Anyone using 2.5"+ /3" N/A exhaust system???


Is it possible to fit more than 2 silencers on an EK4 is there any way of making a 2.5, or 3 inch system quiet :)
 
Hey guys,

I've been quoted around £400 for a custom made full system, this includes modifying the existing manifold as my current system needs repairing/replacing.

I'm going to see the guy on Friday to discuss what I want. I've been advised as it's B20 I'm best off going for a 3" system but I'm also aware the car will need re-tuning again. At the moment I cannot afford £300 - £400 for a remap/tune.

If the car is not tuned after the system has been replaced will I be down on power massively, also will this affect the way the car runs do you think?

What if I was to replace it with a 2 or 2.5" aftermarket system, again would the car need re-tuning and would the driveability be affected?

Any advice would be great.

Thanks!
 
If its any help my 235hp B20 has a RM01A which is 2.7 inches i think, so cant be that restrictive?
 
Edgar friendly said:
Hey guys,

I've been quoted around £400 for a custom made full system, this includes modifying the existing manifold as my current system needs repairing/replacing.

I'm going to see the guy on Friday to discuss what I want. I've been advised as it's B20 I'm best off going for a 3" system but I'm also aware the car will need re-tuning again. At the moment I cannot afford £300 - £400 for a remap/tune.

If the car is not tuned after the system has been replaced will I be down on power massively, also will this affect the way the car runs do you think?

What if I was to replace it with a 2 or 2.5" aftermarket system, again would the car need re-tuning and would the driveability be affected?

Any advice would be great.

Thanks!
Click to expand...

The car will be running lean. Potential engine failure!

My Hi comp B18 went from a genuine spoon system 2.5" to a custom spoon style true 2.5 all the way through with longer baffles (No real effect to map with the baffles)

I gingerly drove this to my tuner on super light throttle. He scoped down the barrels to look at the pistons and there was slight evidence on detonation. Upon inspecting the map we where very very lean! With my engine it would have gone pop very soon due to the hi compression and no knock sensor.
 
ijwhiteman said:
The car will be running lean. Potential engine failure!

My Hi comp B18 went from a genuine spoon system 2.5" to a custom spoon style true 2.5 all the way through with longer baffles (No real effect to map with the baffles)

I gingerly drove this to my tuner on super light throttle. He scoped down the barrels to look at the pistons and there was slight evidence on detonation. Upon inspecting the map we where very very lean! With my engine it would have gone pop very soon due to the hi compression and no knock sensor.
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Bloody hell! Really? :shocked:

Bit worried now about what to do as I can't afford a re-map of any kind. :(

What do you think then, just go 2.5" and see how it goes or would I potentially suffer from the same problems no matter what size exhaust I go for?

Mine's not a Hi compression engine apart from the B20Z block, everything else is pretty much standard you know, surely a replacement system is not going to cause the engine to go pop?

I'm not doubting what you're saying btw. The problem I've got is it was mapped on Crome and it's a long trip back to the tuner for work which I don't really want to do.
 
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Edgar friendly said:
Bloody hell! Really? :shocked:

Bit worried now about what to do as I can't afford a re-map of any kind. :(

What do you think then, just go 2.5" and see how it goes or would I potentially suffer from the same problems no matter what size exhaust I go for?

Mine's not a Hi compression engine apart from the B20Z block, everything else is pretty much standard you know, surely a replacement system is not going to cause the engine to go pop?

I'm not doubting what you're saying btw. The problem I've got is it was mapped on Crome and it's a long trip back to the tuner for work which I don't really want to do.
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I can only speak from my experiences and can neither say it will be ok or it won't.

Personally any mapped car has set parameters based on what has been tuned. OEM ecu's can cope with breathing mods but I don't know about mappable ECU's... Can they "learn" in the same way? If it was me get your exhaust, park her up and get it mapped at a later date when funds allow.
 
ijwhiteman said:
I can only speak from my experiences and can neither say it will be ok or it won't.

Personally any mapped car has set parameters based on what has been tuned. OEM ecu's can cope with breathing mods but I don't know about mappable ECU's... Can they "learn" in the same way? If it was me get your exhaust, park her up and get it mapped at a later date when funds allow.
Click to expand...

I understand, I may have to get it back to Daz then for him to re-map if that is the case.

As for parking the car up I can't. It's my daily driver so I'm screwed as I need it.

Thanks for the info too.
 
Edgar friendly said:
I understand, I may have to get it back to Daz then for him to re-map if that is the case.

As for parking the car up I can't. It's my daily driver so I'm screwed as I need it.

Thanks for the info too.
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Give Daz a call and ask his opinion he might say if you stay the size it's been tuned it will be fine or may just need slight tweaking.
 
He did say a few weeks back that a 3" will dramatically alter the way the car runs so will need a re-map but I wasn't expecting anything like engine failure, best that I get it checked tbh.
 
Edgar friendly said:
He did say a few weeks back that a 3" will dramatically alter the way the car runs so will need a re-map but I wasn't expecting anything like engine failure, best that I get it checked tbh.
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Sorry to worry you put the risk is there.
 
Lee s said:
If its any help my 235hp B20 has a RM01A which is 2.7 inches i think, so cant be that restrictive?
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In fact I think Rm01a's are only 60mm systems so more like 2.38". I think people miss the point. It not that a 2.25 or 2.5 will be restrictive as such just that a larger 2.7 or 3" will be more capable and suited to a tuned vtec. Are you not curious to what your engine is capable of with a 2.7 or 3" system.

As to the question. I doubt an exhaust change will effect the likes of a lower comp b20 as it would a high comp b18. Margin for mixture difference is much more forgiving on a lower comp engine. But getting it tuned as soon as you can is advised.
 
KieranEG6 said:
In fact I think Rm01a's are only 60mm systems so more like 2.38". I think people miss the point. It not that a 2.25 or 2.5 will be restrictive as such just that a larger 2.7 or 3" will be more capable and suited to a tuned vtec. Are you not curious to what your engine is capable of with a 2.7 or 3" system.

As to the question. I doubt an exhaust change will effect the likes of a lower comp b20 as it would a high comp b18. Margin for mixture difference is much more forgiving on a lower comp engine. But getting it tuned as soon as you can is advised.
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Ah I see. pretty happy with the performance really.
 
Just wanted to say thanks for the responses I've had it's much appreciated.

Spoke with Daz before and he says it will definitely need a retune again if I go 3" and has advised that I don't exceed VTEC or maximum throttle until he's remapped it.

Really glad I checked now and was informed by you guys otherwise I wouldn't have had a clue.

Cheers.
 
Lee s said:
Ah I see. pretty happy with the performance really.
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As Kieran said a 3" system on a setup like yours would be pretty savage I reckon, not that it needs the extra power of course.

I'll let you know how mine feels if I go for one mate.
 
jugbugz said:
it doesnt always scale that way. 218whp can be around 230-240 true bhp. All dynos aint scaled the same.
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yeah its 218whp off of dynospot racing's dynojet in San Jose CA. They also built the entire motor up...

3" exhaust is nice, but loud. A few tracks I exceed max levels allowed with 3" setup.
I have a 2.25 tune, 2.5" tune and the 3" tune for the AEM ECM/ECU.
I load as needed to meet the size exhaust being used.
 
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tama666 said:
yeah its 218whp off of dynospot racing's dynojet in San Jose CA. They also built the entire motor up...

3" exhaust is nice, but loud. A few tracks I exceed max levels allowed with 3" setup.
I have a 2.25 tune, 2.5" tune and the 3" tune for the AEM ECM/ECU.
I load as needed to meet the size exhaust being used.
Click to expand...

Yep my RM01A decatted hits 98db@ 45 degrees which is the limit for most uk tracks.
 
I drove the car down to the guy who's going to be making my exhaust for me, had a good chat with him about my plans and explained that I want to go for a 3" system.

He reckons 3" is too much for the power the car is running at present and feels 2.5" is more than sufficient. Says I should have better torque with the 2.5" and that I wouldn't be getting anything off a 3" system.

He's running a MK2 Escort with a Cosworth YB turbo engine some 350 horse and he says he has a 3" system on that as it's required for such big power but he say's it won't be needed on mine, anything below 250bhp and you don't really need a 3" according to him. I asked him about a 2.7" system but he doesn't have the facilities to do one, only 2.5 or 3".

He's also going to cut the 4-1 manifold and change it to a 4-2-1 instead which will give me better ground clearance and better pull throughout the range. It's going to be similar in style to a Spoon N1 with a rolled lip and it's going in next week to get done I'm hoping once I've sorted all the niggly bits out.

Really looking forward to getting it fitted, hopefully should get a decent sound off it too!
 
2.5 is good! go for it!!!!
3" would be fine too and more room to grow into...just food for thought. You will want more power at some point, you know it! :))
 
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