Here is the dyno with the best run (Highest RWHP) pre cats and the best run post cats.

Good to note the gains were across the power band in both HP and Tq.

As I guessed, the AFR is much higher now. It is close to optimal level, unlike the stock cars that fell off to 10 and beyond in high revs.

 

I think the change in the AFR will surprise you. After your tune, where were you at?

 

Hey, great results. It appears the gains in the mid range were even more, ask the shop to provide the maximum gain in the power band ( largest delta / change ) instead of just maximum peak gains. Low end to mid range torque gains are significantly improved.

It appears the cats significantly alter the AFRs more than a standard catback does. However it's still not perfect. With a good high quality tune, it will look as if you drew a straight like across all the way from 2500rpm to redline at 12.1. You are definitely much closer than you were, so it's a big step in right direction, great job!

 

Here is the largest delta in HP. The gap was 18HP at 5400RPM pre and post cats.

 

Here is the largest TQ delta-16ft/lbs at 4,900RPM.

 

Hello there!

I currently have the Quicksilver SuperSport exhaust installed on my Aston and was considering installing some cats to gain additional power. My question was whether the car becomes too loud following the installation of the cats? Is it worth the additional 10hp?

Keeping in mind I drive it almost on a day by day basis

 

Hi Ali-
Its loud, very loud. If it was a DD for me I would probably put on Stuarts touring exhaust or revert to stock.

Here is a clip I just did that somewhat gives you an idea of the sound.

 

Sounds familiar ^

 

Hey Detomaso,

First off, Excellent job providing thorough scientific data for the Aston Community, providing both maximum peak & largest delta charts is a huge help to those looking to purchase cats down the road. Im so glad to see more and more aston owners doing proper scientific testing both pre/post mod, Great Job!

As I suspected, the gains were even greater in the mid-range of the power band. Typically with high flow cats, the largest gains will be at roughly the same rpm as peak cylinder pressures (aka peak torque). If you look carefully, both of the largest deltas occur right around peak torque (4900-5400rpm).

Very strong results, congrats on the great gains!

Keep posting future updates!
007

 

I had Quicksilver on my V8V, then moved to a Larini complete system. However, it was so loud that few people would follow suit. It sounded like a '60s muscle car. By combining the exhaust with the AM power pack, the car was most certainly stronger.

 

@007-Thanks, I could not agree more. I was looking for this for a long time but it did not exist. These are gains that were well worth the money IMO for this type of car. The peak you speak of is also around where the car drops to in the next gear when shifting if you are pushing it hard.

@Scott-when you say complete system....cats and exhaust?

 

I got the AM power pack and Quicksilver as well on my V8V and it's an awesome sound. Sometimes I just drive without the radio on to enjoy the roar.

 

That's not by coincidense either. Aston engineers specifically arranged the gear ratios in a narrow fashion in order to maximize the modest power the engine has. Once modified, the effects are only pronounced even more. I will say a few extra hundred rpm definitely helps, 7600 rpm is the perfect redline IMO.

 

Yes, I did the cats, pipes and box. The sound was wonderful and I loved cutting extra weight.