Intake Manifolds opened to reveal VIS - Page 2

jigga622 · 01-21-03, 02:32 PM

man you guys are nuts. i'm just worried about my headgasket going.

*Dv8* · 01-23-03, 02:07 PM

the upper Intake manifold, is rough, very rough. is it worth spending 395 to have extrude hone polish it up? Does it seem like a bottle neck? For the moment forget about the exhaust manifold, pretent they are optimal.

~Hybrid

Dave C ver2.0 · 01-23-03, 03:00 PM

If you want to get maximum possible performance: Yes.

**B+O** · 01-24-03, 01:20 PM

Quote:

Originally posted by Dv8
the upper Intake manifold, is rough, very rough. is it worth spending 395 to have extrude hone polish it up? Does it seem like a bottle neck? For the moment forget about the exhaust manifold, pretent they are optimal.

~Hybrid

you'd be suprised at how little amount of roughness can hurt power... its worth the the money...might even take (speculation of course) a tenth, maybe less off your time.

Just some guy · 01-26-03, 10:39 PM

From Experience...
I you decide to D.I.Y. you might want to invest in the highest RPM drill you can find, buy the proper grinding bits and polishing wire brushes.
You can spend a good 3 days (5 straight hours each day) and do a very good job.
If you want to know the whole process just ask me, but its very long. Gains are minimal. a good (.1) can be dropped. If you decide to send it to Extrude Hone you probably wont gain much more. I put my life into that intake manifold and I was just happy that I did feel the slightest gain. Good Luck

**502 MotorSports** · 01-26-03, 11:26 PM

I think I like your sig [some guy]...that's a good start...now make it work for you bro...just be cool, and remember what I said

NickD · 01-27-03, 06:10 PM

If you don't send it to Extrude Hone go to a body shop and have them hot tank it. That will get rid of all oil deposits, grime buildup and lef over gasket peices. Making it much easier for you to start porting and polishing it. Additioanlly you can have it bead blasted for asthetics. It comes out that dull, pure aluminum color, I then clearcoated and baked mine for a nice look. But you can paint it any color you wish at that point.

After you port and polish anything have it sent back to the machine shop to be hot tanked to assure all metal filings and any residue left over from the polishing process have been removed. Hot tanking is cheap, I was charged ~$15/peice and it's worth it for cleaning. Saves endless hours of sitting there with wire brushes, carbuerator cleaner and laquer thinner scrubbing away.

Dave C ver2.0 · 01-27-03, 06:38 PM

Quote:

Originally posted by NickD
If you don't send it to Extrude Hone go to a body shop and have them hot tank it.

You do mean machine shop don't you Nick?

NickD · 01-27-03, 06:41 PM

Quote:

Originally posted by Dave C ver2.0

You do mean machine shop don't you Nick?

Oh yeah, a machine shop would probably be better... :p

Thanks Dave

Dave C ver2.0 · 01-28-03, 02:09 PM

Unlocked. Contentious posts deleted.

BlackIICoupe · 02-18-03, 01:31 PM

Variable Intake Systems
I'm familiar with several engines that use a variable intake charge system. Toyota calls it TVIS; For Mazda it's VICS....regardless of the name or manufacturer, the priciple is the same:

The heads are optimized for breathing the large amounts of air needed at high RPMs, but this causes a problem....at low RPM's the smaller volume of air is moving too slowly to mix well and give you the torque you so desperately want and desire. A valving system is introduced into the intake manifold to reduce the flow rate, in turn speeding up the smaller intake charge, causing it to mix better and burn more fully and evenly.

As for removal--- that's a highly charged(pun intended) debate in any engine forum that has any type of VIC system, and there's theory, evidence, and dyno sheets to back up any side. But for the most part, a stock engine generally needs it;badly in some cases. A mild to moderately modded engine= arguements. It's a balance of what you have, what you want, and what you want to give up. Most cases of "productive" removal involve cams and/or cam timing. For instance, my little MR2 had the TVIS removed, but the exhaust cam has been adjusted to bring back the low end. Heavily modded and big forced induction-- yeah, you'd probably want it out of the way....but that's not for me to say, every project is different.

Porting and Polishing
In the head, porting and polishing is often done, though modern day engines don't respond as well to this as much as the old days without there already being other mods which the ports in the head are becoming a bottleneck for. Here's the key though--

Porting is for moving a larger volume of air.
Polishing is for increasing speed of the air flow.

Here's the kicker though....most old school engines are ported on both intake and exhaust, but only the exhaust ports are polished! The reason being is that the small amount of surface "rough", though not as bad as what you're describing in the manifold DV8- just not shiny, is good for tumbling the air a bit to help mix that air/fuel some more. But the exhaust side you want moving out as fast as possible, and a nice polished port helps create the laminar flow that really gets those gases moving, and improves scavenging.

And lastly(mostly directed to DV8), the oil in the manifold can be pretty normal, especially since I'm guessing you like staying high in the revs?

Where that oil is from is most likely from the PCV line. Pick up(or make) a catch can, and install it to prevent it from getting that bad again.

**502 MotorSports** · 04-02-03, 04:29 AM

unsticking and adding to the FAQ.

Thanks Chris

Merlin the Wrench · 07-15-08, 01:07 AM

will give you a hot tip for max power. (1) the Legend is too heavy and the suspension to fragile to be a real racer so we should all give up on trying to do this and enjoy the comfort and ride of a wonderful touring type car. There is no finer.

(2) If you must race and want to have it ported, don't make the porting so smooth that it is like a mirror or you will create a laminar flow and get less air through than if it was a little rough. If the flow becomes a laminar flow, you will lose perhaps more flow than a stock manifold at high rpm. (3) pay equal attention to the back side of the valves. Consider swirl cutting and polishing them. 3 angle minimum. Flow each valve. (4) My guess, and it is only a guess, is that the throttle body and exhaust manifolds are more limiting to HP on our engines than the manifold and heads. Someone willing to spend some time on a dyno tuning these items into a better flowing air intake and set of headers would probably benefit more from it then they realize. It isn't just about size, harmonics have a lot to do with getting air through an engine. Air + fuel = hp. More air, more HP.

Last - I don't differ with the prior post as to laminar flow down a straight exhaust pipe because it probably doesn't happen except at the outside edges of the flow. Laminar flow in an intake manifold on the downside of a turn can significantly cut the size of the flow.

uPnoRthACme · 07-15-08, 02:14 AM

Wow, I think that's a record ressurection.

5 years 3 months.

A lot has changes since those posts merlin. Thanks for the input though.

The legend is heavy, but weight reduction is a must. I have managed 380lbs in track form. 340 lbs in DD form.

About the suspension. Independent rear and wishbone front? Thats a pretty nice set up if you ask me. Stock springs and struts need to go though if you plan on racing, K sports are the answer.

Merlin the Wrench · 07-15-08, 12:35 PM

Beautiful design but light. Found that out when a gal in a rabbit tapped my right front when she changed lanes about 10 years ago into my 1992, it completely collapsed with the tire under the wheelwell. Her rabbit was barely dented on her fender. My whole right front suspension was trashed and the car ended up totaled from the damage it did.

01-23-03, 02:07 PM	#17 (permalink)
Dv8 Banned Join Date: Jan 2002 Location: CA Posts: 4,865 Car 1: 91' 3.5lt Extreme DV8ED Hybrid 6spd Car 2: 03' G35c Blk on Blk Car 3: 92'Yukon/06'Trailer iTrader: (11)	the upper Intake manifold, is rough, very rough. is it worth spending 395 to have extrude hone polish it up? Does it seem like a bottle neck? For the moment forget about the exhaust manifold, pretent they are optimal. ~Hybrid __________________ AEM EMS Powered. 9 yrs and counting. Results, Where are yours? 12.953@107.865MPH 95 deg. Jun. 07' 3.5 6spd-#55 jet Nitrous 316WHP@5500RPM 345Lb-ft@4100RPM NOS 06-07'N/A 234WHP@5700RPM 229lb-ft@4600RPM 06-07' 13.782@99.135MPH N/A 95 deg. Jun 07' 03' G35c Auto Vortech Supercharged pshhhh 311WHP 274WTQ13.1@102MPH-on the brakes(108MPH) Hand fabbed Go-Kart 18whp 24wtq 8 page spread Honda Tuning 09-06' issue PM or Email only. Respect that! My Legends Website www.2slik4u.com

01-23-03, 03:00 PM	#18 (permalink)
Dave C ver2.0 rh eller Join Date: Jan 2002 Location: Rockville Md Posts: 1,951 Car 1: 92 L sedan and 88 LS sedan (wifes) iTrader: (1)	If you want to get maximum possible performance: Yes. __________________ Started rebuilding IC engines in 1968 at the US Merchant Marine Academy. Don't think you know more than me about auto/IC/control systems unless you can document your education.

01-26-03, 10:39 PM	#20 (permalink)
Just some guy Registered User Join Date: Jan 2003 Location: Ft. Lauderdale, FL Posts: 6 Car 1: 94 White Coupe iTrader: (0)	From Experience... I you decide to D.I.Y. you might want to invest in the highest RPM drill you can find, buy the proper grinding bits and polishing wire brushes. You can spend a good 3 days (5 straight hours each day) and do a very good job. If you want to know the whole process just ask me, but its very long. Gains are minimal. a good (.1) can be dropped. If you decide to send it to Extrude Hone you probably wont gain much more. I put my life into that intake manifold and I was just happy that I did feel the slightest gain. Good Luck __________________ Its all MENTAL. The KEY to sucess is Strength in knowledge. Last edited by Just some guy : 01-26-03 at 11:56 PM.

01-26-03, 11:26 PM	#21 (permalink)
502 MotorSports 502MotorSports.com Join Date: Jan 2002 Location: ATLVILLE Posts: 9,445 Car 1: e39 540i Car 2: e46 325xi \| e46 330i Car 3: S430 iTrader: (0)	I think I like your sig [some guy]...that's a good start...now make it work for you bro...just be cool, and remember what I said __________________ The Hotness! Elevate Your Standards.... Legend Mod Money! Jasmyn \| Final e39 Pics \| 502MotorSports MySpace

01-27-03, 06:10 PM	#22 (permalink)
NickD Bk F*er Join Date: Jan 2002 Location: Lebanon, NJ Posts: 2,633 Car 1: 1991 Frost White L Sedan Car 2: 1999 BMW 328i 5speed iTrader: (0)	If you don't send it to Extrude Hone go to a body shop and have them hot tank it. That will get rid of all oil deposits, grime buildup and lef over gasket peices. Making it much easier for you to start porting and polishing it. Additioanlly you can have it bead blasted for asthetics. It comes out that dull, pure aluminum color, I then clearcoated and baked mine for a nice look. But you can paint it any color you wish at that point. After you port and polish anything have it sent back to the machine shop to be hot tanked to assure all metal filings and any residue left over from the polishing process have been removed. Hot tanking is cheap, I was charged ~$15/peice and it's worth it for cleaning. Saves endless hours of sitting there with wire brushes, carbuerator cleaner and laquer thinner scrubbing away. __________________ 1991 Legend L Hybrid (gallery) 1989 Legend L 5speed (totaled) 1999 BMW 328i 5 speed http://demandred.dyndns.org/sig-small.jpg http://demandred.dyndns.org/bmw-small-sig.png

01-21-03, 02:32 PM	#16 (permalink)
jigga622 Banned Join Date: Feb 2002 Location: pa Posts: 2,960 Car 1: 94 ls 6-speed black on tan iTrader: (0)	man you guys are nuts. i'm just worried about my headgasket going.

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01-28-03, 02:09 PM	#25 (permalink)
Dave C ver2.0 rh eller Join Date: Jan 2002 Location: Rockville Md Posts: 1,951 Car 1: 92 L sedan and 88 LS sedan (wifes) iTrader: (1)	Unlocked. Contentious posts deleted. __________________ Started rebuilding IC engines in 1968 at the US Merchant Marine Academy. Don't think you know more than me about auto/IC/control systems unless you can document your education.

02-18-03, 01:31 PM	#26 (permalink)
BlackIICoupe Fast & Furry-ous Join Date: Feb 2003 Location: N. Illinois Posts: 99 Car 1: 1993 Black Legend L 6spd Coupe iTrader: (0)	Hey, a chance for the new guy to give some insight!!! Variable Intake Systems I'm familiar with several engines that use a variable intake charge system. Toyota calls it TVIS; For Mazda it's VICS....regardless of the name or manufacturer, the priciple is the same: The heads are optimized for breathing the large amounts of air needed at high RPMs, but this causes a problem....at low RPM's the smaller volume of air is moving too slowly to mix well and give you the torque you so desperately want and desire. A valving system is introduced into the intake manifold to reduce the flow rate, in turn speeding up the smaller intake charge, causing it to mix better and burn more fully and evenly. As for removal--- that's a highly charged(pun intended) debate in any engine forum that has any type of VIC system, and there's theory, evidence, and dyno sheets to back up any side. But for the most part, a stock engine generally needs it;badly in some cases. A mild to moderately modded engine= arguements. It's a balance of what you have, what you want, and what you want to give up. Most cases of "productive" removal involve cams and/or cam timing. For instance, my little MR2 had the TVIS removed, but the exhaust cam has been adjusted to bring back the low end. Heavily modded and big forced induction-- yeah, you'd probably want it out of the way....but that's not for me to say, every project is different. Porting and Polishing In the head, porting and polishing is often done, though modern day engines don't respond as well to this as much as the old days without there already being other mods which the ports in the head are becoming a bottleneck for. Here's the key though-- Porting is for moving a larger volume of air. Polishing is for increasing speed of the air flow. Here's the kicker though....most old school engines are ported on both intake and exhaust, but only the exhaust ports are polished! The reason being is that the small amount of surface "rough", though not as bad as what you're describing in the manifold DV8- just not shiny, is good for tumbling the air a bit to help mix that air/fuel some more. But the exhaust side you want moving out as fast as possible, and a nice polished port helps create the laminar flow that really gets those gases moving, and improves scavenging. And lastly(mostly directed to DV8), the oil in the manifold can be pretty normal, especially since I'm guessing you like staying high in the revs? Where that oil is from is most likely from the PCV line. Pick up(or make) a catch can, and install it to prevent it from getting that bad again. __________________ JD http://home.comcast.net/~spastic_muse/cres_sig.jpg Black '93 Legend L 6spd Coupe Black '87 Toyota MR2 T-bar

04-02-03, 04:29 AM	#27 (permalink)
502 MotorSports 502MotorSports.com Join Date: Jan 2002 Location: ATLVILLE Posts: 9,445 Car 1: e39 540i Car 2: e46 325xi \| e46 330i Car 3: S430 iTrader: (0)	unsticking and adding to the FAQ. Thanks Chris __________________ The Hotness! Elevate Your Standards.... Legend Mod Money! Jasmyn \| Final e39 Pics \| 502MotorSports MySpace

07-15-08, 01:07 AM	#28 (permalink)
Merlin the Wrench Registered User Join Date: Jan 2003 Location: sacramento Posts: 863 Car 1: 1995 L sedan; past 1992 L sedan iTrader: (0)	don't make it that smooth will give you a hot tip for max power. (1) the Legend is too heavy and the suspension to fragile to be a real racer so we should all give up on trying to do this and enjoy the comfort and ride of a wonderful touring type car. There is no finer. (2) If you must race and want to have it ported, don't make the porting so smooth that it is like a mirror or you will create a laminar flow and get less air through than if it was a little rough. If the flow becomes a laminar flow, you will lose perhaps more flow than a stock manifold at high rpm. (3) pay equal attention to the back side of the valves. Consider swirl cutting and polishing them. 3 angle minimum. Flow each valve. (4) My guess, and it is only a guess, is that the throttle body and exhaust manifolds are more limiting to HP on our engines than the manifold and heads. Someone willing to spend some time on a dyno tuning these items into a better flowing air intake and set of headers would probably benefit more from it then they realize. It isn't just about size, harmonics have a lot to do with getting air through an engine. Air + fuel = hp. More air, more HP. Last - I don't differ with the prior post as to laminar flow down a straight exhaust pipe because it probably doesn't happen except at the outside edges of the flow. Laminar flow in an intake manifold on the downside of a turn can significantly cut the size of the flow. __________________ Best Wishes Steve Last edited by Merlin the Wrench : 07-15-08 at 01:18 AM.

07-15-08, 02:14 AM	#29 (permalink)
uPnoRthACme Registered User Join Date: Mar 2005 Location: Haverhill, Massholechusetts Posts: 817 Car 1: 92 Ls sedan Blk/type F Car 2: 94 6-spd Coupe Car 3: sr20det gt2871 240sx iTrader: (10)	Wow, I think that's a record ressurection. 5 years 3 months. A lot has changes since those posts merlin. Thanks for the input though. The legend is heavy, but weight reduction is a must. I have managed 380lbs in track form. 340 lbs in DD form. About the suspension. Independent rear and wishbone front? Thats a pretty nice set up if you ask me. Stock springs and struts need to go though if you plan on racing, K sports are the answer.

07-15-08, 12:35 PM	#30 (permalink)
Merlin the Wrench Registered User Join Date: Jan 2003 Location: sacramento Posts: 863 Car 1: 1995 L sedan; past 1992 L sedan iTrader: (0)	front sus Beautiful design but light. Found that out when a gal in a rabbit tapped my right front when she changed lanes about 10 years ago into my 1992, it completely collapsed with the tire under the wheelwell. Her rabbit was barely dented on her fender. My whole right front suspension was trashed and the car ended up totaled from the damage it did. __________________ Best Wishes Steve

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