325e stroker wuestions

[ThomasE30]

Hello new user here! I am looking at getting a 85’ 325e soon and had a few questions. The guy I’m getting it from has it set up with a 2.7L 325e engine with a 2.5 head on it. I’m very new to strokers and had a few things to ask. The car is loud and was wondering if that’s just how stroker engines are in general or if it could just be that it has a cat back with the exhaust manifold. I’m learning more about exhausts and I know that the cat back would increase the sound but I didn’t know how much. I want a exhaust that has a nice rumble but not incredibly loud where I have to turn the car off at a drive through. He did mention that he would turn down the throttle screw to try and make it quieter I think but that would just shut off the car. When he would turn it back up it works perfectly fine though. Just looking for some feedback about the exhaust and stroker questions. Thank you for any help!

[Reichart12]

I would do my best to confirm it actually has the 2.5 head on. If you have any pictures we can help with that. But off the top of my head I would check the intake manifold area. The e engines had a cold start valve that should be have been retained when switching over to the i head and management system. Changing the head like this should have no impact on the sound. Take a peak under the car and see whats up with the exhaust. And I have no clue whats going on with a throttle screw. Sounds like manually raising the idle to me but idk?

[ThomasE30]

I would do my best to confirm it actually has the 2.5 head on. If you have any pictures we can help with that. But off the top of my head I would check the intake manifold area. The e engines had a cold start valve that should be have been retained when switching over to the i head and management system. Changing the head like this should have no impact on the sound. Take a peak under the car and see whats up with the exhaust. And I have no clue whats going on with a throttle screw. Sounds like manually raising the idle to me but idk?

Thank you for the response! I don’t really have any good pictures of the heads or anything but a picture of the engine with the hood open. He did say that it’s running a cat back exhaust with the stock exhaust manifold. He was gonna out on headers but didn’t want to have to drop the money for that since he’s selling it.

[Andre3127]

I would do my best to confirm it actually has the 2.5 head on. If you have any pictures we can help with that. But off the top of my head I would check the intake manifold area. The e engines had a cold start valve that should be have been retained when switching over to the i head and management system. Changing the head like this should have no impact on the sound. Take a peak under the car and see whats up with the exhaust. And I have no clue whats going on with a throttle screw. Sounds like manually raising the idle to me but idk?

No. The cold start valve is NOT retained with the 2.5 head swap. The M1.3 system used on the 2.5 head does not utilize a cold start valve. When doing this swap, the only thing retained from the m20b27 is the block and rotating assembly. All of the engine management is switched to 2.5 stuff.

[Reichart12]

No. The cold start valve is NOT retained with the 2.5 head swap. The M1.3 system used on the 2.5 head does not utilize a cold start valve. When doing this swap, the only thing retained from the m20b27 is the block and rotating assembly. All of the engine management is switched to 2.5 stuff.

Oops you're right. Definitely meant to say "NOT retained". Good catch.