Ok...I'm curious if from strictly a MPG standpoint...if this is a worthwhile swap.
I know that the Quad4 will have considerably more power...but that's not the issue I'm asking about.
Figuring on both cars having a 5 spd...and being as identical as possible notchback coupes...
What kind of mpg can I expect from either/both.

Reason is...with current gas prices...I'm looking for an economical 2nd vehicle...and my auto trans '87 GT just doesn't cut it.
Not going to get rid of the GT...just wanting to add another Fiero to the stable.

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--David


Golden Triangle Fiero Club

I consistently get 35mpg with my Duke. I am mostly on the interstate when I commute to work. If I drive around town a lot, I get 30mpg. I think most get numbers similar to this if they are kept in good condition. I cannot comment on the Quad 4.

Jim

Edit: Mine is mated with the 5 speed Isuzu.

[This message has been edited by jimbolaya (edited 05-26-2008).]

A guy in a local club has a Notchback w a Quad Four and a 5 speed Isuzu. He claims 27 Hwy MPG but mileage goes way down when he drives it hard.

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87GT - with 3800SC Series III engine, 4T65eHD
87GT - 3.4L Turbocharged engine, modified TH125H
" I'M ON THE LOOSE WITHOUT THE JUICE "

I have a 86 duke w/ auto and I get between 26-30 around town.

So I'm guessing that a Quad4 5 spd notch...will get a little less mpg than a duke...but perform better than a stock 2.8V6.lol.

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--David


Golden Triangle Fiero Club

An engine produces more power by by combining more fuel with more air and burning it.

More power = more fuel

More fuel = more frequent fill ups, is that what you are looking for?

I've owned several dukes, most averaged 25-30mpg. I've also owned a Quad 4 Beretta and Achieva and both of those got 26-29mpg while delivering almost double the HP of the duke. That is why my Indy is going to get a Quad 4.

I own an 86 Quad 4 HO 5-speed, and an 84 Duke auto. With the 84, I have gotten 41MPG, highway, and with the Quad 4, I have also gotten 41MPG. The Quad 4 is alot more fun to drive, and I think on average, gets a few MPG less, mostly because it is more fun to drive. But, the HO version of the Quad 4 recomends premium, and while you can run regular, I think the fuel mileage will suffer.

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84 Fiero Sport Coupe #1192 :: 86 Fiero Base Coupe Quad 4 HO :: 1998 Dodge Neon EX 2Dr 2.0L DOHC Auto

One car, three setups on my 84 Indy Pace car:
Iron duke, 125-C Automatic........ 33 MPG at 60 MPH average speed
Iron duke, 4.10:1 4 Speed.......... 33 MPG at 50 MPH average speed
Quad 4 HO Getrag 3.94 (W41)... 33 MPG at 60 MPH average speed

FYI, the Iron dukes top speed was 105 MPH with both the transmissions.
The Quad 4... I will never know. It is too scary to drive that fast.

The quad 4 dynoed at 167 HP and 144 Lb-ft.
My GT's 2.8 put down 112 HP and 144 Lb-ft.

In conclusion: You will have the power to smoke the V6 Fieros, and the gas mileage of the duke.

But all that, is right foot adjustable, and The Quad NEEDS the high octane fuel to survive. 87 is not a good idea on an engine that runs 10:1.

David, I inquired last week about the mileage and performance from Quad 4 mated with an automatic OD. There were very few responces from the members. I am also considering a Quad 4, but I would prefere an automatic with OD. I usually get 39-41mpg between my house an yours driving 69 or brelow, over 70 it drops to 37-39.
Joe Crawford

Yeah Joe...I saw your post also.
From what I can gather...the mpg difference doesn't warrant the swap.
However...if the performance gain is worth it...then you won't suffer much in the mpg department by performing the swap.
I'm going to try to find a low miles 5 spd Duke car I guess.

That being said...another small question...
On the '88s...I know they upgraded the suspension.
Is the suspension on the base 4cl coupe...the same as on the GT?

the 4 cyls are missing the rear sway bar. I think the spring rates are different, but nothing more then that.

IMO, the Quad four engine is not a bad choice but an unusual choice of engine. It looks difficult to swap, (may not bolt to the Fiero trans) expensive to rebuild and somewhat hard to find in low mileage condition. The HO high output 190 HP version has plenty of mid range power but also very hard to find. With just a few simple mods you can make 200HP- very good power for a four that rivals many sixes. The plus is that it is an economical mileage engine with power to spare. I've only seen a few Quad Four Fieros and I've wondered why the swap isn't popular. I wouldn't rule out the engine that replaced the Quad four- the Ecotech.

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87GT - with 3800SC Series III engine, 4T65eHD
87GT - 3.4L Turbocharged engine, modified TH125H
" I'M ON THE LOOSE WITHOUT THE JUICE "

[This message has been edited by Dennis LaGrua (edited 05-26-2008).]

if i were to make an engine swap. i was thinking of getting a V6 for the gas you will save but have good power.
and now reading this thread about the quad 4 engine. i would love to get one of thos engines in my fiero. good on gas and have plently of power.
if i were to do any engine swap i would rebuild the engine. you never know what the last owner did to the engine if they drove it hard all the time or what. and the engine could have been sitting for along time.

i have a question for the quad 4 swap tho...
how much does it cost to do a complete swap?
and would it be worth it in the long run?