300WHP Supernatural 3.XX Coming Soon! (Page 24/54)
La fiera SEP 04, 10:32 PM
I spoke too soon. My lady reminded me of some chores I have on the house and that I promised my neighbor when he asked me for some help.
After that then I can tear my Fiero apart to do the upgrades. Besides, she bought me the diff! Whatever she says I'll do!
Happy wife, happy Fiero owner!!
Spadesluck SEP 05, 01:54 PM
Look good Rei

I like the attention to detail you did on the masking off the heads for paint. I never thought of doing it that way. I always just tore it by hand and did the best lines I could. Thank you for that.
lou_dias SEP 05, 05:11 PM

quote
Originally posted by pmbrunelle:
I did not see that video yet.

At 6:10 in the video, we see that your heads are very different than ordinary Fiero heads. On the stock car, the intake port is much smaller, and it is hard to see the valve. In this video, we see a lot more of the intake valve stem.

I know that Glyptal 1201 is a common choice to help the oil flow and return to the oil pan, and the Glyptal 1201 does not degrade and end up in the oil pan, clogging the suction screen.

I suppose the Dupli-Color with ceramic is a paint you have experience with, and it works just like the Glyptal?


His CNC ported heads eliminate the vane that splits the airflow around both sides of the valve stem. This is where me an him differ in philosophy. Though I can't deny it increases overall flow.
pmbrunelle SEP 05, 09:07 PM
If you're doing light modifications to the Fiero, keeping more or less the same intake concept as stock, then probably it makes sense to keep the vane.

On Rei's engine, the ports are huge; they're nothing like stock. Everything upstream of the valve, it's like he threw it away and replaced it with something made using the Supernatural methods he knows. In this case, it wouldn't make sense to keep a vestige of the Fiero intake design.

[This message has been edited by pmbrunelle (edited 09-05-2020).]

La fiera SEP 05, 10:56 PM

quote
Originally posted by lou_dias:

His CNC ported heads eliminate the vane that splits the airflow around both sides of the valve stem. This is where me an him differ in philosophy. Though I can't deny it increases overall flow.



If the design was to promote low speed torque I would leave the vanes in. If I were to leave the vanes at the speeds the air travels through the ports on my heads it would cause choke.
Yes, I want to speed up the air going from the top of the runners all the way to the valve opening port and with the vanes in place it would speed up too much at high rpm causing a choke like mentioned before. By removing the vanes and having the intake manifold runners do all the air speeding while carrying more CFM and more air mass at a higher RPM would make the heads and intake combo more efficient at higher RPMs. So basically all I've done is to shift the efficiency to higher RPMs by removing the vanes but make the intake to act as the vane.
More like taking a small spoiler and replace it with a bigger spoiler, they are two spoilers but work at different speeds.
Blacktree SEP 08, 06:07 PM
Regarding the vanes in the intake ports: The Chevy Power Manual says they increase port flow by 15%. But they don't say under what conditions. Conventional wisdom says the vanes split the airflow to go around the valve stems. For a long time, I subscribed to that school of thought. But lately I have reconsidered.

I doubt the vanes are much more aerodynamic than the valve stems. So I don't think the idea of splitting the air to flow around the valve stems is completely accurate. I think they're actually vortex generators, to improve swirl at idle and low RPM. At higher RPM, they're probably an airflow restriction. That would explain why Ryan Falconer removed the vanes in his race heads.
La fiera SEP 08, 09:58 PM

quote
Originally posted by Blacktree:
I doubt the vanes are much more aerodynamic than the valve stems. So I don't think the idea of splitting the air to flow around the valve stems is completely accurate. I think they're actually vortex generators, to improve swirl at idle and low RPM. At higher RPM, they're probably an airflow restriction. That would explain why Ryan Falconer removed the vanes in his race heads.



Bingo!!!! And if you think about it that vain is a reverse spoiler. So, my thinking is that the vain does not split the airflow, but according to Bernoulli's theorem it speeds up the air traveing OVER the vane the same way the air travels under a spoiler as air travels faster under the spoiler and slower on top.That discrepancy in air speed causes turbulence in the combustion chamber making the air fuel mix more homogeneuous.
And like your conventional wisdom told you that same vane at hight rpms would be a restriction causing a choke and increasing pressure at that point. That increase in pressure at that point also increases temperature making the mixture less efficient due to less denser hotter air and it is like a avalanche, the higher the rpms the worst it gets.
It's the same principle why turbo/super charged engines need some kind of charge cooling.
But how about if you go the other way, low pressure high speed air charge? Then the opposite happens! That's what I have accomplished with the Supernatural system.
FieroWannaBe SEP 09, 11:37 AM

quote
Originally posted by La fiera:

And like your conventional wisdom told you that same vane at hight rpms would be a restriction causing a choke and increasing pressure at that point. That increase in pressure at that point also increases temperature making the mixture less efficient due to less denser hotter air and it is like a avalanche, the higher the rpms the worst it gets.



To me, it looks to be that GM abandoned the use of port obstructions in intake ports in the early to mid nineties. The Gen II and Gen III v6, vortec heads for the SBC, LT1, as well as the later duke heads, all ditched the swirl ports and vanes, in favor of shear ramps and more typical port shapes with geometries that put more emphasis on seeing the valve heads. Its clear they started to use more sophisticated CFD in their design past the 80's low speed torque obsession.
La fiera SEP 09, 09:06 PM

quote
Originally posted by FieroWannaBe:


To me, it looks to be that GM abandoned the use of port obstructions in intake ports in the early to mid nineties. The Gen II and Gen III v6, vortec heads for the SBC, LT1, as well as the later duke heads, all ditched the swirl ports and vanes, in favor of shear ramps and more typical port shapes with geometries that put more emphasis on seeing the valve heads. Its clear they started to use more sophisticated CFD in their design past the 80's low speed torque obsession.



In my case, the flowbench I've used over the years (which I only use as a reference tool) revealed that at low lift (.100-.250ish) that vane has some minor improvements in flow.
Past that the loss was substantial compared to the gains at the low lift numbers. And since the cams in the stock 2.8/3.1/3.4 engines had very low lift, it is obvious why GM put the vanes there.
Blacktree SEP 09, 11:19 PM

quote
Originally posted by La fiera:... at low lift (.100-.250ish) that vane has some minor improvements in flow.
Past that the loss was substantial compared to the gains at the low lift numbers.


Thanks for the info.

But now I feel like a doofus for leaving the vanes in my 3.4 build. LOL