200 cel -> testpipes + FVD Sound version.
 

I have been thinking.. :D Yes, it´s true..

I read and have heard that those running test pipes actually get less drone than the ones running eg 200 cel sport cats. Can this be correct? Or is it just the increased overall volume that makes the drone less obvoius?

If so, would you think that I could use my old 200 cel cat-pipes, just drill (and use general violence) out the cat-substrate and use this as test pipes? Or will the actual "bulb" where the cat used to be create drone or some other bad effects?

I run: ebay headers (no cats) and FVD sound version at the back.

Circuitwerks, the company that sells a lot of the ebay test pipes, sells a "resonated" version of them which is what you're describing. I have no idea what they sound like but you may try to reach out to circuitwerks and ask, or find someone who has installed those.

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If your 200 cell sport cats are still good, wouldn't it make more sense to save the labor of drilling them out, sell them, buy some catless midpipes to install, and pocket the difference as future beer money?

I get your point.. I cannot pass MOT with those cats, I doubt they are genuine 200cel, they basically suck.. :-)

I have Manzo catless headers and Manzo catless test pipes with a circuitwerks v2 muffler. I get little to no drone. I don't have any experience with the stock exhaust as I almost immediately removed it.

They are cheap and on eBay ;)

That said mine pass a UK MOT and have done for several years. 1 year it was very tight for some unknown reason but the next year with no changes there were no issues.

That´s the thing with cheap, if they work it´s great, if not, no big deal.

Plan now is to just cut the cats out and weld in a bit of pipe to run them as "testpipes".

We call then decat pipes and you can buy them on ebay too. There are one which are straight through pipe and others which look like they have a cat but it has no core.

Thanks for replys guys, soon I will know the answer.. Cut the cats away and made me a qouple of straight pipes. So I will go: Catless headers -> pipes -> FVD Sound version.

After a looong wait I´ll finally have my day at the dyno in the middle of mars this year. Doing the classic 987-airbox/MAF, IPD + 74mm TB + full day mapping on the dyno. Wish me luck! Was aiming for the 996 intake but didn´t manage.

I have a pair of Fabspeed 987 sport-cats that i was going to remove the cat "bricks" and use on my 986 that I will sell.

Hi all. Has anyone tried using one of those mini-cats. It supposedly prevents a code from popping up by fooling ECU into thinking there is a cat. Here in NJ they only do the emissions by connecting to the car's port and reading the codes. I would love to know.
Thank you.

Robert did you get your dyno accomplished? Apologize if I missed the post, would be interested in seeing the results.

Hey Robert, just as a heads up, I've been running catless for a little while now and am going back to install cats (tonight hopefully). If you've got a dedicated track car that's one thing, but I underestimated how dirty a car engine really is.

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The best Dyno plots to see are a comparison to before mods Vs with mod. I did post such a plot with a baseline standard run, then each of the set of mods I did and all run on the same Dyno. Sadly the picture hosting site link is broken so the plot won't show.

How you doing? I looked at those but been a good time back.

No actually not, the car is still at the shop. We had troubles attaching the tow hook so my reserved dyno time went up in smoke. Ever since the car is at the shop waiting for someone to cancel their reserved time. It´s extremely frustrating.. The plan is to first add the anniversary tune to manage the larger MAF, then tune it from there..

Will report back as soon as I get the car back!

:dance: <--- Me, waiting...

Hey, I see, how did you come to that insight? Measurements or did you actually notice anything physical?

At first I ran true straight pipe, terminating in turndowns near the rear bumper (but still under the car). The noise was so loud is was unbearable. Ear plugs were mandatory. Interestingly , even straight piped, there's still a drone! Even with ear muffs (and I wear good gun muffs) I still didn't care for the sound of the engine below 3k rpm because of that drone. In addition to this, the smell was horrendous. I haven't hooked up my afr meter yet but there's no black smoke so I'm assuming I'm not running too rich (it's a 2.7l on 996 tune with 82mm throttle body). But the fumes were just overwhelming at anything under 100mph. This would probably be better if I had terminated the turndowns behind the rear bumper but even with that I would not run it as a daily driver. I've added aftermarket short cats and internal baffles to the pipes, which has helped significantly. The car sounds great and the smell way better, but cruising is still a bit loud. So I'm gonna remove the internal baffles, leave the cats, and add shorty mufflers with the turndowns terminating behind the bumper this weekend.

No numbers yet, but I'm hoping to get it in the dyno in a month or so after the fuel trims have had plenty of time to level out.

Btw, if you're having a pro tuner work on it and you beate to the dyno, ask him to play around with the variocam a bit and see what happens. I wrote up a post about it recently seeing if anyone has tried this yet, but no one has responded. I'm willing to bet that there may be some extra torque to be had by adjusting the disengagement point.

Is this set-up for a street car or a race car, Plus do you have to do emissions in KY, Thanks...Frank

Mine? Street setup. No emissions in KY. Half the pickups in the state would be off the road if they started doing that lol.

I will say one thing about my setup that I am just now realizing (and this may be taught in exhaust 101 but all my wrenching knowledge is self discovered) - By removing the factory muffler and terminating the straight pipe before the bumper, I was effectively trapping the exhaust under the vehicle. The exhaust is filthy regardless, but this is likely why it was so profound for me.

I learned this the hard way the other night - refilling the ac I had the car idling in a stationary position OUTSIDE for about 15 minutes. When I was done with that I shut off the engine to allow the exhaust to cool for about 10 minutes and then crawled underneath to start fitting new shorty mufflers. Anyway, there was so much carbon monoxide trapped in that bonnet that in less than 5 minutes I managed to give myself carbon monoxide positioning. Not fun.

What doesn't kill you makes to stronger, right? ;)

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