GM "Vortec" heads, good or crap?
 

The idea of the Vortec head was that fuel would swirl helping the gas and air stay in suspension better at lower speeds, giving better torque and economy in the lower range. I would assume such an idea would be patented if it works. (my guess is spinning anything would whirl out the fuel but whatever)

Were they actually some kind of an economy/torque breakthrough or is it just all marketing BS? Are there more efficient heads on the market in terms of BSFC for power generated on whats otherwise the same engine? Someone else discussed hemi vs wedge vs bowl combustion chamber shapes, i'm not sure if the Vortec really fit any of them.


I do know that the large engines like the 8.1 Vortec in motorhomes got more like 8.5mpg instead of 6mpg from previous generation 454's in similar chassis seemed to get... it was almost diesel levels of mileage which I found interesting, hence they were still in the Top Kick and such when most other medium duties went diesel only.

search some GM forums is the best i can say, they will likely have more information on the particular heads. I would venture to guess that they may be better than the previous generation, a ported and polished head/combustion chamber is still the best.

a more efficient burn gives more power, win-win.

Ford had something called "High Swirl Combustion" on some of their 80's 4-cylinder engines, I doubt they'd have just forgotten whatever lessons they learned from that on subsequent designs..

"Swirl" and "Tumble" were all the rage in the engineering circles at that time.

Suzuki had it back in the early 80 TSCC, twin swirl combustion chambers, useful for carbs I'm thinking FI negated lots of the gains.

vortec heads are a HUGE improvement over previous heads. Vortec heads make more power than almost any other factory chevy head before them.

and they got better mileage.

big caveat - be careful about ignition timing. they do NOT like nearly as much ignition advance as previous heads.

I was running roundy round around the year 2000. I had a guy build me a pair of heads for 800 dollars for the pair of heads, including new bare castings, valves, port work, etc.

It made as much power as the iron DART heads with over 2600 dollars of work done to them.

Vortec is cool stuff, until you look at the 5.3/6.0 heads.

Then the old vortec heads are JUNK. 5.3 and 6.0 make BIG power, great mileage, all around very cool stuff.

Swirl, tumble, etc., are all air movements at the control of their physical & atmospheric environements.

"Injection" however, is under the control (within limits) of the computer, ie: it does a far BETTER job of air/fuel mixing than did the old mechanically derived "head swirl/flow tumble."

Vortec heads are awesome, I totally agree with drmiller100. I did a a lot of forum reading/research last year when I was building up a 350 V8 for the Z28 - Vortec is hands down best bang for the buck horsepower-wise. The vortecs were designed to flow a lot more (in low-lift conditions, where the valve spends the majority of its duration) than prior heads, and a revamped combustion chamber allowed a faster burn of the mix. This allows us to run less ignition advance and still get the complete burn. Less ignition advance means less time where the combustion has already started while piston is still traveling up to top-dead-center (TDC). Any combustion prior to TDC serves to slow the piston down, decreasing efficiency. More flow, less advance needed, both seem to be a win for mpgs.

x2

Although I'm not sure the flow numbers are all that great. If you've not looked at one, the vortec intake port resembles a spiral staircase in the bowl area, just under the intake valve. It must really get the air swirling as it enters the combustion chamber, resulting in a fast more complete burn, that produces lower rpm torque at cruising rpm.

I would believe vortec flow numbers at .5 inch lift are not overly inspiring as far as raw numbers.

However, if you look at the entire flow of .05 lift through .5 (the area under the curve) the vortec heads do SOMETHING right because they give HUGE horsepower, huge torque, and great mileage.

Again. Vortec heads are the best all around streetable heads ever made for the 5.7, and they are arguably the best iron heads ever made for the 5.7.

They are the greatest thing ever until you see the 5.3/6.0 heads and look at the numbers of what they can do.

For power sure, but this is ecomodder. :)

Thats kind of what I was wondering... was it a fad and marketing nonsense, or was it a radical step up vs past solutions? What about now (since everyone is so power hungry and I rarely see mileage improving each year in most vehicles, most 10 year old listings show the exact same figures), did they go for more power or are newer powerful heads just as efficient?

Thats kinda what i'm wondering, unless there are diverging opinions...

Is the consensus that the new 4.8/5.3 type engines should produce BETTER efficiency (dont care about power) at the same part throttle load than older swirling everything type heads?

Could you expand? I'm not an expert in any of the newer designs, only older small blocks. Again remember i'm mostly caring about mileage, not ultimate power, to include mileage under differing levels of load. (ie moderately higher towing loads but not full throttle is an example)

efficiency is improved by the following:
high compression.
fast burning of the air fuel without detonation
consistent burn rates
little heat lost to the cooling jackets.

Horsepower is all of the above, and add to that high air flow rates.

They are not mutually exclusive. The vortec heads do all the above, but the 5.3/6.0 does it even better.

GM Fastburn, vortec, LT1 and LT4 were all kind of chasing the same port and combustion chamber design.
But they were limited by 50 year old valve placement, 50 year old cylinder head bolt placement, intake to head mating (well vortec and LTx have their own intake) and a few other things.
GM was chasing the mythical MPG and hosepower unicorn with those designs.
But couldn't nail it.
It wasn't untill the newer 2007+ LS serries came out that GM took every thing they leaned they coldn't do with on the SBC format and finely used it to build the engine they always wanted and only then they were able to catch up to that unicorn and and run him over...
Maybe some one could post a pic of what that might look like.