Returning Fiero Owner - Let's Talk 2.8 Breathing (Page 9/14)
jjd2296 APR 11, 02:14 PM
I have lots of increase in low to
Mid range now with my 3.4 pr swap. Ported heads cam etc but it chokes out after 4500. Kinda kills it for me. I would rather sacrifice 10 fpt from 4500 upward to get 18hp more from 4500-5500 + it’s all preference.
jjd2296 APR 12, 09:15 AM

Lou I should also have mentioned that after I do all of this next years plan is to add a supercharger! lol


quote
Originally posted by lou_dias:


Wow you did a nice job there, but remember - I speculated that there is such a thing as too big an opening. I did lose a few ft*lbs of torque below 4600 rpm if you watch the video I made of my dyno on the first page of this thread. However - if you're going for power to 6000+ rpm then great!
sourmash APR 13, 07:38 AM

quote
Originally posted by jjd2296:

I have lots of increase in low to Mid range now with my 3.4 pr swap. Ported heads cam etc but it chokes out after 4500. Kinda kills it for me. I would rather sacrifice 10 fpt from 4500 upward to get 18hp more from 4500-5500 + it’s all preference.



I started building a 3.4 PR eng and got distracted. Got the headers but I probably wouldn't port these iron heads very much. Does the 3.4 in a Camarobird choke out above 4500? Because it if doesn't have a limiting intake it should benefit nicely from a cam, lifters, headers.

EDIT: "The power rating of the 3.4 L (3,350 cc) L32 ("S-code") used in the Camaro and Firebird was 160 hp (119 kW) at 4,600 rpm and 200 lb⋅ft (271 N⋅m) torque". So it peaks at 4600 stock.

[This message has been edited by sourmash (edited 04-13-2020).]

jjd2296 APR 13, 10:50 AM
That’s stock numbers. Ported heads, lifters, heads ported and custom manifolds Cam etc etc. Will change those specs My issue is increasing ng the breathing not the rest of the swap.

[This message has been edited by jjd2296 (edited 04-13-2020).]

cvxjet APR 13, 11:40 AM
Remember- the rated HP at RPM is just a rating.....The actual power curve will go on beyond that RPM. Case in Point; LS7 engine is rated at 505 HP at 6300 RPM, but that engine will pull all the way to 7000. I suspect that the 3.4 F-body with it's original manifold will pull strongly to at least 5000 and maybe 5500....The big problem is the Fiero >>2.8<< intake manifold which allows a 2.8 to pull to 6000......The 3.4 Liter at 4900 rpm will equal the flow of the 2.8 @ 6000 rpm.

I still think that someone should have made an adapter lower manifold to allow use of the canted valve aluminum heads from the 3400-3900 V6s with the Fiero upper manifold so that it looked stock (Obviously the upper would need the "Dawg" mod)
sourmash APR 13, 11:41 AM
Yeah, my post states those are stock numbers.
On the ported heads, did you post flow numbers before and after or was it done at home?
lou_dias APR 13, 01:03 PM
Instead of the forced induction route, me and Rei (LaFiera) went the route of more compression and bigger cams.
A 260 cam should still be a decent forced induction-capable cam. Ours aren't. But that's what it's all about: different strokes for different folks.

When you do forced induction, I recommend switching to E85. We run E85 naturally aspirated and still made gains of 7-10% more power. Fuel economy goes out the window, but that's usually always the price you pay.

[This message has been edited by lou_dias (edited 04-13-2020).]

jjd2296 APR 13, 03:40 PM
well ill be at the equivalent of a 272 cam once I switch to 1.6 roller rockers. I don't have AC so my plan next year is to install a v1 vorterch supercharger where the ac compressor would be. Fierosound was nice enough to give me a template for the bracket as well as other info I need. I don't think there is anywhere here in Ontario Canada to buy E85

[This message has been edited by jjd2296 (edited 04-13-2020).]

La fiera APR 13, 09:04 PM

quote
Originally posted by jjd2296:

That’s stock numbers. Ported heads, lifters, heads ported and custom manifolds Cam etc etc. Will change those specs My issue is increasing ng the breathing not the rest of the swap.




JJ, the cure for your problem is simple. Give the runners plenty of volume and speed and the plenum should have at least 3.5 liters of volume (it has to be big).
The bigger the plenum, the more torque you'll make and since HP is a mathematical calculation based on torque, you'll make the HP.
That 262 cam you have is basically a stock cam. The aftermaket cams available for these engines are way too soft, even the roller versions from WOT.

The problem you have is that you are emptying the plenum way too early and then the TB is not big enough to keep the plenum filled at higher rpms.
The Vortec Supercharger will do about the same but since you are compressing the incoming air you are heating it up at the same time.
Now you have the weight of the supercharger, extra heat, and also need extra fuel to prevent detonation (even if you use E85 you'll need more fuel if you are supercharged).
Also the engine has to spend hp to turn the supercharger, in other words it will not be efficient.
You'll make more power but at the expense of efficiency. And that is not taking into consideration the engine sound, It'll sound like a hurt duck or a Buick Grand National.

That is what made me charge ahead in research of the ultimate intake, cam and head combo, it didn't exist so I had to make it.
The norm is that if you can't make power NA put a supercharger or a turbo. Not me, I don't give up that easy.

But the bottom line is that it is your personal build and I respect that. I wish you the best on your goals.
pmbrunelle APR 13, 09:41 PM

quote
Originally posted by lou_dias:
When you do forced induction, I recommend switching to E85.




quote
Originally posted by La fiera:
and also need extra fuel to prevent detonation (even if you use E85 you'll need more fuel if you are supercharged).



E85 is the Loch Ness Monster of Canadians.

We've heard tales of it, but never seen it with our own eyes.

I'm not certain the fuel even exists!


quote
Originally posted by La fiera:
That is what made me charge ahead in research of the ultimate intake, cam and head combo, it didn't exist so I had to make it.
The norm is that if you can't make power NA put a supercharger or a turbo. Not me, I don't give up that easy.



Now, I'd like to see someone take on the challenge of doing it under a stock decklid.

[This message has been edited by pmbrunelle (edited 04-13-2020).]