What kind of mileage does a Pontiac Fiero get with a V8 in it?

[Cameron J]

I have a 1987 Fiero with a 5-speed. I'm considering putting a Cadillac North Star engine in it, but if that drops me down below 20 mpg in mixed driving, I think I'll pass.

Anybody who has done this know about what it gets?

 

[don r]

Fieros have had serious cooling problems. Putting a larger all aluminun engine in a Fiero is going to aggravate that condition, unless you provide much more ventillation. GM had to recall Fieros because they were catching on fire with their V6's. Supposedly they fixed the issue with their V6s. iven enough money to do a project and good enginering, anything is possible.

 

[SharpGuy]

I've always gotten about 20-22mpg city on several 6 cylinders, I've had in the past years. I think 18-20 is what you can expect on your Northstar engine. But since the Fiero is a small light car, you prob will hit about 20 mpg city, maybe 24 highway. You sure that V8 is going to fit into a fiero, I can't see it, you should double check.

 

[Oreif]

Most Northstar swaps get around 24 city and 29 highway average. There is one in our local Fiero club who drove down to Daytona last year and got 32mpg. (he has a manual transaxle.) I have a ZZ4 350 engine with a carb and I get 19 city and 24 highway.

don r ~ It was the early 4-cyl engines that had the fire issue, Not the V-6's. There is no cooling problem with Fiero's. If the cooling system is operating correctly it will keep the engine cool. If he's worried about cooling there is a 4-core aftermarket radiator for Fiero's. I have raced mine around road courses on hot summer days and never had a problem with my 350 V-8.


Northstars have been swapped into Fiero and have not had hany problems.
design1systems.com has all the parts and information on swapping a Northstar into your Fiero.