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      01-09-2017, 06:02 PM   #1
kiysersosae
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Catted hjs Sports downpipes, are they really worth the cost?

Was looking at the performance difference between all the sports cats with 300 cel HJS internals and Fabspeed aside, performance increase is only reported as 9 - 12bhp by Akraprovic and Miltek. There is obviously an improvement on sound and people report throttle response improvement.

What I'm asking is at 1200 is it worth it?

And, if I went with no cat (downpipes for 300) would a tune be needed? Not fussed about the check light as I can reset this. I did run no tune and no cats on the 1M and never had an issue. When I had it on the dyno the afr was absolutely fine.
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      01-09-2017, 08:59 PM   #2
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Tune is not needed for either one but you get max performance when you add a tune with the downpipe.

If you have a JB4, it will hide the code so you can go catless or regular catted (not HJS).

If you have a tune that does not hide the code (JB stage 1, Active 8, Dinan,etc...) HJS are worth it because you will not get a code.
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      01-09-2017, 10:07 PM   #3
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Quote:
Originally Posted by kiysersosae View Post
Was looking at the performance difference between all the sports cats with 300 cel HJS internals and Fabspeed aside, performance increase is only reported as 9 - 12bhp by Akraprovic and Miltek. There is obviously an improvement on sound and people report throttle response improvement.

What I'm asking is at 1200 is it worth it?

And, if I went with no cat (downpipes for 300) would a tune be needed? Not fussed about the check light as I can reset this. I did run no tune and no cats on the 1M and never had an issue. When I had it on the dyno the afr was absolutely fine.
Fabspeed has posted dynos on 1) a stock exhaust with a stock DP and 2) a stock exhaust with a 200 cell catted HJS DP. The delta is 30+hp and ft-lbs, as I recall. For $1100, that is darn cheap per hp.
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      01-10-2017, 02:49 AM   #4
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Quote:
Originally Posted by BruceM View Post
Fabspeed has posted dynos on 1) a stock exhaust with a stock DP and 2) a stock exhaust with a 200 cell catted HJS DP. The delta is 30+hp and ft-lbs, as I recall. For $1100, that is darn cheap per hp.
Appreciate that, but the situation why I left them out. There results show 30hp difference which equates to a 21hp difference over akrapovic who are running the same inner as fabspeed but only 100cel less, can this be a true delta?
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      01-10-2017, 03:09 AM   #5
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Quote:
Originally Posted by kiysersosae View Post
Appreciate that, but the situation why I left them out. There results show 30hp difference which equates to a 21hp difference over akrapovic who are running the same inner as fabspeed but only 100cel less, can this be a true delta?
I dunno. We should ask Fabspeed. I doubt they would fudge their charts, because if they did there would be lots of refunds to pay, at the very least.
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      01-10-2017, 09:54 AM   #6
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It's all about balance of the gain and sacrifice.

A catless system that give you 100% flow and CEL and a smelly car.

You have the option with HJS 200 cell to flow 10% less so you're CEL free and have much less smell to live with.

One step further, a HJS 300 cell (EU6) comes with smog test guarantee and smells the same as stock, with 10% less flow over 200 cell.

Now you think about how 10% flow affect performance. That will have everything to do with your mods. But there's definitely diminishing return in play, meaning going from stock to 300 cell probably get you 80~90% of the gains (dependent of the peak flow demand from you mods) of a cat bypass system. If you can handle CEL, don't care emission and are fine with smell, pursue the remaining gains with catless dp.

Personally never been able to live with smell. To me 200/300 cell sit nicely in between restrictive stock and cat bypass.
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      01-11-2017, 05:27 AM   #7
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Quote:
Originally Posted by SeanWRT View Post
You have the option with HJS 200 cell to flow 10% less so you're CEL free and have much less smell to live with.

Personally never been able to live with smell. To me 200/300 cell sit nicely in between restrictive stock and cat bypass.
Sean,

BCS here in the UK flow tested their oversized n55 200cpi hi flo cat DP against their n55 decat DP. Delta was <5%.

I've been running BCS HFC DP in my EWG M135i for 2.5years c/w JB4 - all good.

BP
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      01-11-2017, 05:31 AM   #8
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Quote:
Originally Posted by SeanWRT View Post
You have the option with HJS 200 cell to flow 10% less so you're CEL free and have much less smell to live with.

Personally never been able to live with smell. To me 200/300 cell sit nicely in between restrictive stock and cat bypass.
Sean,

BCS here in the UK flow tested their oversized n55 200cpi hi flo cat DP against their n55 decat DP. Delta was <5%.

I've been running BCS HFC DP in my EWG M135i for 2.5years c/w JB4 - all good.

BP
Thanks for sharing.

I guess it has everything to do with cat design. HJS cat is very effective maybe different.

It prove my points anyway - diminishing return in going from high flow to catless.
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      01-11-2017, 09:24 AM   #9
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Any one have comparisons to the ER catted downpipe?
http://evolutionracewerks.com/node/269
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      01-11-2017, 03:31 PM   #10
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So the factory cat is 400cel....so, is a 100 cel reduction worth it, I'm not sure now. I think going with the richter 200cel for UK guys would be the best option, especially if you have the function to clear cel codes
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      01-11-2017, 03:42 PM   #11
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Quote:
Originally Posted by kiysersosae View Post
So the factory cat is 400cel....so, is a 100 cel reduction worth it, I'm not sure now. I think going with the richter 200cel for UK guys would be the best option, especially if you have the function to clear cel codes
The 200 shouldn't throw a code, so I don't see any reason to go with a 300
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      01-11-2017, 04:52 PM   #12
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Originally Posted by LBBDrew View Post
The 200 shouldn't throw a code, so I don't see any reason to go with a 300
I've heard its hit and miss with the code but I can clear it so it's not that big an issue. I just think the price 1000 for 300cel hjs vs 450 for non hjs 200cel, I think the 200 is worth it.
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      01-11-2017, 04:54 PM   #13
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Quote:
Originally Posted by kiysersosae View Post
I've heard its hit and miss with the code but I can clear it so it's not that big an issue. I just think the price 1000 for 300cel hjs vs 450 for non hjs 200cel, I think the 200 is worth it.
Ah I was referring to the 200cel HJS (Fabspeed, ER), but those are still ~$1,000
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      01-11-2017, 05:10 PM   #14
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Originally Posted by LBBDrew View Post
Ah I was referring to the 200cel HJS (Fabspeed, ER), but those are still ~$1,000
You think a non hjs is worth it then?
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      01-11-2017, 06:45 PM   #15
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Our Sport Cat Downpipe is 100% the best route to go. It is a simple bolt-on and go have fun modification and being CEL free. I definitely do not recommend running a catless downpipe without a tune. There are a whole host of issues that could arise from that. Just because you didn't have issues in the past, doesn't mean the car was running healthy.

Check your PMs - I'd love to chat more about getting you set up!

Also our dyno results are from a direct comparison of the stock M2 then Sport Cat Downpipe installed. Both tested in the same day and under the same conditions and with awesome results!
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      01-11-2017, 06:56 PM   #16
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Quote:
Originally Posted by Fabspeed Motorsport View Post
Our Sport Cat Downpipe is 100% the best route to go. It is a simple bolt-on and go have fun modification and being CEL free. I definitely do not recommend running a catless downpipe without a tune. There are a whole host of issues that could arise from that. Just because you didn't have issues in the past, doesn't mean the car was running healthy.

Check your PMs - I'd love to chat more about getting you set up!

Also our dyno results are from a direct comparison of the stock M2 then Sport Cat Downpipe installed. Both tested in the same day and under the same conditions and with awesome results!
What other issues are you talking about? I've never heard of people with catless downpipes having issues, and I haven't had any yet..
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      01-11-2017, 07:03 PM   #17
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Quote:
Originally Posted by photos_by_ronnie View Post
What other issues are you talking about? I've never heard of people with catless downpipes having issues, and I haven't had any yet..
Issues with running a catless downpipe with no tune results in CELs and possible overboosting. Removing the cats without adjustment of the ECU is definitely something I would not recommend.
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      01-11-2017, 09:15 PM   #18
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Quote:
Originally Posted by kiysersosae View Post
So the factory cat is 400cel....so, is a 100 cel reduction worth it, I'm not sure now. I think going with the richter 200cel for UK guys would be the best option, especially if you have the function to clear cel codes
kiysersosae,

Stock cat is 600 cell, below is a HJS 300 vs stock 600 comparison picture. What's more, metallic cats provide even more flow at any given cell count than ceramic counterparts that 99% of stock uses, because cat wall can be made much thinner, allowing for greater effective diameter.

Check out more from my review on HJS DP here.
http://f87.bimmerpost.com/forums/sho....php?t=1339166

Sean
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      01-13-2017, 03:57 PM   #19
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OK, after some good chats with Fabspeed I've decided to purchase their downpipe (200 cel). I think the deciding factor was the amount of people on here that comment on there service and the fact it's a 200 cel with hjs,i shouldn't forget how easy they have been to deal with.
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      01-13-2017, 03:59 PM   #20
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Quote:
Originally Posted by kiysersosae View Post
OK, after some good chats with Fabspeed I've decided to purchase their downpipe (200 cel). I think the deciding factor was the amount of people on here that comment on there service and the fact it's a 200 cel with hjs,i shouldn't forget how easy they have been to deal with.
Congrats!!

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      01-13-2017, 03:59 PM   #21
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Quote:
Originally Posted by kiysersosae View Post
OK, after some good chats with Fabspeed I've decided to purchase their downpipe (200 cel). I think the deciding factor was the amount of people on here that comment on there service and the fact it's a 200 cel with hjs,i shouldn't forget how easy they have been to deal with.
Thank you! It's been a pleasure working with you.
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      01-14-2017, 05:13 AM   #22
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Congrats!!

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Will do
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