Welcome to TBICHIPS.COM

This is my page dedicated to gas mileage.  This has to be the most common question I am asked is how to improve gas mileage and will a performance chip hurt the mileage.

Well a lot of things contribute to lower gas mileage and some you have control over and some things you do not.  I find most vehicles can be improved on but I will admit that big block chevy engines are the hardest.

The key number one change you can make that will yield you the most gas mileage increase won't cost you a dime.  Sounds to good to be true well your not going to like it.

SLOW DOWN.  Americans do way too much smacking the go pedal.   I am not talking about doing 10 miles per hour under the speed limit or any craziness such as that but I will hit on that a bit in a minute.  Its the jack rabbit starting every time you take off from a stop.  If you want to get better gas mileage, you need to make a conscious effort to limit the launches.  I can beat my wife every time at the gas mileage game. She has a relatively old 1999 Infiniti I30 (it was cheaper to buy used than a Maxima) and the window sticker shows its gets a best of 28mpg on the highway.  If she drives it, it gets 26 which doesn't sound too bad but if I drive it and follow my rules on gas mileage.  I can get 31.  Best so far on that car is 31.5.   The key is when you take off from a stop use 25% or less throttle.   If your rpms go over 2000 rpms between gear changes your likely guzzling fuel.   It doesn't hurt too bad to hit it once in a while just not like a teenager at every stop light.  My black magic truck gets 19city 24hwy pretty easily but if I play too much, I can drop it down in the 14mpg range too.

Things you can't change is weight of the vehicle (other than don't haul around the kitchen sink unless its necessary).  Its going to take a certain amount of horsepower to make that truck/car or whatever run 60, 70 or 80mph down the highway.  We have very little control over that.  Tire Pressure does help. Check it at least monthly and keep it at the max level.  This reduces unnecessary drag and will reduce that hp level needed to push your heavy beast through the wind.  Large tires have more drag than small tires.  Now I am not saying put little 4" wide tires on your truck but keep that in mind.  Next is ride height.  I have lowered the black magic truck 3" in the front and 4" in the rear which reduces the overall frontal area of the truck by tucking the suspension into the chassis.  More wind you have to push the more horsepower its going to take. Which leads me to speed, I like to drive fast just as much as the next guy but on these trucks when you get to about 70mph it takes a lot more hp to go faster due to the amount of wind your pushing and that horsepower is going to take a big hit on your gas mileage.  If you can try to stay right at or just below the 70mph number.  You will be surprised at how that helps.

Increasing the fuel efficiency of the engine itself.  I know that is the one you were wanting all along but gas prices aren't getting any cheaper we all are going to have to start applying some of those above items to our daily routine whether we like it or not.  Chevy SBC engines are pretty fuel efficient compared to a lot of others engines but the more power we can pull from that 350 cubic inch motor without significantly increasing the amount of fuel it requires will help bring those gas mileage numbers up.

1. We will start with the exhaust since its on the tail of the motors processes.   Problems here will back everything up and TBI trucks and cars have the worst exhaust design possible.   Just check out out the dyno numbers on the Black Magic truck from just changing the Y pipe.  I did not significantly change the fuel after that modification and 40hp at the rear wheels is a significant improvement.  So I recommend changing everything from the engine to the bumper.  I will post more informatoin about the flowtech headers and Y pipe that I am ordering for the Plum Simple project as well as how it performs.  The large pancake cats used on most of the TBI trucks and cars is rather restrictive and heavy.  A nice high flow cat isn't that expensive and will shed some weight that you don't have to carry around and some more horsepower for the few times you do get to play.

2. Next is going to be a set of underdrive pulleys. This can free up as much as 15hp and that 15hp isn't going to cost any fuel to make so it goes straight towards that hp number that we have to have to move are vehicle down the road.  They are cheap. I think it was $50 for the set that I ordered for the plum simple project.  While underdrive pulleys will hurt your AC operation at low rpms and the alternator doesn't charge well at idle.  the improved power and gas mileage is more than worth the trade off.  At over 1300 rpms all accessories are running just fine.

3. Ignition system.  MSD Blaster coil to throw a hotter spark down the wire, a nice brass terminal distributor cap and rotor button to have less corrosion than aluminum and some nice aftermarket low resistance plug wires so we don't loose spark energy during the travel from the distributor to the plug and of course a nice set of plugs and with TBI vehicles I have had the best luck with factory AC Delco plugs.  But the more complete burn of the fuel the bigger the bang and thus more horsepower on the same amount of fuel which should add another 5-8hp to our free hp number.

4. Air intake, if the motor doesn't breathe well its not going to make good efficient power.  The stock air cleaner setup is pretty restrictive and I have a bunch of info on www.tbichips.com/truckmods.htm to help you out there.

5. Next  the chip. I can gain a good 12+hp at the rear wheels even on 87 octane fuel as shown on the plum simple dyno base runs.  That chip did not add any fuel to the stock programming to achieve those power numbers so that extra power didn't cost any fuel to make and while part throttle won't have the full 12hp gain there is a gain there and that helps push the beasty down road consuming less fuel.

6. Electric radiator fan.  The mechanical fans driven by the water pump on these older vehicles is ancient technology.  Its heavy and robs power that can be used at the wheels.  Converting to an electric fan with a nice fan switch will reduce this parasitic load on your motor.  A cheap 16" fan off ebay $50  and a fan switch kit which you can get off ebay for about $25.

7. Gearing. Many trucks out there didn't come with overdrives or someone has removed them and that is really going to hurt fuel economy. However, a  lot depends on the weight of the vehicle.  I run a mild gear in the black magic truck and it runs right at 1700 rpms at 70mph but I have a LOT of torque available and weights 3950lbs so it   requires very little throttle to maintain 70mph and that part is the key.  If your truck is constantly shifting out of overdrive on the slightest grade then you aren't running enough gear.  The heavier you are the more rpms you need to turn to get that torque number up.  Typically between 2000-2400rpms at 70mph is a good range to stay between.  The 2wd plum simple truck with 3.42 gears and 4L60E trans runs right at 2100 rpms at 70mph and I believe that is going to be a good number for it.  But if you don't have overdrive your quickly going to be pushing the 3000rpms mark at these higher speeds and while that isn't going to hurt the engine gas mileage will definitely suffer.

8. Oil, strangely enough using the 5w-30 light weight oil does help reduce the amount or resistnance the engines rotating assembly experiences during normal operation.   Using synthetic oil is also a good idea.  Running synthetic oil for 5k miles vs standard oil  for 3k miles the cost isn't that much for using the synthetic.

9.The engine itself.  While the TBI heads don't flow very well the swirl ramp in the intake runner does just that. Swirls the air entering the combustion chamber just like the Tornado device you have all seen advertised.  Well TBI and Vortec heads both do the same thing automatically just vortec heads do it without hurting air flow.  This swirling keeps the air and fuel mixed well and improves efficiency of the engine.   The key thing GM left out of the trucks is they should have put the roller cam in the trucks just like they did the TBI cars.  Roller cams have less friction so less potential power is being robbed.  These engines also utilize low tension rings which wear less on the cylinders due to less friction so if you rebuild your engine keep that in mind.  Is it worth converting to a roller cam?  Well it depends on the cost of the parts.  I think long term you will get enough benefit to justify the cost.

Now is all this going to turn your 12mpg suburban into a 30mpg Honda.  No, but you will be pleasantly surprised just as to how well it can do when the above is applied and that can be the difference between being able to keep you big beast or having to sell it off for something that does get better gas mileage.

Pretty much all the small block V8 Chevy engines are capable of getting at least 16cty - 20mpg hwy with the correct modifications and driving skills.   Now you big block 454 guys, those engines are pretty inefficient but strong and their strength is what makes them guzzle fuel.  Gearing is pretty much your only choice.  The fewer rpms that heavy 454 rotating assembly has to turn the less fuel its going to drink.   I have seen these get as good as 17mpg but it takes overdrive, a mild gear and the right modifications and driving to pull it off.