Don Terrill’s Speed-Talk

For those of you who port 4 valve per cylinder style heads I have just come up with a way to get the same results but potentially cut the cost by about $1000-1200 form a PolyQuad modified head.

Is that likely to interest any attendees to the REC seminar???
DV

It just occurred to me that in the largely V8 populass of ST that many might not be aware of what I meant by the term 'PolyQuad'
So for the benefit of such here is a quick description.

PolyQuad is a method of having the benefits of variable valve timing without any extra parts on an otherwise conventional 4 valve setup. When used with variable valve timing it adds to the low speed torque output to about the same extent as the VVT did in the first place. As for top end power this usually shows an increase of a percent or two although on the race Mitsubisi that I did the head for back in 2004 produced 110 lbs-ft and 95 hp more than the regular ported head done by a nationally recognized expert.

The 'polyquading' of a 4 V head involves usig 4 different size valves, changing intake to ex elevation, port biasing and chamber reshaping. All this boils down to a decrease in cross flow at low rpm and an increase in mixture motion. This 2 L Mitsubishi engine made 1172 observed RWHP on slicks in the middle of a hot and humid Florida summer day. But how, you may ask, did it do when raced. Well at the final round of the import nationals at Palmdale Ca. it did not beat the opposition - it annihilated the best the rest of the country could throw at it. This proves once again the BS stops when the flag drops!!!
DV

If you are a cash constrained hot rodder getting more with less is always a goal to strive for. Although it may seem a luxury at first sight having a small lath capable of machining valves proves to be a valuable asset. I have a Smithy wich I use to do many things. One that proves extremely good value for the investment of the lath is the ability to rework valve forms and also lighten them. Here I am talking about stock valves or reasonably priced mid range valves that are good for street performance. If you know what to do re-shaping and lightening the valves can really pay off. How about 250 rpm more before loss of valve train control and 15 lbs ft more low speed torque (2200 rpm). As rpm climbed the torque increase dropped off progressively. Peak torque went up by about 5 lbs-ft and peak power (at 6750 rpm) increased by 3-5 hp. Granted the top end output increase is hardly worth shouting about but the domino effect comes into play here. If the low speed torque was satisfactory before the valve mods then with the modified valves the motor could stand having a little more cam in it without loss of drivability. that can return as much as 25 hp increase! I hope to have all the details of this including a bunch of graphs by REC date.
DV