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2bular NA Evora Exhaust System

49K views 104 replies 34 participants last post by  John Z 
#1 ·
I received the last pieces of my 2bular NA Exhaust System today.
You can see the "PreCat" O2 sensor ports in the Header Collectors, and the "PostCat" Ports on the distal end of the Metallic Cat.

I'm anxious to get them installed, but it may be a couple weeks, since I'm waiting for my new 2 post lift to arrive, and I've got a couple races coming up.

I'll post photos of the install, along with before and after Dyno data.
 

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#3 ·
ahh... and the B side too :)
 
#100 ·
Very nice, Don!

The Evora's have come a long way from having nothing available.. Now we got an awesome CAI, several of exhaust upgrades...even a couple of supercharger kits to choose from.

It's only a matter of time before someone offers an engine swap solution!
I am new with my NA Evora and have been looking around for supercharger kits but the only ones I found are upgrade to already supercharged engines. Let me know where I can find those kits.
 
#9 ·
Hopefully there won't be a proven S version come along. My vow not to mod would be seriously challenged.
And please, no CAI either!
 
#18 ·
1 upstream and 1 downstream for each cat's element.
 
#21 ·
I finally got around to getting my 2bular exhaust system installed on my Evora. I decided to have VSA Motorsports do the install, rather than do it myself. They have done the installs before, and know the routine, so they could do in a couple days what would take me a week. Thanks to Alan, Sergio, and Stephan for their expertise, and attention to detail !

Aside from some minor adjusting, the system install was straight forward, but time consuming. It took 2 full days, start to finish. Extending the O2 sensor harnesses was easy, but took a long time to figure out the routing and required lengths. The 2 Post Cat sensors, which had to be extended, were lengthened about 3-4 feet, to allow a neat routing along the rear sub frame. They were mounted using adel clamps, screwed into rivnuts placed in holes that were already in the sub frame. See Photos.

The weight difference between the Stock Manifolds-Downtube- Cat and Stock Muffler to the 2bular Headers-Downtube-Metallic Cat and Lotus Sport Muffler was 19.74 lbs., of which 13.5 lbs was the difference in the mufflers.

The sound of the 2bular system and Lotus Sport Muffler is amazing ! It has a soft rumble at idle, and has a full, but not excessively loud tone on easy acceleration. The more throttle you give it, the more robust it gets, and under full acceleration it sounds serious. The good news is that cruising at 70-75 MPH in 5th or 6th gear, at 2,500 RPM, you can barely hear the exhaust note. It is definitely not objectionable for conversation or listening to the radio. However, as soon as you accelerate at all, or load it going up a hill using more throttle, the sound picks up.

I did Dyno runs with the completely stock exhaust just before the install, and will repeat them on the same Dyno with the new exhaust system after a few hundred miles to allow the ECU to adjust. The good news is that it NEVER threw a CEL after the installation. I'll post the before and after Dyno results here, after I get them.
 

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#30 ·
Phew! That is one clean car Don! I can see your install guys got the heat-shields exactly right - well done to them. :cool:
Lambda wiring extensions: I have Ray on your side of the pond on the hunt for a supplier for these - hopefully someone who works to the same standard as VSA!
I've e-mailed you some info on the headers.
Our test mule didn't have the Radium intake set-up - didn't want any skewed results. We've since found combining the 2bular headers/downpipes + Radium is a step too far for the ECU - you need an ECU re-flash to get the best from that combo - ah well.
 
#31 · (Edited)
After driving my Evora for 350 miles, with the 2bular Exhaust system, I did the post installation Dyno runs today.

The graphs below show the Pre vs Post system Dyno results, in the Standard and SAE formats. The Pre was with a completely stock Evora, as delivered. The post is with the 2bular Headers-Downpipe-Metallic Cat and a Lotus Sport Muffler. The only change was the exhaust system, NO CAI, and NO ECU re-flash tune.

The dyno technician said that the drop in HP and torque between 3,200 - 4,300 RPM, in today's Post run, was due to his accelerating it from 2,600 RPM today vs 3,200 RPM last time. Starting at the lower RPM apparently "loads it up" initially.

The Air / Fuel graph shows how rich the stock Pre set up runs, topping out at the maximum 10.0 lambda at 5,900 RPM. On today's Post runs, they could not get the lambda O2 sensor to work, on any of the 3 pulls we did. BTW, ALL of the dyno runs were very consistent on each day's runs, within 1 HP.

The net gains were 13.26 Maximum Wheel HP, and 5.78 Ft Lbs of torque. Using the Standard 263.15 HP, and figuring a 15% drive train loss, that equals 309.6 Engine HP. Even with a low 10% drive train loss, it calculates to 292.4 Engine HP. But more important than the absolute number is the relative gain. The 13.26 Wheel HP gain equals 15.6 Engine HP gain. This is a 5.3% HP gain !

So, if you want more power, along with an amazing exhaust note, go for the complete Header-Downpipe-Metallic Cat System. And, I'm sure there is more HP available with the addition of a CAI and ECU Tune.
 

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