Performace Chip

[wwest]

"...Or was something wrong, VERY wrong, with your engine to begin with....??"

Something you may have overlooked, actually three things.

1. Carburetor.... Whereas an OBDII, MAF/IAT equipped engine will automatically adjust, correct for a freer flowing intake, a carbureted engine might very well show a performance advantage, with your "CAI", especially at higher throttle openings.

2. Air Filter...You installed two BRAND new air filters when you "lifted"the lid, perhaps since the old one was completed clogged/blocked..??

3. Bird's nest...somewhere in that intake duct...??

4. HOT intake airflow...That intake duct undoubtedly has two intake paths, one for fresh, cool, intake airflow, and a second, typically vacuum motor selected, that pulls HOT intake airflow in over the exhaust manifold. Vacuum motor stuck in HOT intake position..??

5. Some combination or even All of the above...??

[Randy&Bonnie]

..

[wwest]

"...Or was something wrong, VERY wrong, with your engine to begin with....??"

Something you may have overlooked, actually three things.

1. Carburetor.... Whereas an OBDII, MAF/IAT equipped engine will automatically adjust, correct for a freer flowing intake, a carbureted engine might very well show a performance advantage, with your "CAI", especially at higher throttle openings.

2. Air Filter...You installed two BRAND new air filters when you "lifted"the lid, perhaps since the old one was completed clogged/blocked..??

3. Bird's nest...somewhere in that intake duct...??

4. HOT intake airflow...That intake duct undoubtedly has two intake paths, one for fresh, cool, intake airflow, and a second, typically vacuum motor selected, that pulls HOT intake airflow in over the exhaust manifold. Vacuum motor stuck in HOT intake position..??

5. Some combination or even All of the above...??

Four things are not likely.

Do you mean to imply that 3 things are....??

I can accept that.

It's obvious the engine simply wasn't getting enough air flow through the stock air filter system,

Yes, in comparing the before and after engine performance improvement sequence it would also be my guess that the OEM intake path was somehow blocked, flowing over the exhaust manifold, the air filter you discarded was horribly clogged

most likely do the added header and free flowing exhaust.

No, given the RANGE of the improvement there simply HAD to be something more.

"free-flowing exhaust..."

Removed a failed/plugged catalytic converter...??

[smooth1]

The only way you'll be able to tell is on a dyno, with and without the mod.

I agree that "measuring" the change can be performed on a dyno, however, "feeling" the change can be very real. For example, there are a number of "changes" that an experienced race driver can tell his crew chief about throttle response that a Superflow SF-902 or an SF-600 Flowbench CANNOT.

"..experienced race driver..."

I agree...

But how many of those do we have amongst the overall RX ownership populace.

5...??

Sorry, perhaps I used an inappropriate example. My point is that "changes" in throttle response can be "felt" very often by an average driver. There are literally hundreds of posts right here on this site that describes "seat-of-the-pants" (butt dyno) experiences. :D

"..literally hundreds of posts...."

Yes, and I'm willing to bet good money that the clear majority of those "seat-of-the-pants" judgments of improvements were significant biased due to the fact that the "judge" had already spent a not insignificant amount on the modification.

I'd bet that in the majority of those "posts" you could have told the owner that the modification had been done when actually it was not and the owner judgment would have remained the same, POSITIVE.

CAI, Cold Air Intake, K&N, simple 10 cent 1/4 watt resistor in the IAT circuit, etc.

wwest,

Granted, we all want our goodies to perform after spending our money.

You said "The only way you'll be able to tell is on a dyno, with and without the mod."

I said, no, that's NOT the only way.

How many of the modifications that you are proposing have YOU had dyno tested?

NONE. But the intention of my mods have NEVER been to increase HP/torque but to increase FE, and I can check THAT with a pencil and pad.

On how many modifications have you seen any certified dyno test results? Have you ever experienced a change with one of your modificatons WITHOUT a dyno test?

Yes, see above..

Again, my point is simple, I've made modifications to enhance engine performance on a variety of engines,

both race and street,

"both race and street.."

Aha, so you acknowledge that your "butt" meter has been sensitized (calibrated..??) via racing mods....

and was able to "notice" improved (sometimes worse) throttle response and I didn't need a dyno test to experience the change.

During flight training, private pilot, the instructor kept on me to pay more attention to keeping the airplane's center of gravity "correct" in a turn, I simply didn't get "it". Then I started taking my wife along on trips. I soon figured out that my "butt" meter need to be calibrated, sensitized, to the center of gravity NOT being "vertical" for my, her, body.

As far as... "you could have told the owner that the modification had been done when actually it was not and the owner judgment would have remained the same, POSITIVE."

I agree, but a "placebo" has been known to cure a disease. :P

Hmmm...

Are you implying that a "placebo" engine modification might actually result in a performance improvement...?

"I hereby withdraw the question.."

You also said "So your idea should work but the HP gain may be only 10-15% and therefore might not be really noticeable."

In my experience, a 10 to 15% gain in HP would be VERY noticeable.

I agree, but each of us differs in the level of butt sensor sensitivity, and some have even been "trained" to increase that sensitivity.

In fact, I've heard some very experienced engine builders state that experiencing (via your butt dyno) a change as little as a two or three numbers in torque in not unusual. On my Toyota truck at 110 HP, a 10% gain would be 121 HP with a similar gain in torque number. This gain would mean the difference between driving down the freeway at 65 MPH in 4th gear max, or being able to cruise down the freeway at 80 in 5th gear

If you got that level of gain with a 110HP (MAX HP) toyota engine then the WORLD needs to know.

"cruise (as in CRUISE..!!) down the freeway at 80 in 5th gear."

For most of us, " 65 MPH in 4th gear max" would imply WOT, actually using the full 110HP, whereas "CRUISE" would imply partial, or even "light" throttle. If you got that level of gain at light/partial throttle, starting out with a 110 max HP engine, then the world needs to know how you did it. Or was something wrong, VERY wrong, with the engine to begin with..??

Ask me how I know.

I'm asking, but BOTH questions, how do you know and how in hell did you do THAT..??

If the native 110 HP only got you up to a maximum speed of 65 MPH then you had to be producing upwards of 150HP, at only partial throttle yet (Cruise, remember..??), to get to 80 in 5th gear. Assuming even 1/2 way open for CRUISE, partial throttle, then the maximum HP after your mod might have been upwards of 250HP.

That's over a 200% gain, not 10-15%.

At the end of the day, 5 pulls on a dyno is WAY more interesting than anything my "butt dyno" can deliver.

I take back my thought that you have racing experience, 3 spins around Daytona in a GT3 to calibrate/check my butt dyno is WAY more interesting than standing by and watching a dyno run.

A $100 chassis dyno test provides some really interesting data to consider. A $1,000 engine dyno test sheet is even better to review and stare at, especially the numbers!

How did you get from a "$100 chassis dyno" to a $1000 engine dyno test sheet.

Oh, engine vs chassis.

I hereby withdraw the question.

Hi wwest,

Great questions and excellent commentary. I'll happily do the best I can to answer them. stay tuned..... I still work for a living!

Hi wwest,

Getting back to your question about increase HP. Here's a what I experienced on my 1985 22R 4 cylinder, 5-speed, stock 96 HP 2.4L engine, carb'd. I installed a Doug Thorely header and opened the stock exhaust tubing, couldn't find the cat to re-install, so that mod was about a 10% increase in HP and torque numbers. This engine was in very good mechanical condition, no blow by, good compression, properly tuned, etc., in fact, for as many miles on it, it ran like raped-ape compared to some others I'd driven with the same engine.

With 33" tires, I could only use 4th gear at freeway speeds and was limited to about 65 MPH in 4th gear and about 3200 RPMs, without flooring it and getting into the secondary. 5th was just too tall to pull it down the freeway with stock 4.10 diff gears.

This engine has a peak torque at 3400 RPM. I could easily hold 75MPH in 4th at about 4,000 RPM, but that RPM for cruising seemed a tad high for my old engine (about 180K miles then).

I had an idea for some time and finally got around to making the modification. I drove the truck to Lake Havasu City and back, about 475 miles round trip. Two weeks later I planned on the same trip. Before I left I took about 30 minutes and made my modification. I simply removed the center bolt in the carb that held the top of the air filter lid on, extended the bolt about 3", extended the breather tube, stacked another identical stock air filter on top, put the lid back on. This in effect, created a gap around the filter canister about 2". I then made the same trip to Havasu and back. This time I was amazed!! I could actually shift into 5th gear, and could maintain 80 MPH at 3200 RPM!! Since I was tracking my gas mileage for every tank, I calculated about a 1.5 to 2.0 MPG increase, from an average of about 19 to an average about 21. If I hadn't experienced it myself, I'm not sure I'd believed the difference it made.

What I meant about the "butt dyno" experience is that the real data from an actual dyno test is confirmation of BD feelings. But, I agree that on the track exhileration and adrenalin is awesome!!

Here's a photo of my "double-gnarly air filter mod"....

R&B, that's a totally different scenario though. In the "old days" of carbs, instead of adding another air filter, you could have simply rejetted the carb, and set it up to run leaner. Sounds to me like the original setting was too rich. In these new ECU controlled cars, any adjustment you do before the MAF/IAT, the car just compensates and adjusts. Whereas the old systems wouldn't really change anything unless you changed it. And everyone knew that factory settings were on the rich side, so, just up the air intake and leave the fuel system alone and you effectivley leaned out the system to gain more power. That's just not how cars work anymore.

[wwest]

"..Sounds to me as if the original setting was too rich..."

But not due to the carburetor's metering jet(s).

Remember that the gain in "performance", engine HP, with the "stacking" of the intake filters was nothing less than dramatic.

So something other than the metering jets being too large had to be "in play".

With metering jets that LARGE you wouldn't have wanted to lite a cigarette anywhere close by.

[Randy&Bonnie]

..

[wwest]

"..you guys are over analyzing this..."

Maybe, or probably so.

"..With 33" tires, I could only use 4th gear at freeway speeds and was limited to about 65 MPH in 4th gear and about 3200 RPM, without flooring it and getting into the secondary."

Then.....

"I could actually shift into 5th gear, and could maintain 80 MPH at 3200 RPM."

"chart" that apparent torque change yourself and I think you will then understand our confusion.

My guess remains, your OEM intake ducting was either blocked or stuck in the "cold start" intake air heating mode or both.

[Randy&Bonnie]

..

[wwest]

My guess remains, your OEM intake ducting was either blocked or stuck in the "cold start" intake air heating mode or both.

Nope.... not it! Good guess though.

How do you know...??

Or...

You may NEVER know.

The simple act of removing the air filter assembly may have been enough to jar the cold start vane/door loose and out of the cold start position it was stuck in.

I assume it wasn't altogether easy to "gently" remove those over-center lid clamps.

I don't know if your's uses a vacuum motor nor which position the vacuum might drive the vane/door into.

I once had a carburetor icing problem in a Ford Pinto I4 because I had inadvertently left a vacuum line off. In that case the vacuum motor never went into the cold start position.