LS4 / F40 swap - fieroguru (Page 75/216)
Trinten APR 14, 09:52 PM
That's so nice. I'm still jealous at how well your mufflers seem to work in those videos.
Do you have a phone app or anything that would record what the peak decibels get to in the car when you're cruising at highway speeds?
fieroguru APR 14, 10:05 PM

quote
Originally posted by Trinten:

That's so nice. I'm still jealous at how well your mufflers seem to work in those videos.
Do you have a phone app or anything that would record what the peak decibels get to in the car when you're cruising at highway speeds?



Thanks! Its not all about the sound, but when they sound good its just better!

Cruising is quieter than my old SBC car and there is zero drone which is very nice. However, the loud pedal makes things loud in a hurry... especially behind the car. I will check with the EHS guy at work in the morning to see if I can use the plant's decibel measuring tool for a day or two.
Trinten APR 14, 10:22 PM
Thank you!
dskebo APR 15, 12:42 AM
Hey call me crazy but I enjoyed every second of the ride even when you caught up to the slow car. Thanks for the ride.
KissMySSFiero APR 15, 08:25 AM
Just download a decibel app. Should do the trick.
dobey APR 15, 09:31 AM
Does sound pretty great now. What was the loud "clink" sound that happened at the same time the headlight door fell down when you let off the gas? Tools on the floor?
fieroguru APR 15, 04:59 PM
Thanks guys!

The loud clink when I started slowing down was some tools in the passenger floor board rolling around and hitting each other.

The LS4/F40 car did its first trip for the daily commute and lots of stop/go traffic. Its in town manners aren't as nice as the old SBC, the 12 lb flywheel and the 224/232 camshaft are the likely culprits. Over time I should get the hang of stop/go of dialing in just the right amount of throttle to take off from a stop light. After driving the 2.5/125C DD it seems like everyone decided to slow down about 20mph...

On the way to work this morning I finally did a WOT 3rd gear pull from about 2600 to 6100. The % A/F error between the commanded (12.69) to the wide band readings was within 1.1% for the pull and no data point was off more than 3.6% off... pretty good for the extrapolation I did in the upper range. A couple more pulls and I should have it dialed in very close.

The Maximum values were:
Commanded Torque: 321 @ 4411rpm
HP calculated from Torque: 329 @ 6200 (hadn't peaked yet)
TPS: 100%
MAP: 98 (baro was 98 when I started the car). However by 3500 RPM is was down to 97 and above 6K it was down to 94.8Kpa - I think the air filter is too small.
MAF Airflow lb/min: 42.1 The other LS4 guy running the same camshaft, DT headers, Fast 102 intake, NW102 throttle body, and the LS7 MAF is pulling 44 lb/min so I am at least in the right range. However, this reading really makes me wonder about the accuracy of the commanded torque calculation (maybe there is a portion of the tune I haven't changed that it uses for the calculation). Who knows...
Timing: 22 degrees above 5K

I also took a few decibel readings today all from inside the car in the center console area (NOTE: interior is not fully assembled yet):
Idle windows up: 81-82
Idle windows down: 83-84
55mph cruise in 5th: 89-90
55mph cruise in 6th: 84-85
55mph coasting: 83-84
65mph cruising in 6th: 90

Outside car:
10' to the side idling: 87
10' to the rear idling: 90
10" to the rear with throttle blip: 90... I don't think the app I downloaded reads above 90 decibels as it should easily be in the 110 range

I will try to get the decibel meter from work.

Overall I am very pleased with the setup and will continue to refine the tune. Hopefully in a week or two I will schedule it on the same dyno I used for my SBC car so I can get some actual #'s.

[This message has been edited by fieroguru (edited 04-15-2013).]

dobey APR 15, 06:01 PM

quote
Originally posted by fieroguru:
I don't think the app I downloaded reads above 90 decibels as it should easily be in the 110 range

I will try to get the decibel meter from work.



The phone apps for it aren't really all that great. They're OK at making rough estimates, but they use the microphone in the phone, which is very small, and has its limits. The microphone and audio hardware often also has built-in noise filtering, to try and cancel out background noise while talking on the phone. This is why so many of the videos on YouTube of people rattling the heck out of their trucks to death with their 10KW stereo installs, sound so bad. Modern phones may have reasonably fast Internet connections, reasonably good cameras, and a microphone, but they're still just phones, not movie studios.

It will definitely be interesting to see how different the readings from a professional dB meter are.
Kemp3 APR 16, 11:29 PM
Very nice Guru , I envy how refined the sound from your LS swap is . I know the camera doesn't do it justice and its probably a little louder in person, but the sound of your normal driving is nice in my book. When you got into it a little it got louder but manageable I would say.

Great job
fieroguru APR 17, 06:02 PM
I was able to check out the dosimeter at work and do some readings.

At Idle:
10' in front of car: 68
10' to the side: 73
10' to the rear: 75
@ exhaust tips: 98
In car windows up: 70
In car windows down: 71

Rev to 6500 RPM:
10' to the rear: 97.3
@ tips: 121

While driving:
60 mph in 5th: 83
60 mph in 6th: 79-80

I would like to get the in car decibels down to the 75ish range if possible, first order of business is putting the rest of the interior back in.

Some readings from the 2.5/125C Fiero (with GT exhaust and no cat):
In car idle: 65
cruise at 55: 72
cruise at 65 74

[This message has been edited by fieroguru (edited 04-17-2013).]