Ok guys. I did some mods.
Dynomax 3" cat back SI/SI.
Super chip flip chip
Cold air intake (velocity tube).
I was hoping for more perfromance than I got. Did I forget to do something else the motor that I should have with my mods? Did I leave any mods out that I should have done? Should I have gone with 2.5" instead of 3" exhaust.
Please help? The truck has good top end and good highway passing speed but the low end seems sluggish. I notice any decent power gains until around 3,000 + RPM.
what can I do????

 

I vote yes on the 2.5", I think 3" is too big and you will lose low end. Of course more opinions will be coming soon I am sure.

 

Hey man I've got the same mods but I have a Magna flow SI/DO 3" in and 2-1/4" out. I have the same complaint. How ever I noticed when I took it back to ford for some things I put the stock air box back on and the low end was much more responsive. Call me crazy or maybe its just my truck. If you do get this resolved please let me know. Good luck

 

It probably is the 3" exhaust however I already have it installed and don't want to spend more $ to replace the whole system. Can just the tail pipe from the muffler be reduced without destryoing the system? Also...will changing the "y" pipe increase low end?

 

2winturbo,

Did you do all these mod's at one time? If you did, make sure you reset the computer and give it time to adjust & learn. also Im sure with the superchip it will take for the computer to adjust from 87octane to 92. give it time it will get better.

 

2winturbo,

Part of the problem is the exhaust, the other is the nature of the 4.6L. It doesn't make peak torque till 3250 rpm and max HP till 4500. That is a long time to wait. The mods you have made, do increase the output but they do not change at what RPM they happen. Within 2 driving cicyles the chip will show most of its gain, the rest will come slowly for another 8-9 cycles. As for the exhaust try 2½ pipe on the outlet side.

Regards

Jean Marc Chartier

 

Guys,

I have a F-150 that I put a 3 1/2 exhuast on. This was a bad idea. I thiught it would be alright because it had a supercharger on it as well as a superchip. With this in mind, I went to a 3" flowmaster and it is hot. I would wait for the computer to have a chance to re-learn and adjust to your new mods. You can speed this process by disconnecting your battery cable and turning the headlights on for 5 minuts then re hooking up your battery. Mike Troyer gave me this info and this trick workes well. Hope this helps.

Bones.

 

Some of the import mags are now showing total gains AND losses. You are spot on to say that a more restrictive intake may help low end power. Similar to exhaust size, the intake restriction plays a part.

As for the original question, keep in mind that many mods will raise output, but often the increases occur at higher peaks. Depending on the combo, you might have raised your torque peak to a RPM level you don't run at as often. Personally for a truck, I try to buy mods that keep the torque peaks low, but have still found that my peak power seems to be a bit higher than stock on my 5.0 powered truck.

 

Well...I just got off the phone with the Dynomax tech guy...I asked him the same questions. He told me I probably wouldn't gain enough low end by changing the tail pipe to make it worth my trouble. I also asked him about headers...his response was again I probably wouldn't gain enough over stock manifold to make it worth my trouble...unless I needed to change the manifold because it was cracked or something then he said go with headers. He told me my best bet would be going with an aftermarket "Y" pipe. I will give this a try and post my results. Thanks to everyone for the input.