32V Hyperutetic Pistons and Supercharging A Formula for Disaster?
Monday, August 30, 1999
Supercharging the 32V Cobra has become more and more popular over the past 2 years and is without a doubt, the number one choice for a power adder. But, throughout the Mustang performance scene we’re seeing and hearing about more and more 32V owners with broken pistons and damaged short blocks. With almost a solid 10:1 compression ratio and 8 – 10 psi of boost from a Vortech or other supercharger, many feel the stock hyperutetic pistons are a weak link and break much too easily.
So are the stock hyperutetic pistons and supercharging a formula for disaster?
Let’s provide a few answers before going any further. Hyperutetic pistons are up to the task of serious supercharging and power levels, don’t worry about them. But, you need to make sure that your combination is not tuned overly aggressive. With that said, let’s get into the details.
Yes, forged pistons are stronger than hyperutetic ones and can sometimes tolerate more abuse. But the 32V engine is not nearly as weak as some people think it is. We have had extensive experience with hyperutetic pistons and under the conditions they break, a forged piston would have been damaged as well. Many 5.0 owners get away without breaking their hyperutetic pistons because the head gasket seal is inherently weak and will usually blow before piston damage can occur.
The hyperutetic pistons in the 32V Cobra engine can easily handle horsepower levels in excess of 700 hp. But, as with ANY piston in a 10:1 engine and good sealing cylinder heads, they’re prone to failure when serious detonation occurs.
The Real Problem
The chronic piston breakage and damaged 32V shortblocks that some shops experience over and over isn’t because of an inherent weakness, it’s improper or overly aggressive tuning.
With almost a 10:1 compression ratio and 8 – 10 psi of boost, proper octane and spark timing is essential. Too many people do not respect the cylinder pressures that are being created with this combination and if too low an octane fuel is used or too much spark is added something will give, and it’s almost always the pistons.
Since its introduction, we have sold over 100 Vortech kits for the 32V Cobra and installed and tuned more than 70 of them. We feel that the chip that is included with the kit isn’t as good as it should be and it’s difficult to develop one set of parameters that can function safely anywhere in the country. There are too many variables such as elevation and regional gas quality. So all of the kits that we install come custom tuned with our own chip using C&M’s software and a high-end wide-band air/fuel ratio analyzer.
Of the more than 70 Vortech kits that we’ve personally installed and tuned, NOT ONE HAS BROKEN A PISTON OR EXPERIENCED OTHER ENGINE FAILURE.
We consider our tuning to be very down to earth and conservative. It is much more important to us that our customers have a reliable package than a record setting hp number. Too many people are too concerned with having a dyno-jet printout that is higher than someone else’s. One of our customers took his Vorteched Cobra (that we installed and tuned) to another speed shop for a promise of higher hp numbers. As they promised, he walked away with a higher hp number than with our tuning. But he also walked away with several broken pistons that they refused to be responsible for.
Roughly 20% of the Vorteched Cobras we’ve built have returned for more boost and larger injectors. We routinely run more than 14 psi and have still had zero problems. In ’98 we set up one of our 32V customers, Howard Schwartz’s 97 White Cobra, with over 16 psi of S-Trim boost on a stock shortblock. The car has been featured in Super Ford and MM&FF and has run as quick as 11.00 @ 127 mph. To this day he still hasn’t had any problems. But that level of boost requires high-octane fuel and Howard has run Turbo Blue since the boost was raised to its current level, not a feasible option for many people. But the proper fuel and tuning that is on the conservative side have kept his street car fast and reliable.
Hopefully you’ve gathered a little insight from this article, it wasn’t meant as a commercial for our tuning, we’re not the only ones who understand how to make reliable 32V power. But if you’re contemplating to or already have supercharged your 32V Cobra, remember that the hyperutetic pistons are more than up to the task of serious horsepower, and a Vortech can turn an already fast car into an even faster one and still be reliable. But you need to make sure that whomever tunes your car has plenty of experience and isn’t disregarding the safety of your engine to make themselves look like a hero. Be satisfied with a slightly lower peak hp number than you saw on a bulletin board and be comforted with the knowledge that your engine will stay together.