pinto/zetec equilibration history
I have refrained from posting on this but wanted to clarify a few facts. First, my understanding was that the goal was to have the two engines equal mid 2007. The first major problem was virtually no one ran zetecs in national trim or natl events in 2006 or the first half of 07. There were a few of them run in the pro series in 06 and the zetec was clearly the desired configuration come mid 06 and 07 in pro trim (e.g. Mike Andersen’s mid 06 season conversion). And I understand the tire differences and arguments for this.
We did the test at Summit Point at the end of 06 and at the end of the day we arrived at the 2007 map and restrictor. The testing ended when the track closed and not when we had completed all testing. For the final configuration the cars were run at equal weight and in nearly identical configurations. It was my opinion that the final map and restrictor left the pinto at a partial throttle disadvantage in low and medium speed corner exit. On the penultimate lapping runs the pinto and zetec were dead equal coming off the corners in lapping but the zetec had a slight disadvantage at top end. That led to the final configuration and we did three full throttle drag races with excellent parity. The final test was another lapping test and I felt the pinto was at a disadvantage in partial throttle corner exit with equal top speeds. Time ran out and that was the closest we came up with. Final situation, in my opinion, is the zetec had a 30 lb disadvantage relative to the testing weights but had a corner exit advantage and fuel injection (i.e. real time pressure, temp, mixture and throttle mapping). Seemed like a reasonable place to start 2007.
Since then, I believe the corner exit advantage was confirmed but a top end difference seems to have arisen. The test was done with a fresh good QS pinto motor, but there are always reasons that the top end performance could have been off, it was very cold on the test day.
So we monitored the situation closely but very few zetecs ran nationally and the zetecs were dominating the pro series with scca mapping in 2007. It was not clear what changes to make during 2007 with virtually NO national scca data but lots of antidotal commentary. At the end of 2007 Chas wins the runoffs and LaRue comes in second which made it even more difficult to make a change to increase the zetec performance. As far as I could tell Nikki had the same approximate advantage in Runoffs qualifying and the race as he did the previous two years. And the aluminum head was then in the pipeline with uncertain effect. At the end of 2007 I favored lightening the pinto flywheel and increasing the restrictor with similar weight, the intention being a moderate adjustment to equalize the bottom ends and give the zetec better top end performance. Then came the aluminum head. I will post my comments on the aluminum head, pinto longevity, and my thoughts on what to do next in a separate post.
-Rick Silver
Aluminum head and pinto upgrades
I personally was totally opposed to the aluminum head as it was the last thing we needed when we were in the middle of the pinto/zetec equilibration. I thought there would be lots of pinto heads and engines coming available and I knew how hard accurate equilibration was. I argued very strongly that if the aluminum head was made legal then it had to have a weight penalty and it should not be an open development piece. So it was suppose to come in as a nominally equal component not to be hand ported and a weight penalty to compensate for the lower center of mass. In came a piece with a 3 to 4 horse power increase over a broad range of RPMs and this was after the combustion chamber was made legal. This completely screwed up the equilibration program.
In my opinion the aluminum head should not have been allowed in class with the clear advantage it came in with. No previous testing and no attempt to restrict its performance was wrong. Of course the aluminum head fiasco occurred while the manifold fiasco was occurring. Both items I was totally opposed to. I worked very hard to prevent the manifold and to restrict the aluminum head as these presented an almost insurmountable challenge to the equilibration process that was underway. Final decisions on these items were and are made by the comp board and BoD, matters which I do not want to comment on.
As far as pinto longevity goes, my understanding directly from the engine builders is that a major piston redesign would help with longevity of the cylinder bore and ring lands, but the rods are not a real option due to stroke, piston geometry, and wrist pin placement conflicts. The pinto top end I would say will always need to be rebuilt every 500 miles. But I felt our initial commitment was to never eliminate the pinto and equilibrate the pinto and zetec with at most a modest weight differential.
If one tries to equilibrate the zetec and aluminum head, then you are mandating the aluminum head if you want to be competitive with a pinto. I feel very strongly that it is not acceptable to mandate the aluminum head as it has substantial costs, cannot be easily integrated as a stressed member and was never intended to have this kind of an advantage.
Based on what we have been handed, the only fair option then seems to be to equalize all three configurations. Take another month or so and come up with a modified Zetec map and/or restrictor to match the aluminum head, boost the steel head pinto and lighten the pinto flywheel. I fundamentally do not believe we should equalize the zetec and aluminum head and screw the steel head pintos because the aluminum head should never have been allowed that kind of advantage, although with this scenario in principle everyone could own a top flight configuration for enough money. What I don’t like about equalizing all three configurations is to what steel head do you equalize, Coello’s head or whose. In the end I would pick a very good steel head, a legal zetec, and equalize them to what are suppose to be invariant aluminum heads. This would include a lightened pinto flywheel, low cost steel head pinto modifications and a new zetec map and restrictor.
-Rick Silver
Proposed FC Engine Rule Changes
A set of proposed rule changes to the FC engine specs has been placed on SCCA website. The proposed changes were recommended by the Formula advisory committee as well as the Comp Board. This is now out for member input as a package rules change.
Dyno curves from the various configurations will be posted by Dave Gomberg within a day or two. The goal of these equilibration changes are to have all three engine configurations at equal weight and nearly identical HP curves over the usable RPM range. The new specs move all three performance curves substantially closer than the previous configurations.
The basic changes are:
The Zetec gets a larger 1.340 restictor and a new map. The new map and restrictor makes the Zetec nearly identical to the Aluminum head. The Zetec is up about 1.5 HP from 5600 to 6000, about equal from 6000 to 6400 RPM and the Aluminum head has a 1.5 HP advantage from 6400 to 6800. This should produce nearly identical performing engines.
The aluminum head receives a lightened flywheel. From 14.4 lbs to 9.5 pounds. The current Zetec flywheel and crankshaft/connecting rods are significantly lighter rotating masses than the pinto and this lighter flywheel is intended to equilibrate the rotating mass differences which are not measured by the dynos.
The iron head pinto will get a new optional camshaft which yields a 3 HP gain from 5800 to 6800 RPM over the current allowed cam and also the lightened flywheel. The Aluminum head currently has a 2.0 to 3.0 HP performance advantage over the iron head for the usable RPM range. The new cam for the iron head is intended to compensate for the aluminum head HP advantage and lower center of mass. The iron head equilibrated to the aluminum head is based on a very good, top 10 % iron head, but not the very best.
The goal in making these changes was to do so at a minimum cost to competitors yet still achieve parity. This is viewed as the only fair way to get all 3 configurations at the same weight and nearly identical HP across the entire usable RPM range.
The lightened flywheel and iron head pinto camshaft are optional and not required parts. The optional camshaft can be installed with the iron head in place on the car. The flywheel can be either machined to the minimum weight or the approved alternative flywheel used.
-Rick Silver
Keep the Pinto the same weight.
First, where can we find the specs on the Elgin cam? I looked at the Elgin online catalog and could not find it. Cost?
Second, the proposal states that the cam and lightened flywheel will be optional for Pintos while the weight increase to 1200 lbs is NOT optional. It may as well be mandatory as you will be taking 2-3 hp off every stock Pinto engine effective immediately. Considering the current state of the class and the economy, do you think it is fair to effectively mandate the additional cam/flywheel expenses for Pinto owners to offset the immediate increase in their weight? Again, this will be MANDATORY just to remain competitive until we witness race results.
Keep the weight of Pintos at 1190 lbs regardless, at least for a year.
Rob Poma
FC #7