4 Piece 32v Cam Swap
Thursday, January 12, 2012
It may be a bit labor intensive, but it’s the only way to do it correctly on the 32v Cobra’s and Mach-1’s.
“Pulling the motor out to do the cam & valve spring swap.”
An increasingly popular add-on for most 4.6L’s these days has been the addition of larger cams. For the guys who want to stay naturally aspirated, but have run out of bolt-ons to do… and above all, are looking for the bad-ass sound of a rumpy idle of bigger cams, we have a solution for you…
For the early ’96 to ’04 2-valve GT’s, and the 3-valve applications this is a relatively easy job. We’ve found cams that will bolt into the 2v and 3v’s without a valve spring change required, and the cams can be installed with the motor still in the car. This usually takes approximately 4 to 6 hours of labor.
This is not the case with the 32v applications like the ‘96+ Cobra’s and the 32v equipped Mach-1s. Contrarily to what some might say (especially the backyard do it himself-er). You cannot properly/neatly perform a cam & spring swap on a 32v in the 2004 and older style Mustangs without removing the engine; and performing the work while the engine is mounted on a stand as we prefer. This, in our opinion, is the only way to do it right. Plus removing the engine from a mustang for us is easy and routine.
Once on an engine stand — the cams and above all the 32 valve springs can be swapped more easily for the recommend springs to go with the larger cams. Also, one thing we do not do is “degree” the cams. Once again; contrary to popular belief and internet hype and fads…. We simply put them in the way they are, right out of the box and go!! This has caused no problems at least for us on street and mild race applications. Degree-ing the cams on modular’s is tough to do, and adds a huge increase in the overall labor to perform it, to an already expensive cam & spring swap on 32v cars. We’ve installed lots of cams in many 32v’s already and have had great results all around, and have never degreed any of them.
The Crower Cams we’ve selected for these 32v applications offer a nice sounding idle, and can add as much as 30 to 45 RWHP on naturally aspirated applications providing the car has all of the other bolt-ons (primarily long tubes and some induction upgrades). And we’ve already seen boosted 32v’s gain as much as 75rwhp with the bigger cams. But with or without boost, bigger cams do come with a trade-off. They can and will often cause losses in low RPM power and TQ. As long as the cams aren’t to big, and providing the car has a larger rear gear ratio, and with a good custom tune – the losses can be minimized.
We unfortunately were not able to make the time to make base pulls on the highlighted project car that got the cam upgrade. But its a somewhat typical 2004 Mach-1 equipped with the usual bolt-ons and long tube headers. This set-up usually gives out right around 305 to 315RWHP on our in-house DynoJet. Totally stock these are about 265 to 275 RWHP.
As can be seen in the RWHP dyno results when comparing a totally stock Mach-1, to the one we’ve mod-ed with cams, headers, plus tuning – there is about a gain of about 60 hp, and 60 ft/lb tq at the rear wheels at the peaks. Depending on what area of the curves you look at, the gains are higher. We’re not able to show a direct comparison of exactly what this project car gained at the wheels. But it’s a pretty safe bet to say that the cam set was worth about 20 to 30RWHP over a Mach-1 that already had headers and a couple of other bolt-ons.
If you take a close look at the TQ graph, you will note that there is some TQ loss under 3000rpms, and all the gains really kick in at about 3800rpms and up. The loss under 3k RPMs is negligible, and quickly goes unnoticed with the popular 4.10 gears most guys would do to these cars, or a supporting looser TQ convertor for the automatic trans equipped cars.
Pulling the motor out to do the cam and valve spring swap…
Stock Torque vs Mods (w/cams, headers, exhaust, & tuning).
Stock HP vs Mods (w/cams, headers, exhaust, & tuning).