I came across a test by Hot Rod magazine in which an 11 hp. gain was made by simply swapping the coil packs and plugs in a 5.7 Hemi. I found this horsepower gain surprising. Although the new coil packs produced 40,000 volts under load, as opposed to 25,000 volts for the stock ones, it is common knowledge that aftermarket ignition systems, high voltage coils, etc. do not result in horsepower gains for low rpm stock engines. Where they are needed is in 8-9,000 rpm race engines. Furthermore, a good spark plug firing in a normal engine will discharge around 8k volts or so, which is way less than a coil that has the ability to put out 40, 50, or even 70k volts. The spark will jump the plug gap when it can and this is usually under the 10k volts mark. That being said, here are the dyno results: Stock 303 hp.@5,250 rpm; 337 lb/ft@4,300 rpm New Coil Packs and Autolite Plugs 314 hp.@5,150 rpm; 347 lb/ft@4,250 rpm Here is the link to the article. Is this an advertising ploy? Has anyone tried it? For $379, it sounds like a cheap way to increase your horsepower. https://www.hotrod.com/articles/get-11-hp-more-from-your-hemi-with-this-easy-bolt-on/
F.C.A. spends millions of dollars on R & D and they could not increase the coil efficiency? * Sorry forgot, "One must have the hemi orange coils" > 'Just another way to entrap the feeble'.
guys that I know who race and do a lot of high performance stuff told me for a stock 5.7 the factory coils do the job.. don't waste money on that.
Ignition system improvements have been the best area for fake claims as it is easy to change the components, plugs and coils, but hard to actually measure the performance gain if any for that change. The FTC reached a settlement with Split Fire for such claims: https://www.ftc.gov/news-events/pre...les-ftc-charges-economy-efficiency-claims-are Mopar Action's Richard Ehrenberg has also stated many times that if the stock ignition is firing the plugs properly, higher output ignition or multiply pathway plugs will not improve things. Many people let the ignition go to the point where misfires occur. They then "upgrade" to high performance plugs or coils and claim that there is a power increase when what really happened was a simple tune-up restored original performance. My '68 340 Barracuda never benefited from Accel distributor, cap, rotor, and performance plugs. It turned a 13.40 @ 105.38 with stock components and never improved with aftermarket parts.