Put a GenII Intake, and opened up the exhaust with a Gibson cat-back. I have realized modest gains but not quite what I expected. Seems to be several flat spots in the run up through the gears.
My questions are:
Should I have replaced the cat as well (130k miles on truck)? I did not want to install headers but if a more free-flowing cat is available that's no problem. Will the computer adjust to the increased air flow/exhaust, or can the OEM computer be "re-mapped"? Should I take it in and have a chip installed?
No surprise there. Increasing the flow doesn't do much until the engine RPM is high enough to outflow the stock components. Below that threshold it's the engine flowrate that dicates performance.
On the newer engines the entire system is tuned and the intake and exhaust match the engine better than in the older designs. It's not as easy to see a noticable improvement by changing bits and pieces.
The easiest and cheapest way to improve performace is to use a higher ratio gear set in the rear axle, and have the speedo compensated for it. I don't think you'll lose much on top-end potential speed (which doesn't matter unless you're racing), but you'll see a big improvement in street range driving.
Quit fartin around and take it to a "calibration shop" that has a dyno. Even clunky old Tucson has a calibration shop and they told me ~$150 for a test and guaranteed improvements. Do what I say, not what I do... I hadn't got around to taking mine in yet. ;) Still plan to tho.
I found a bunch of old ford 2 barrel carbs at the scrap yard like mine and bought 'em... took 'em apart and found one that had emulsion tubes that were drilled different than mine... tried them and WOW! :)
Talked to one of the fellas at the calibration shop about it and he told me I figured out their "secret" to fixing old 2 barrel (2100) ford carbs. Cool huh? I had asked about installing a new edelbrock first so they'd have something worth-while to work with... they said "no, don't waste money on that, we can fix the ford carb to work just as good" So I set out experimenting on my own to see what I could do. Since then I bought a set of jet reamers and they turned out worth it too.
Your truck's a different animal I don't know $%!# about it, but there are people that do and want to help, you just have to hand them a little $ for motivation. ;) If you're serious about better performance you'll be glad you did it "like you mean business" instead of huntin and peckin like you're doing now.
This is the recommended sequence in adding mods to improve performance:
1- FIPK - you already did that
2- Catback exhaust - ditto
3- Superchip/Supertuner (U$300) adds 10-20 HP, improves tranny shifting and mpg. Bad news is you need 92+ octane gas.
4- Rear end gear swap (U$900 to 1500) going to 4.10 gears will improve acceleration. Bad is loss of mpg and top speed. (1999 and up need a new program (item 3) to change the gear ratio calculation in the computer for the speedometer.)
5- Electric fans (U$360) about 10-20 hp and better cooling and cooler AC.
6- Underdrive pulleys (U$200) another 5-10 hp but less charging capability which is important with a big stereo and the above electric fans. Add U$200 for a
130amp alternator if you have the 90amp model.
This is it for general mods. After this you are getting into heavy duty visa bills: Supercharger (U$3500), Large intake and throttle body and modified maf (U$500), Nitrous injection (U$500), add custom computer programming and tuning to any of these for U$300+ each.
Very useful for low end improvements, and you won't lose nearly as much gas mileage as people think. I speak from experience here.
Of course the higher amp alternator on an underdrive pulley pulls as much HP as the stock one with the stock pulley.
A roots style supercharger is the best way to add low end power, if you have the coinage.
Blah. Great for Saturday night, but what about everyday driving?
But an engine is still an engine, and as I said until the engine outflows the intake and exhaust any improvements there are basically moot. The one improvement you didn't mention is the CAM(s), which is the single most critical factor for airflow and power. You can piss away a thousand dollars on inprovements that add 10~15 HP at 5500 RPM and not improve the "off the line performance" by more than a couple of percent. Low end torque is a very different goal from high end horsepower.
MotorsForum website is not affiliated with any of the manufacturers or service providers discussed here.
All logos and trade names are the property of their respective owners.