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450Z Sound


marcg

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Due to some setbacks the 450Z has been parked for far too long.

It's now back together and seems to be running well.

Hear it at: http://www.youtube.com/watch?v=f1gnwez41SM

It still has a sort of raspy exhaust note though.

Would this be from the resonator mufflers? Or should I have put the crossover before the mufflers rather then after?

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DANG! Car looks WICKED fast! :shock:

 

The raspy flapping type note sounds like exhaust leaks, a couple/few at the head/s or collector pipes, cracked headers/manifolds? Or possibly if dual mufflers, glass of steel packed style, one of them is more blown/worn out than the other?

 

Regardless, the car is definitely running on all 8 and looks wicked quick! :2thumbs:

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That sounds and looks awesome! The raspy noise is probably from the crossover being post mufflers. It would probably smooth the exhaust note a lot if it was before the mufflers. Unless your mufflers are the glass pack type and not real mufflers. Then I don't think it'll make much difference. My 77 (granted this is the stock l28) has a resonator (Federal model no cat) where the cat would normally reside and that thing makes the exhaust really raspy no matter what muffler I put on the car. Seems like the popping of the exhaust flame into the resonator will echo down the pipe. But I don't have a lot of experience with V8 exhaust so I'm just giving my opinion, nothing to write a book on.

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Is that a VH45?

If so, what temps are you seeing?

Mine is reaching 190 to 195 DEGF on normal hill climbs. but drops right back down after the top. Driving hard will obviously bring it up to those temps also.

According to the FSM for Q45 the thermostat will not open completely until 194 DEGF which will totally close off all recirculation paths. So it would seem that hot water will recirculate in the block a little bit until 194*.

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Yes they are the glass packed type. When I had just a muffler ( http://www.youtube.com/watch?v=T41-cjlksyM ) it sounded a lot better, but did not breathe as well.

 

 

That sounds and looks awesome! The raspy noise is probably from the crossover being post mufflers. It would probably smooth the exhaust note a lot if it was before the mufflers. Unless your mufflers are the glass pack type and not real mufflers. Then I don't think it'll make much difference. My 77 (granted this is the stock l28) has a resonator (Federal model no cat) where the cat would normally reside and that thing makes the exhaust really raspy no matter what muffler I put on the car. Seems like the popping of the exhaust flame into the resonator will echo down the pipe. But I don't have a lot of experience with V8 exhaust so I'm just giving my opinion, nothing to write a book on.
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I have had some cooling issues. Still testing to see if I have them solved. I tend to run in the 195 - 210 range. With occasional peaks to 230.

 

Is that a VH45?

If so, what temps are you seeing?

Mine is reaching 190 to 195 DEGF on normal hill climbs. but drops right back down after the top. Driving hard will obviously bring it up to those temps also.

According to the FSM for Q45 the thermostat will not open completely until 194 DEGF which will totally close off all recirculation paths. So it would seem that hot water will recirculate in the block a little bit until 194*.

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I have had some cooling issues. Still testing to see if I have them solved. I tend to run in the 195 - 210 range. With occasional peaks to 230.

 

Kinda figured. Just thought maybe you had something figured out. Seems many Q45 owners are experiencing the same occurence. I have not figured out what is the problem either as my coolant capacity is more than the Q45 and I have changed the water pump and the thermostat with Nissan parts. Radiator is new with dual Spal fans.

 

My theory is that the thermostat was not designed correctly and is not closing off the bypass soon enough. I cannot prove that though as I cannot watch it working inside the engine. However, looking at the old one, the bypass closing disk is hardly worn at all. Just my thoughts...

 

Sorry about the thread jack. Now back to your regular program...

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You are correct. I got the car running last Monday and called Linda at SMP to see about track time and she let me on the Nelson circuit for about 2 hours last Thursday evening.

Still feels like the clutch is slipping from time to time.

We both ran it fairly hard (8/10) for most of the 1.5 hrs with the occasionally hard charge sprint at 10/10 for about 4 laps. The temps were good until we went 10/10.

I may look into this thermostat issue.

My son and I will be running this Sunday with the OMSC at the Mosport DDT.

Like to see you if you make the time.

Incidentally my son has a Z31 AE with some tweaks. We'd like to here about your VG33ET. He's talked about that conversion a lot.

Let me know if your coming.

 

 

That looks like shannonviiiiiiiiiiiiiiiiiiiille raceway :D

 

Let me know when you'll be there next. I need to see this beast.

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  • 2 months later...

I assume this is NA engine?! The x-over is quite important if you want to get a tuned exhaust and all the HP you can. I don't know exactly how to calculate where you should have the X-over, but there is an old Hot Rod trick, you take a small brush and some regular paint, then you paint a thin line from the collector and back ~2-3feet. Then you drive the car and make sure it gets in working temp.. Then some of your paint should be burned away and where the "burn" stops is a good spot for your x-over! X-over location has to do with exhaust pulsation, speed and heat..

 

With all this said, your x-over should be before the mufflers. If you have stainless exhaust you get more resonance/metallic/hard sound aswell. Resonance mufflers will give it a more hollow/metallic sound. I prefer full flow glasspack mufflers. And also the length and diameter of pipe after the muffler will affect the sound.

If you have a car to do easy tests on it's quite fun!

 

Just a comparison, the identical bikes, just diffrent material in muffler shell!! (Carbon Vs. Titanium)

Carbon:http://www.youtube.com/watch?v=LvU_O0gmrPE

Titanium:http://www.youtube.com/watch?v=-xPBtvZXvm8&feature=related

 

I don't know if you can hear the diffrence on the computer but in real life the titanium has a much harder/sharper exhaust note. ( I used to own one w. titanium mufflers..)

 

Congrats on a very nice car!

Best regards,

Sebastian

Edited by seb280z
More info :)
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  • 2 months later...

hey, I'm possibly picking up a Q45 here soon with body damage, so I'm parting it and using the drivetrain :)

 

Do you have a build thread? Or any useful information like Engine/trans mounting and wiring and all that jazz? I cant wait to get mine going, looks like it runs very strong. And its only about 500lbs.

 

Also, Im hoping you converted it to a manual transmission?

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Two80z4ne, I have a fairly good overview of most of the steps I took to create the 450Z. Check out: http://www.cardomain.com/ride/563982/3

The 3rd page has most of the details. The wiring diagram there is too small and out dated to help you. Send me a PM with your email address if you need the wiring diagram for this conversion.

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