Back in the early seventy's cars used VERY high octane fuel, probably 100 octane or more, the compression ratio on those engines were 11:1-14:1 this made a HUGE difference in power, then in 1973 or so they started doing emission stuff, and dropped compression ratios and used lower octane fuels, the cat alone did not reduce the power of these vehicles. i do not use a cat on ANY of my fiero's, when i got my 85GT it had one on it, a high flow cat-co cat, i removed it, and put on straight pipes, no muffler or anything, no noticable increase in power, im sure it gave 1-2HP but not much, I could see through the old cat, alittle light came through, so i know it wasnt bad.

can someone confirm that back in the 60's and early 70's they had higher compression and higher octane fuel?
im only 22 years old, what do i know

matthew

and Slammed I am not a Damn Noob. I have owned Fieros for 6 years now and have been around the Fiero Community for 5 years of it.

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Don Pottorff
Red 88 Fiero 2M4
Silver 86 Fiero 2M4

I have a recall duke in my 84 Fiero, I checked the casting date and it was July 1988. The bottom end of my motor has never been apart. My Fiero has 151000Miles on it, I estimate about 120000 of them miles are with the current motor. Last winter the head was taken off port matched and polished, along with the intake and exhaust manifolds, the TB was also polished. This motor still has the stock valve train, valve seals, rings, etc... With just that change, I managed to pull a 18.1sec 1/4 at 70.1MPH, this is with an automatic, full tank of regular gas, stock air filter, and everything in the car.

I found a site that calculate RWHP from 1/4 times and speed, it calculated out to be 89RWHP, not much, but this motor made 92HP at the crank stock. Estimating drive train loss, I have about 100HP at the crank. But, when I was at the track, there was a 10-15MPH headwind, and the elevation here is about 1800feet.

I shall see what difference I get when I finish with my duke. I should have a better cam, a Fiero Store Header, new valve train (stock), and different pistons and rings (maybe flat top pistions). this should complement the head work that has been done.

P.S. My dad did all the port matching and polishing. He used to work for Cosworth doing head work for their racing engines, so he knows what works and what doesnt, he is also a registered mechanic. He thinks the 2.5L port design is crap, with crappy castings to boot.

That would probably bring you to what, about 130HP? Anyone?

Also, I think I heard somewhere removing the cat would give you more horespower, but lower torque (or something)

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'86 2.8L
'86 2.5L turbo put to sleep

THE SHAUN LIVES....!!!!!

BS'er's and PHAGS BEWARE!!!

dude...200hp out of a duke.. you are a NOOB

JM
THE SBC PUNISHER!!

http://www.fiero.nl/forum/Forum1/HTML/036728.html

Go thru the pics. There are some nice dukes in there and there's a few that push some HP but are not you average 2.5L Iron duke. Mine for example is a 3.3 liter Super Duty rated at 300 HP with 13.5:1 compression and dual sidedraft webbers...

I think what got some people in a bunch was the " My friend said and they know all " instead of the "can I do this" approach.

Personally I like the extra 4 cylinders myself.

and FASTINDYFIERO you have a pm.

Rob D.

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I have heard from several mechanics from Back yard shops and from Dealer shops say that just removing the Cat on some cars can bring as much as 50 More hp since they are so restrictive on an engine. This was also from a My Cousin who worked in this shop.

That post was full of so much crap, I didn't know what to call BS the most. I wouldn't call those guys described as "bolt-turners" let alone mechanics. I'm sure their street cars run the 1/4 mile track in 4 seconds at 350mph and that the local police ask them for help on high speed pursuits. (I'm not making that up, someone told me that once out on the smoke deck)