My goal is to get 25+ mpg from my 99 XJ with 30 x 9.5 R15 ATs - Page 11 - JeepForum.com
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post #151 of 3865 Old 07-28-2013, 06:09 PM Thread Starter
Charley3
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Quote:
Originally Posted by ninjakid View Post
Got a question for those of you in this thread.
Slight derailment from the current discussion but relevant to aerodynamics.
What does your front end look like facing it directly?
How much of a gap between the bumper and grill?
Attachment 650445
What I was doing today.
Mocking up a test insert using foam packaging I found lying around.
PO slid into a fire hydrant years ago and even with the front clip and pretty much everything else replaced all the mounts (no frame issues at least) are tweaked so there is more than a inch of gap on the passenger side and 1/2 a inch on the right.
Air going through that gap was just slamming into the frame that supports the radiator.
What is the gap like for you guys?
I have less gap than you do for sure.


Warning: I often edit my posts a few times to get them complete or correct errors.
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post #152 of 3865 Old 07-28-2013, 07:34 PM
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Yeah, I really didn't do a great job of describing oil numbers. Let me put a little more effort into making it as understandable as I can (cuz they're not the most intuitive).

5w-40 example. When the oil is cold, it acts like a 5 weight would WHEN COLD; a 5 weight oil would be insanely thin when hot. As it gets hotter, basically, there are polymers that change their shape in order to "transform" the oil into a 40 weight. By the time it hits 100 deg C, it acts like a 40 weight would WHEN HOT; cold 40 weight oil would be crazy thick when cold.

I'd like to add that "cold" is defined as some temperature below 0 deg C and varies from one winter grade to another. "Hot" is defined as 100 deg C.

FYI, a cold 5 weight is still thicker than a hot 40 weight.

Reality: the science used to rate these oils isn't as precise as it could be, and lots of gray areas develop especially in regards to what viscosities an oil has over a range of non-standardized temperatures, how well it holds-up over time, how well it holds-up to multiple heat cycles, and how it behaves under pressure (both literal and figurative).

I think that's plenty oil talk for this MPG thread. Regarding aerodynamics again, wheel wells are a major culprit also. At speed, tires "scoop" air up into the wells and generate some nasty turbulence. If you look at many high speed automobiles, they have ports on their sides that allow air to flow freely out of the wheel wells. Porting our wheel wells isn't really practical, but there are things that can be done to reduce the impact such as deflecting air away from the tires to reduce how much hits the tires and gets spun into the wells--I've thought of fabbing small shields to place at at the base of the front of my rear fender flares to redirect air either under the vehicle or out to the sides (probably under).

Build Thread -- https://www.jeepforum.com/forum/f177/whats-chrokeese-build-thread-2525690/
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post #153 of 3865 Old 07-28-2013, 08:21 PM
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Quote:
Originally Posted by mschi772 View Post
Yeah, I really didn't do a great job of describing oil numbers. Let me put a little more effort into making it as understandable as I can (cuz they're not the most intuitive).

5w-40 example. When the oil is cold, it acts like a 5 weight would WHEN COLD; a 5 weight oil would be insanely thin when hot. As it gets hotter, basically, there are polymers that change their shape in order to "transform" the oil into a 40 weight. By the time it hits 100 deg C, it acts like a 40 weight would WHEN HOT; cold 40 weight oil would be crazy thick when cold.

I'd like to add that "cold" is defined as some temperature below 0 deg C and varies from one winter grade to another. "Hot" is defined as 100 deg C.

FYI, a cold 5 weight is still thicker than a hot 40 weight.

Reality: the science used to rate these oils isn't as precise as it could be, and lots of gray areas develop especially in regards to what viscosities an oil has over a range of non-standardized temperatures, how well it holds-up over time, how well it holds-up to multiple heat cycles, and how it behaves under pressure (both literal and figurative).

I think that's plenty oil talk for this MPG thread. Regarding aerodynamics again, wheel wells are a major culprit also. At speed, tires "scoop" air up into the wells and generate some nasty turbulence. If you look at many high speed automobiles, they have ports on their sides that allow air to flow freely out of the wheel wells. Porting our wheel wells isn't really practical, but there are things that can be done to reduce the impact such as deflecting air away from the tires to reduce how much hits the tires and gets spun into the wells--I've thought of fabbing small shields to place at at the base of the front of my rear fender flares to redirect air either under the vehicle or out to the sides (probably under).
Check out one of my earlier posts where I brought this up. I may or may not have made mention of an idea or two. I have a "special project" that we are working on trying to get all of the theory and testing out of the way. We are trying to eliminate those high-pressure wells. Idea one: Draw air for CAI from there. Two: Vent the fender wells through to the louvered hood. Three: Vent through the transmission tunnel. Why is porting the Fender wells impractical? Also, reduce all of the effects by pushing the wheel out flush with the fenders, running as solid a wheel as possible (think moon style), filling the fender area with as much tire as possible, and running with the fender wells as full as possible.

Fender skirts would be a big help, but I do have my limits.
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post #154 of 3865 Old 07-28-2013, 10:12 PM Thread Starter
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Quote:
Originally Posted by Newtons3 View Post
Check out one of my earlier posts where I brought this up. I may or may not have made mention of an idea or two. I have a "special project" that we are working on trying to get all of the theory and testing out of the way. We are trying to eliminate those high-pressure wells. Idea one: Draw air for CAI from there. Two: Vent the fender wells through to the louvered hood. Three: Vent through the transmission tunnel. Why is porting the Fender wells impractical? Also, reduce all of the effects by pushing the wheel out flush with the fenders, running as solid a wheel as possible (think moon style), filling the fender area with as much tire as possible, and running with the fender wells as full as possible.

Fender skirts would be a big help, but I do have my limits.
I think moon wheels might prevent enough air from getting the brakes and air cooling them when driving down mountains, etc. Over heated brake rotors warp. Not sure about drums.

I always look for an open wheel to cool brakes better.

Though of course you have a point for reducing wind drag.

===

Yes, I do down-shift for hills when appropriate, but sometimes down-shifting is not enough. Often I have to ride brakes down a mountain here. So more air-flow to brakes is my preference, even if it costs me some fuel economy from drag.

Warning: I often edit my posts a few times to get them complete or correct errors.
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post #155 of 3865 Old 07-28-2013, 10:27 PM
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Quote:
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I have less gap than you do for sure.
Guess that's what happens when a person loses control on icy pavement and hits something at 25.

Took a 70 mile trip with the foam installed and no movement and slightly less howling when driving at 55.

Discovered there are rolls of hvac sheet metal behind work from constructing the place 7 years ago.
Hope to do something like fastplastic has done.

Is pressure in a cherokee wheel well as much as a sports car with its small enclosed wells or is it the turbulance thats the bigger issue?

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post #156 of 3865 Old 07-29-2013, 02:30 AM Thread Starter
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That wonderfully awesome Flexalite radiator with triple electric fans is to expensive. It's the best thing, but to much money.

So I'm going to replace my stock mechanical fan with an electric fan. I need to figure out what to buy. Then I can save money, and continue using my stock electric fan and radiator which are in great condition.

Does anyone have recommendations for an electric fan to replace my mechanical fan? A kit would be ideal, or a link to a write up. Looking for easy and effective, if possible.

Warning: I often edit my posts a few times to get them complete or correct errors.
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post #157 of 3865 Old 07-29-2013, 04:28 AM
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Quote:
Originally Posted by Charley3
That wonderfully awesome Flexalite radiator with triple electric fans is to expensive. It's the best thing, but to much money.

So I'm going to replace my stock mechanical fan with an electric fan. I need to figure out what to buy. Then I can save money, and continue using my stock electric fan and radiator which are in great condition.

Does anyone have recommendations for an electric fan to replace my mechanical fan? A kit would be ideal, or a link to a write up. Looking for easy and effective, if possible.
Search Taurus electric fan....
On another note anyone have any data to back up that a 205 thermostat will gain you a mpg or 2 iv seen claims up to 4mpg........

"****, I might **** around and bring the Jeep back No doors on it, flexin' with the seat back"
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post #158 of 3865 Old 07-29-2013, 05:27 AM
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here are a few things ive picked up
  1. having synth gear oil helps
  2. also take a look underneath see what sticks out and gets in the air flow path , hammer grind and reroute as needed
  3. the best way to loose a pound is to find 16 places to loose an ounce
  4. hi energy ignitions help but sometimes dont mesh with cats
  5. 4 hole injectors atomize fuel better period
  6. put a little more air in the tires
  7. brake caliper need to be 100%
  8. the best plugwires and coils arent gonna hurt
  9. dont have a single exhaust leak

Quote:
Originally Posted by Charley3 View Post

Does anyone have recommendations for an electric fan to replace my mechanical fan? A kit would be ideal, or a link to a write up. Looking for easy and effective, if possible.
twin taurus e fans , trim to fit radiator

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post #159 of 3865 Old 07-29-2013, 11:19 AM
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How does a high energy ignition mess with a cat? Also, Ive never seen any evidence that four hole injectors atomize better/worse than any others.
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post #160 of 3865 Old 07-29-2013, 11:33 AM
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Originally Posted by Newtons3 View Post
How does a high energy ignition mess with a cat? Also, Ive never seen any evidence that four hole injectors atomize better/worse than any others.
the best ignition for burning fuel was dropped when cats arrived because if you burn the fuel too well it makes the emissions worse

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post #161 of 3865 Old 07-29-2013, 11:48 AM
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I'm very skeptical about that ignition-cat claim, but I strongly value cats for what they do ad would never want to inadvertently compromise one, so if you have a supporting source, I'm interested in seeing it.

I've seen some demos comparing atomization of single and multi he injectors and did see a clear difference, but there may have been some bias.

Build Thread -- https://www.jeepforum.com/forum/f177/whats-chrokeese-build-thread-2525690/
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post #162 of 3865 Old 07-29-2013, 12:00 PM
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Charley, thank you very much for correcting the info on the t-stat. I just ordered one up! I will definitely be following this thread so that I can make some adjustments to my rig. Unfortunately, mine is going to mainly be a commuter/ski vehicle with a large roof box on the top. So that will hurt the mileage a bit, but doing some of these mods should help me gain a little back.

Thanks for the info everyone!
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post #163 of 3865 Old 07-29-2013, 12:18 PM
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Quote:
Originally Posted by mschi772 View Post
I'm very skeptical about that ignition-cat claim, but I strongly value cats for what they do ad would never want to inadvertently compromise one, so if you have a supporting source, I'm interested in seeing it.
it has to do with how much un burnt fuel the converter needs to do it job

it ( the converter ) burns the extra fuel to get/stay hot and seperate the gasses and do other things on sub par ( less expensive ) converters

link > put your tin foil on

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post #164 of 3865 Old 07-29-2013, 12:50 PM
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Was looking up a stuff about the oil cooler/warmers and I am almost positive the one hesco is selling is a aftermarket heat exchanger used on the majority of the late model 1.8t, 2.0 8v and 1.9 TDI VW and Audi Models.


VW filter: 2.47 gasket I.D, 2.75 O.D., 3/4-16 thread.
4.0 filter: 2.42 gasket I.D., 2.8 O.D., 3/4-16 thread.
http://www.fcpeuro.com/products/audi...ehr-078117021a
http://www.amazon.com/Dorman-918-140...sim_sbs_auto_2
New ones can be found for 40'ish online.
Can probably find one cheaper but a 3/4-16 3 1/2 tube.
http://www.ebay.com/itm/Oil-Cooler-H...-/370044253738
Not sure about the nut but finding one would be easy enough.
Think I'll try this when I do a oil change in a couple months.
A lot cheaper than hesco if it is the same.
You guys think it'll fit?

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87 Wrangler, 4.2, TF999, NP231
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post #165 of 3865 Old 07-29-2013, 12:54 PM
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^Yep, that is the one that is on my 04 Audi 1.8T. I would highly recommend FCPEuro, they are awesome. Free shipping over $25 and a basically unlimited return policy. I have ordered tons of stuff for my Audi from those guys.
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