Hey guys-
Curious-has anyone ever dyno'ed their Vantage before and after just adding the Cats? I am specifically interesed in one that had the performance upgrade and exhaust already done previous.

I am asking this because I have seen the before and after on exhaust + performance upgrade and its substantial. I have heard from an AM service director that the Cats only really add noise and that he saw a 1 hp gain before and after.....

Thanks

 

I'd have trouble believing just 1 hp. I didn't dyno before and after with just that mod, but you probably know my experiences at this point. The stock cats are really restrictive. The difference is probably more noticeable in my car due to the SC, but I think it's a lot more than 1 hp in an otherwise stock car.

 

Was the dyno of the RSC upgrade or the AM power upgrade?

 

Could not agree more. I like you had always heard about how restrictive the stock cats were and assumed like everyone that they would provide a great gain. Problem is this guys does LOTS of upgrades to Vantages all over Texas (he has even bored out a 4.3 ported and polished it). He did the dyno before and after on the same car. Thats why I am curious if anyone else can prove the gains without the assumptions.

 

The initial dyno was done after the AM Power upgrade and Quicksilver SS exhaust were already installed. The second dyno was done after they added the 200 cell cats to the other upgrades. To this he said 1HP and a lot of noise.

 

Interesting...who is porting/polishing and boring out the 4.3? What displacement are they going to?

 

I did not ask him that but he mentioned the gains were minimal as the ECU would need to be further tweaked to take full advantage of the gains. I am wondering if ECU tweaks would also be necessary to take full advantage of the less restrictive cats.

 

What was the HP increase after the AM power upgrade and exhaust?

 

That's probably right...I have a secondary ECU which makes a huge difference by overriding the stock parameters.

 

Car is a 2006 standard trans

The car already had the quicksilver exhaust on it and read 297hp. AM installed their AM Power upgrade to the car and tested it again. This time it came to 333 for a 36 rear wheel hp gain. The corrected adjustment through power loss of the drive train and climate conditions of the day put the car at 426hp.

 

Had never heard of a secondary ecu! Does this serve the sole purpose of overriding the stock ecu?

 

Yeah. It completely alters the fuel trim for each throttle position and load to account for the extra air from the SC.

Something like this would be probably be necessary with a stroker motor as well to account for all of the changes.

 

More noise is definitely correct. Most people will need to go down a sound level on the exhaust.

+1 HP is not at all consistent with the result and feedback from a number of our clients. People have posted 25BHP gains from adding our 200 cell cats to their supercharged cars, and reported very good results on NA cars. There's no doubt that the RSC ECU upgrade allows you to extract more from the catalysts than just adding them by themselves, but 1BHP does not sound right.

From a couple of your posts about the source of these results, and some of the other modifications they have done, I suspect I might actually be familiar. If it's the same company, they contacted us a while ago with a set of 'our' cats which had failed (turned out to be Larini's) and also enquired about custom mapping for a car to which they had done a lot of head work, which had not produced the desired improvement in results. I believe this car was also fitted with our catalysts but I'm not sure that the results were accurate if that is the case.

Again, I'm inferring, and I could be wrong about the source but we have seen excellent results from the catalysts. Prodrive's UK-only upgrade of ECU + 200 cell cats (which is backed by AM) brings the 4.3's up to 425BHP. I'm sure Prodrive, and AM by extension wouldn't be offering that up if it didn't perform as stated....

 

Hey Stuart-
Thanks for the reply. This was all done at the AM dealer in Houston. That does sound strangly similar....

I agree with what you are saying, but it still begs the question. Has anyone upgraded just the CATs w/o a remap ideally on a car with exhaust and the performance upgrade already and done a dyno before the cats and after?

We all assume it would be a greater gain but I only know of one source that has done it. My concern here in the states is now that I have the AM power upgrade with ECU mods, if I add the CATs will it really increase HP without further ECU tweaks. I do not know of any companies stateside that can fine tune the AM ECU to take full advantage of this mod. Thoughts?

 

I haven't seen a before & after on the specific mods you are asking about, but the ECU program we offer, although it produces great results as a standalone product, is designed to maximize the potential gain from performance catalysts.

All of the N24 & GT4 race cars I have come across are running this program and 200 cell catalysts, the team principals tell me they are worth at least 20BHP. These guys aren't in the habit of installing modifications that don't make the cars go faster. If it doesn't cut the mustard in competition, it stays on the shelf.