What is it with the transmission sound?

  • Thread starter Thread starter meck_rb7
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cleanLX
And, it does not have to be a straight cut box to have the whine... mine is not straight cut (but is not production spec either, neither the gear pitch or the thickness) and it has a pronounced whine when under full load... and a quiet whine at part throttle or deceleration.

The race boxes are also face-plated (dog-ring, aka no synchros) which is why you get the clunk on up/downshifts, it's the lugs smashing into the ears.
This also happens when you go on/off throttle as the transmission slop bangs the lugs/ears... which is why when you see race cars going slowly (yellow flag) you'll see them "jerk" when applying/lifting throttle... in a race car this is heightened as the motor is set up to run at higher rpms and isn't real happy lugging about, but the jerkyness starts with the lugs/ears banging about, and the engine being unhappy doesn't help matters.
Click to expand...

Yeah I have a customer with a Cobra kit car that has a 700HP 514 Ford engine and a stock Ford top loader 4 speed, even that thing bounces jerks around at low RPM, because of the cam profile it isnt very "happy" when you try driving at less than 2500RPMs. Between the manual trans and differential there is quite a bit of gear lash. You dont happen to have a G-Force do you?
syncro-dog.jpg

This might help explain the gear lash between a production and race transmission. The big or bottom row of teeth are the actual "gears", these are helical cut gears not straight cut, but the "thingy" in the second row is the standard synchro vs a dog ring. The opposite teeth (not shown) on the dog tooth engagement transmission are not a tight fit to the dogs shown, they are actually a pretty loose fit which makes it possible to engage or disengage the next gear.
 
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@fastone371
Astro A5, 575tq version, synchronized for now, but, may pro-shift... cannot face-plate... detroit TT and 4.56's out back.
4bolt 306, solid roller, turns on around 4500 and signs off at 8000... it too hates steady throttle below 2500 :)...
I too am making ~1.36hp/cu.in (stock iron heads holding it back), so, I know what that Cobra likely drives like.
1.36hp/cu.in. naturally aspirated in a pump gas pushrod V8 ain't no walk in the park.

Good job on that 514.
 
cleanLX
@fastone371
Astro A5, 575tq version, synchronized for now, but, may pro-shift... cannot face-plate... detroit TT and 4.56's out back.
4bolt 306, solid roller, turns on around 4500 and signs off at 8000... it too hates steady throttle below 2500 :)...
I too am making ~1.36hp/cu.in (stock iron heads holding it back), so, I know what that Cobra likely drives like.
1.36hp/cu.in. naturally aspirated in a pump gas pushrod V8 ain't no walk in the park.

Good job on that 514.
Click to expand...

Thank you. I was a little a little disappointed to see that it was in fact only 1.36 HP per CI but I suppose its a pump fuel motor and the heads are essentially an aluminum carbon copy of the factory 429 Cobra Jet production head. Is your car a drag car??
 
I understand why its a dogbox and they whine so its realistic. Now I always hated how on some cars its louder than the engine noise, which in some case's is also realistic, especially on Gt5 and 6 where 90% the cars sound terrible when you remove the standard exhaust. So if you need a adjustable gearbox, but dont want to deal with the annoying exhaust sounds, you are stuck with the annoying gearbox sound. They need to make a option to either turn the gearbox volume down, or swap the adjustable ratio to a normal transmission.
 
@fastone371
yep, production heads make for a good choke point.
Mine is full interior, full weight street car, that also wears slicks/skinnies on occasion and gets launched at 7000rpm... front and rear chassis/suspension is a compromise between launch and corner... rear more focused on launch, front more focused on surviving street life.
 
Some gearwhine sounds good, some are disgusting.
Best example, assetto corsa - mx5 cup car. After 30s my ears start to bleed. never drive this car again because of that sound^^
 

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