Auction on E-bay- regardless of the Fiero referrence, is it possible to get 30 to 40 horsepower on a 3.1 or 3.4, even the front drive versions, just with "ported heads" and 31CC chambers? I find this claim dubious, but I am NOT an expert in this area...


Here is the auction Info:


"3.1 3.4 FIERO- BERETTA V-6 PORTED CYLINDER HEADS"

COMPLETE SET OF HAND PORTED CYLINDER HEADS

TITANIUM RETAINERS.

31CC CHAMBERS

NEW BEEHIVE VALVE SPRINGS

PC VALVE SEALS

THESE HEADS WERE ORIGINALY COMPLETED FOR A GM PACE VEHICLE.

BOLTING THESE HEADS ON YOUR 3.1 OR 3.4 WILL GAIN AN ADDITIONAL 30-40+ HORSEPOWER !!!!

[This message has been edited by FieroFanatic13 (edited 02-20-2008).]

With the proper intake, exhaust, and cam, a 30-40 HP increase would be attainable. But I can't see getting 30-40 HP just from swapping cyl heads.

Edit to add: with 31cc combustion chambers, they must be aluminum cyl heads. They won't work on a Fiero V6 without some serious modifications. Just a word of warning.

[This message has been edited by Blacktree (edited 02-20-2008).]

The auction is misleading. First it sounds like they are the aluminum heads (they flow better than the cast iron even in stock condition)
Second they are most likely using the head flow data increase to calculate the horsepower gain. On a real engine, the properly matched cam, intake set-up and exhaust system modifications would also be required. When they run the head flow data, they probably ran the flow up to .6" or higher lift but any flow over .5 is not realistic as the largest cam for a 60* V-6 is .5" lift max and even less for the 3X00 series with aluminum heads. (no aftermarket cams available, Although custom cams can be made.) Just porting the heads by themselves will not give you "30-40hp", You might see roughly 10hp.

Increasing the flow of the heads, intake, or exhaust by themselves will give you small gains. Doing the entire path (intake to exhaust) is where your huge power gains come from. When I built my 3.4L I gained about 80hp total with better intake, ported/polished/shaved heads, Performance exhust manifolds, Performance muffler, and a larger diameter exhaust pipes.

they are alum heads.
gen 3, I think.

I don't think you could get that from just porting even V8 heads. FYI most HP quotes you see are over estimated Id say cut them in half.

quote Originally posted by 2.5: I don't think you could get that from just porting even V8 heads. FYI most HP quotes you see are over estimated Id say cut them in half.

depends on your setup. if you got the cam, the headers & the intake to take advantage of the ported heads, it sure can make that difference. just another piece of the HP puzzle.

quote Originally posted by Oreif: The auction is misleading. First it sounds like they are the aluminum heads (they flow better than the cast iron even in stock condition) Second they are most likely using the head flow data increase to calculate the horsepower gain. On a real engine, the properly matched cam, intake set-up and exhaust system modifications would also be required. When they run the head flow data, they probably ran the flow up to .6" or higher lift but any flow over .5 is not realistic as the largest cam for a 60* V-6 is .5" lift max and even less for the 3X00 series with aluminum heads. (no aftermarket cams available, Although custom cams can be made.) Just porting the heads by themselves will not give you "30-40hp", You might see roughly 10hp. Increasing the flow of the heads, intake, or exhaust by themselves will give you small gains. Doing the entire path (intake to exhaust) is where your huge power gains come from. When I built my 3.4L I gained about 80hp total with better intake, ported/polished/shaved heads, Performance exhust manifolds, Performance muffler, and a larger diameter exhaust pipes.

3X00 cams, NA, turbo and SC'ed

http://wot-tech.com/shop/in...act=viewCat&catId=31
http://milzymotorsports.com/

80 hp from an iron 3.4 na? is this recorded on a dyno? thast a 50 percent increase in power which is quite a bit for an na engine. especially when orief got 225 and i think thats the most power anyones made. could be wrong of course, in which case id like a set of heads like yours.

http://cgi.ebay.com/ebaymot...dZ1QQsspagenameZWDVW

aluminum heads, chambers look good but crappy pics of the ports

[This message has been edited by megafreakindeth (edited 02-20-2008).]

quote Originally posted by FieroFanatic13: Auction on E-bay-

Enough said. Without supporting mods, maybe 10 HP if you have a restrictive head setup. With supporting mods, on some engines, it can be a big diffrence.

Cylinder head porting can get big HP gains if done right the more air and fuel the more HP so 30 HP is not a real lot this is why racers spend big bucks on heads to get more flow .
I built engines for a living and went to thr school of automotive machinist in Huston Tx

Not with the stock intake manifold and exhaust headers (we are talking 60 deg PR) they cant support what the stock heads can flow.

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Trueleo.com/fiero.htm
RSpiderII@aol.com

Orief has it right.
the whole system has to be considered. Yes porting can make a big differrence if the rest are done properly to size for the powerband you want.
30-40 hp on a 3.x just due to the head porting is completely misleading, and beyond the realm of believability for any mass produced engine!
While I firmly believe the heads are THE most important part of getting power out of a motor, if you don''t back it up with the right goezinta and goezoutta plumbing, and proper camming, its just a waste if you dont do it all. just more ebay hype.

well if my trueleo headers/intake and 260h cam, plus some heads i dont have will give me 240 crank hp then sign me up for those heads. seriously

Oreif and engine man are both correct,, the flow bench can develope remarkable horse power!! but porting and polishing with out the flow bench is a stab in the dark ,, there are articles in the automotive performance magazines that will HELP every fiero owner to understand this craft ..I have been posting often when I see an article in a performance magazine on porting, port matching,polishing,or performance from valves ,springs, rollers..if to cheap to purchase check it out at albertsons or other places!! this month SUPER CHEVY march issue has a A1 article on porting ,my views differ from what I read in the forum..I have mucho experience but no fiero experience (a spare set of heads awaits me) so I just recomend you read the flow experts ..LISTEN TO THE EXPERTS ,,read and learn.... the port match article I recomended is at odds with my own beleave.. but good solid info .. My company said that if you are well enough to travel to the doctor s office to be examined and get a doctorsexcuse.. you are well enough to come to work + you will make money and not spend it to help greedy expensive doctors buy yachts and expensive vacations..

quote Originally posted by megafreakindeth: 80 hp from an iron 3.4 na? is this recorded on a dyno? thast a 50 percent increase in power which is quite a bit for an na engine.

Actually it has been recorded at least twice on a dyno. Once with my carb'd 3.4L and then a year later on the EFI 3.4L I built for a friends car.
Both cars had about 200 rwhp (carb'd with auto was 197, EFI with manual was 205) and the estimated crank horsepower based off the chassis dyno is over 230hp. Also there was a member "Donk 316" who had a carb'd 3.4L in a Pace Car and he had an estimated 237hp based off of his chassis dyno.
The thing is the heads were reworked, larger cam, better flowing intake and exhaust, increased compression, and dyno-tuned so it wasn't just a head rework, It was a combination of many things.

Just a side note to this discussion, GM rated the 3400 at 175hp and the "ram air" version of the 3400 just had a better flowing head and was rated at 185hp.

[This message has been edited by Oreif (edited 02-21-2008).]

quote Originally posted by uhlanstan: ......My company said that if you are well enough to travel to the doctor s office to be examined and get a doctorsexcuse.. you are well enough to come to work + you will make money and not spend it to help greedy expensive doctors buy yachts and expensive vacations..

lol - cute.
O/T - but - dang - are they endorsing the spreading of disease? the main reason for NOT going to work when sick is to NOT make others sick.

remarkable gains are possible from porting the manifolds and heads with out other modifications...Porting is not just grinding and opening up the hole ,of course this is basically what I do?? .because I never had access to a flow bench.I read and listen to the experts,then followed thier advise as well as I can..You need to cc the chamber,(never mastered this)you must measure the ports to ensure equal flow ,you can make a few simple measurement tools from plastic bottles, bigger is not better unless you are building an all out 1/4 mile drag car, just read the articles, intelligence gathering about a subject you are interested in will make you better at it,,I have never ported a set of fiero heads and untill I do with success,I have little voice .. But do not disparage the flow bench experts they discuss what works. when I started measuring my port work the performance of my engines increased.. I know little about port work so I follow the advise of experts and adapt what I learn to what I eyeball ..you want each cylinder sucking equally.. I do not want to start a dispute (thats my political post) I want to start education not so much for the knowledgeable posters but for the many readers of these post ,who will produce more efficient engines and more interest in fiero.... I ve gotten older and wonder ..is the perfect woman still beautiful,deaf, blind ,dumb and owns a liquor store???

[This message has been edited by uhlanstan (edited 02-21-2008).]

quote Originally posted by engine man: Cylinder head porting can get big HP gains if done right the more air and fuel the more HP so 30 HP is not a real lot this is why racers spend big bucks on heads to get more flow . I built engines for a living and went to thr school of automotive machinist in Huston Tx

If you have a performance intake and injector/carb setup to feed the flow of teh heads of course. Plus the limits of teh exhaust to let it back out.