Speedtech top mount kit

SlowE93

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Jul 2, 2017
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N54 owners ......deep down we know our motors will never sound good but, we will never admit that. Manifolds can't help them 😄
Naw....I can admit it.
I have redone my exhaust multiple times. I got midrange to sound almost exotic like, but top end was not. So tried again, and again, and again, to where it just sounds like a tractor now (zero drone though) and I just live with it.
 

fmorelli

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Naw....I can admit it.
I have redone my exhaust multiple times. I got midrange to sound almost exotic like, but top end was not. So tried again, and again, and again, to where it just sounds like a tractor now (zero drone though) and I just live with it.
Nothing a cross-plane crank engine won't fix.
 
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rac

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Nov 14, 2016
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Yeah not on twins but put a single turbo on it and they sound great in my opinion

i agree. especially twins that keep the dual mid-pipes and delete cats (which is probably the majority of modified n54s!), sound the worst.
tractor noises and rattly wastegates... yea... the best i made my old twins sound was deleting the dual midpipes and going single exhaust from DP's back. that mitigates those 3 cylinder noises as much as you can with twins.
 

martymil

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Sep 6, 2017
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I got to say this kit looks good and is one of the nicest top mounts I've seen and if my twins ever let go I'd look into trying this kit
or something similar if it can be made to fit RHD, the biggest issue is the lack of room for a proper down pipe.
 

rac

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Nov 14, 2016
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rhd: the widening at cylinder 3-4 consumes the space i am using for my down-pipe. most likely the only cast top mount that would practically work on rhd would be a more traditional log manifold hugging the block closer passing through there.
 

135i2

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Jul 23, 2017
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rhd: the widening at cylinder 3-4 consumes the space i am using for my down-pipe. most likely the only cast top mount that would practically work on rhd would be a more traditional log manifold hugging the block closer passing through there.
RHD: After developing my two bottom mount kits, I am doubtful that you'd get a 3.5in or 4in dump past the manifold runners, steering shaft or top section of the steering box. Not likely a free flowing dump that wont vibrate on something it shouldn't under heavy load. Log style as per Simply Tuning is the only top mount RHD manifold that gives you a shot at a half decent dump as the runners tuck close to the block. Happy for someone to show us the way with this kit for RHD.
 

rev210

Corporal
Feb 24, 2019
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335i - 08 Coupe .
Be a 3 inch dump situation for this one on RHD, if it even fits? Based on experience , not a deal breaker.

Based on my experience and understanding with different platforms. If you pick one of the favoured turbos able to make 1100hp and decide to run around 900/1000hp on the street (so within a half decent efficiency island for the turbo) .The difference between a 3 inch dump with an attached 3.5 street exhaust and 4inch 'open dump' exhaust is usually 40/50hp peak at the motor with around 1psi give or take additional backpressure pre and post turbo . Tuned. Thats a real world number. That 1psi is bugger all ,so you will get away with the same gate size for either just making a psi of boost off the gate pressure more on the 4 inch over the 3 inch. Mitigated by boost control without the need to change gate sizes or even springs usually. Over 1100hp the differences creep up as you max out turbo compressor efficiencies and backpressures become actually problematic. But, here you should be talking actual turbo choice and/or turbine size and AR. Since if the 4 inch dump is barely saving the turbo your margin for error is going to be way too small anyway.
If you did a search I would think there likely a few youtube vids around with dyno comparisons as its a common tuning myth.

So to recap , the dump being 3 inch is a non issue for folks running a full exhaust on the street and upto 1000hp or so. Getting even a 3inch dump past rhd steering is an issue though.👍
 

rac

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Nov 14, 2016
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Be a 3 inch dump situation for this one on RHD, if it even fits? Based on experience , not a deal breaker.

Based on my experience and understanding with different platforms. If you pick one of the favoured turbos able to make 1100hp and decide to run around 900/1000hp on the street (so within a half decent efficiency island for the turbo) .The difference between a 3 inch dump with an attached 3.5 street exhaust and 4inch 'open dump' exhaust is usually 40/50hp peak at the motor with around 1psi give or take additional backpressure pre and post turbo . Tuned. Thats a real world number. That 1psi is bugger all ,so you will get away with the same gate size for either just making a psi of boost off the gate pressure more on the 4 inch over the 3 inch. Mitigated by boost control without the need to change gate sizes or even springs usually. Over 1100hp the differences creep up as you max out turbo compressor efficiencies and backpressures become actually problematic. But, here you should be talking actual turbo choice and/or turbine size and AR. Since if the 4 inch dump is barely saving the turbo your margin for error is going to be way too small anyway.
If you did a search I would think there likely a few youtube vids around with dyno comparisons as its a common tuning myth.

So to recap , the dump being 3 inch is a non issue for folks running a full exhaust on the street and upto 1000hp or so. Getting even a 3inch dump past rhd steering is an issue though.👍
100% agree. there are so many other bottlenecks on the n54 regards airflow worrying about the DP size is a complete waste of time.
and your dead right, making a 3" fit nicely is a big enough problem as it is - i dont think you will get a 3" to fit with this kit.
 
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rev210

Corporal
Feb 24, 2019
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335i - 08 Coupe .
What cars sound good to you then? Vq s?
Well if you think about that question, my public answer (as an N54 owner) will be; "No engine sounds better than an n54 with a tuned length top mount, single turbo , with a bonnet exit dump pipe and screamer pipe, ghost cams and full aggressive burble mode in MHD!"

But, between us N54 owners ,there is a very very long list of engines that sound actually good. Including large number of V8s, V10s etc and even other inline 6s both NA and forced induction.

Lets put it another way......although no question there are worse sounding engines, its not hard to make an N54 sound really bad. We have options for tonally offensive sounds we can tune in or out of our cars 😂
 
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RuskiRacer

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Jul 17, 2019
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Well if you think about that question, my public answer (as an N54 owner) will be; "No engine sounds better than an n54 with a tuned length top mount, single turbo , with a bonnet exit dump pipe and screamer pipe, ghost cams and full aggressive burble mode in MHD!"

But, between us N54 owners ,there is a very very long list of engines that sound actually good. Including large number of V8s, V10s etc and even other inline 6s both NA and forced induction.

Lets put it another way......although no question there are worse sounding engines, its not hard to make an N54 sound really bad. We have options for tonally offensive sounds we can tune in or out of our cars 😂
Oh yeah I've heard my fair share of awful sounding n54s and I just think ti myself how did you guys get to this point. Because what I've done with my exhaust i think it sound better than a majority of n54s I've heard. S85 is one of my favorite sounding motors though
 
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