After I changed the pulley and had the Eurocharged tuning done to my XFR I did a dyno run. A short time later I added the Mina Exhaust. The exhaust note is intoxicating, and I love to hear it growl.

I wondered if the exhaust had improved my HP so I put the car back on the dyno this week. Same dyno, almost same environmental conditions (rare for Houston) and my HP results were almost exactly the same as the HP with pulley and tune and stock exhaust.

Now, I'm not saying the car doesn't benefit from the Mina exhaust but apparently the pulley and tune and stock exhaust on the XFR were a good combination as well.

Perhaps if you had a stock exhaust that was more restrictive or did not do the other mods you would get a performance boost. If I'd known there was no HP gain, would I have done the Mina exhaust? Yes, just for the sound.

Here is the Dyno chart, 480 HP at the rear wheel.

That doesn't surprise me, you don't really see much if any performance gains from an axle back exhaust

Thanks for posting - it's great to see evidence of the impact on HP.
I'm assuming your flat green line is the torque curve and the rising one is the HP? So the before and after aren't both on this chart?

I had actually read elsewhere on this forum a few people claiming the Mina exhaust gave lower HP at low revs and a bit higher (10-20hp) at high revs. Did you notice any difference in HP at low revs, or are the curves basically the same across the board?

I was looking to order from them could you give me input on their shipping speed,thanks.

I don't recall the exact amount of time it took for them to arrive but I don't recall any delay in shipping, you can (should) call them and confirm they have them in stock. I'm sure they came by FedEx or UPS Ground, it is a huge box and they are well packed. The workmanship is impressive.

I went back and looked at my dyno run before the exhaust. The torque curve looks the same as the post exhaust dyno curve. I would repost the earlier chart but I set off a bunch of people because I asked them to display both crank and wheel HP and some thought it was the tuner trying to confuse people.

Now I'm thinking of getting a local shop with a Dynojet to run the car as I'm curious about the difference between the DynoJet and Dyno Dynamics. Clearly I have too much $$ and too much time right now.

I bought two Mina exhausts and they each took about twoi weeks to arrive. Their claim is in the low teens for HP gain, when you are talking 500HP car I would not expect to see that on any dyno chart. You could have more than 50HP difference at this level just from bad fuel and ambience change from one day to another.

Yes they've been super responsive w/ customer service so I feel good about proceeding peace for the input.

I just ordered my Mina exhaust - took 5 days to come. Installed today and it's outstanding!

Mina exhaust provided decent power gains on my previous, normally aspirated 4.2 XK. I always prefer acceleration testing vs. dyno and in this case the 70-110MPH acceleration over the very same road section produced a full 3.1 second improvement over the stock exhaust.

But, most of the gains were at high RPMs as my test included starting to accelerate at nearly 4000 RPM and going to redline. The car did actually loose low end torque with the Mina to the point where pulling away from very low speeds on the freeway required a downshift that was not required with the stock exhaust. I also picked up low RPM drone.