The old cut up manifold into trumpets idea

[rjahl]

Good read if you have a few minutes.


https://www.autozine.org/technical_s...e_exhaust.html

[konner412]

Originally Posted by rjahl

Good read if you have a few minutes.


https://www.autozine.org/technical_s...e_exhaust.html

Thanks for the content! It was a really good read. Makes a lot of sense why manufacturers use a multiple stage intake manifold.

[Dru128m]

I read that article trying to do my research, it is very good info. If there's any wizards out there who want numbers. From the back of the valve to the trumpet mouth is about 18 inches, and from the exhaust port to the collector is also about 18 inches. In my head that balance seemed a good starting point.

[Biginboca]

Wow I need to check this forum more often this is a cool idea that I have thought about before too. On the open runner set up that Bob did it made like 5 more whp with cut up N52 manifold vs similar set up on a N54 with an air filter. So there’s a little power there for those with a higher risk tolerance.

Starting with the N52 manifold as your cut up makes more sense than the N54, the N54 runners are kind of square and smaller ID than the N52 ones. Really would be great if someone could find the optimum length runner and a simple bolt on filter set up with N52 manifolds, they are so cheap and easy to mod.

[Dru128m]

Well so far so good. Still some kinks being worked out, but I'm driving it daily. I kind of have a little warm up routine that I need to go through on the cold starts and rapidly falling revs into an idle should be avoided, but not complaining. I do have a weird noise (like a belt squeal, but not) at certain rpms/load that I think is induction related, but more throttle makes it stop. I think smoothing the sharp edges off the trumpet inlets might solve it. All in due time, right now I'm just enjoying the snowy roads.

[E92William]

Man that's ballsy to be driving it around with no filter, no way I'd do that here

[konner412]

Originally Posted by Dru128m

Well so far so good. Still some kinks being worked out, but I'm driving it daily. I kind of have a little warm up routine that I need to go through on the cold starts and rapidly falling revs into an idle should be avoided, but not complaining. I do have a weird noise (like a belt squeal, but not) at certain rpms/load that I think is induction related, but more throttle makes it stop. I think smoothing the sharp edges off the trumpet inlets might solve it. All in due time, right now I'm just enjoying the snowy roads.

Nice! I'm amazed y'all have got this thing pretty much figured out.

[Dru128m]

Sorry guys no real updates. Just waiting on the next revision from Bob. Looking for the right muffler in the meantime. The stock resonator is all that's left, and while sounding ok, it needs a little help. If money was no object I'd get the Laptorr system from the headers back, but that's not happening. What do you guys think about a flowmaster 40 series, dumb idea?

[konner412]

Originally Posted by Dru128m

Sorry guys no real updates. Just waiting on the next revision from Bob. Looking for the right muffler in the meantime. The stock resonator is all that's left, and while sounding ok, it needs a little help. If money was no object I'd get the Laptorr system from the headers back, but that's not happening. What do you guys think about a flowmaster 40 series, dumb idea?

It's all good brother. I've been wondering what a flowmaster would sound like myself. Go for it. Can't imagine it sounding bad at all. Should have a nice growling tone to it.

[E92William]

This is a 128 with a flow master muffler. I spoke with the guy who owns the car and he didn't know which flowmaster it was though

[Dru128m]

That might have sold me on giving it a go. Wish there was some driving but it sure sounds good sitting there. I'm thinking the stock res should control the drone while the flowmaster gives it a growl. Have Bob dial in a little more burble on the overrun, what could go wrong.

[E92William]

I remember it being pretty aggressive when driving in video, wish I remembered the guys Instagram.

[Dru128m]

So I finally recorded some driving noises. Here's a run through the rev range in 2nd gear. I chose the worst weather in 3 weeks so it's windows up, sunroof vented.

[Rebellato]

Sounds awesome, congrats!


Just found this post https://www.e90post.com/forums/showp...4&postcount=14 , the way he cutted the manifold keeping these velocity stacks should be better in a lot of ways

[Dru128m]

I almost left all my runners conjoined like that, but thought they looked better separated. I'm kicking myself a little for choosing form over function. I may just make one up like that for daily driving, as filtering the individual runners is proving problematic, where I can filter that with a foam block and steel screen easy.

[E92William]

I think if you search around you'll find some pictures of one that has a pipercross filter that went all the way around. Pretty cool. I'll admit it does look a lot better separated

[accomotors]

Originally Posted by Dru128m

but more throttle makes it stop.

[chris82]

wow!!!

[tree233]

Have you figured out how to make it fail in the closed position rather than open position?

[b1aze]

Originally Posted by tree233

Have you figured out how to make it fail in the closed position rather than open position?

Do you mean the VVT system or the throttle body?

[Dru128m]

I'd would need to ask Bob specifically about that. It was one of the things on the list, but at this point I'm unsure. VVT is normal and the throttle body is only connected electrically. If valvetronic fails open the plan is: clutch in and kill the motor.

[tree233]

Originally Posted by Dru128m

I'd would need to ask Bob specifically about that. It was one of the things on the list, but at this point I'm unsure. VVT is normal and the throttle body is only connected electrically. If valvetronic fails open the plan is: clutch in and kill the motor.

Ah okay. Tho I don't think you can turn off the engine until the car comes to a complete stop... Give it a try. You might need a kill switch.