doctorj77

Hi everyone, haven't been on here for well over a year. I have a somewhat odd question. I still love the hell out of my 06 GT. But something has been nagging me ever since I put those Thumpr cams in. I used to enjoy reving the car and hear the mufflers burble on the decel. I no longer have that since I put the cams in. In fact, the rpms literally hang and extra second or two, and ridiculously come down slow.

Of course no burble on the decel. I want that back. But without removing the cams. Since I have the under-drive pullies, cams, charge motion deletes, my motor is about as free moving as possible.

If I remove the pullies and go back to stock ones, since that will add some drag on the motor, I'm wondering if the decel will move quicker, resulting in that muffler burble I'm referring too. Has anyone has similar thoughts after they went to cams? Anyone tried the same thing? Or am I the only one who's being a crackhead?

Acerbus 2.0

Crack is bad for you, mmmmk. Kind of weird wanting to purposely reduce the performance of your car just for sound...
Anyway. I'm pretty sure decel is controlled by the tune. One of the little things I liked about the Bamachips tune was how quickly the revs came back down, compared to Brenspeed's VRRRRRROOOOOOOOOOOooooooooooooooommmmmmmmmmmmmmmmm .. (anyone who has Bren tunes get the idea).

Talk to Brenspeed. He may be able to adjust the tune to satisfy your crackheaded needs.

UltraKla$$ic

I love all the mods to my car including the UDP's and BAMA 93Race tune. I have no issues with a lag on decel. This car snaps! Sounds like a tune issue like mentioned above.

Franchi

I have all the mods you have as well and mine winds down pretty quick with zero lag. As those prior stated, talk to your tuner.

Lax07

If anything shouldn't it rev up and down more freely with all those parts? If no load is on the engine, then the engine is going to go back to rest, period. I would agree with the others that the engine lagging is most likely a tune issue. I think once that is sorted out you will find the engine revs up and down faster than stock.

doctorj77

Well the revs up nice a quick. Just as you would expect is. Its only on the decel I was referring too. I talked to Brenspeed yesterday. They advised to leave the pullies in place. That they could revise my tune just as everyone has suggested. So I'll give that a try.

doctorj77

Finally got a updated tune put back on from Brenspeed. Granted, with cams, the revs will not come down super quick. That's just the nature of the beast, especially with a DOHC setup. But they were able to reduce it a bit more, I think anyway. So this should tide me over for another 6-8mo before I get nit-picky about something else.........

Tylus

so I'm not the only one to have noticed that effect the Brenspeed tune has.

I've been considering having them revise my tune to tone things back a little bit. It's just a tad bit too aggressive for a daily driver.



so is your burble back? I downshift alot to hear the exhuast vice using my brakes. no way I want to lose that sound

doctorj77

Well to be honest, I don't have that exhaust burble much anymore since moving to my mods like the cams, delete plates. Combined those two have removed that element from my sound.

I have noticed that Bamachips tune the revs seemed to come down fairly quick. But something about his tune just didn't work quit right. I decided to go with Brenspeed, since they were the cam installers and they put the car on a dyno to tune it correctly.

Unfortunately right now I have about a foot of snow, so my experience with the tune is limited to the garage. I mean I think I can see a difference in this revised one, but won't truly know until I get the car out on the road.

siggyfreud

In most ECM's there is a function called throttle following. It essentially opens up your idle air control valve more when you let off the throttle, to control the rate that the engine comes down from RPM. This is to prevent the engine from dying from decelerating (the engine, not the car) too quickly.

It should be something that, at least to a certain extent, can be altered by the tune. This is assuming the Stang ECMs use this function. My tuning experience is from the LT1 era.