Increasing Horsepower/Torque/MPG

illicit_hunter

I own a 1998 Dakota Club Cab with a 318 (5.2) in it. It is a 4WD truck. So far I have put straight pipes on it (back from the cat), a K&N FIPK Intake, and a new serpentine belt that routs underneath the A.C. Compressor. Is their anything else that I can do to increase HP, TQ, and MPG??????? I have heard that punching out that cat and just welding it back up their for "apperance for the coppers" will increase all of these.

Mr_Shiftright

Not a good idea.

You can probably find a freer-flowing catalytic for the car and that might give you something like 8 HP. For fuel mileage you can run harder tire pressures and not use your AC as much, and you might try synthetic oil as well. As for more HP and torque, you're going to have to go into more exotic modifications and that can get expensive...you might investigate custom throttle bodies, custom intake system and finally internal engine modifications.

illicit_hunter

Thanks, I already eliminated the temptation of using the A.C. by getting a routing a new belt totally bypassing the compressor, i will look for a high flow cat

dakota0

have you tried to get a chip for it..i heard in the 5.2 and the 5.9's you can get a stage two chip and its suppose to wake it up..you can also get headers and a low restriction cat for it too.

dakota0

i have a standard 2000 4.7 dakota sport. its a lil quick for what it is. ive put on it gibson headers with the racing gibson duels high flow cat k&n tube with filter a throtal body spacer and a tornado can you estimate the power it has now...i can stay with 4.6 mustang gt's now

chevyguy5

I HAVE A 327 11:5-1 COMPRESSION 2.02 INTAKE VALVES ON THE DUMPLE HUMP FUELLEE HEADS LUNATI 2-6OOORPM RACE CAM WITH VICTOR JR INTAKE AND MIGHT DEMON 650CFM CARB ON TOP
BOTTEM END IS BRAND NEW AND WAS BALANCED WHEN IT WAS BUILT
IGNITION IS HEI SUPERCOIL AND I RUN HOLLEY ELECTRIC FUEL PUMP. THIS SET UP IS INSIDE A 81Z28 AND I AM WONDERING WHAT KIND OF HORSEPOWER CAN I EXPECT THIS THING TO MAKE
BEFORE THE VICTOR JR INTAKE AND DEMON CARB IT RAN A SAD 14.2 IN THE 1/4 MILE AND I WONDER WHAT KIND OF POWER IT MAKES NOW WITH THE NEW TOP END. ANY ESTIMATES WOULD BE WELCOME AND IM JUST LOOKING FOR A GUESS UNTIL I CAN GET IT ON A DYNO. THANKS ALOT AND KEEP MAKIN THAT POWER

mtrialsm

Just installed a K&N air filter assy. on my 4.7 Quad.
Very neat installation, the hardest part was putting the
rubber seal around the new air box.
At normal acceleration and speeds, sounds is almost the
same as stock, but under hard throttle the noise is high.
A dyno print out was in package, at 4400 rpm they showed
an 8 HP gain. I doubt that I've ever had the rpms over 4000
anyway.
I'll monitor mpg. Power seems smoother and a little more responsive?

Mr_Shiftright

Generally any HP gains with a free flow air filter will come at very high RPM and will favor larger engines over smaller ones.

mtrialsm

Drove to Fla. last week, maybe a slight increase in MPG?
Coming back home and after putting 400 miles on truck
with new K&N intake, the engine stumbled and sputtered a couple of times at a red light. Then the check engine light came on.
Engine smoothed back out and ran flawless for the next 100 miles back home. Checked the mal. engine code and it was
"O2 sensor, lean". I reset the code and will monitor for a repeat.
Has anyone esle seen this after going to a high flow intake system?

cydd420

99 S-10 K&N replacement filter in stock air box. First 100 miles ran like crap. Asked a mechanic friend and he said to get the K&N cleaner kit do a really light cleaning on it. Do not follow the directions when reappling the red oil. He said to just spray it on with one quick swipe. Too much oil on it from the factory was clogging one of the senors.

xtec

I put in a K&N replacement filter on my 06 Charger 3.5 and I had less power and lost 2 mpg with it.I think the K&N is a waste of money.I heard of others who say they don't feel any differance with a K&N.I was thinking about a Jet chip,
but read some customers reaction ,and some say they work and some say its a waste of money.It must depend on the vehicle you put them in.I did have a dual Borla cat back system put on and feel a little more power and MPGs.

97bandit

did you find a high-flow cat yet?

okko1

most cars are factory tuned for mpg and moderate perfomance but mostly for reliability and driveability. there are no 50 dollar mods that your gonna feel. and when you start make changes that you can feel you give up some of the previously mentioned comforts. do your research some motors like back pressure and so when you releive them you actually go backwards. the quickest way to improve quarter mile times is by changing the gear ratio. this comes at a cost though and that is fuel. remember a v8 at 275-300hp in a stock application is maybe 20 hp from max out without internal mods

paisan

Actually I'd argue that most V8s are the ones that can best feel gains from free-flowing exhaust. After that Turbo cars will feel it the most. 4 and 6 cylinder engines need that back-pressure.

-mike

okko1

well i have been building street cars for some time and it is true that if you were to go from a single exhaust stock high restriction muffler to a dual exhaust with a quality after market high flow mufflers you might see some minor improvement in performance but for the most part it's just gonna sound fast. the hp gains that k&n and many of these other after market vendors discribe are at wide open throttle and maximum rpm. in which case are not remarkable for the most part. i am not saying that there is no measureable gain i am saying that unit of gain would not be felt by the seat of the pants.

Mr_Shiftright

Yep. The bigger the engine and the higher the rpm, the more HP will show on the dyno (and it will be modest at best).

paisan

I agree, especially on 4 cylinder cars, intake and exhaust will be modest at best.

-mike

tc07

On GM's 4.3 engine with distributor ...up to at least 2001 model as I had, Put on an MSD Ignition, HP distributor module, rotor and cap. Next add MSD ignition coil and Taylor (or a good set) of wires. Then put in AC Delco Rapid Fire or Bosch +4 sparkies. I did this and GAINED 5 MPG highway and Dyno'd 28+ HP! I then added Hypertech Power programming due to having to put on 245/50/15 tires and traction bars to get needed traction on dry pavement...not to mention wet.
In all the MSD ignition more than paid for itself in gas savings the first year I had the S-10, EXT Cab and LS Sportside bed. I just sold it after having it 7 years.

the_big_al

I ran a K&N in an '01 4.3 in the stock air box. Took it out after a few months and went back to cheap paper... I noticed a slight drop in MPG with the K&N and no real increase in HP - at least not noticable...

With out doing serious engine modification, I don't know that there is a real effective way to really make a factory tuned engine "perform". You can do chips and ECM programs, exhaust systems, K&N filters and such, but do they really make a difference?

Would I really see a difference in the performance of a 4.3 chevy motor with a cold air intake, a ECM reprogram, and a free flowing exhaust system? I have done cat-back to dual 2 1/4's, but it is mostly sound. If it would make a difference I would be willing to do a full exhaust system including new headers, a free flow cat and new mufflers. The truck has 104K on and so no worry's about the exhaust warranty. Also reprograming ther ECM and doing a full cold air intake, but only if it would make a noticable difference. Not just some measly 10 HP. If not than I'll just stick with the stock until it needs to be rebuilt and then either rebuild it and bore it out and stick a super charger on it, or completely replace with a LT-1 crate motor.....

dezso3

Generally, as an engine gets bigger, its horsepower increases. Horsepower doesn't just depend on the size of the engine, but also whether it is turbocharged or supercharged. But are these the only things that horsepower depends on, or are there more variables? For example, the Lincoln Town Car has a 4.6 Liter V8, but it only has 239 horsepower, whereas the Lexus LS 460 also has a 4.6 Liter V8, but has 380 horsepower. The Toyota Camry XLE also has a regular 3.5 Liter V6, and has 268 horsepower, which is still more powerful than the Lincoln Town Car. The Chevy Impala also has a 3.5 Liter V6, but only has 207 horsepower. The Subaru Impreza WRX STi has a 2.5 Liter turbocharged engine with 305 horsepower, which is more powerful than an engine that is almost twice as large, the 4.6 Liter V8. So what exactly accounts for the huge differences in horsepower between engines of the same size that are NOT turbocharged?

Mr_Shiftright

Well it's not size. You can't just double a 3L engine to 6L and expect twice as much horsepower. Doesn't work that way, as there are pumping losses, etc.

There's compression ratios, breathing, cylinder head design, camshaft configuration, efficiency of the driven accessories (fan clutch or electric fan vs. fan blades, for instance), even type of oil used.

The Porsche 917 in 1971 was in its fiercest form a 5.4L engine, and it put out 1100 HP, with dyno peaks of 1500HP.

So amazing HP is possible---but this would hardly be a street engine.

And thus, we have all kinds of compromises made by the automaker, and some of these compromises might sacrifice HP for quietness, economy, or easier and cheaper mass production methods.

There are any number of powerful engines out there today but they may not be as durable as their "lesser" competitors.

zaken1

The basic thing which determines the horsepower of a given size engine is how much air/fuel mixture can flow into and out of it. This is called volumetric efficiency. It can be changed in many ways; by increasing the compression ratio; by enlarging the size of valves and ports; by enlarging the intake and exhaust system or improving their flow rate, and by increasing the distance the valves open or the length of time they stay open (with a performance camshaft). There is an advantage and a disadvantage for each of those changes.

Just increasing the compression ratio will improve power; but it also will require the use of higher octane fuel. And many performance engines already require the highest octane fuel that is available. So if you increase the compression ratio on an engine that already requires high octane fuel; the engine will begin pinging and knocking. If it is not retuned by retarding the igntion timing; such an engine will soon self destruct. But if you retard the ignition timing; the power will drop back to less than what it was before the compression ratio was increased. So this is an example of why some types of modifications are just not possible on certain engines. And many owners who build up their motors soon become tired of paying higher prices for premium fuel; just to get an an occasional blast of power.

Installing a bigger exhaust system, or a bigger intake system, or a bigger cam; or enlarging port sizes will all produce power increases at high engine speeds; but they will also REDUCE power and economy at low and medium engine speeds. And in addition; they will increase pollution. There is no free lunch in the power increasing world; every gain comes with a corresponding trade off. And this is something that all too many enthusiasts don't discover until after they have spent months or years of hard earned money and many hours of labor modifying a previously well balanced motor to make more power; only to discover that it has been transformed into a rough running, noisy, thirsty beast; which needs constant attention, can't be smoothed out, and frequently won't pass smog inspections.

Car manufacturers use sophisticated computer programs to design engines so that all the systems work together harmoniously. They certainly know how they could make their engines more powerful; but they also know what the downsides would be. And when you're designing an engine for a car that is not going to be raced; and in which smoothness, reliability, and great fuel economy are most important; the best way to achieve those goals is to not tune it radically. Other manufacturers try to build engines which have a little less smoothness and economy, but produce somewhat more power. And yet other companies build the most powerful motors they legally are allowed to sell. That's why engines of the same displacement are made with very different power ratings.

My brother in law, who was a physicist, decided to buy a new Chevelle in 1966. He had the mistaken idea that the most powerful engines had the best quality. So he ordered his new Chevelle with the most powerful 396 cid big block engine that was available. And he soon came to hate the rough running, thirsty motor. Eventually, he had the motor taken out and replaced with a low output small block 283. And he was much happier with that motor (despite the fact that he had ruined the resale value of his Chevelle SS 396).

2008f350newbie

Hey Zaken1,

I just bought a 2008 F350 6.4L Diesel/Turbo with 73,000 miles on it for my Landscaping company.... I'm trying to figure out what the smart decision would be to increase my MPG. Everyone keeps telling me there are chips that come with computers that I should buy, but I'm not so sure that I want to mess with them after reading some of these forums. You seemed to be very wise and intelligent with cars and I wanted to ask someone like that about them. Are there some chips and programs I should go with and a lot that I shouldn't or a combination I should do or what? I get 12.3 mpg now but would like it as high as possible....

I've been told by a number of people it would increase my turbo a lot which will help reduce engine use/help fuel efficiency, but I don't want to ruin the turbo and waste money on another when this one is perfectly fine. Your help would be tremendously appreciated, I'm a rookie with these Super Trucks coming from a 99' Silverado....