Recent Topics
Longo Toyota, El Monte, CA Sale Expires 10/31/2014
by Cristobal
16 minutes 25 seconds ago
How to Determine Air Compressor CFM Output
by threeputtpar
23 minutes 17 seconds ago
My Biggest Driving Pet Peeve
by DBMaster
24 minutes 53 seconds ago
Shaky wheel and vibration when braking - causes?
by itguy08
40 minutes 16 seconds ago
Buying a canadian car and towing it across
by stockrex
42 minutes 9 seconds ago
Tallahassee 's finest
by stockrex
44 minutes 9 seconds ago
looking of opinion... oil for cherokee 4.0 DD
by hcbarger
47 minutes 34 seconds ago
Noticed a big MPG improvement going to Syntec 0w20
by L_Sludger
Today at 10:19 AM
Diesel additive giveaway.
by BMWTurboDzl
Today at 09:54 AM
M1 Prices at WalMart all over the place!
by racin4ds
Today at 09:52 AM
Power line quality or wiring/switch issue ?
by youdontwannaknow
Today at 08:59 AM
Excellent Dealership Experience!
by threeputtpar
Today at 08:10 AM
Newest Members
canakin, jackqa, Artistic_1, hiphop29, scotty1
51470 Registered Users
Who's Online
103 registered (ARCOgraphite, 3800Series, asand1, 04SE, 9 invisible), 1744 Guests and 174 Spiders online.
Key: Admin, Global Mod, Mod
Forum Stats
51470 Members
64 Forums
220129 Topics
3476228 Posts

Max Online: 2862 @ 07/07/14 03:10 PM
Donate to BITOG

Page 1 of 2 1 2 >
Topic Options
#3130805 - 09/20/13 02:55 PM Intake Runner Surface
84zmyfavorite Offline


Registered: 07/14/10
Posts: 648
Loc: Wenatchee, W.A.
I Thought I had finished Porting and Yes Polishing the 92 Jeep 4.0 7120 cylinder head that Im putting on my 2000 Jeep Cherokees 4.0 reBuild, when a couple of AutoTech teachers told me the intake runners are too smooth, they should be roughened up, so the fuel will atomize with the air correctly. How "Rough" or irregular should a cast iron intake runner and bowl be for correct atomization of fuel/air?


Edited by 84zmyfavorite (09/20/13 02:55 PM)

Top
#3130848 - 09/20/13 03:52 PM Re: Intake Runner Surface [Re: 84zmyfavorite]
95busa Offline


Registered: 10/15/05
Posts: 1059
Loc: Virginia
Not at all. It is port injected is it not?
_________________________
2005 Ford F250 Super Duty 4x4
2009 Dodge Grand Caravan
2006 Chrysler Pacifica Touring

Top
#3130864 - 09/20/13 04:34 PM Re: Intake Runner Surface [Re: 84zmyfavorite]
Kuato Offline


Registered: 10/23/05
Posts: 3075
Loc: Northeastern MT
Hmmm I have always been told that smoother is better, less drag on the air going in.

The injectors should be doing the atomizing, not the side walls of the intake runners!
_________________________
Amsoil

04 Jeep Wrangler 2.4, MT, 184k
13 F150 4x4, 5.0, 25k

Top
#3130882 - 09/20/13 05:02 PM Re: Intake Runner Surface [Re: 84zmyfavorite]
dparm Offline


Registered: 04/19/10
Posts: 12519
Loc: Chicago, IL
You do want some tumbling to aid in atomization, yes. It largely depends on the design of the plenum and runners, however.
_________________________
2011.5 BMW M3 saloon ZCP
der stärkste buchstabe der welt
Castrol Edge Professional TWS 10w60 + Mahle OX 254D3

Top
#3130896 - 09/20/13 05:41 PM Re: Intake Runner Surface [Re: dparm]
OVERKILL Online   content


Registered: 04/28/08
Posts: 26271
Loc: Ontario, Canada
Originally Posted By: dparm
You do want some tumbling to aid in atomization, yes. It largely depends on the design of the plenum and runners, however.


Yes, however it is far less relevant to a SEFI engine than it is to a carbureted one smile
_________________________
Network Engineer
02 Expedition
01 BMW ///M5
06 Charger R/T

Top
#3130967 - 09/20/13 07:14 PM Re: Intake Runner Surface [Re: 84zmyfavorite]
Oldmoparguy1 Online   content


Registered: 01/21/05
Posts: 4037
Loc: Charlotte, NC
Smooth is better in general for high rpm full throttle operation. For every other regime, a lightly pebbled surface is better. The closer you get to the valve the more the surface finish matters. The inside of the curve where the runner turns toward the valve is a critical area. An interesting trick is to lightly groove the high area across the runner with something like 16-20 grooves per inch a few thousandths per inch deep, just for the curved area. Looks kind of like a dull almost stripped bolt. BTDT...

Wayne
_________________________
Experience is that thing you get immediately AFTER you need it.

Top
#3131220 - 09/21/13 03:02 AM Re: Intake Runner Surface [Re: 84zmyfavorite]
Shannow Offline


Registered: 12/12/02
Posts: 26601
Loc: a prison island
A little rough in port fuel injected is good for the air...see golf balls.

As to carbs, this is the first time anywhere in the world, these pics will appear.

First three photos are of fuel being injected ahead of the throttle plate in a rectangular section inlet manifold, at varying inlet manifold actual (corrected for density) velocities.

Throttle at around 45 degrees



Open throttle


All pics at stoichiometric, and show that with a car or TBI, "atomisation" isn't that real, a lot of the fuel was still fuel.

Throttle body did a lot of "mixing", that was pretty much negated only inches downstream with over 10% of the fuel settling to the manifold floor.

Problem with it on the floor was that it's running slower than the airflow, about 10-15% of the air velocity at WOT



and at lower manifold densities, the fuel goes even slower



Steady state, same amount of fuel makes it down the hole as air, but whip the throttle open, and the fuel on the floor is picked up, and runs into the engine, and there's a momentary lean pause while the fuel film catches back up with the air...8"/second is fairly slow...thus need for accelerator pumps.

A turbulent boundary layer along the floor would have made an interesting extension to the work.

Top
#3131302 - 09/21/13 06:09 AM Re: Intake Runner Surface [Re: 84zmyfavorite]
SteveSRT8 Online   content


Registered: 10/10/08
Posts: 14866
Loc: Sunny Florida
Originally Posted By: 84zmyfavorite
I Thought I had finished Porting and Yes Polishing the 92 Jeep 4.0 7120 cylinder head that Im putting on my 2000 Jeep Cherokees 4.0 reBuild, when a couple of AutoTech teachers told me the intake runners are too smooth, they should be roughened up, so the fuel will atomize with the air correctly. How "Rough" or irregular should a cast iron intake runner and bowl be for correct atomization of fuel/air?


Smoother is good up to a particular point. Laminar flow is a big issue when tweaking for HP. The PROPER roughness allows a film to attach and then 'lubricate' the rest of the air, allowing slightly better flow and volume.

Wet manifolds have a lot more tricks as Shannows excellent photos show you. Dry manifolds are MUCH easier to tweak...
_________________________
"In a democracy, dissent is an act of faith."
J. William Fulbright
Best ET-12.79 @ 111 mph
4340 pounds, Street tires
Just like we go to Publix

Top
#3131789 - 09/21/13 06:37 PM Re: Intake Runner Surface [Re: 84zmyfavorite]
84zmyfavorite Offline


Registered: 07/14/10
Posts: 648
Loc: Wenatchee, W.A.
Thank You All for the exellent replies. The Auto Tech Instructors I was talking to used the golf ball analogy and also talked about where the runner "Blends" with the Bowl is an important area. Since I have already pushed the limit on wall thickness, a sandblaster was recommended for uniform "pebble-ing" or roughing of surface as was a Dremel, which I do have and spent using nearly 35 hours on the porting and polishing,.. Used it today for couple of hours enlarging oil return holes in Block(they were pitiful, jagged broken off holes). The Next 4.0 head I work on I will make channels or fins in the Intake runners as suggested. I have seen fins on certain intake runners, some nearly 3/8ths in tall. I will really try to get pictures on here soon. Of course Ive said that for a while now. Thanks Again!


Edited by 84zmyfavorite (09/21/13 06:41 PM)

Top
#3131804 - 09/21/13 06:54 PM Re: Intake Runner Surface [Re: 84zmyfavorite]
84zmyfavorite Offline


Registered: 07/14/10
Posts: 648
Loc: Wenatchee, W.A.
The engine is a 2000 Jeep 4.0 block and 1992 cylinder head(7120) with MultiPort Injection, equal length runner Intake manifold with rectangular runners in both manifold and cylinder head. Injectors are nearly touching cylinder head when bolted up, so only time for fuel and air to mix is in cylinder head runners.


Edited by 84zmyfavorite (09/21/13 06:56 PM)

Top
#3131913 - 09/21/13 09:03 PM Re: Intake Runner Surface [Re: 84zmyfavorite]
DuckRyder Offline


Registered: 10/20/05
Posts: 1437
Loc: Atlanta
_________________________
Robert
  • 1996 Acura 3.5RL
  • 2005 Honda Civic Sedan
  • 1972 Ford F100
  • 2012 Volkswagen Jetta TDi

Top
#3132182 - 09/22/13 08:49 AM Re: Intake Runner Surface [Re: 84zmyfavorite]
OVERKILL Online   content


Registered: 04/28/08
Posts: 26271
Loc: Ontario, Canada
Originally Posted By: 84zmyfavorite
The engine is a 2000 Jeep 4.0 block and 1992 cylinder head(7120) with MultiPort Injection, equal length runner Intake manifold with rectangular runners in both manifold and cylinder head. Injectors are nearly touching cylinder head when bolted up, so only time for fuel and air to mix is in cylinder head runners.


Sounds similar to the SEFI Ford's that fire the injector at the back of the intake valve.

Here's how my old TFS-R aligned with my ported GT40's:
_________________________
Network Engineer
02 Expedition
01 BMW ///M5
06 Charger R/T

Top
#3132570 - 09/22/13 03:33 PM Re: Intake Runner Surface [Re: 84zmyfavorite]
84zmyfavorite Offline


Registered: 07/14/10
Posts: 648
Loc: Wenatchee, W.A.
Nice, Im thinking my 99 Cherokees 4.0s manifold, gasket, cylinder head mating look like that as well. I thought That is Port Matching. where the walls and gasket are the same size dimensions, like That! I am a plumber(though New construction), I should borrow a poop Scope from a Service plumber a see what my 99s 4.0 looks like inside all bolted together. Of course Ill clean the scope first. Maby.


Edited by 84zmyfavorite (09/22/13 03:36 PM)

Top
#3132573 - 09/22/13 03:38 PM Re: Intake Runner Surface [Re: 84zmyfavorite]
84zmyfavorite Offline


Registered: 07/14/10
Posts: 648
Loc: Wenatchee, W.A.
Thanks DuckRyder.

Top
#3132609 - 09/22/13 04:13 PM Re: Intake Runner Surface [Re: 84zmyfavorite]
OVERKILL Online   content


Registered: 04/28/08
Posts: 26271
Loc: Ontario, Canada
Originally Posted By: 84zmyfavorite
Nice, Im thinking my 99 Cherokees 4.0s manifold, gasket, cylinder head mating look like that as well. I thought That is Port Matching. where the walls and gasket are the same size dimensions, like That! I am a plumber(though New construction), I should borrow a poop Scope from a Service plumber a see what my 99s 4.0 looks like inside all bolted together. Of course Ill clean the scope first. Maby.


That's the idea thumbsup

My heads were port-matches to a Felpro 1250. The intake, out of the box, matches a Felpro 1250. So the alignment was very close to perfect.
_________________________
Network Engineer
02 Expedition
01 BMW ///M5
06 Charger R/T

Top
Page 1 of 2 1 2 >