GM "Vortec" heads, good or crap?

[stillsearching]

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.

[ksa8907]

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.

[shovel]

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..

[Frank Lee]

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

[roosterk0031]

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.

[drmiller100]

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.

[gone-ot]

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."

[tim3058]

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.

[metromizer]

Originally Posted by tim3058

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.

[drmiller100]

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.