Project 3400 Roller Cam Block (Page 29/82)
ericjon262 FEB 09, 04:54 PM

quote
Originally posted by lou_dias:

So seeing as how the 3.1 is the only motor to have all generations of heads...

Gen 1: 150 hp (iron)
Gen 2: 140 hp (aluminum, but intake ports are fail)
Gen 3: 170 hp (roller cam with bigger ports over gen 2)

If you ask me, Gen 1 heads flow better than Gen 2 even if the Gen1 were stock (not ported). Gen 3 was an improvement over Gen 2, but its not proven better than ported Gen 1 heads yet.
We have GM flowing 275hp from a 2.8 probably with an open exhaust and we have a 3500 flowing 274 hp definitely with an open exhaust from Gen3 heads.



Lol wut?!

you're kidding right? let's see some graphs to show what the HP and TQ curves look like. the gen 3 WILL have the broadest torque curve. Hell, a stock 3100 dyno'd 160 WHP on 60V6.


------------------
I know these lines Look crooked on paper, but I swear I've got them straight in my head.

Built not bought...

http://www.fiero.nl/forum/Forum2/HTML/119122.html

[This message has been edited by ericjon262 (edited 02-09-2013).]

lou_dias FEB 09, 08:09 PM

quote
Originally posted by ericjon262:


Lol wut?!

you're kidding right? let's see some graphs to show what the HP and TQ curves look like. the gen 3 WILL have the broadest torque curve. Hell, a stock 3100 dyno'd 160 WHP on 60V6.



Anyone can claim "stock"... Here's a 3400 with some light mods doing about ~160 at the wheels. Mods are listed.
http://www.youtube.com/watch?v=K270RdBmQ0A

The numbers I quoted are GM's numbers.
http://www.edmunds.com/chev.../features-specs.html
Gen1 3.1 made 140 hp in the Camaro and Firebird (1990-1992) with 8.5 compression...but I'm pretty sure there was a minivan version that made 150hp, regardless that's the same as Gen2. From what I remember about the 3.1 motors is that there was a special one that used the 1.72/1.42 valves where as most used the 1.6/1.3 valves and they made less power. Let's put it this way, a 3.1 with the Fiero cam, Fiero compression ratio and Fiero HO valves would be rated at 150, just like the 2.8 is rated at 140 in line with the 3.4 being rated at 160.

So:

GEN1 2.8 = 140hp (Fiero)
GEN1 3.1 = 150hp using Fiero parts and compression ratio, non-HO versions made 120-125 and the 1991 Pontiac 6000 and Firebird/Camaro-140 with 8.5 compression instead of the Fiero's 8.9
GEN1 3.4 = 160hp which came with 1.72/1.42 and Fiero cam STOCK - but we're not comparing the 3.4 in this case, just heads
GEN2 Aluminum head spec: LH0 3.1 made 135-140 hp.
L82 Gen3 made 160HP
LG8 Gen 3 made 170-175 hp

So I stand by my statement that the roller cam design separated the men from the boys, not the heads.

PS, here's Will selling Falconer IRON heads that flowed enough for 300HP:
http://www.thirdgen.org/tec...s-falconer-race.html
I wil note that the exhaust ports were ported to D shapes. I personally wasn't impressed with them because they got right of the vane on the intake, where as Oreif's ported flow #'s didn't and posted higher numbers. That's why I opted out of that sale and got my heads ported right. I did port my exhast side much more than Oreif though.

[This message has been edited by lou_dias (edited 02-09-2013).]

sleevePAPA FEB 09, 08:30 PM
Lou,

if you have the time and resources I suggest you bolt on an LX9 topend to your 3400, get rid of the assembled steel cam in favor of a solid core grind. the assembled cam found in those engines are known to break, im sure you would hate to have that happen, LOL. Have you asked around at 60degreeV6.com? theres way more support for the 660's over there and im sure more than a few can offer up some good results.
Joseph Upson FEB 09, 08:35 PM
I wouldn't put too much trust in those numbers as a measure of expectations Lou, keep in mind that GM has to work within EPA guidelines to avoid certain penalties and could've been holding that motor back. The 3.9L was rated ~240/240 initially but they displayed a ~270/258 HO version at a SEMA show that never went into production. Although the 2003, 3100 Century and Grand Prix are late models regarding cylinder head design, GM Powertrain states 175 hp and 195 lb/ft @ 9.6:1 compression and that's a pretty serious advantage over the 3.4L which has .3L of additional displacement and pretty much the same compression at 9.5 if I recall correctly. That's 56.5 hp per litre vs. 47.1 hp per litre, something to think about.
Joseph Upson FEB 09, 08:38 PM

quote
Originally posted by sleevePAPA:

Lou,

if you have the time and resources I suggest you bolt on an LX9 topend to your 3400, get rid of the assembled steel cam in favor of a solid core grind. the assembled cam found in those engines are known to break, im sure you would hate to have that happen, LOL. Have you asked around at 60degreeV6.com? theres way more support for the 660's over there and im sure more than a few can offer up some good results.



I do believe those cam failures were secondary to intake manifold leaks where cam bearings were damaged from coolant contamination first and failed some time after the repair due to runout that eventually caused the cam to break from fatigue.
lou_dias FEB 09, 08:51 PM


One thing you don't see in this image is the narrower bottom end of the aluminum head. Also, the aluminum head goes flat then falls to the valve. The iron head offers a smoother transition and there is plenty of material that can be removed to increase flow.
Joseph Upson FEB 09, 08:59 PM
It looks simple in terms of a cut away, but the runner design may justify those differences, you also have to keep in mind the limitations posed by effective velocity, I would imagine that there is a point where engine output would need to be increased to stay within range of flow capability, one of those too much, or too little is bad situations. I ruined a perfectly good set of 350 heads before gaining that understanding, by over porting the intake runner.
lou_dias FEB 09, 09:07 PM

quote
Originally posted by Joseph Upson:

I wouldn't put too much trust in those numbers as a measure of expectations Lou, keep in mind that GM has to work within EPA guidelines to avoid certain penalties and could've been holding that motor back. The 3.9L was rated ~240/240 initially but they displayed a ~270/258 HO version at a SEMA show that never went into production. Although the 2003, 3100 Century and Grand Prix are late models regarding cylinder head design, GM Powertrain states 175 hp and 195 lb/ft @ 9.6:1 compression and that's a pretty serious advantage over the 3.4L which has .3L of additional displacement and pretty much the same compression at 9.5 if I recall correctly. That's 56.5 hp per litre vs. 47.1 hp per litre, something to think about.


Joseph,
My argument is that the crowning achievement of GEN 3 is the roller cam...which I've retrofitted and made comparable power DESPITE a mediocore tune and intake neck restriction. Heck even my CR ratio is close to a stock 3500.
lou_dias FEB 09, 09:14 PM

quote
Originally posted by Joseph Upson:

It looks simple in terms of a cut away, but the runner design may justify those differences, you also have to keep in mind the limitations posed by effective velocity, I would imagine that there is a point where engine output would need to be increased to stay within range of flow capability, one of those too much, or too little is bad situations. I ruined a perfectly good set of 350 heads before gaining that understanding, by over porting the intake runner.


The aluminum heads do a lot more direction changes within the head. It forces the air too "swirl" If you look at the shading you'll see what I mean. The iron heads offer a straight shot into the combustion chamber. If you look at the choke points of the two heads, you can see that it's easy to enlarge the iron head choke point, again providing more overall flow. Aluminum heads are good at producing low end torque. I don't think they can truly keep up with properly ported and polished iron heads on the top end. Yes, the 3X00 intakes are higher flowing, but again, there are fixes for that on the Fiero side as well.

Basically, iron head performance has been limited by bad intakes. Oreif built 2 3.4's with the 272 cam. One made 197 rwhp and the other 20X (I forget maybe 205rwhp). I wish he had used the 3400 block and cam. One was carbureted and the other used the Trueleo intake. I believe both used a ported stock exhaust. The Fiero performance problem lies in the intake and the tune, not the heads

[This message has been edited by lou_dias (edited 02-09-2013).]

Joseph Upson FEB 09, 09:29 PM
The shortest distance between two points is a straight line, the aluminum head is closer to it than the iron head as it is already pointing downward at the valve more so than in the iron head and that seeming choke point may be for the benefit of velocity. Except for high revving, I believe you will lose a good bit of bottom end performance if you grind away the areas you have circled. The trend in the cylinder heads I've been seeing including the LS motors is a raised runner ceiling to reduce the angle before entering the cylinder. Whatever you decide I hope it works.