Originally Posted by ohmyf150

I have the 16612 installed on my Screw and I also have the 18" wheels. I have towed 5-8000 lbs for a total of about 15,000KM in the past 10 months with the exhaust on and have not had a problem. There is about 1.5" of clearance between the pipe and tire.

I once pulled a 30' trailer with 4 compact utility tractors and attachments with the total weight being 9600 lbs (verified on the scale and yes, I know too much weight for the truck... ) for 350km into a really strong head wind. The truck was working hard that day and my spare is still fine.

I think MGDFan is on to something with you truck not quite running right to generate that much heat. Towing and the Magnaflow exhaust should not cause this to happen.

Originally Posted by Stealth

My Roush Off Road won't be setting my spare on fire. They designed the system right the first time.



Magnaflow needs to fix this design flaw.

Originally Posted by BlackDawg

I don't like the look of the pipe routed under the spare like Roush/Borla does there split duals out the back. Would really look like crap on a lifted truck where it's so obvious imo.

Originally Posted by Superchips_Distributor

Just FYI - There is some info I don't agree with being claimed/represented here, perhaps due to an apparent lack of understanding of the many various factors that must be taken into consideration when tuning each individual vehicle in determining what A/F to command and correct to.

First - it is NOT correct that the "optimum" A/F ratio for all gasoline N/A motors is 13.0:1. Each engine & configuration varies a bit even from one seemingly identical F-150 to the next. And this also completely ignores whether you are aiming for peak HP, or peak torque - or the highest average power, or best average power under the curve, etc. Peak horsepower is but one tiny factor in a vehicle's actual performance, as well.

Not only is it not true that any one set A/F will always by "optimal" or even achieve maximum peak power for all engines, or even all F-150 gasoline engines in N/A trim (meaning naturally aspirated), but what many seem to forget (or maybe never really knew to being with) is that you have to take the amount of load on the motor (and no, I do NOT mean only the PCM's calculated VE) , and potential length of sustained loading into consideration in determining what A/F's to command & correct to - and not just in O/L, but also in C/L (surprise!) in some cases.

Yes, you can tune a 3400 lb 5.0/5.8-based MUSTANG that is naturally aspirated (meaning non-supercharged, non-turbocharged) to somewhere between about 12.8:1 - 13.2:1 to achieve peak power and generally be OK up to certain speeds. (And by the way, no, it is NOT true that exactly 13.0:1 always gets you absolute peak power in all of even those engines.)

But you CANNOT do that to any truck or SUV and be safe under all operating conditions, nor would you ever tune a typical F-150 truck or SUV (or most other trucks & SUV's) to 13.0:1 - they aren't 3400 lb Mustangs with slippery aero profiles, they are trucks & SUV's with much different load characteristics & resulting operating conditions. You cannot tune a truck or SUV like you tune a much lighter car - these aren't Honda's that can take 13.2:1 for approximate best power and survive.

Remember people, it's about LOAD - load, load LOAD - & the resultant operating temperatures - and I don't mean engine coolant temperature.This is just one of the many differences between a seasoned knowledgeable expert tuner and those who simply do not have that accumulated expertise - and please remember, I'm not knocking anyone here, we're just talking in general, so please, don't anyone take offense here, OK? The reality is that there are unfortunately these days, far too few "tuners" doing gasoline engine tuning (or making posts on some web site presenting themselves as having such knowledge) that actually understand and look at the things that must be taken into consideration to correctly determine the most appropriate A/F for any given vehicle/engine configuration - which are extremely basic things like the engine timing, EGT's & exhaust valve temps, just for starters.

Far too many think that commanding one set A/F ratio and then hopefully setting up the spark so there is no *audible* denotation are the things that matter in that regard, and that is just not remotely complete, and thus not appropriate. When was the last time you saw en EGT gauge installed, even on a Lightning (aside form customers of ours, that is), let alone any N/A motor? Probably a pretty rare thing - unfortunately.

It's very easy to have a motor showing what appears to be "safe" A/F's yet have EGT's & exhaust valve temps skyrocketing and on your way to potentially serious engine damage - without leaning on the "safety" of the various temperature models in the PCM that are designed to dump extra fuel above & beyond anything you command when certain conditions are met - and relying on those failsafe models is poor tuning anyway - and heck, many tuners don't really even know those functions exist, or when and under what conditions they actually kick in, or even the inherent reliability & consistency rate with which they will actually enable themselves.

Again, it's thorough knowledge & expertise that is required for proper tuning, not just guessing at one single parameter or thinking that you can determine the proper A/F ratio only by whether an engine is normally aspirated or forced induction. A/F's do NOT even remotely begin to tell you everything you need to know - IMHO, no tuner in their right mind would EVER deliberately command a typical naturally aspirated F-150 to a 13.0:1 A/F and send it on it's way like that. I literally cannot tell you how many "tuners" and "name" chipmakers we've had to educate on this - the majority of whom still don't get it, because they don't do the R&D/testing required.