turbo & Gas Mileage

[66Sprint6]

I am lookin to do the turbo this summer, hopefully in the beginning but anyways, how will it effect my gas mileage? Im sure itll make it worse, but if Im lookin to go easy, could I use a boost controller and turn it down to save gas and then turn it up to haul tail? What do yall think.
Heres my mindset on what Im gonna be runnin whenIm done.
T5 (hopefully)
to4b turbo, BOV wastegate (TBD) intercooler from rx7 (maybe 2 welded together) J pipe from stock manifold until I can afford header. Thats about it for now, maybe a turbo timer cause I drive this everyday
What yall think
Matt

 

[Anonymous]

I doubt you'll see much, if any, change in your highway mileage, since a turbo basically 'disappears' at those rpms and power levels. However, if you can't keep your foot out of the noise pedal, it could be pretty bad. Your engine is only going to use more gas when you have the hair-dryer up to speed, but if your cruising you shouldn't see any difference.

 

[66Sprint6]

Thanx Ernie,
The loud pedal WILL be to the floor way to much, especially concidering how much it is now with what little Ive done so far, lol. I cant wait, I only need money now!
Matt

 

[rbohm]

8) keep your fat foot out of the throttle, and you could see a gain in highway economy. the reason is that the turbo even though it may not be producing boost still moves extra air through the system and takes some load off the engine. thus you get the same power for less throttle pressure, and thus better mileage. perhaps as much as 2 mpg in steady state cruising.

 

[CobraSix]

That's the beauty of turbos. They will not drastically change the mileage so long as you keep off the pedal. Case and point. When I was looking at Volvos. I looked at NA and HPT (High pressure Turbo) versions of my car. The mileage was essentially the same. Maybe 1MPG difference.

Slade

 

[xctasy]

One point we all need to note with turbos is that under low-load, they are as good as, or even better than the stock 90 hp net 200 engine unturboed. When the foot goes down, a 200 hp 200 cube six uses as much fuel as a 200 HP 302 V8.

That's why really boosted carbed turbos need an adjustable mixture supply. Note that GM's Buicks ran 800 cfm 4-bbl Quadrajets, which were lean sober drivers off -boost, and could feed 500 at wide open throttle.

Primarily, the advent of the resurgance in turbo engined GM, Fords, Saabs, and Porsches in the late 70's was because of the CAFE fuel regs. The turbo engines could rack-up good numbers with a small 231, 2.3, 2.0 or 3.0 engine which had the gearing of a 350, 3.3, 3.0, or 4.6 engine. Even dud engines, like the el-cheapo 301 Pontiac Turbo, were good econo engines compared to the 403 Olds.

Put the hammer down, and they'd drink it up as much as there bigger engined stablemates.

 

[Anonymous]

the more fuel ya use the better, i think.with the twins on my 300 i think that i could probably get my milage as low as 5mpg when i dial it to the fun mode. i can get bout 10 if theirs a lot of cops out when im heading home. but the fun far out weighs the cost of premium and oct. boost. if i can figure out how to add a pic to this i would show you my latest creation.she is well over 300 hp to the ground with fairly conservitive mapping.[/img]

 

[broncr]

There's a paragraph on turbo mileage in Bell's "Maximum Boost".

To summarize, he says a turbo WILL hurt your mileage under ALL circumstances. A turbo presents a small restrction to the exhaust, even when operating without boost.

"If your driving habits are about the same as most, your mileage will drop about 10% city and 5% highway."

If I put a 460 in the little mule , I'd be lucky to get half my current mileage. With a turbo, I could come close to simulating a 460 & still have a 300ish while cruising. That makes a turbo sound VERY appealing.


broncr

 

[CobraSix]

The difference in the turbo and non-turbo versions of my Volvo is about 1MPG on the highway.

Trick is to design the turbo system to flow better, like using a turbo header vice exhaust manifold. Free up some flow in order to restrict it some

Slade

 

[66Sprint6]

I think Im going to go with the stock manifold J pipe combo until I can afford to look into getting a turbo header fabbed up. I like this discussion, and the thoughts of having stock 200ish gas mileage under low boost and then 302 style power when rhomping on it is awesome to me. In all reality, I would rather be fast than economical, but reliability rules over all for my daily ride. Thanx for the help guys, keep on postin if more comes to mind, the more I can learn the better before this turbo project goes underway!!!
Matt

 

[broncr]

Some of the guys here were recommending Bell's "Maximum Boost" and/or MacInnes' "Turbochargers" as good reads on the subject. I got 'em both for Christmas & the guys were right, there is a lot of good information contained. I think my wife found them both at Amazon. I like to read up on anything before I jump into "doing".
WARNING beware of BOOST FEVER. It can be extremely dangerous.

Luckily for me, I found a temporary cure - a full body makeover for the lil mule. When I recover from that, I'm sure the old symptoms will start creeping back - elevated pulse, difficulty concentrating on anything else, obsessive desires to build one... and on and on.

broncr

 

[66Sprint6]

I need to get rid of my boost fever, it destracted my studyin for class last semester and Im bout to start another even harder one. Hmmmm.... wish I could just have the money to put it in now, SEE there it is flairin up again. I need some tylenol...
Matt