret it. on the INTAKE. too big on the exhaust and you will have zero low end and mid range.
on turbo exhaust applications i just remove the top lip,and make it open earlier. you don't need to make the exhaust close later on turbo. you don't want too much overlap.
09-17-03, 03:42 PM
#31
Airflow is my life
Originally posted by peejay
I don't believe you will physically be able to *get* to that point, unless maybe you have a J-bridge.
Look at the port area on a 300+ HP peripheral port engine, then look at how much area combined is in the two port runners, then get back to me. You'll find they are about the same.
I don't believe you will physically be able to *get* to that point, unless maybe you have a J-bridge.
Look at the port area on a 300+ HP peripheral port engine, then look at how much area combined is in the two port runners, then get back to me.
You'll find they are about the same.
09-21-03, 10:16 AM
#32
Lives on the Forum
I'd call the Racing Beat templates as mild also.  I've run much larger street ports on my car, and they are much larger than the Racing Beat templates.  The hard part about the 13BT's in the FC's is that the water jacket is so close - check Mazdatrix website in their FAQ section for pics.
-Ted
-Ted
09-22-03, 11:58 AM
#37
you don't need a large street port template. you just use the rb template and carefully make it close as late as you can. i honestly use my pinky finger to feel behuind the port and see where i am.
09-29-03, 03:12 PM
#43
Lives on the Forum
mild exhaust port - engine is only supposed to see 300hp.  I have people already ragging me how come so small!  Too early of a port opening and the torque drops quickly - I've seen it with my own engine.
-Ted
09-29-03, 04:17 PM
#44
Originally posted by rotariesrule
silver rotor, did you trace a template or did you do that freehand?
silver rotor, did you trace a template or did you do that freehand?
www.can-saf.com
Last edited by silverrotor; 09-29-03 at 04:19 PM.
10-06-03, 02:49 AM
#45
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PORK CHOP
Originally posted by RETed
We've run some pretty crazy ports and none have really affected idle that much.  I wouldn't worry about it.
-Ted
We've run some pretty crazy ports and none have really affected idle that much.  I wouldn't worry about it.
-Ted
I drove Ted port job. Runs good and to my surprise idles really smooth too. How ever I can not see you get more than 18 mpg on high way with that closing timing. NA is much more sensivetive to port changes. Too late closing mpg and low rpm response willl go to ****, too early opening or too much over lap will need free flow exhaust or turbo which most people will neglect. Port timing is the key more then size.
10-06-03, 02:56 AM
#46
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Oh Ted I just build a motor for Warren's 88 TII and today he ran 12.4 @ 121 MPH with street tires and Gabs. I was suprised too. I did not go crazy on the port like you.
11-15-03, 10:42 PM
#48
Originally posted by RETed
mild exhaust port - engine is only supposed to see 300hp.  I have people already ragging me how come so small!  Too early of a port opening and the torque drops quickly - I've seen it with my own engine.
-Ted
mild exhaust port - engine is only supposed to see 300hp.  I have people already ragging me how come so small!  Too early of a port opening and the torque drops quickly - I've seen it with my own engine.
-Ted
11-19-03, 06:43 AM
#49
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Over porting can cause loads of problems.
Trust me i know! On my previous experiment,the port timing was so much ,the engine couldnt start with the starter,it wasnt turning it fast enough.(the compression was 95 per rotor face,all of them within 1 psi off eachother)
On the exhaust porting part, RETed has a very nice port.It doesnt open or close quicklly ,and the results should be excellent.
Net Seven : Sounds to me like your going to have alott of timing..i wouldnt expect torque to be at low rpm
Trust me i know! On my previous experiment,the port timing was so much ,the engine couldnt start with the starter,it wasnt turning it fast enough.(the compression was 95 per rotor face,all of them within 1 psi off eachother)
On the exhaust porting part, RETed has a very nice port.It doesnt open or close quicklly ,and the results should be excellent.
Net Seven : Sounds to me like your going to have alott of timing..i wouldnt expect torque to be at low rpm
