Hey guys,

My car rides really smooth at low cruising rpm's until it reaches around 3300+ rpm. Then I can feel the engine run noticeably rougher. There is no hesitation and it pulls hard to redline, but if you cruise in any gear and cross the 3300rpm threshold, it feels like I've hit a resonance with the car and things start to shake and vibrate much more in the car. It wasn't like this when it was NA. Currently running a begi s6 with diypnp. Car is a 94. Any ideas what this could be?

Tried searching, but no luck.

Thanks,

Long

 

Are your AFR dialed in?

Id check your motor mounts.

 

#1 thing to check is your tune. what are your afr's and are they consistant or jump all over the place? What is your timing table looking like in that area?
Next I'd inspect the mounts like sk suggested

 

Sounds like an AFR issue. I'm currently dialing out some enrichment that were in my tune when it was on the dyno. I found a general scaling factor, but I would hit spots like you are referencing. Autotuning go rid of them.

Tip* autotune at approximately the same ambient temp if you are going to do it in multiple sessions. Especially if your MAT corrections are not dialed in.

 

Been autotuning for a while. Crusing AFR's are at 15-15.5. My mounts were replaced with MS comp at the beginning of summer.

AFR's are pretty consistent IMO. I will post up my timing table, but it's the "hybrid" timing table posted in the timing thread a while back.

 

Die ******

 

I had a similar resonance problem after installing a new motor. Wasn't the tune. I went through everything and found contact between the car and the exhaust under certain loads. Could be a contact issue?

 

I think this is it because it only started happening after the turbo install but I can not visually see any contact.