Xtremespeed

I've been wearing out Matt at FSP, Doug at ECS and Patrick G, trying to plan my first fi setup. After years of chasing 9 sec time slips in a n2o Camaro, a stock setup doesn't hold my interest long, so my plan is to install the base ECS kit with meth and headers. This however will not be a drag setup although it may eventually make a pass on occasion.

One of my main concerns is keeping the car enjoyable for the long road trips that my wife and I enjoy together. It seems that cats are not really an option with this setup and that will really affect the sound level. The car already has a Magnaflow axle back system on it. For comparison, my '00 Camaro that went a best of 10.12 @ 133 had ARH cats on it to keep the sound level down. Without fi and meth, this wasn't a problem but apparently will be with fi and meth.

Another issue seems to be the bov. I have read a few things and talked to Doug at ECS and I'm looking into installing 2 bov's to reduce the noise. I love the whistle of the superchargers, but I don't want the street sweeper sound I've read about on here.

Matt recommended at least a valve spring change for the power levels I'm looking at, and it almost seems a waste not to change the cam at the same time since the valve springs are the hardest part, but once again, it's something that will undoubtedly add to the noise levels.

I'm afraid I already know the answer (leave the car stock or live with the noise levels) but if you guys have any thoughts or ideas on a setup that will be a happy medium I'd love to hear about it.

BUILD STARTED IN POST 36

Eric ray

This might intrest you:

Unreal

My wife can drive my 1200rwhp ECS powered vette. Drives great. Just keep some good mufflers on it to keep it down.

No reason to mess with something like the i1 as long as she has throttle control.

Xtremespeed

Cool thought. Thanks for the info. I really am kinda set on the ECS setup though. Just interested in ways to keep it as quiet as possible through the exhaust and bov.

Xtremespeed

I know what you mean. Wife will actually drive the car very little. It's just a matter of being able to talk and listen to the radio on long trips without the exhaust and bov being too loud. Corvette's have so much road noise to contend with already.

MARSC6

The exhaust will be considerably louder after the FI and headers are installed. Not sure how loud your axle back is now but you may need to look for a quieter option.

The BOV won't be bad depending on your gear selection. Just don't cruise around town in 2nd gear and its not really that loud.

Xtremespeed

It's really not loud at all and my wife doesn't mind it, but I still have manifolds and cats right now.

MARSC6

Just the headers make a huge change.

Xtremespeed

Exactly what I'm worried about. Maybe I need to look at using a cutout to bypass the cats under boost conditions or extra bullet mufflers at the end of the x pipe or both. Surely I can find some way to tone it down for cruising.

Still want to see if anyone has any experience running 2 bov's to reduce the noise there as well.

Unreal

Run 2 BOVs, but has no effect in noise IMO. In fact made it louder but I have a Ysi pullied for max boost. Putting a filter on a BOV makes it quieter.

Blackonblacksls

Put some z06 or zr1 mufflers if you want to keep noise down and still breathe good.

realcanuk

Running a Vortech Mondo BOV which has a filter on it and I don't get that street sweeper noise, which I didn't want. I actually don't hear it at all in the car.

Xtremespeed

Cool. That's what I'm looking for.

Doug at ECS I think is the one that mentioned that running 2 all but eliminates the noise so I'm surprised to hear it made it louder for some.

Xtremespeed

That might be an option but honestly, most Z06 mufflers I have heard, after adding headers and removing cats, sounds pretty loud to me, even with the blades closed, just a higher pitch than the Magnaflow. That's why I was thinking about adding some bullets or something inline or using cats and a cutout to bypass them under boost. Just thinking out loud so to speak.

Unreal

On the base kit it should make it quieter. When you have a bigger blower maxing out one, and add a second, that is just more air escaping and louder. So unless you have a big blower pullied for max, shouldn't be louder. In my case 1 BOV couldn't vent enough so adding a second just added more noise and more air getting out.

Streetk14

I have cats on my setup, but my ZR1 mufflers are whisper quiet with my ARH headers. It's so quiet with the flaps closed, they're almost always open. The ZR1 or 2011+ Z06 mufflers are the best of both worlds if you ask me.

Xtremespeed

So are you running the ARH cats? Not wooried about melting them down?What's difference in the later model ZR1 or Z06 mufflers vs. the older ones? My last Vette was an '07 Z06 so I'm familiar with them.

Streetk14

Yes, I have the ARH cats. Others may have had different experiences than me, but I've had pretty good luck with cats. Tuning and how you use the car will have a large bearing on how they survive. It's a risk I'm willing to take.

And the newer Z06 or ZR1 cans are different than the original 2006-2010 Zo6 bi-modes. Quieter in quiet mode and quite aggressive and awesome sounding when open. You can easily identify them as they have perforations inside the tips kind of like the C6 NPP mufflers.

Xtremespeed

Lots of good info. Are you running meth on your setup? I believe it is a bigger contributor to cat problems than just fi.

Streetk14

Yes, I've ran meth on my last 3 LS builds. I don't think meth itself is an issue with cats. I think it's the fact that most running meth are running more boost and making more power.

Some guys have a theory that running rich is harmful to cats. I have to disagree based on experience and what I see in GM factory tune files. Look at a ZR1 file, and you'll see they're in the .71 lambda range (~10.5:1) from 5500 rpm on up. Near peak torque, they still command around .74 (~10.86:1). These are ~550 rwhp cars that need to warranty the cats for 100k miles.

Again, this is just my opinion, but I think it's more about tuning, power level, and how it's driven. I try to keep my boost levels reasonable so I can run a decent amount of ignition timing. That might be tough to do on something like an un-restricted ECS system making ~15 psi.

Some guys just say dump the cats with FI. I like the lack of smell and the more mellow exhaust tone with them. Just this Friday, I finished working on a fully catless BMW 135i. The thing stunk up the entire shop. I could smell it while driving with the windows down. We also had a newer 997 Turbo S in the shop with no cats. Same thing --- smelled like someone was running a 60's small block car in the shop. Everyone was yelling at the tech to turn it off or hook up the ventilation system.

In case you're curious, here's what my car sounds like with the catted ARH headers and ZR1 axle-back: