SlvBullet

iTrader: (8)

I started this project last year with the extra air hose to the airbox. see

https://www.clublexus.com/forums/7403669-post52.html

The next step was the performance exhaust. I got the dyno done today and added ~12 whp. Like Barcardi, I am using the Dr. Gas X-Crossover in the place of the 3rd cat which was eliminated. I am also using the Dr. Gas X-Scream mufflers - one on each side.

see www dot drgas dot com for more details and prices.

I went with 2.5" ID all around to match the PPE headers that will get installed next. All the pipes including the OEM resonators were eliminated and replaced with SS (not polished) 2.5" ID pipes. We used Vibrant SS polished 2.5" ID resonators. After the fact I have read that the Vibrant Ultra Quiet Resonators might not have had the drone I have now at about 1800 rpm. Both these are flow-thru performance resonators. The Dr. Gas tips also have built-in resonators.

The dyno shows 251 whp which translates into about 313 at the crank assuming about 20% loss. The factory OEM spec is 288 engine HP so I'm moving in the right direction.

Next step are the headers. I can feel the extra power but will test at the track later in the month - road track and drag strip.

Here are some pictures and the dyno results showing the sequential improvements.

HMD

Nice project , Can you upload video of the exhaust sound

reelbb

Nice exhaust, very clean with minimal bends. I'm thinking of replacing the downpipe and midpipes as well. But I don't want the drone, had it on the last lexus and it really spoiled the driving experience for me.

bacardi11

iTrader: (1)

reelbb
if you don't want the drone use the stock res. like I did. I also have the Dr Gas exh. with X pipe. I did't use the stainless steel much cheaper. slvbullet went for the best but you pay for it. very nice setup. they are custom Mustang muffler by Dr Gas great sound.
this setup works.

reelbb

Yeah, I've been eye-ing the megan downpipe on ebay for some time now. But the crimp bends on the midpipe is my main concern, it's the ugliest looking piece of engineering I've ever seen as well as being the most restrictive part of the exhaust. I'm running Toms axle back at the moment and it sounds subtle but aggressive.

Right now my main concern is towards mid and hi RPM's, so I think I stick with a Y pipe configuration. A larger diameter Y downpipe would give me that with minimal lost of torque down low. You have to remember that exhaust dynamics is more concerned with flow consistency more than flat out flow. You don't want the flow going back and forth and slowing around any bends.

Also, for the OP, be ready to replace your downstream O2's every 6 months is you do the headers(speaking from experience). The unburned fuel from the headers doesn't agree with OEM O2 sensors very well. But all in all, think it's a job well done and thanks for the dyno post.

SlvBullet

iTrader: (8)

What really increased the cost was the labor for putting all those peices and welds togeather. Re. Drone, I'm getting used to it and manage it with the accelator or shifting. After the header install I'll see what it sounds like and if necessary change to the ultra quite vibrant resonators or doma close end 1/4 wavelength pipe.

SlvBullet

iTrader: (8)

Here is the last Dyno video on youtube with the Dr. Gas/MachV exhaust and the PPE headers. You can hear the new sound just at the beginning then closer to the end.

The Reported HP and torque is at the rear wheels - dividing by 0.80 to compare with engine HP of 288 OEM gives 333 engine HP - 45 HP gain




For comparison with the first dyno I had nearly OEM is here:


Thanks to Dan @ MachV for the videos