Noweeds & Headers on a ZL1

[serviceguy]

On the fence with a NoWeeds purchase,,I want to keep my Original Cats. I'm looking for opinions on the sound with OE cats and NoWeeds ?

[gen=5]

Originally Posted by Deke736

Does anyone have this setup? I currently have the Noweeds diverters on my ZL1 and am getting ready to add headers (most likely Stainless Works) with high flow cats, and I wanted to find out if there would be any fitment issues. From the pictures I have seen, and from looking at my current setup, it looks like it should all bolt up just fine. I'm interested to find out if anyone has experience with this setup and how the install went.

I'd also love to get your thoughts on the sound with the diverters open and closed.

Thanks!

I have it on my ZL1 I can send you a video if you P.M. me your email as it wont post to the forum from my iphone ?
One thing i always notice is with a blown heaveir car is the torque always seems to go away with LT's (not 4-2-1 just 4-1headers)and the car feels slower on the low end at low speeds until it gets passed a certain rpm band..its because the headers allowed the power band to move up in rpm a little bit..It was really noticeably on my SRT-10 as i had a blower installed and then headers last..it felt like i lost 50 rwhp until it picked up speed and i got used to it....I went and dyno it again because at first i thought something was wrong...It's why 4-2-1 make more low end torque...while the same HP..

[gen=5]

Originally Posted by dlct3

I ran with full open and 75% open (which sounded almost the same). I didn't have time to try other settings. I wasn't able to get it out today, but reprogrammed for about 40-50% open. Will try that What's your favorite setting if not 100%?

It's because you have catts i would think...one thing i do not understand is that if you still have factory catts what is the real point,as the biggest gain is and always will be removal of the catts and going to a off road pipe.
On my dodge ram I had back in 1998, I install a exhaust and gain the normal 10-15 rwhp..but when i installed after market catts it was only another 10hp total...
So on later on i just went to a off road pipe and gain a huge 35rwhp over stock catts..and 30 whrp over aftermarket catts...
If your doing it for sound alone fine its a personal thing,but for power just the off road pipes alone will give you plenty of gain since on the ZL1 the muffler is bypass wide open throttle anyway..
Does anyone have a dyno gain with the dump's over ,off road pipes and open exhaust only..It cant be more than a 5rwhp if that i would think...

[gen=5]

Originally Posted by dlct3

I would also like to hear if anyone has dyno'd with them open vs closed on a ZL1 with pulleys, mods, etc? It may be me, but when they are open I actually feel like a little power loss and throttle response is lost. Closed feels more crisp. I do have some mild mods. 608rwhp 614rwtq.
Kooks headers
Kook Hi-Flo Cats
Tune
Air Raid CAI
9.55 Lower
2.85 Uppe
Ported Snout
FIC 95lb injectors
KDI Heat Exchanger
Innovators West Dampner
VMAX CNC LSA TB


Do the mods make a difference (in the pedal feel/response with NOWEEDS) or has anyone with a similar setup dyno'd to prove results? Would really appreciate the help. Closest dyno is 2 hours away for me to try myself.
Thanks for help

AS i posted before your losing low end torque with them,same as with a heavy car and 4 into 1 Lt headers...some people dont believe it,but some back pressure is good..the reason race cars are open is one weight 2..they make so much power that any exhaust would hurt although some racer's do run the exhaust out passed the door's to the axle to gain some back pressure..3.Also if your racing the point where the loss of low end torque doesn't matter either because of the cam's rpm range,and the stall is much higher in the rpm band than the motor will be operating ever,so the car is moving long before it's ever felt......a street car needs the low end torque for normal driving....

[dlct3]

Originally Posted by gen=5

AS i posted before your losing low end torque with them,same as with a heavy car and 4 into 1 Lt headers...some people dont believe it,but some back pressure is good..the reason race cars are open is one weight 2..they make so much power that any exhaust would hurt although some racer's do run the exhaust out passed the door's to the axle to gain some back pressure..3.Also if your racing the point where the loss of low end torque doesn't matter either because of the cam's rpm range,and the stall is much higher in the rpm band than the motor will be operating ever,so the car is moving long before it's ever felt......a street car needs the low end torque for normal driving....

Thanks for all the feedback. Sorry, to be clear I do have Kooks Hi Flo cats... not off-road, but at least better than stock. Also, its a M6 if that helps better explain. Didn't install the NOWEEDS for any power gains... just sound, but didn't expect any loss of power either. I guess in the high end the peak HP may be up 5-8 from what I've found, but the "seat of the pants" feel of the torque loss is much greater. :(

Also, I took the car out tonight. Tried several different opening %'s. Seems like I agree with Normagene on the amount open for sound quality without drone. The 15-20% (basically as fast as I could get the diverter flaps to stop moving after I started them) area sounds a lot better than 50-100% and it also felt like the power & throttle. response was still there.

[v8]

Thats a nice sounding Cam

[v8]

Originally Posted by Nickey31

2" kooks headers with no weeds



<iframe width="560" height="315" src="//www.youtube.com/embed/YUzTZ_Gi4QQ?rel=0" frameborder="0" allowfullscreen></iframe>

Opps forgot to include this

[Nickey31]

Originally Posted by v8

Thats a nice sounding Cam

Thanks. I am very happy with the car and the exhaust note. I thought I would reply to some of the other comments.

% opened:
In town, I rarely use the No Weeds diverters. However, if I do, I just barely crack them open. That seems to be enough to hear the lope. At car shows, I tend to open them all the way up upon entrance. When open and at idle, the car will start to dance.

More or Less Power when open
There are far too many variables but at the track, my best 60' times have been with the diverters wide open. The car was tuned with them closed, so I thought the decrease in back pressure would decrease boost. I am not consistent at the track, so I can't tell you if them being open or closed really helps or not. I think I can say, it doesn't seem to hurt.

[cybercoaster]

Anyone going to the fest? I would like to hear noweeds with headers. I already have noweeds and plan on pfadt.

[Deke736]

Originally Posted by cybercoaster

Anyone going to the fest? I would like to hear noweeds with headers. I already have noweeds and plan on pfadt.

I'll be at the Fest. I just got my Stainless Power headers in yesterday and they'll be going on ASAP.

[EvilZL1]

If only headers and no cats, off road pipes didnt void the powertrain warranty..I would be all over it man.

[Nickey31]

Originally Posted by SSSylentZL1

If only headers and no cats, off road pipes didnt void the powertrain warranty..I would be all over it man.

Most tuners pick up the warranty that you may lose from GM. But this is my 2nd modded car and I have yet had any issues. IMO if you are going to mod your car, have it done by one of the known tuners that offers a written warranty. If it wasn't for this warranty, I likely would never have modded my car.

[EvilZL1]

Originally Posted by Nickey31

Most tuners pick up the warranty that you may lose from GM. But this is my 2nd modded car and I have yet had any issues. IMO if you are going to mod your car, have it done by one of the known tuners that offers a written warranty. If it wasn't for this warranty, I likely would never have modded my car.

I will do a little researching before choosing a tuner. Hopefully I can find a great deal so that I can make a move.


Sent from my iPad using Tapatalk

[Deke736]

Originally Posted by Nickey31

Most tuners pick up the warranty that you may lose from GM. But this is my 2nd modded car and I have yet had any issues. IMO if you are going to mod your car, have it done by one of the known tuners that offers a written warranty. If it wasn't for this warranty, I likely would never have modded my car.

This isn't entirely true. The only tuners I have seen that give a warranty are the shops like SLP, Lingenfelter, Nickey, etc. that sell their "package cars" through traditional dealer networks as new cars (like yours), and that warranty is either built into your price, or you pay for it like any other option. A typical performance tuning shop is not going to give you a warranty on your powertrain after they tune your car for headers. They may stand behind their tune, but don't expect it to be like a warranty from GM.

My car is tuned by Jannetty Racing. If my supercharger fails (for any reason) and GM pulls my ECM and sees my tune, I am pretty sure Ted isn't going to warranty that, nor are most other tuner shops.