I posted this over in the mach 1 section but have gotten no replies.... Anyway I got a 2004 mach 1. I got a new old stock naturally aspirated 4.6 aluminator (10:1 compression, forged internals) with 03/04 cobra heads already on it, cometic gaskets, and arp studs. I am going to put an eaton on it. I got a complete kit from a guy with a termi who went twin turbo. It is not ported, but has a 2.76 pulley, a lfp extreme intercooler and lfp dual pass heat exchanger and a billetflow idler on the bridge. I got the cobra fuel pump, a sct 2600 big air MAF, and 39 lb injectors. E85 is not in my area do so I will have to run 93 octane. My question is: Will the 2.76 pulley produce too much boost for this higher compression engine on pump gas? I know the answer would be yes if it didn't have forged internals, but it is forged. I plan on getting a good tune as I know it is very important for my setup. If it is safe, about how much horsepower would I put down? Is the cobra fuel pump enough, or should I add a kb BAP? Any advice would be greatly appreciated. Thank you.
Aluminator swap
- Thread starter MACHSTR
- Start date
You could drop the running or dynamic compression with a set of aftermarket cams. The late closing intake valve would put a more pump gas friendly squeeze on the mixture and also make more power. The Comp Stage IIs would bring you near a good 93 octane dynamic compression ratio.
If your tuner is half way decent you'll be perfectly fine. Just make sure it's a safe tune. Don't fear compression. I've run 10.5:1 with 14psi on pump with a turbo kit. Worst case, just put a slightly larger pulley on it. No reason to spend 2k on cams unless you want to.
What works and what is optimum are two different things. Consider Vizard's work here:
Last edited:
Oh neat a graph with value's that say F on them.
What's optimum is not camming an eaton only car. He will also make more power running 10.5:1 than 8.5:1 albeit with more heat.
Don't run around spouting off dynamic compression and suggest off the shelf cams.
Sorry you are not able to appreciate the work of industry scholars. Those off the shelf cams produce an 8:1 dynamic compression ratio in a 10:1 static compression 4.6. They also have an overlap that is very complementary for supercharging. You would know that if you had bothered to calculate it rather then just spouting off yourself. Regardless of the supercharger used, the OP will be able to use more boost with more timing without detonation at the correct dynamic compression for the fuel used at the right engine temperature (what the chart implies from actual research).
Let me slow this down for you chief. If he spent 2k to cam (with off the shelf which is pointless since you can get custom grinds for cheaper and perform better) he would make next to no "more" power and would simply just have spent 2k to sound cool.
You can run around spouting dynamic compression all you want, here is the honest to god truth. It doesn't matter. The guy has a set combo already installed, he doesn't need to be told to spent thousands of dollars to "optimize" his 500rwhp car. Your suggestion breaks the bank account adds ZERO power and makes it a c hair safer. The cams you suggested are also very large for an eaton only car but you already know all about cam profiles so why bother?
Just because you "read" something from a "scholar", which don't use that term unless they are a PHd holder otherwise he's a mechanic, doesn't mean it applies to all engines. Joe off the street doesn't need to "optimize" his engine with 2k upgrades when he could just pulley down or pull timing.
I understand what the F's mean, but for a supposed "scholar" he should label his graphs as if I used that in my field I would get laughed out of the room and I only have a masters degree.
Pretend to be Mihovetz somewhere else.
Users who are viewing this thread
