Topic: Engine rebuilt, now equal length headers make boxer rumble

[SlowLGT]

Just had the engine rebuilt with forged pistons, new bearings, and new crank due to a broken ring land (Full story can be seen in my build thread). After I put the engine in, the car sounds completely different than it used to with the gtspec ELH. It almost sounds stock with a catback. Idle and boost both seem fine, and logs look clean.

I have looked for exhaust leaks by getting under the car and feeling around the flanges with my hands, did not find any air pulsing.

I guess the possibilities could be 1. I set timing wrong 2. there is an exhaust leak I have not found yet 3. car is running on 3 cylinders 4. It's completely fine, I am tripping out.

Here is what the car has, and * indicates new hardware.

New shortblock*
- Mahle 4032 pistons 8.5:1 CR
- King XPG bearings
- New OEM crankshaft
- ARP head studs and rod bolts
Heads resurfaced and valve seats 3 angle machined *
Group N motor mounts *
Group N dog bone mount *
TGV delete *
Borgwarner EFR 6258 turbo with IWG and .64 housing
GTSpec ELH
Custom T25 up pipe and v-band down pipe
Custom TMIC with Vibrant core
3 inch straight through exhaust
DW740 side feed injectors
DW65C fuel pump


Here is what the car sounded like before the engine build.


Here is what the car sounds like now at idle.

[Zac]

Lower RPM still has a little rumble, how does it sound higher in the rev range?

[SlowLGT]

Lower RPM still has a little rumble, how does it sound higher in the rev range?

Compared to the track video and what I remember, it sounds more boomy and more subaru.

Just checked the plugs going to the coil packs, I did not mess up firing order 

Next step: take off the timing belt covers and see if I screwed up timing.

[Stehle]

To be honest, I sat in my legacy gt while it idled and watching your second video and it sounded similar to my car... Maybe slight difference as I don't have elh? (I dont get that crackle/back fire)

[GrantC]

4. It's completely fine, I am tripping out.

^--- my vote.

[funk32]

^--- my vote.

[rith]

It sounds fine to be honest.

[SlowLGT]

Thanks guys. Now I feel dumb about cancelling last Friday's tuning appointment with Sunny. I'll finish the pre dyno checks (boost/vacuum leak, compression test, oil change, etc.) and rebook with Sunny.