S'vette

I have received my ARH midlengths and the quality looks really good. I have an appt on the 8th for the install and tune. I will be doing a dyno before the install, after the install, and then after the tune. All in the same day hopefully (all done by a shop). I know they do not require a tune but I want to satisfy my curiousity. I will also try and get a weight of the stock and the ARH pieces to along with all this. I will keep this post updated when I get this completed.

A question I do wonder about is, I live at an elevation of about 4000 ft on the average and I know that is a HP killer compared to closer to sea level. So lets say my stock car dynos at 400 hp/tq. Im assuming the same car would dyno about 410 hp/tq at much lower elevations? So if the midlengths gain as advertised (26 hp/tq roughly), will I gain less than that at my 4000 ft elevation compared to if I had this done at much lower elevation on the same car? Or would the gain be equal at both elevations (if dyno and all were equal)?

Thanks.

more to come...


ARH headers and high flow cats = 32 lbs
stock piping =
stock hp/tq = 389/390 (1st run) 382/383 (2nd run) corrected
ARH headers hp/tq = 413/427 corrected (was present for that run)
ARH headers with tune hp/tq = 432/445 corrected

7LitreC5

Unless you ask to see the "real" dyno numbers the numbers will be corrected to sea level.

I am looking forward to seeing the difference with the mids and the mids/tune. I am als interested in hearing what you think of the sound with the mids.

S'vette

^^^ OK I didnt know about the corrected numbers so I will make sure I get both if possible. The sound is one of the reasons I am doing this too. I had a C6 with cam, full exhuast and it was super loud, it sounded good but just too loud in the cabin. So this time I want both worlds so a little louder but semi quiet when cruising.

7LitreC5

I have a set of mids that I haven't installed yet because I don't want to make my car too loud. Does your car have NPP?

S'vette

Yes mine is NPP also and I dont thinkit will get alot louder with just the mids.

Stingray Al

I will be a lot louder!! In a good way

7LitreC5

Is it a lot louder all of the time or only at WOT? With or without cats?

Jakeman11

I have the mids for over a year, almost 11,000 miles. Installed at ARH on Long Island. Added Corsa X pipe at Carlisle last year and have the NPP exhaust. Great sound, no tune, and car is more aggressive and really pulls in 2d and 3rd gears. AHR was really good and Nick, followed up on my satisfaction of the middies. Curious to see if there is a big difference with a tune as Nick didn't seem to think it mattered too much with the mids.

davidtcpa

Steve, I did the same thing with my C6 and it was super-loud. However, if you do just full length headers with cats and x pipe in the stock mufflers, you will be fine. The cam made it much louder.

Elite275

If getting tuned, why the mid's over longtubes?

Since you have NPP the loudness won't be an issue. You can quiet them down whenever you want. Open it will only be a lot louder at WOT for the most part.

tblu92

In run my C7 with NO MUFFLERS--and just dual quad 4" Flowmaster tips
The car is NOT that loud or obnoxious ---Mostly because these cars have 4 cats that quiet them down a lot----I have MAP Performance ported stock exh manifolds---It is just barely louder than a C7 with NPP with the valves opened-----

tyho

I have a 2015 z51 M7, also with ARH catted mids, a Borla catless x-pipe, Hallteck carbon cai and B & B Bullet exhausts. I deleted the NPP valves and all and had a tune done that bypassed the AFM valves and the 1-4 skip shift. The car is loud but not overly so. After just the ARH install the car was louder then stock, especially when wot. I did not have the tune done until after everything was installed. The cai added a little more noise and the exhaust added some more. The secondary cats are removed when the x-pipe went in, really no noticeable difference at this point. I think you will like the little extra growl wit the ARH mids. Please let us know the results from your experiment, eg. weights, hp, etc.

S'vette

I was going to do the mids with no tune but then I got curious so I wanted to do the dynos stock, mids only, and then tune to see the differences. I have also heard the gains will be close to the LTHs for less money, so we will see.

S'vette

Well hopefully the tune will net the normal gains it does on just stock cars so another 15hp with the mids gains should be nice. Hoping the tune will account for the extra air flow to add a few more but who knows. Kinda why I decided to do the tune because I wasnt able to find any real numbers for the mids with and without a tune. Im at a high elevation so Im not sure if that will affect my gains on the dyno when corrected or not.

S'vette

Maybe after another deployment the cam can be done.

BTW what HP/TQ are you at now with the cams and all? What cam did you do?

7LitreC5

Are you still planning on doing this on Monday?

S'vette

Yep, I take her in the first thing in the AM. Should get her back the next day.

S'vette

Just a quick update on the upgrade. Had a stripped O2 sensor on the stock pipes so had to wait for a new one delaying things a day. I was present for the dyno run with just the headers and no tune, very strong and louder at WOT. Numbers are on the 1st post. car will be ready in the Am and will get the final numbers and weight.

Higgs Boson

just going to throw my 2 cents in here:

I had catless long tubes with catless X pipe and NPP on my 2014 C7 and it was very loud.

I have installed catless mid lengths with stock Xpipe and NPP on my 2016 Z06 and it sounds "just right." I would imagine it also sounds great with aftermarket cats....but either way, keeping the stock Xpipe in there really makes a difference and tones down the headers in a very good way.

If you are headers averse due to noise, I would recommend mid lengths with or without cats and the stock Xpipe (NPP helps a lot, it's loud when open).

S'vette

Not averse to headers, my main reason for doing this was to go with something initially that would not require a tune but thenI said what the hell, I will do all this so there would be more info on the numbers before,after, and after with tune so others can see. And this way I stills aved some money by going mids and not longs so if the numbers add up, which it looks like they are, it will be close to LTHs anyway. Im probably looking at 430 hp and 440 tq to the wheels with this option. From 382/383.