Thread: 454 fiero

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Originally Posted by stovens

Could be differential gear ratios.

yea I thought about changing the differential gears it currently has a set of 308 gears but I figure with enough power I would push thou's gears with out a problem.

As for the Carb size I thought it might have been too small as well but everyone tells me it not. I'll try an get a video up an posted in a couple of days of the car running an the flat spot just so everyone knows what I mean.

the carb probably has an internal vacuum leak. pull the carb off remove the 4 screws that hold the float bowl remove the float bowl and jet plate put a good strait edge from screw hole to screw hole if you see any light under the center of the straight edge that's your problem experienced mechanics over tighten those float bowl screws and bend the carb body cut a piece of glass to the width rap i piece of 600 wet and dry over it with wd 40 carefully sand that surface until you have contact across the that surface reinstall the float bowl and jet plate with new gaskets. and DO NOT OVER TIGHTEN THE SCREWS what I think is happening vacuum is leaking not only from the transition circuit but also the main circuit vary common problem .......ted

You get that 454 running correctly and you will not need hop up parts...keep it simple..that car with the 454 only weighs 2800/2900 lbs or so....hang in there you are getting it!

I would equate a 454 in a Fiero to one of these small scale speed boats. It's sort of the closest thing to strapping a motor to your back. It should scream reguardless of the heads, etc, as long as the gear ratios are right, and it's tuned and built correctly.

Originally Posted by donie

You get that 454 running correctly and you will not need hop up parts...keep it simple..that car with the 454 only weighs 2800/2900 lbs or so....hang in there you are getting it!

I def agree. I was thinking about it an even if I could only get say 350 Hp out of it, Thats alot of power considering what came out of it an the fact that its 1000 pounds lighter then any camaro or mustange an what not should help it.




Ok so I was thinking about it do any of you guys know anything about exhust? I was looking at the car an it runs 2 1/2 pipe off the manifolds in to a 2 in to 1 muffler that runs 2 1/2 inch pipe to the back. heres my question. What if I eliminated the muffler an ran a true dual exhaust with glass packs 2 1/2 inch all the way do you think that there could be any real power gains? I just think that having both exhaust pipes combined in a 2 1/2 inch pipe might be giving it two much back pressure, an not allowing it to breath enough. I will try an get some pics of the exhaust an what not this week. i just dont have any batteries for my camera an what not. but I was thinkin that the exhaust might be too restrictive.

ok so here we go. I still havnt been able to fix it but here is a video of the car running an I try to demonstrate the best that i can the flat spot.


http://s132.photobucket.com/albums/q...hotrodclub.flv

What's a Fiero? I don't own 12 of em anymore, as I once did, but when the stockers and 4 parts cars left I still kept the two V-8 cars. one with "stock" 300 HP Northstar and 5 speed, the other with a built 377 SBC and 4 speed. Keep after it Fieroboy, when you get that thing running right you won't ever have more fun with your pants on.

Cheers,
Lotsa

jesus you never should have gotten rid of the fiero's this one is my 6th one. I had one with a push rod 3.4 from a mid 90's firebird. this is def my baby just got to figure out the crab. did you see the video that I had posted?

looks like you need to play with the pump cam buy the cam kit $15 and bigger discharge nozzeles and try a 50cc pump if you do not have one

Great video, sorry I don't have any usefull advice, Pat's the man with these big blocks. Sounds real good, except for the flat spot. Steve. To me it sounds like lack of fuel to carb, after you bump it, almost like an air burp, but when you hold it down it does fine. Good luck, good post for us to learn from. Steve.

Originally Posted by fieroboy_gt

jesus you never should have gotten rid of the fiero's this one is my 6th one. I had one with a push rod 3.4 from a mid 90's firebird. this is def my baby just got to figure out the crab. did you see the video that I had posted?

I tried to watch the vid, but my computer is so old it just gives me 3 second bursts and is really hard to watch. It sounds like you've tried the common carb fixes already..... how is your vacuum advance/retard set up? ported vacuum or full manifold? could the quick throttle blips be causing a timing problem via the vacuum pot? try disconnecting and plugging that vacuum line and see if it helps or hurts the bog. just a thought.

Lotsa

yea Im getting plenty of vacume. the timming advance works great if I unplaug the vacume line form the canister it has a had time even ideling. thats all working. I might have to large of jets in it. Im not sure off the top of my head. but both the primary an the secondarys are in the 80's like 81 primary 88 secondary somthing like that.

Originally Posted by fieroboy_gt

yea Im getting plenty of vacume. the timming advance works great if I unplaug the vacume line form the canister it has a had time even ideling. thats all working. I might have to large of jets in it. Im not sure off the top of my head. but both the primary an the secondarys are in the 80's like 81 primary 88 secondary somthing like that.

main jets are not going to do what you have going on its a fuel shot timming deal at the rigth time . you need the accelerator pump shot to add fuel so there no flat spot . if you roll it on very slow and it works then you need more fuel .it very well could be to much as well at the wrong time. bigger jets are not going to help but would not be a dead spot off idle

You have a definite carb problem and I suggest you find a book like the one I posted or similar and read it from cover to cover. The one I posted explains in great detail how to tune a Holley carb.

Originally Posted by NTFDAY

You have a definite carb problem and I suggest you find a book like the one I posted or similar and read it from cover to cover. The one I posted explains in great detail how to tune a Holley carb.

so heres a question could a carb thats running like shit hurt cars overall proformance an gas mileage. I get like 4 miles to the gallon. an with a 7 gallon gas tank thats a short trip if you know what i mean I was thinking I would get more like 8 to 10. maybe im a dreamer.were can I find that book that you up loaded on here