Project 3400 Roller Cam Block (Page 38/82)
La fiera APR 29, 04:22 PM
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[This message has been edited by La fiera (edited 04-29-2013).]

lou_dias APR 30, 11:37 AM
No big deal.
I am waiting for an update to see if the new hub has arrived.

If these heads are a performance increase, then great. However, I believe to you should alter your program to leave the vane in. If you look on the top wall of the intake ports, you'll see a crevice that compensates for that vane and directs air to the front facing part of the valve where as the vane directs air around the valve stem to the sides and back. This is what balances the pressure around the valve.

It seems that not much improvement was done to the exhaust...or am I wrong?

Update:
Collision center has received a UPS update that it is en-route. Should show up tomorrow.

[This message has been edited by lou_dias (edited 04-30-2013).]

La fiera APR 30, 02:08 PM

quote
Originally posted by lou_dias:

It seems that not much improvement was done to the exhaust...or am I wrong?




That was the intentional for stock compression motors.
lou_dias APR 30, 02:48 PM

quote
Originally posted by La fiera:
That was the intentional for stock compression motors.


Let me assure you that even 2.8's would benefit from exhaust porting. Stock exhaust valve is 1.42". It is under-served by 3/4" or 7/8" ports...
Blacktree APR 30, 04:22 PM

quote
Originally posted by lou_dias: Let me assure you that even 2.8's would benefit from exhaust porting. Stock exhaust valve is 1.42". It is under-served by 3/4" or 7/8" ports...


When I saw the flow numbers, my first thought was "that's gonna need a really exhaust-heavy camshaft!" A head with great intake flow and weak exhaust flow isn't going to scavenge well.
La fiera MAY 01, 12:24 PM
You guys got a point but bigger is not always better. There's got to be a balance between the intake and exhaust velocity.
The port size will dictate at what RPM rate the velocity is optimum for that specific RPM.

The faster the exhaust exits, the incoming air will travel at a faster rate and the opposite happens when the tables are turned.
The theory behind this is to bring in large amounts of air volume at hi velocity. That is why the components of the intake side (TB, Plenum, etc) are out of proportion compared to the exhaust.
Now, being that these heads where going to be on a 2.8 I opted for the smaller exhaust port.

For the 3.4 I'm building a totally different head, of course with a little bigger exhaust port.
Just look at my dyno sheet and look where the power is compared to yours, everything is just a balancing act.
http://www.oil-endurance-pr...icion/pontiac-fiero/

Can't wait to see more videos of you racing!

Cheers
lou_dias MAY 02, 12:33 PM

quote
Originally posted by La fiera:

You guys got a point but bigger is not always better. There's got to be a balance between the intake and exhaust velocity.
The port size will dictate at what RPM rate the velocity is optimum for that specific RPM.

The faster the exhaust exits, the incoming air will travel at a faster rate and the opposite happens when the tables are turned.
The theory behind this is to bring in large amounts of air volume at hi velocity. That is why the components of the intake side (TB, Plenum, etc) are out of proportion compared to the exhaust.
Now, being that these heads where going to be on a 2.8 I opted for the smaller exhaust port.

For the 3.4 I'm building a totally different head, of course with a little bigger exhaust port.
Just look at my dyno sheet and look where the power is compared to yours, everything is just a balancing act.
http://www.oil-endurance-pr...icion/pontiac-fiero/

Can't wait to see more videos of you racing!

Cheers


Flow is about balance and scavenging. Oreif's heads flowed more than Falconer on the intake side but less/stock on the exhaust and his motors made 200rwhp. Falconer, while having a poorer intake thru-put (and much poorer than yours) had better exhaust thru-put and made 275+ hp. This is what is amusing about heads and flow #'s 158cfm/port is enough to flow 275+hp...yet we have heads with more cfm on the intake making less HP in both...this extends to AL heads as well...which is why I've always said the heads aren't necessarily the primary restriction on Fiero engines. Typically it's the intake system and exhaust system that fails at supplying(or allowing air to leave) the heads with enough air flow.
Will MAY 03, 03:19 PM

quote
Originally posted by lou_dias:

Yet another example of iron heads putting down 240+ lbs*ft ... who would have thunk it?



Caddy 4.9's put down close to as much torque as my Northstar...

But they won't even come close to the horsepower.
lou_dias MAY 03, 09:20 PM

quote
Originally posted by Will:


Caddy 4.9's put down close to as much torque as my Northstar...

But they won't even come close to the horsepower.


Well your motor ain't going in my car is it?

Here's my 4.9 dyno before a new tune and all the wiring fixes...
http://www.fiero.nl/forum/A...130314-1-086966.html

[This message has been edited by lou_dias (edited 05-03-2013).]

ericjon262 MAY 03, 09:59 PM

quote
Originally posted by Will:


Caddy 4.9's put down close to as much torque as my Northstar...

But they won't even come close to the horsepower.



and requires more displacement to do it...