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Ford truck performance questions


CMil's Avatar
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Join Date: Apr 2002
Posts: 432
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02-13-05, 11:37 AM   #1  
Ford truck performance questions

Yep, it's me again. Same truck, too ('94 Ford F-150, 4.9l I-6, E4OD, 2WD). I want to improve the performance of this truck a little, without going to the extreme of changing the entire engine. My plan thus far includes an MSD replacement ignition coil (direct replacement, but a little hotter spark), possibly an MSD-6 ignition system (if I can determine for certain that it will work with the TFI system), and headers from Clifford Performance. I've seen in some performance parts catalogs something called a throttle body spacer, some with and some without machining to induce turbulence in the incoming air. Text in the ads for these claim they will improve power AND fuel mileage - can anyone verify or debunk these claims? I'd like to hear from users and/or experts before I lay down bucks for one. Thanks in advance - Chris

 
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Desi501's Avatar
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02-13-05, 02:11 PM   #2  
About the only one of the changes that will help in any way are the headers but don't eliminate the O/2s in the process.

 
CMil's Avatar
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Join Date: Apr 2002
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02-13-05, 04:26 PM   #3  
Don't think a capacitive-discharge ignition would help with power OR mileage? Hotter coil won't do any good either? How come? I suspected the throttle body spacers were just so much snake oil, but I'm not willing to part with nearly a hundred dollars to find out. Desi501, let me know why you don't put much stock in the ignition changes, if you would please! Thanks - Chris

 
mechanic's Avatar
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02-13-05, 05:43 PM   #4  
Ignition changes.... the mixture is getting lit off by the stock ignition. You can drop several hundred into a hipo system and all you will get in return is the mixture getting lit off.

Aftermarket ignitions start to shine where compression pressures are much higher than stock, we are operating at high rpm and harmonics are inducing timing changes (this is an exotic motor), we require timing retard for NOx or a two step or sundry other drag strip requirements. Once the combustion process is started, everything else relies on how much charge is in the cylinder, whether the mixture is homogenous or not, combustion chamber design....

Unless we are going from breaker point ignition to electronic ignition (and we have no special high performance requirements), aftermarket ignition isn't much better than throttle body spacers, tornadoes and fuel line magnets.

Engine mods need to be considered as a group of changes... certainly every motor built has a particular weak point but addressing just the weak point may not free up enough power to make the change worthwhile.

Along with the change to exhaust headers, cam timing needs to be considered as well as intake flow (we don't want turbulence here... we need smooth laminar flow with a very small boundary layer in order to ensure maximum cylinder scavenging) and injector flow rate. Changes will also be required to the spark and fuel curves programmed into the PCM.

We have a stroker RB Dodge... 500 inch. $17,000 CA invested and we aren't done yet. Horsepressure costs money... how fast can you afford to go?

Bottom line... there is no replacement for displacement.

 
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