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Pondering "size of engine vs Gas Tank" by hetterbr
Started on: 07-23-2013 01:19 PM
Replies: 11 (366 views)
Last post by: crashyoung on 07-26-2013 12:39 AM
hetterbr
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Report this Post07-23-2013 01:19 PM Click Here to See the Profile for hetterbrClick Here to Email hetterbrSend a Private Message to hetterbrEdit/Delete MessageReply w/QuoteDirect Link to This Post
I have always marveled at the possibility of removing the 2.8 out of my Fiero. I have watched with great enthusiasm as various members on this site continue to push the limits of what can be installed in our tiny cars. But last night, as I sat, dreaming about a larger engine in my car (I know, sad that I dream about that and not more sultry things), a tiny voice popped up and said "but your car only has a small gas tank, won't you be constantly stopping to put gas into it?".

So here is my Pondering. I would love to put a new engine into my car (someday). Is this something to be concerned about? Many people will say that with great power comes great responsibility - that must mean more trips to the gas station. or if you have to ask the price you can't afford it - again I wonder if that is talking about the gas station.

I'd hate to be sitting at a light and a kid in a little ricer pulls up next to me and wants to race. I however, look at the gas gauge and since it shows only half a tank, I have to decline because if I punch it, I will be on empty before the next street light.

Does anyone have any thoughts on this subject? Or maybe the voices in my head should get on a different subject.
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N3M3S1S
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Report this Post07-23-2013 01:24 PM Click Here to See the Profile for N3M3S1SClick Here to visit N3M3S1S's HomePageClick Here to Email N3M3S1SSend a Private Message to N3M3S1SEdit/Delete MessageReply w/QuoteDirect Link to This Post
I guess it all depends on what you're wanting to swap. Almost any swap you do is going to equal the 2.8's mileage and most of the time better it. I hear all the time of even the 4.9 swaps getting about 30mpg highway, and 3800's doing even better than that.. So.. I wouldn't worry about.
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Khw
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Report this Post07-23-2013 01:41 PM Click Here to See the Profile for KhwClick Here to Email KhwSend a Private Message to KhwEdit/Delete MessageReply w/QuoteDirect Link to This Post
If your going to a newer engine/trans swap the mileage of that engine will most likely be equal to or better than the 2.8. Now if you swap to a more archaic engine using older tech for fuel management, your mileage will most likely suffer. For instance a 3800 NA has 205 hp, so more powerful than the 2.8, and in my Bonneville a much heavier car I averaged around 23 mpg. In a lighter Fiero the mileage would be even better.
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2.5
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Report this Post07-23-2013 02:51 PM Click Here to See the Profile for 2.5Send a Private Message to 2.5Edit/Delete MessageReply w/QuoteDirect Link to This Post
Yeah with the stock 2.8 at 140 hp... you could double that and still get 30 mpg, which some people dont get with their 2.8's. The transmission of choice has something to do with that as well. Probably a good choice would be an LS V8. You could also hop up a 3800 SC. With computer tuning you could dial in mpgs as well.
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Fiero84Freak
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Report this Post07-24-2013 08:17 AM Click Here to See the Profile for Fiero84FreakClick Here to Email Fiero84FreakSend a Private Message to Fiero84FreakEdit/Delete MessageReply w/QuoteDirect Link to This Post
As stated above, most modern drivetrains that are swapped into Fieros get much better gas mileage than the L44 2.8L V6 that came in the Fiero.

However, I will suggest that you look a bit out of the box in that you'll notice I did not say "engine" but "drivetrain." In addition to modern engines being more fuel efficient, modern transmissions are more geared properly for modern driving habits. The most obvious example is that when the Fiero was built in the 80's, the US national highway speed limit was 55 MPH. The gearing in all the transmissions were optimized for a cruising speed of around 50-55 MPH. In 2013, driving 55 MPH on a major highway in North America will mean you're likely going to get ran over. However, driving at those speeds is the only way to optimize fuel efficiency. By the time you get to 60 MPH and above, you're pushing beyond what the transmissions in the Fiero were meant to cruise at. And not saying Fieros can't go that fast because obviously they can, but they weren't designed as a package to maintain those speeds.

Thus, while it can be cost effective and easy when performing an engine swap to use the same transmission that came in your Fiero, this usually is not ideal. Not only for what is stated above, but also because you have to consider most all modern transmissions have much lower mileage that ones in Fieros as well (i.e., they are likely in much better shape used).

The degree of how you want to pursue this can go from one end of ease of swap-ability to a far end of a lot of work. On one end, you could say for example swap in a F23 FWD Getrag with modern gearing. It's **relatively** easy to do as it's well documented and the parts to swap it can be had easily (or made). On the other end, you can attempt to swap in something like say an automatic that carries it's own controller separate from the ECM, and then having to figure out how to make it shift and operate properly in a Fiero.

The gas tank in a Fiero isn't bad if you know how to stretch the fuel and drive the car "properly." You can easily see well above 200 miles a tank in a 2.8L if it's properly tuned up, in good shape, and you drive it like a granny.
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Fierofreak00
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Report this Post07-24-2013 08:59 AM Click Here to See the Profile for Fierofreak00Click Here to Email Fierofreak00Send a Private Message to Fierofreak00Edit/Delete MessageReply w/QuoteDirect Link to This Post
If it helps, my car has a 3800SC with a Getrag 5speed and obtained 29.8 MPG on the way to the 30th show and 29.4 on the way back. I cruised mostly at 70mph @ a tick over 2000 rpm. I normally see 25-26 normal driving to and from work (40 miles each way) that includes some spirited driving mixed in. -Jason
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fieroguru
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Report this Post07-24-2013 09:11 AM Click Here to See the Profile for fieroguruSend a Private Message to fieroguruEdit/Delete MessageReply w/QuoteDirect Link to This Post
My LS4/F40 (382wph) pulled down 29 mpg (70-75 mph) going/from the 30th and gets 20mpg on my daily commute (19 miles each way with lots of stop/go/turns).

I wouldn't say the F23 has modern gearing (for higher speeds/lower cruise rpms), as most of the time swapping to it will increase your cruise RPM's vs. the fiero getrag. It is a new/strong transmission, but swapping in the F23 will not improve your fuel efficiency like the F40 will.

As for the size of the fuel tank. I normally fill it up at 200-220 miles, but when traveling the interstate I fill up at 280-300 miles. The larger stock fuel tank does help lessen the frequency of the fuel stops.
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Report this Post07-24-2013 10:45 AM Click Here to See the Profile for dobeySend a Private Message to dobeyEdit/Delete MessageReply w/QuoteDirect Link to This Post
Most importantly, is the fact that most modern cars don't necessarily have larger gas tanks than the Fiero does, either. Especially the small cars. Most of them have 10-13 gallon tanks.

If you're really worried about fuel economy, and want to do an engine swap, do a small Ecotec with a turbo, with the M32 6-speed out of a Chevy Cruze Eco. The Cruze Eco can reliably get 45 MPG highway. The 1.4 Turbo in it, also makes peak torque at about 1800 RPM and has a relatively flat torque curve throughout the powerband, up to about 6000 RPM. The top gear in that transmission is probably about the best you're going to get in a currently available FWD transmission in a GM vehicle, for cruising MPG. I've gotten up to 47 MPG in a Cruze Eco, myself, and there have been reports of some people getting over 50 MPG with them.

Build a 2.0 or 2.2 Ecotec with a turbo, and you can probably still get 40 MPG highway with that transmission, and probably still get 25 MPG city.
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Gokart Mozart
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Report this Post07-24-2013 11:56 AM Click Here to See the Profile for Gokart MozartClick Here to visit Gokart Mozart's HomePageSend a Private Message to Gokart MozartEdit/Delete MessageReply w/QuoteDirect Link to This Post
Don't know what year your car is but 87/88 have a 12 gallon tank vs 10.2 for earlier years.
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mattwa
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Report this Post07-24-2013 01:41 PM Click Here to See the Profile for mattwaClick Here to Email mattwaSend a Private Message to mattwaEdit/Delete MessageReply w/QuoteDirect Link to This Post
I agree on the subject of the F23, the most common version with the 3.94 final drive will have a cruising speed higher then the Fiero Getrag 282, however if you get an FY1 F23 with the 3.63 Final Drive from a Cobalt XFE, your cruising speed will be lower then the Fiero Getrag because 5th gear in the F23 is 0.69, compared to 0.72 in the 282.

IMO, 3.94 FD is too low for anything with alot of power in a car this size/weight, the gears blow by too fast and you have a higher cruising speed. It does work great where it was originally installed, in a 2.2 ecotec cavalier (I drive one daily), with 140HP.

[This message has been edited by mattwa (edited 07-24-2013).]

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jaredmurray88
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Report this Post07-25-2013 10:26 AM Click Here to See the Profile for jaredmurray88Click Here to Email jaredmurray88Send a Private Message to jaredmurray88Edit/Delete MessageReply w/QuoteDirect Link to This Post
Sorry to hijack but could you give some more info on the cobalt trans like year and such. Right now I have a getrag for my v8 but a local yard has bookoo cobalts and I can't find info on which I could use in the future for a spare.
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crashyoung
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Report this Post07-26-2013 12:39 AM Click Here to See the Profile for crashyoungClick Here to Email crashyoungSend a Private Message to crashyoungEdit/Delete MessageReply w/QuoteDirect Link to This Post
I built a 460 HP SBC for my Chevy II Nova which had a 12 gallon tank,
it never was a problem, as the engine sipped gas when driven mildly,
but you could watch the needle drop during wide open throttle, but it
was better to watch the scenery change!
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