exhaust-engine flutter

[GOTSOOT]

I have recentley noticed a fFlutter sound coming from the exhaust pipe when accerlerating up thru the gears when on a road that has trees and bushes along side of the trk. -gives the exhaust something to bounce off of ,so I can actually hear it better? I recentley installed 370`s and had the timing bumped and the gov. modified. Would return valves be the culprit ( just a guess)This only happens at about 1600 to 1800 rpm`s . Some one jump in and give me your most appreciated opinion.

 

[Skydiver]

I am not sure but it could be MORE POWER.

Tim

 

[sewman]

What did you set your timing to?

 

[cumminsgetme]

Check the fuel pressure..... this will let you know whether it's fuel related.

 

[DMC]

It may be your wastegate is in need of being calibrated. Since you did some minor mods it is probably pushing more air than it can get rid of. You may need to free up your exhaust system.



Good luck

 

[HoleshotHolset]

As if I know anything... but I'll agree with sewman..... yours sounds like my truck which is in dire need of a timing advance adjustment.



Matt

 

[F Simkowski (In Memory)]

goatherder:

I'd suggest you find a stretch of road with a nice solid continuous wall on the exhaust side of the truck, or even a tunnel or long underpass. Lower the passenger window and listen to the exhaust note at different and constant throttle.

Your fluttering sound maybe the result of the exhaust being reflected back in a broken pattern due to the broken reflectivity of trees and bushes, as opposed to a solid continuous object



Frank S.

 

[sewman]

I recently put in a Gov Kit & couldn't get it to rev over 3,100

Piers said to advance timing alittle which I did & got it up to 3,400

but the last time I did it I was in a hurry(fatal mistake) & when I took the pin out of the pump to flip it around it was broke & since I just had to take it for a spin & on a Sat afternoon I figured I'd get a new pin on Mon. well whrn I started it up it had a strange echo sound in exhaust,took it out for a few miles made sure it was warmed up got on it,egt's much lower& had alot more power,

about a 1/2mi down the road I stopped ran it through the gears\& slide alittle sideways going in 4th felt real good until I pulled in the driveway,I hoped it was a hose,but it blew a head gasket. So now I'm setting the timing around 16 & leaving it alone.

Bob

 

[cumminsgetme]

sewman,

Have you noticed your truck popping at high rpm under full throttle? We have similar mods and my truck has a very agressive popping at high rpm. It has been the pain in my a$$.



goatherder,

I doubt it would your timing if you just bumped it..... depending on the baseline you started at. What did you set it at? My guess is that it's fuel related. Check your supply and return lines real well.