First off, a big thanks to those board members who have posted how to's for replacing the cats and air filters in various posts over the years. Those resources were invaluable to me in getting mine installed. I also thank Irish for his many replies to my emails regarding these and other topics over the past months. After an initial false start, I've been checking gains, such as they are, on my car as I have gone through the process of installing cats/filters (done in one go) and subsequently adding the RSC ECU tune.

One comment about installing the RSC filters, the opening at the top of my filters (and I understand those installed by others) is a touch large in comparison to the flange that it mounts on inside the air box and the vertical height of the filter is a little smaller than that inside the airbox. You can address this through a variety of means, adding a thin piece of foam underneath the filter to push it up onto the flange; using a couple pieces of duct tape to build up the surface thickness of the airbox flange etc.

Another big thanks to Stuart of RSC who has generally been above and beyond in responding to my emails if I've had questions/issues with any of their products. This included responding to and urgent email one evening just after I downloaded the stock ECU code to the LiveTune unit the first time and discovered that this caused the car to a) throw some engine codes and b) drop into limp mode when I drove it anyway. As it turns out, some cars (not all cars apparently) will throw codes when the ECU is accessed (either to up- or download) and there is a simple procedure to clear them (perform three restarts and clear the codes with the LiveTune unit each time). After this, no more codes. The Livetune unit itself is very handy to have, the software is slick and effective at transferring files to and from the unit with a PC. The only downside is that the sw is PC only. Need a Mac version guys!

A note before you have a look at the results. They are lower than what I've seen posted elsewhere (at least with the cats/filters, not sure if there has been a pre- post- dyno on the ECU tune) and I am not yet finished. Stuart has sent me a revised tune with more aggressive settings for fuel and spark. I have not yet uploaded this (no time yet and I did not want to do it prior to the Mosport track day I just attended). At some point I wil re dyno the car after uploading this updated tune. But my assumption is that the tune I received is what all 4.3 owners with cats/filters installed would receive so I'm posting the data here for reference.

The dyno results were all performed in the same unit (a Mustang dyno - a custom version of the AWD 1750 unit but used for these tests in 2WD mode) that is co-owned and operated by Velocity Injection and Engineered Automotive near Toronto. The baseline was in relatively cool and dry conditions in May (with parasitic losses measured for subsequent runs), the cats/filters and cats/filters/ECU measurements were done in warmer more humid conditions in May and July respectively. The results are corrected for climatic conditions. The only variable that was not the same through each test was that I had 94 octane for the baseline, 91 for the cats/filters run and 94 for the cats/filters/ecu run.

I was disappointed with the results of the cats/filters run - +1.6% hp and +2.4% torque - and thought it might have something to do w the octane difference. However, the gains after adding the ECU tune don't suggest this was an issue - + and additional 2.2% hp and 1.6% torque. Totals after all mods were +3.8% hp and 4% torque. Based on what I had read, I was conservatively hoping for about double that. I don't have any explanation for the modest gains.

I could have made the results look a bit better by using the lowest baseline result compared to the highest post mod result but I don't see why one would do that. Each dyno consisted of three runs and quite reliably there would be about a 2-3 hp gain from run 1 to 2 and then runs 2 and 3 were essentially identical. All runs were WOT from around 2500 rpm in 4 gear. AFR/Lamda comparisons are provided in a separate printout

In terms of value for the money, I am absolutely sold on the cats primarily bc of the amazing sound they provide. It's about half the cost of a performance exhaust, gives you modest power gains and a fantastic increase in the volume and sound quality of the engine. When first installed they are _HOT_! The heat just wells up from under the car and through your seat. After a few hundred miles, when they've had the opportunity to accumulate some carbon build up, the heat is not as bad. Ditto for the sound. It's freakish when they first go on (a metallic blat blat sound reminiscent of a race tuned car) and this tones down somewhat as they are broken in. If you are not into crackles and pops however (at least one stalwart here prefers those on his breakfast cereal) then the cats are probably not for you. Lots of added complexity to the exhaust note with the cats but it also cranks up the volume. While I'm more of an old world wine fan appreciating the subtlety of Burgundy, Brunello or Barolo over the obviousness and amped up quality of most Napa cabs, it seems my tastes run the opposite when it comes to car noise. Maybe that will get boring over time, dunno, I'm loving it now. There is a slight drone with the cats when cruising at highway speeds (100-140 kmph) but I don't find it objectionable.

The tune certainly provides some subjective improvement in throttle responsiveness that is welcome. You will have to relearn throttle positions on corners however. The place your foot instinctively travels to to maintain velocity while also keeping grip will be wrong. You will surprise yourself pushing the back end out. It's a fairly quick adjustment to make but a noticeable one. Not going to make any more subjective comments on the tune, I've got no data to back it up so it's neither here nor there if I think the car 'feels' faster.

 

The car air/fuel ratios still need to be tuned properly (as you stated of course). Still plenty of power to be picked up, your air fuels should be 12.5 across the entire power band for maximum power gains.

 

I can't understand your results as my seat-of-the-pants analysis after I did the cats, air filter and rear muffler box modifications there was a remarkable difference in performance. But not for the modifications, I would have sold my car.

As for Irish, he's the best.

 

^^^No offense intended, but I wouldn't listen too much to the seat of your pants -- butts don't always provide an accurate indication of what's going on. The increased noise promotes the perception of increased power and acceleration, which may not actually be there. As an example, I can control the exhaust valves on my V12 with a remote. When I run the car with the valves open (louder), the car seems much faster, even though it isn't.

 

I'm my real world job I work in medicine/science and controlled trials are the bona fide gold standard that drives what we do. I don't want to impugn anyone's opinion but to me, if you can get data, you ought a get it to support an opinion (hence my final sentence).

That said, the data is as good as the conditions of the experiment. I am not providing 0-60 or quarter mile data, both of which might well show differences that relate directly to the 'seat of the pants' assessment where WOT in 4th might not.

I thought it important enough to attempt to test the mods objectively that I invested time and money to do so. I hope this encourages others to do the same and post here.

 

Nice to see those numbers. I just has Air Filters, Cats, and Exhaust (all from RSC) as well as a new set of door sills installed on my 08. It certainly feels snappier and it sounds awesome. ECU and Shifter tunes are next up on the list.

 

A high quality ECU tune is the best bang per buck IMO. Cats are a close 2nd.

 

Pls consider getting a high quality dyno done pre- and post- tune. I think the community would be very interested in additional results.

When I get the chance, I will redo the dyno with the updated tune I recently received and post here. I'm planning to wait until the weather cools down and dries out a bit though as that is the one variable from my tests that bugging me. Should be corrected for but I do want to repeat when the climate conditions are similar to baseline just in case has contributed to the unexpected results.

 

Of course I agree, wasn't saying that in a negative way, just saying once a more finalize tune is done you should pick up another 13hp roughly.

Keep us informed

 

^^^ Wasn't interpreting it negatively at all. Definitely want to update as more info becomes available. Just noting that it might be a while before I can.

 

nice figures..

 

Nice work, tune really needs to be played with though..like some have said the AFR still needs improvement. The only real gains I see are @6000rpm with the latest tune vs the run previous to that, tune puts a large dump in fuel and richen's things up to get the little boost in HP, you can see it in the graphs...not the best way of doing things though, the power above 6000rpm really comes from the cooler temp boost in AFR..
Like 007Vantage pointed out, get it dead between 12.5-12.8 and you will see a nice bump in TQ down low and HP up top..also when you do your runs, make sure you wait for the downstream sensors to work, if there in the -time-out- period..car will run rich even if your ratio is perfect and at engine operating temp (you can see them kick in when datalogging them).

 

Ya, I'm also puzzled about the AFR readings. Does not look like what has been posted elsewhere. Still scratching my head. Have not yet installed the updated tune that Stuart kindly sent me. Weather has been too crappy lately to go out and play.

 

Omg, hehe..don't start with the weather, I've got no A/C at home, gotta love the humidty we've been having..

 

Hey Aston.ca... just realized I posted this in the wrong thread, I'm assuming you have seen it though. We put our car on the dyno for you just to double check the AFR. I'm still not 100% sure what's up with your car, not having the chance to get my hands on it and see, but it is strange that you saw such low gains from both the cats and the ECU. Obviously there's always going to be a range of test results and someone's will always be on the low end, but I am still surprised.

Should look something like this: