Polishing intake runners - Page 2

JustJeff · 11-14-2010, 07:20 PM

^NoDOHC

Makes perfect sense to me and helps solidfy what seemed logical in concept. Explaining it in terms of energy spent follows right along with what I was thinking.

My thoughts were that if you suddenly give pressurized air MORE space it's going to create "turbulance" as it expands. Then when the chamber/runner constricts back down it requires more energy to press the air back into the smaller area. You're pressing the air against an angled surface and the suspended fuel is going to hit the side and come out of suspension.

That scenario seems equally damaging to the process as having a lip exposed.

NoDOHC · 11-14-2010, 07:32 PM

The issue that we have with your runners is that we have to worry about both fuel suspension and air flow. The good news is that changes in area and steps will both hurt both.

I wish that I had dyno'ed my engine before the intake maifold modification, but I am reasonably sure that it helped.

RETed · 11-15-2010, 03:35 AM

Quote:

Originally Posted by JustJeff

That sounds awfully prone to simply making them wider but not matched much better than the factory did. I'd think having them widen and then constrict back down would equally help pull the fuel out of suspension just as much as an uneven lip. Like NoDOHC posted. Hhmmm but perhaps allow the air to flow "better".

I think, at this point, that you're over-thinking the whole thing.
The stock intake manifold system SUCKS.
Any mods to help flow will get you gains.

-Ted

***TitaniumTT*** · 11-15-2010, 07:21 AM

Agreed..... to a certain extent...
Smooth transitions are key. I had to open up the RE mani's to the point where I had to cut the gasket. To make sure they were always the same, I built a template out of some 1/4" AL so that I can quickly and accurately trim the gaskets. I then smoothed the runners and tapered them as much as possible. This was on the UIM to LIM. The LIM to the block was closer, but still a little off.

t_g_farrell · 11-15-2010, 12:18 PM

Just poking my nose in here for a second but what about reversion? Isn't that
supposed to be preserved when porting the intakes on a rotary?

***TitaniumTT*** · 11-15-2010, 01:14 PM

That's port timing, not port matching

***TitaniumTT*** · 11-15-2010, 01:22 PM

It's definately a good discussion to have but it's a whole different can of worms that's been opened a few times before. However, you're right, and it should be preserved. It's one of the reasons I believe that when it comes to port timing, less is more when porting. For example, I never touch the closing of the exhaust or the opening of the intake......

JustJeff · 11-15-2010, 08:04 PM

Quote:

Originally Posted by RETed

I think, at this point, that you're over-thinking the whole thing.
The stock intake manifold system SUCKS.
Any mods to help flow will get you gains.

-Ted

Definitely true about over thinking. In one of my threads I posted that I'm disturbingly perfectionist and I loose sleep over tiny details. Perfect example right here.

***TitaniumTT*** · 11-15-2010, 10:08 PM

It's the little details that make an entire package perform at it's peak.

Take mine for example

And FWIW, I'm an OCD perfectionist as well.

scotty305 · 11-16-2010, 12:04 AM

Cool thread. I have occasional access to a flow bench if people are interested in before/after testing or comparisons. There are some rough assumptions that must be made: mainly that the engine doesn't suck a smooth steady stream of air like the pump in the flowbench, there are quick pressure (vacuum) fluctuations as the engine 'gulps' air in while the intake ports are open. It will probably be a while before I get around to testing intake manifold porting or modifications on my car, but if anyone local wants to stop by and measure their setup(s) feel free to send a PM.

11-14-2010, 07:32 PM	#17
NoDOHC The quest for more torque Join Date: Sep 2008 Location: Sheboygan, Wisconsin Posts: 855 Rep Power: 17	The issue that we have with your runners is that we have to worry about both fuel suspension and air flow. The good news is that changes in area and steps will both hurt both. I wish that I had dyno'ed my engine before the intake maifold modification, but I am reasonably sure that it helped. __________________ 1986 GXL ('87 4-port NA - Haltech E8, LS2 Coils. Defined Autoworks Headers, Dual 2.5" Exhaust (Dual Superflow, dBX mufflers) 1991 Coupe (KYB AGX Shocks, Eibach lowering springs, RB exhaust, Stock and Automatic)

11-15-2010, 07:21 AM	#19
*TitaniumTT* Test Whore - Admin Join Date: Mar 2008 Location: Right Behind you son Posts: 4,581 Rep Power: 10	Agreed..... to a certain extent... Smooth transitions are key. I had to open up the RE mani's to the point where I had to cut the gasket. To make sure they were always the same, I built a template out of some 1/4" AL so that I can quickly and accurately trim the gaskets. I then smoothed the runners and tapered them as much as possible. This was on the UIM to LIM. The LIM to the block was closer, but still a little off. __________________ -The Angry Stig- DGRR 2009, 2011, 2012 & 2013 - Best FC DEALS GAP!! WOOHOOOO!!!!! 2015 Audi S4 - Samantha - Zero Brap S4 2004 RX8 - Jocelyn - 196rwhp, 19mpg fuel to noise converter 2000 Jeep Cherokee Sport - Wifey mobile - Now with 2.5" OME lift and 30" BFG AT KO's! So it begins 1998 Jeep Cherokee - 5 spd, 4" lift, 33" BFG's - Rotary Tow Vehicle 1988 'Vert - In progress 1988 FC Coupe - Gretchen -The attention whore BEAST! I'm a sick individual, what's wrong with you? I'm pure Evil I'm still insane, in the best possible way. I think Brian's idea of romance is using lube. Your rage caused the meteor strike in Russia. The Antichrist would be proud of his minion. You win with your thread. Most everything It's a truck with a steel gate on the back. Just a statement of fact Motec M820, AIM dash, ported 13B-RE Cosmo, 6-spd trans, 4.3 Torsen, custom twin wg fully divided mani, Custom 4" split into 2x 3" exhaust, Custom HMIC, Custom custom custom custom I like to welder stuff.... No Bolt-ons allowed. Dyno'ed @ Speed1 Tuned by me - 405rwhp on WG.... WM50 cuming soon. *-Angry Motherfcker Mode ENGAGED-**

11-15-2010, 12:18 PM	#20
t_g_farrell Waffles - hmmm good Join Date: Aug 2008 Location: Huntersville, NC Posts: 757 Rep Power: 0	Just poking my nose in here for a second but what about reversion? Isn't that supposed to be preserved when porting the intakes on a rotary? __________________ 1980 GS stockport, Fat Nikki, RB Dual Facetfuel pumps, Holley regulator, RB Street port exhaust, 2GDFIS, MR2 MK I electric fans, 2G strut bar, relayed fans, lights and fuel pump, LEDs Project Fat Nikki Budget 12A rebuild Video setup < $30.00

11-15-2010, 01:14 PM	#21
*TitaniumTT* Test Whore - Admin Join Date: Mar 2008 Location: Right Behind you son Posts: 4,581 Rep Power: 10	That's port timing, not port matching __________________ -The Angry Stig- DGRR 2009, 2011, 2012 & 2013 - Best FC DEALS GAP!! WOOHOOOO!!!!! 2015 Audi S4 - Samantha - Zero Brap S4 2004 RX8 - Jocelyn - 196rwhp, 19mpg fuel to noise converter 2000 Jeep Cherokee Sport - Wifey mobile - Now with 2.5" OME lift and 30" BFG AT KO's! So it begins 1998 Jeep Cherokee - 5 spd, 4" lift, 33" BFG's - Rotary Tow Vehicle 1988 'Vert - In progress 1988 FC Coupe - Gretchen -The attention whore BEAST! I'm a sick individual, what's wrong with you? I'm pure Evil I'm still insane, in the best possible way. I think Brian's idea of romance is using lube. Your rage caused the meteor strike in Russia. The Antichrist would be proud of his minion. You win with your thread. Most everything It's a truck with a steel gate on the back. Just a statement of fact Motec M820, AIM dash, ported 13B-RE Cosmo, 6-spd trans, 4.3 Torsen, custom twin wg fully divided mani, Custom 4" split into 2x 3" exhaust, Custom HMIC, Custom custom custom custom I like to welder stuff.... No Bolt-ons allowed. Dyno'ed @ Speed1 Tuned by me - 405rwhp on WG.... WM50 cuming soon. *-Angry Motherfcker Mode ENGAGED-**

11-15-2010, 01:22 PM	#22
*TitaniumTT* Test Whore - Admin Join Date: Mar 2008 Location: Right Behind you son Posts: 4,581 Rep Power: 10	It's definately a good discussion to have but it's a whole different can of worms that's been opened a few times before. However, you're right, and it should be preserved. It's one of the reasons I believe that when it comes to port timing, less is more when porting. For example, I never touch the closing of the exhaust or the opening of the intake...... __________________ -The Angry Stig- DGRR 2009, 2011, 2012 & 2013 - Best FC DEALS GAP!! WOOHOOOO!!!!! 2015 Audi S4 - Samantha - Zero Brap S4 2004 RX8 - Jocelyn - 196rwhp, 19mpg fuel to noise converter 2000 Jeep Cherokee Sport - Wifey mobile - Now with 2.5" OME lift and 30" BFG AT KO's! So it begins 1998 Jeep Cherokee - 5 spd, 4" lift, 33" BFG's - Rotary Tow Vehicle 1988 'Vert - In progress 1988 FC Coupe - Gretchen -The attention whore BEAST! I'm a sick individual, what's wrong with you? I'm pure Evil I'm still insane, in the best possible way. I think Brian's idea of romance is using lube. Your rage caused the meteor strike in Russia. The Antichrist would be proud of his minion. You win with your thread. Most everything It's a truck with a steel gate on the back. Just a statement of fact Motec M820, AIM dash, ported 13B-RE Cosmo, 6-spd trans, 4.3 Torsen, custom twin wg fully divided mani, Custom 4" split into 2x 3" exhaust, Custom HMIC, Custom custom custom custom I like to welder stuff.... No Bolt-ons allowed. Dyno'ed @ Speed1 Tuned by me - 405rwhp on WG.... WM50 cuming soon. *-Angry Motherfcker Mode ENGAGED-**

11-14-2010, 07:20 PM	#16
JustJeff RCC Contributor Join Date: Mar 2008 Posts: 505 Rep Power: 18	^NoDOHC Makes perfect sense to me and helps solidfy what seemed logical in concept. Explaining it in terms of energy spent follows right along with what I was thinking. My thoughts were that if you suddenly give pressurized air MORE space it's going to create "turbulance" as it expands. Then when the chamber/runner constricts back down it requires more energy to press the air back into the smaller area. You're pressing the air against an angled surface and the suspended fuel is going to hit the side and come out of suspension. That scenario seems equally damaging to the process as having a lip exposed.

11-15-2010, 10:08 PM	#24
*TitaniumTT* Test Whore - Admin Join Date: Mar 2008 Location: Right Behind you son Posts: 4,581 Rep Power: 10	It's the little details that make an entire package perform at it's peak. Take mine for example And FWIW, I'm an OCD perfectionist as well. __________________ -The Angry Stig- DGRR 2009, 2011, 2012 & 2013 - Best FC DEALS GAP!! WOOHOOOO!!!!! 2015 Audi S4 - Samantha - Zero Brap S4 2004 RX8 - Jocelyn - 196rwhp, 19mpg fuel to noise converter 2000 Jeep Cherokee Sport - Wifey mobile - Now with 2.5" OME lift and 30" BFG AT KO's! So it begins 1998 Jeep Cherokee - 5 spd, 4" lift, 33" BFG's - Rotary Tow Vehicle 1988 'Vert - In progress 1988 FC Coupe - Gretchen -The attention whore BEAST! I'm a sick individual, what's wrong with you? I'm pure Evil I'm still insane, in the best possible way. I think Brian's idea of romance is using lube. Your rage caused the meteor strike in Russia. The Antichrist would be proud of his minion. You win with your thread. Most everything It's a truck with a steel gate on the back. Just a statement of fact Motec M820, AIM dash, ported 13B-RE Cosmo, 6-spd trans, 4.3 Torsen, custom twin wg fully divided mani, Custom 4" split into 2x 3" exhaust, Custom HMIC, Custom custom custom custom I like to welder stuff.... No Bolt-ons allowed. Dyno'ed @ Speed1 Tuned by me - 405rwhp on WG.... WM50 cuming soon. *-Angry Motherfcker Mode ENGAGED-**

11-16-2010, 12:04 AM	#25
scotty305 Rotary Fan in Training Join Date: Mar 2008 Location: Culver City, CA Posts: 84 Rep Power: 18	Cool thread. I have occasional access to a flow bench if people are interested in before/after testing or comparisons. There are some rough assumptions that must be made: mainly that the engine doesn't suck a smooth steady stream of air like the pump in the flowbench, there are quick pressure (vacuum) fluctuations as the engine 'gulps' air in while the intake ports are open. It will probably be a while before I get around to testing intake manifold porting or modifications on my car, but if anyone local wants to stop by and measure their setup(s) feel free to send a PM.