I don't understand. If you are talking about the Gen 2 aluminum heads, they flow worse than the Fiero iron heads do (hence the FWD 3.1 motor makes no more power than the Fiero 2.8). The later alumium heads won't swap onto the Fiero block without putting the compression ratio too high.
Originally posted by KurtAKX: I'm going to begin with a disclaimer: I think the Trueleo intakes are a well thought-out and good product.
That said, I may be overstating the glaringly obvious here, but neither this dyno data nor the data provided on the Trueleo Fiero Intake site give CYLINDER TO CYLINDER flow distribution for a given delta-P, which is what Will was up HitesFiero's A55 about. Not to say it was never done, but it's not provided in this response, any of the threads covering the development of the intakes (any of them, short or long runner), nor is it on the website.
Will's concern for this may be too much - the flow distribution of many factory and aftermarket intakes is terrible- I can't imagine that HitesFieros could be substantially worse than a 1970s/1980s factory of aftermarket piece. Look no further than the Edelbrock intake base for the 2.8, in which the runners are intentionally different
To Hites- the pressure differential seen by each intake runner between atmospheric pressure and a downward moving piston (and scavenging) will most likely be pretty much the same as you state. I think the point Will's trying to make is that the same pressure differential can exist at both ends of a sewer pipe as at both ends of a coffee stirrer, and you'll end up with radically different flow rates.
I don't think Francis T claimed to have perfect air distribution though, the OP has made claims with nothing to back them up.
------------------ we're in desperate need of a little more religion to nurse your god-like point of view...
I don't understand. If you are talking about the Gen 2 aluminum heads, they flow worse than the Fiero iron heads do (hence the FWD 3.1 motor makes no more power than the Fiero 2.8). The later alumium heads won't swap onto the Fiero block without putting the compression ratio too high.
the gen 2 heads do flow better, it's the intake that is total garbage on a gen 2 motor. Gen 2 heads flow about like the small port gen 3 heads peak power isn't everything.
------------------ we're in desperate need of a little more religion to nurse your god-like point of view...
I don't understand. If you are talking about the Gen 2 aluminum heads, they flow worse than the Fiero iron heads do (hence the FWD 3.1 motor makes no more power than the Fiero 2.8). The later alumium heads won't swap onto the Fiero block without putting the compression ratio too high.
the Gen II & III engines use a larger dish in the piston due to the smaller CC. i wouldnt hang on to every word of iron head enthusiast, GEN II heads do have better flow characteristics due to the relation of the height of the port to the cylinder and the relation of the valve. GEN II heads stall the port easily because of if the increased flow and velocity from the raised port, canted valves. quench areas were also revised to help create better swirl characteristics for added atomization.
Originally posted by KurtAKX: I'm going to begin with a disclaimer: I think the Trueleo intakes are a well thought-out and good product.
That said, I may be overstating the glaringly obvious here, but neither this dyno data nor the data provided on the Trueleo Fiero Intake site give CYLINDER TO CYLINDER flow distribution for a given delta-P, which is what Will was up HitesFiero's A55 about. Not to say it was never done, but it's not provided in this response, any of the threads covering the development of the intakes (any of them, short or long runner), nor is it on the website.
To Hites- the pressure differential seen by each intake runner between atmospheric pressure and a downward moving piston (and scavenging) will most likely be pretty much the same as you state. I think the point Will's trying to make is that the same pressure differential can exist at both ends of a sewer pipe as at both ends of a coffee stirrer, and you'll end up with radically different flow rates.
Our intakes and headers are VERY limited production items. They're intended for sale to a small market not know for deep pockets. That said, it's quite difficult to recoup R&D $$$! Considering how well our intakes work, think we went spent more than enough R&D dollars on the product. BTW: there are no glaring differences in our runners that would indicate a need for a flow differential testing. One other point, those dyno numbers were taken from one of our first prototypes, currant units have almost 10 fewer seems and thus better flow. To anyone thinking about making a product for the Fiero crowd, keep your R&D cost down.
OP ignore these trolls, you are doing what needs to be done around here. You already have something in hand, not playing armchair engineer. Can't wait to see the results, as everyone should be.
the gen 2 heads do flow better, it's the intake that is total garbage on a gen 2 motor. Gen 2 heads flow about like the small port gen 3 heads peak power isn't everything.
Why aren't Gen 2 heads a common upgrade for the Fiero 2.8 if they flow better? Do they also put the CR too high?
Then make it easier on us all, Will. Design one yourself. Be sure to have it do everything exactly right in the design phase. That way no one will have to build one to test as it will be right to start with.
quote
Originally posted by Grantman:
Will, Remember this design?
Yes, I do. Thanks for bringing it back up.
Unfortunately I never saw dyno results for that piece.
Accolades,Salut, this seems like a difficult project to complete ,I like this very much .. do you really think 20 to 25 horsepower would be possible ?? as the cost will be high for the cheapskate Fiero owners!!So many Fiero enthusiast have cobwebs on thier credit cards & wash thier paper plates !! but even a $500.oo cost might be possible if the performance is there,Fierophiles might break out the skimask & pistol for a worthy project!! the Fiero 2.8 needs more torque ,but horsepower sells any projected date for usable model to mount on engine this is one of the more worthy attemps I have seen for an attractive fiero part ! Im A rooting for you,,Im thinking about this with the excellent truelo exhaust
Funny thing about small CC combustion chamber heads... LS6 pistons are flat top with larger CC heads. What comes around goes around. Yep, the valves aren't splayed either...
I believe GM used dished pistons, splayed valves and smaller CC heads to keep the height of the V6/60 down and not because it was a better design. They needed to keep low profile hoods for FWD cars. All those "changes" weren't always "improvements".
[This message has been edited by lou_dias (edited 03-04-2013).]
OP ignore these trolls, you are doing what needs to be done around here. You already have something in hand, not playing armchair engineer. Can't wait to see the results, as everyone should be.
Well said.
Also, this is supposed to be a build thread, not another "engine part fanboy" debate.
Funny thing about small CC combustion chamber heads... LS6 pistons are flat top with larger CC heads. What comes around goes around. Yep, the valves aren't splayed either...
I believe GM used dished pistons, splayed valves and smaller CC heads to keep the height of the V6/60 down and not because it was a better design. They needed to keep low profile hoods for FWD cars. All those "changes" weren't always "improvements".
BBC's have splayed valves, SBC's don't. Hemis have completely different valve and chamber geometry that's more like that of a 4 valve engine. More than one way to skin a cat.
Funny thing was I was thinking last week about how difficult it would be to make a semi-stock looking 2.8/3.1/3.4 intake plenum. What do you think these will go for if/when you're ready for production?
I was going to resign myself to more medieval methods to open the stock one up. I realize there's other ones out there, but I don't want something that looks like an AT-AT sitting on my engine block.
Originally posted by Canyonflyer: Funny thing was I was thinking last week about how difficult it would be to make a semi-stock looking 2.8/3.1/3.4 intake plenum. What do you think these will go for if/when you're ready for production? I was going to resign myself to more medieval methods to open the stock one up. I realize there's other ones out there, but I don't want something that looks like an AT-AT sitting on my engine block. I'll stay tuned!
I think the Trueleo looks great. If you look at the Northstar and LSx intakes, you'll notice some things. It's basically a TPI intake redesigned to be low-profile. On the Fiero V6, you have the fuel rail and injectors sitting below the main intake plenum. "Newer" low-profile designs aided by other "tweaks" have moved the fuel rail(s) and injectors so that the big tube that, for instance on a Trueleo intake, would normally sit high, now sits between the heads and the intake tubes were made to go over the top to give them the correct TPI tube-length.
The intake tubes make a J around the top of the main intake tube. What we are seeing here is a "modern" TPI intake. Since V6/60 heads have not been redesigned with relocated injector ports, we can't have "low-profile" intakes but thanks to the Fiero's rear deck height, we don't "need" them either.
[This message has been edited by lou_dias (edited 03-07-2013).]
TPI intake runner length (plenum to valve): ~26 inches LS runner length (plenum to valve): ~14 inches Northstar runner length (plenum to valve): ~16 inches
Get off the TPI kick.
The V6/60 doesn't have a low-slung intake manifold because the 60 degree bank angle means there just isn't room for it in the valley. There's barely room for the cam and lifters. That's why the cam is so much higher in a V6 than it is in an SBC.
TPI intake runner length (plenum to valve): ~26 inches LS runner length (plenum to valve): ~14 inches Northstar runner length (plenum to valve): ~16 inches
Get off the TPI kick.
The V6/60 doesn't have a low-slung intake manifold because the 60 degree bank angle means there just isn't room for it in the valley. There's barely room for the cam and lifters. That's why the cam is so much higher in a V6 than it is in an SBC.
Wait! You mean they shortened the runners to make horsepower at a higher RPM? Color me shocked! O_o :P
Interesting that you point out the Fiero's deck lid clearance... Ferrari has extremely tall intake manifolds on their V8's; part of the reason those engines achieve phenomenal specific output. They can do that on the V8's because those engines are mid-mounted and dry-sumped. The combination of the two yields large overhead clearance. They have to get more creative with the intake systems for the V12's because those engines have to fit in front-engine GT's under hoods that drivers have to see over.
Interesting that you point out the Fiero's deck lid clearance... Ferrari has extremely tall intake manifolds on their V8's; part of the reason those engines achieve phenomenal specific output. They can do that on the V8's because those engines are mid-mounted and dry-sumped. The combination of the two yields large overhead clearance. They have to get more creative with the intake systems for the V12's because those engines have to fit in front-engine GT's under hoods that drivers have to see over.
It's like epeens Will, it all depends where you measure from.
Sorry for the lack of updates, work and family have keeping me a lot busier than normal. I’ve been experimenting with various welding and brazing materials in an effort to find an economical way to join together the high silicon alloy pieces. I’ve ruled out zinc brazing because the joints where just too brittle. At this point I’ve had good results gas welding the seams with strait AL filler rod and a fluoric acid based flux. Here’s a teaser pic;
I feel not like the proverbial excited little kid in a candy store, but like an excited little kid who is watching how the candy store is being built, while anxiously awaiting the end result!
Thanks for the "teaser pic" on your cast aluminum intake manifold prototype, HitesFiero:
quote
Originally posted by HitesFiero:
With that photo of your developing aluminum prototype being displayed at a similar angle as was the second drawing you posted at the start of your thread, it appears to me that (except for no intake neck or lid at this early stage), the cast version nonetheless is drawing heavily from the drawn one:
quote
Originally posted by HitesFiero:
What I find more interesting is the striking resemblance of the "semi-pyramidal" structure pictured near the rear of the cast prototype, and a similar "semi-pyramidal" shape shown in the fifth drawing you had posted early on:
quote
Originally posted by HitesFiero:
Out of curiosity, is that "semi-pyramidal" structure pictured near the rear of the cast prototype (and the similar one shown in your fifth drawing) intended to promote roughly similar amounts of air reaching each of the intake manifold's six runners --- including the "rearmost" ones (i.e., those furthest from the intake manifold's neck) --- or does it have a different purpose?
Either way, please keep your updates coming, HitesFiero.
That is a really tall box for sure, does it need to be that tall to deliver flow to that lower intake? Looks to me that half that height would still deliver twice what could be sucked down those little intakes in the lower. I know this is kind of apples and oranges, but this intake could be done up for an iron head just as easy as for my Aluminum head engine. Larry
That is a really tall box for sure, does it need to be that tall to deliver flow to that lower intake? Looks to me that half that height would still deliver twice what could be sucked down those little intakes in the lower. I know this is kind of apples and oranges, but this intake could be done up for an iron head just as easy as for my Aluminum head engine. Larry
That carburetor is turned the wrong way! You have the primaries only feeding one cylinder bank! A Quadrajet does NOT have 4-corner idle.
Very exciting! I've always wanted to squeeze some more power out of my 2.8, but really wanted to keep it stock-looking. I will definitely follow the progress of this project!
It's good to see a reply Hites. So many times I've seen a thread where someone has posted about something that could really have potential, then it poops out because they lose interest, life happens, project goes a different way, etc. If it really has enough volume/flow potential I wouldn't mind taking a stab with one in a 3400 or 3900 project.
Assuming that it's an open plenum under the carb (can't imagine it isn't), I don't see a problem. What exactly is the issue?
the primaries are going to favor the front bank to quite a strong degree, and the secondaries are going to favor the rear bank. if this was a square bore carb (4 equal size throttles) without a progressive or vacuum secondary, it might be ok. but this a spread bore, with tiny primaries, and giant secondaries.
------------------ we're in desperate need of a little more religion to nurse your god-like point of view...
That is a really tall box for sure, does it need to be that tall to deliver flow to that lower intake? Looks to me that half that height would still deliver twice what could be sucked down those little intakes in the lower. I know this is kind of apples and oranges, but this intake could be done up for an iron head just as easy as for my Aluminum head engine. Larry
Has anyone tried this sort of idea on a 2.8? Also, would a Holley be a better choice for a plenum like this?
