I had two goals in mind when I switched from my NISMO exhaust with Stillen Y-pipe to the Motordyne XYZ Y-pipe with the Shockwave ))) exhaust (with resonator pipe): http://www.motordyneengineering.com/350Z_exhaust.php

Those goals were to make a few extra ponies and lighten the car up a bit for the track and autox. The car has stock catalytic converters on with a few other bolt-ons (see profile).

Here is the car in track form:


Z Car Garage (www.zcargarage.com) did the pre and post-install dynos. Special thanks to Rob, Vince, Fred, and Forbes at ZCG for being awesome and working late with the install and tune to get my car ready for the track day. They monitored engine temp and timing to ensure the post-test conditions were the same as the pre-test conditions. The dynos were done in the late afternoon while temperature and humidity are the most constant. The pre-install dynos were done at 3:40pm, temp was 73.5F, and humidity was 40% RH. The post-install dynos were done at 4:55pm, temp was 73.5F, and humidity was 40% RH. The engine was run up to the same operating temperatures for the post-install dynos as the pre-install dynos. As far as we could control, everything remained constant except for the Y-pipe and exhaust swap.

Onto the dynos:

3 baseline pulls (all on this graph):


2 post-install pulls (on this graph):


Comparison of best baseline pull (#5) to best post-install pull (#6):



After subtracting some timing with the UTEC, we found a sweeter spot to make some power:



Here are some dyno pulls:

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Revving on the dyno:

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Drive-by:

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In-car acceleration:

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Then we went to Thunderhill for a full HPDE track day:

10 minutes on track:

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Drive by:

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Drive away of my car overall:

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The exhaust construction is second-to-none, and was installed with ease. I have received MANY compliments on how awesome it sounds. Drivers came by during the track event to ask about the car, the exhaust, and the nut behind the wheel.

The Z weighed in at 3060# after the install, which is right about where it was previously, however, the scale is +/- 20#, so maybe there was some weight savings there after all. I'll know once I weigh the NISMO/Stillen set-up when I sell it.

Thanks, Tony and ZCG!

 

What were the gains? (I am blocked at work)

 

Probably within the noise, but on paper, -1rwhp and -1rwtq in total power after the exhaust install. The pre-install curves are lower throughout almost the entire rev band though.

I did pick up ~8rwhp and ~5rwtq after the tune.

 

Thanks for the review!

 

I see a gain of 8 peak horsepower? THat is impressive.

 

After the tune - yes, and I am quite happy with that. The car hadn't been tuned for years, so the exhaust swap was a 1:1 comparison before the tune.

 

god i love the sound of that exhaust. i might buy one by the end of the summer

 

Great write up, awesome documentation and sweet driving bro! Makes me love my shockwave so much more!

 

So to clarify, the run where you gained 8 peak HP includes a tune, correct?

From just the exhaust swap, you were basically net-net.

You gained 8hp from a tune, not just the exhaust.

Just want to make sure I am understanding this correctly...

 

Thanks!

All correct.

 

Good stuff Scott, how does the car feel and sound? What is the reason you went with a single tail pipe? Is it just for weight?

 

how long did it take you to install it and did you use a lift or just jacks?

 

Thanks. Car sounds and feels great for sure. I went with the single for weight and the fact that is comes out the driver's side on an angle, which happens to point away from the sound check at Laguna Seca.

Re-read the original post.

 

Was that your Titan at the shop with the front axle leaking differential fluid everywhere?

 

I have not been to Thunder Hill yet... I can't wait to go.

I hear its the best track on the west coast.

 

damn now *thats* how you review an exhaust. thanks for the post.

personally dislike the look and tone but you cannot deny the power gains and weight reduction of this set up, perfect for what you wanted

 

actually the car was tuned for the old exhaust system if you read. So it was actually the exhaust that made it possible to gain the extra 8 HP with the next tune.

 

OP can you confirm? I don't get this from the narrative...

 

Thanks!

It is a great track. Laguna Seca may trump it though.

Yup, that's my T.

Honestly, hard to say. When I bought it, the "tune" it came with detonated at the high-end from overtiming. I was running 94 octane to compensate for it. Rather than re-tune for the old set-up then RE-tune for the new set-up, we did the 1:1 on 94 octane with nothing else changed, but there were still a few ticks over 6300RPM (with both exhausts). After we made the exhaust change and did the dyno, ZCG pulled some timing to get the detonation in check, and it subsequently made more power. I suppose I don't know for sure if backing off on the timing on the NISMO would have made the same power gains. . .

 

Just goes to show you that even back to back pre/post dynos don't tell the whole story. No one would expect you to pay for a tune for an exhaust that you're about to take off. Kudos for trying to keep everything as objective as possible.

It's worse with FI because even minor changes to a number of variables has such a drastic effect on the result. For example, just letting the car sit 10 mins to cool off will net you 10 whp easily.

EDIT: It is interesting that the stock ECU does not attempt to pull timing at high rpms because of noise, but the UTEC might have been. Just changing the exhaust (to something louder at high rpms) could have set off the UTEC's knock detection and affected the MD result until it was retuned. Just another variable...

Bottom line is you walked away with more power!