A Lot Of You Were Dead On With Your What You Figured To Be My Upgrade. Many Were Just Humorous, Some Conveyed Viable Ideas On Addressing The Issue, And Then There Were Those That Had Nothing To Contribute Beyond Bitching.

Sorry I Upset So Many Of The **** Retentives Out There, Was Just Trying To Have A Little Fun With This And Hopefully Get Some Other Input From Other Members On Their Successes With Attaining More Power While Getting Better Gas Mileage.

**hks Twin Power
**new Platinum Plugs
**new Taylor Plug Wires
**0w30 Synth Oil
The Twin Power Was Installed After The Other Mods And Oil Change. The Other Items Listed Above Had A Positive But Minimal Effect On Mileage And Performance. The Hks Made A Very Noticeable Difference.

Im Currently Running A Rich Mixture And Have Enough Room To Lean Out The Mix. Im Designing And Building A Custom Carbon Fiber Air Filter Box Which Will Lean The Mix Once Installed. I Expect To Improve My Gas Mileage Even More At That Point And My Performance Should Improve As Well.

Before The Install 12-16 Mpg Around Town And On The Highway.

After The Install 16-20 Mpg Around Town And On The Highway.

On A Recent Road Trip I Was Able To Get Almost 24 Mpg Over 19mpg Prior To The Install.

My Driving Habits For The Comparisons Was Essentially The Same With The Occasional Spirited Run.

As I Mentioned In My Thread That Was Eliminated From Public Scrutiny, I Should Be Able To Recover My Investment For The Hks In About 8 Months Based On $3.00 Per Gallon Gas Price. Not Bad Considering The Phenomenal Performance Difference Im Currently Getting. I Dont Think You Can Lose Over The Long Run, For Me It Was Money Well Spent.

Oh, Sorry About The Caps. Just Thought I Give Some Of You Something Else To Bitch About.

Chuck

 

why dont you get iridium plugs?

 

Sorry buddy but I've had twin powers on many of these cars and the mileage is not significantly different. I always avg about 12 mpg on the street and 4 or 5 on the track

 

You do realize that a healthy FD is rated at 19 mpg on the highway right? The HKS TP didn't improve your gas mileage, it simply compensated for the mods that caused your poor gas mileage in the first place.

 

What other mods do you have? My fd with 99k original miles gets 26 mpg on the highway with stock wires, plugs, ignition, and original catalytic converter.

I'm going to pull my engine when it hit 100k to do a full inspection and I may install the above components to see if I get any improvements.

 

owned...and i thought he really did have some some device or technique to get better gas mileage

 

No the original mileage rating was 17 city 25 hwy.

 

maduhbee,
Ive considered iridium plugs, but $35 is a high price to pay for each plug. Is there a 4 to 1 cost benefit ratio in performance and longevity for these over platinum? I dont know but would be interested in seeing definitive data on these used in an fd.

fritz flynn,
I have seen a few posts where members have realized an increase in gas mileage after installing the twin power. Perhaps the amount of increase for mpg is contingent on the level of modding done on the engine. Do you run a rich mixture?


chuck

 

I bought the car about 20 months ago with 19,000 miles on it and completely stock. My mileage stayed about the same - 12-20mpg
with each mod I did. The car ran stronger but there was no significant difference in mpg with each mod until i put the hks in.

I was talking to jimlab about this phenomenom and he attributed it to much more efficient combustion of the fuel being dumped into the engine, the result being better gas mileage.
chuck

 

There is an expert for you.

Think about the practical implications of what you state. Mazda struggled with fuel economy for rotaries, if they could have spent a little $$ on a hotter ignition (cost them what, $30?) and that would have given them a ~4mpg bump in mileage don't you think they would have done it? 4mpg is a 33% (!) increase in "efficiency".

If you figured out where all the energy goes you'd find out that the exhaust is really hot (heat = energy btw), the surface area to volume ratio of the combustion chamber allows more unburnt fuel to go out the exhaust along with allowing more heat to be transferred to the engine (again, lost heat = lost energy). The odd shaped combustion chamber also makes complete combustion more difficult.

 

I thought it was the KD butt plug.

Tim

 

FWIW, this is close to what I'm getting, at least last time I checked. Slightly lower in town (15) and perhaps slightly better (24 mpg W/AC running) on the highway. If I added twin power to my mostly stock car (DP, HF Cat, Cat-back, OEM plugs and wires), should I expect to go through plugs and/or wires significantly faster? Would the initial cost and possible additional costs off-set the gains I'm likely to see? Is there any other down-side to HKS TP?

 

Those are all valid points, but how far can the stock coils go with no detectable breakup?

Depending on his modifications, this could be a perfect candidate to help give the ignition system that little extra umph that it needs for correct combustion for his setup.


I guess the real question is though do you have O2 data to back up the claim that it was indeed a increase of 20-25% and not just low AFRs now translated into higher AFRs and same power?

Ata the very least it is another data point, and it does attest to the usefulness of a stronger spark/ or duration of spark.

Here s a dyno of just the difference between a AEM amplifier and a HKS. Seems pretty easy to see that one is smoother for a longer duration and makes more power. Though it would be nice to see a strait no amplifier vs HKS TP.

Even the dyno plot shows it leaner with a presumably weaker spark.

 

Here's my dyno at 12 psi. No breakup that I can see or feel. If your car is healthy, it shouldn't be an issue unless you're pushing a lot of boost.



Mods in sig...

BTW-After I did the "super overhaul" (see link in sig), my mileage went from about 12 mpg avg to about 19 mpg avg with a best of 23 mpg on a tank with lot of highway miles.

As said above, a properly running car will get decent MPG without the ignition amp. Sounds like maybe your plugs were fouled?

Sonny

 

LOL - phenomenom!!

some of it could be the 20,000 mile ECU switch. not sure what all it changes, I haven't read about it in awhile, but its suppose to make you car run better.

I have a single turbo haltech FD and I get 17/24...and around 10 on boost.

 

Wow, I haven't seen people lash out like this in a while. How is it that everyone gets so grumpy when we're reminded of fuel costs? Or were you guys personally offended when Chuck mentioned teasing you like his girlfriend?


Here are some numbers to chew on: my current average fuel economy is 16mpg. When fuel costs $2.99 per gallon, my fuel cost per mile is $0.187. In other words, a 100 mile trip costs me $18.70. By my numbers, a 20% improvement over my current average would bring the fuel economy up to 19.2 mpg. My fuel cost per mile would be $0.157 instead. Over a 100 mile trip, I would save $3.00.


If the average vehicle is driven 15,000 miles per year, and gasoline prices hold at $2.99 /gallon, an extra 3.2 mpg would save $450. So by that reasoning, it's perfectly possible for the HKS ignition amp to pay for itself. (If your car got 25mpg, you'd save over $1000!)


-s-

 

Ignition breakup occurs under boost, typically higher than stock boost levels. 16 mpg doesn't happen under those conditions...

 

That's what I was thinking^^^

I have first hand knowledge with the twin power. I drove my car to Sevenstock a couple years ago with the twin power connected. I think I got 24mpg. Keep in mind I was in a caravan from Phoenix. 55mph all the way with almost no change in speed. My car usually gets shitty mileage in town 10-15mpg. I took the twin power off for the trip home to see the difference. Guess what? No difference in mpg. approx. 24 mpg on the way home.

 

I wasn't upset about the 2-part mystery posting, But Please Fix Your Computer So That It Doesn't Produce This Takes-Twice-As-Long-To-Read Mixed Caps Garbage.

-Max

 

Get some tuning experience and have whatever gas mileage you want! I've had mid 30's MPG with the AEM and no emissions equipment (read: midpipe and full block off plates). You just gotta sacrifice a *slight* amount of driveability to run those 15-17 A/F ratios in vacuum

 

I was thinking about reprogramming my LC-1 wideband O2 narrow band output to lie to the ECU about where stoich is. Then when dropping into closed loop mode it would aim for 15-17 AFR instead of 14.7 which would help highway mileage a ton. The LC-1 setup is less than $200 and it would lie to the stock ECU just as well as an aftermarket one. Driveability wouldn't be affected much because much accelerator movement would kick it out of closed loop. I would have suggested this in the other thread but I didn't want to make a useless thread any longer .

 

It sounds to me like you had mileage that was poorer than normal (aka stock) probably due to rich tuning. Maybe your twin spark helped a bit to bring you closer to a normal mileage.

Also it is VERY hard to determine fuel mileage accurately just by driving around on the street. There are a lot of variables and the FD is especially sensitive to driving conditions.

I have seen my mileage vary from 25mpg (70mph freeway driving) to 10mpg (hard street driving) to 5 mpg (race track).

 

I still see it as what ever way you look at it, its money well spent.

 

In an FD? With normal driving (i.e. boosting)? Hmmm

 

From another forum:

Quote:
I read on the internet that a car uses a lot less fuel when going downhill. Would the same work if I jack up the suspension in the rear so the car thinks it's on a down grade and therefore uses less fuel?
End Quote

You guys might try that interresting idea .

Regards,
Klaus