head porting

[FieroFanatic]

Does anyone have info on porting iron heads. It would be cool to have a book, video, etc. to go by.Probably be a couple of months before I do it, but I like to think ahead.

[fivepointhustla]

This site is more fiero specific. Iron head porting with pics.

http://www.fiero.nl/forum/Archives/Archive-000001/HTML/20060811-2-060677.html

[Arns85GT]

The results of that engine mod was 132 hp at the wheels. The problem was that with the full port, you will lose some bottom end grunt. The engine revs strong to 6,000 rpm with a Holley carb and 1.6 roller tip rockers.

Arn

[ignoreance]

Different oppinions some say the intake should be ruff others smooth.... But more than that if you want your iron heads flow more you need to work the short turn side with the bump don't take the bump off on the top work around it and behind it... make it glass the gas isn't going to stick or puddle like the last guy on the other board says. If your gas is puddling you need to do your carbs or tune your FI.... cus you got it way to rich. Best thing is to diagram your port first..... take measure's all accross the port then draw a representation of the the port and write down the measures.... you want to get a set of out side calipers. and measure with your dial calipers... Try not to remove more than than .060 unless you know the depth of material. If your going to do custom pistons you can do quite a bit of chamber work and unshroud the flow around the valves but this takes directly away from combustion... and really no amount of milling can return the large loss of compression. I'm talking loosing about 12-15cc of material. So you will need a dome pistion. Its vauge information but the most important thing is draw out what your going to do..... don't jump in with the grinder like 14 year old boy trying to get a girls top off...

[ezrollin]

In my opinion that is a basic pocket port;cleaning up machine marks,enlarging and matching ports,if you go beyon a pp you should have a proven blue print for a given type of head because you can actually lose power or damage the heads.

[Kreb]

Does anyone know of someone who does a good iron head port job for a reasonable price? I suppose that I could try it myself, but it sounds like a fairly nasty job - and if you do it wrong you could do more harm than good...

[Arns85GT]

How to port it yourself

You can do the job at home with some reasonable tools.

I did the iron heads and the attached link lists what you need to know and the bits you need.

Enjoy,

Arn

http://www.fiero.nl/forum/Archives/Archive-000001/HTML/20060811-2-060677.html

[Kreb]

Nice. Thanks! Did you ever run any dyno figures?

[Arns85GT]

dyno

Here it is.

Notice the air/fuel mixture graph. The spike down is the accellerator pump being too rich. You can see where my secondaries at the time were too lean. These two conditions are a whole lot better now. That rich accellerator pump caused a noticable bogg and hurt the lower rpm hp numbers.

There is a spike near the top on the hp chart which was a malfunction in the sensor which you can ignore.

I am hoping to bring that peak hp band back down at least 600 rpm so I have more usable power between 2500 and 3500 rpm by advancing the cam timing. The tuned extractor style exhaust should add probably 5-9 hp overall.

Arn

[Guest]

Didn't you have a different dyno readout then that thing? I mean what program is that? I could have sworn I saw another dyno of yours where it fell on its ass after 5k rpm.

Also the 3.1's dyno more then 110 or so hp at the wheels stock. My bone stock 2.8 did 115 at the wheels through an auto tranny. Most I see for the 2.8's are around 112-117 hp at the wheels. SO for you to do a carb, larger cam, a 3.1 and ported heads and pick up 15 hp is terrible. You never did get flow numbers on your heads, so you might have done more harm then good. You will never know though. But still 130 whp for all that work is not impressive.

Come to the Daytona show. you can dyno it there on a dynojet and get real graphs.

[bszopi]

I have this funny feeling he isn't going to drive from Canada to Florida just to get on a Dynojet...

[SappySE107]

how in the hell do you get 115 at the wheels through a 3T40 with a 135 hp motor? Thats 15% drivetrain loss. Stock 3.1 140hp motor in a beretta with a 3T40 made 100 whp on a mustang dyno. Perhaps your dynojet is a bit high. Even tuned it made 106 whp.

[fivepointhustla]

fieros have a different auto forgot the name/code like 125c

[SappySE107]

Same thing.

[Arns85GT]

Didn't you have a different dyno readout then that thing? I mean what program is that? I could have sworn I saw another dyno of yours where it fell on its ass after 5k rpm.

Also the 3.1's dyno more then 110 or so hp at the wheels stock. My bone stock 2.8 did 115 at the wheels through an auto tranny. Most I see for the 2.8's are around 112-117 hp at the wheels. SO for you to do a carb, larger cam, a 3.1 and ported heads and pick up 15 hp is terrible. You never did get flow numbers on your heads, so you might have done more harm then good. You will never know though. But still 130 whp for all that work is not impressive.

Come to the Daytona show. you can dyno it there on a dynojet and get real graphs.

Shaun, as usual you are totally full of it.

The stock 2.8 dyno showing 107.08 peak hp (as posted on the Fiero forum) does fall rapidly after 5k as did my initial dyno run when I let my foot off the gas at 5200 rpm instead of 6000. (before a tune-up) (see both below)

My 130+whp result is not a bad gain for the limited work done. It will be higher and it is perfectly acceptable for now. Where is your dyno of your 2.8 and the dyno with your ported heads?? Show your sheet if you have one.

There are no ported 3.1 heads on my engine and it has the original cam. BTW I once had a 3.1 rated at 130 hp with an auto and you can bet it did not make 110 hp at the wheels.