: Headers + No Tune?



SkullV
03-08-08, 03:33 PM
Hey guys, I am installing my headers on Tuesday, but can't get the car tuned until Saturday. Am I going to hurt something if I drive around with the headers/high flow cats for the week with no tune? Thanks!

jbss71
03-08-08, 03:58 PM
you could trip at downstream cat code because of the high flow cats. the a/f will be out of wack but nothing the PCM can't handle till a tune

trukk
03-08-08, 04:58 PM
I was told by my tuner that I would be OK with just normal drivng around, as long as I wasn't dogging it. You definately want to get it tuned before going to the track though. at > 5k rpms, you'll be pretty lean.

I'd talk to Bob @ epp since you are thinking of going there, and jsut get his advice on the matter. Certainly couldn't hurt.

My $0.02.

-Chris

The Tony Show
03-08-08, 05:07 PM
I drove around for a month with headers and the stock tune- it'll be fine.

Rey
03-08-08, 05:35 PM
In almost all throttle positions except wide open throttle your ECU will adjust the air fuel ratio to 14.7:1 automatically, and headers air flow increase is well within the ability to so adjust. As for wide open throttle, GM programs the ECU to deliver an overrich mixture of around 11:1. The fuel flow at wide open throttle remains constant with no adjustments by the ECU. What this means for you is that your headers have leaned out the fuel ratio so that it is much closer to optimum of 12.8-13.0:1. If you want to know exactly, buy a fuel ratio meter. They are pretty reasonable in price, like about $350 or so.

The Tony Show
03-08-08, 05:37 PM
Headers don't have that big an effect on A/F ratios, but if anything they make an engine run rich, not lean. I threw a code for Bank 1 & 2 rich during my time without the tune.

CadiKing2006
03-08-08, 09:30 PM
I have headers and high flow cats with magnaflow catback exhaust. No tune yet still searching, no problems either, been 3 weeks

TrazzNJ
03-08-08, 09:51 PM
How do headers make the car run rich and not lean?? Please explain.

jbss71
03-09-08, 09:13 AM
How do headers make the car run rich and not lean?? Please explain.the PCM over adjusts. on ls2s you can get a/f in the 9's with headers. ls6 not near as bad

TrazzNJ
03-09-08, 02:44 PM
How does the PCM over adjust?? If the O2 sensor reads a lean condition, it adjusts to where it wants to be. Even if it could "over adjust" it would at some point read rich and go the other way. If it was "confused" the placement of the O2 sensor or the high flo cats or anything else, It would fight the conditions both ways.
I need to call StealthV and get answers.

SkullV
03-09-08, 03:12 PM
Good luck getting a hold of StealthV!

Natedog
03-10-08, 02:20 AM
I have headers and high flow cats with magnaflow catback exhaust. No tune yet still searching, no problems either, been 3 weeks
Got a sound clip? that's the setup i'm going for and wondering if it drones at all at highway speed... what headers and cats did u go with? thanks

The Tony Show
03-10-08, 09:56 AM
How do headers make the car run rich and not lean?? Please explain.

The O2 sensors see more air coming through the headers and high flow cats and think the car is running lean, so the PCM dumps more fuel than is really necessary into the engine. Rich.

CadiKing2006
03-20-08, 12:05 AM
Hey I went TPIS headers. Video is on youtube. Search "Shamca"

SkullV
03-20-08, 12:11 AM
The answer is GET A TUNE!! My first untuned run on the dyno with the headers and cats I came out at 293whp. The second run was 343 then with some fine tuning I got up to 354. So for all you guys running headers without tunes. Do your V a favor and tune her up!

faylix
03-20-08, 11:01 AM
wow i was gonna wait for the intake manifold... but after reading that i might just get it tuned this weekend.

NormV
03-20-08, 05:53 PM
Daily driving should be fine with headers and stock tune. I would go much above 3K rpms. I am seeing VE showing more air flow in normal driving below 2K rpms by just under 5% on my modified base tune.

Norm

v10boost
03-20-08, 09:09 PM
headers and other simple bolt ons should be fine with out tune. Like someone here said nothing that pcm can not handle. I would be surprised to see much difference with tune or without tune for few bolt ons. My 98 viper with heads, headers, catback, intake put down 70rwhp over stock. when i put the car on dyno, afr was perfect. Anyway I went on and got it tuned and made few more power but IMHO it was not worth it. power and afr graph was just perfect with factory tune and bolt ons. I know it is not always this case but i would be shocked to see much power difference in power with basic mods.

mgscustomtune
03-21-08, 12:10 AM
It will be fine. Hey Cadi King get ahold of me l will set you up.

Keys8541
05-20-08, 01:15 AM
Im in the Northern Virginia area, where can i get a reasonable tune? have Mods with no tune....

TaVern
05-20-08, 07:35 AM
Im in the Northern Virginia area, where can i get a reasonable tune? have Mods with no tune....

I got mine at a shop in Gaithersburg, MD. Shoot me a PM for details if interested... I don't want to advertise them since they're not vendors.

MauiV
05-20-08, 08:04 AM
I remember reading or hearing something about the possibility of throwing codes and the car going into "Limp home" mode. My next purchase is gonna be the Kooks and Im trying to plan it so my tuner is close by to my installer.

qqik4u
05-20-08, 10:09 AM
Im in the Northern Virginia area, where can i get a reasonable tune? have Mods with no tune....

Hey - I am in No. VA also (Ashburn) - When I had my tune done I took it to Tony's corvette http://www.tonyscorvetteshop.com/contact_us.asp

The guys have done V's and he does have a fairly sophisticated programs.

Hope I see you on road sometimes:)

qqik4u
05-20-08, 10:11 AM
I got mine at a shop in Gaithersburg, MD. Shoot me a PM for details if interested... I don't want to advertise them since they're not vendors.

OOPS :eek:- Did not know that I cannot advertise vendors links. Read your msg after I sent the info. My bad

CTSV_510
05-20-08, 11:06 AM
I remember reading or hearing something about the possibility of throwing codes and the car going into "Limp home" mode. My next purchase is gonna be the Kooks and Im trying to plan it so my tuner is close by to my installer.

If you're not going to install them yourself, why wouldn't you just have the tuner do the install? That's what I'm doing, it doesn't seem to make any sense to have one shop do the installation and another shop do the tune.

trukk
05-20-08, 12:51 PM
Im in the Northern Virginia area, where can i get a reasonable tune? have Mods with no tune....
In MD, i've had 3 tunes by different shops:

1) Tony's corvette's. Not realy impressed with their tunes. I had a funky looking TQ curve after going to them, with very minor bolt-ons. had a CEL after them for months that I never got around to getting fixed. Dyno room was impressive though. The did a barebones tune for about $200.

2) Brett @ FBC. He did a nice tune on my car after installing headers and then again after Fast 90/90. I had to come back once for a CEL after the 90/90, for low RPM tweaking. Cost was $500, but you can get lifetime tunes after that by just paying dyno time. FBC & Brett were very accomodating, it is very easy to just pop in and get Brett to tweak something for you inf needed.

3) Jeff @ PSI. He tuned my car after mu cam install. Car runs aweseom at WOT. Had no issues at summit at all (no CEL's). I will ahve to go back in a few weeks, to work out a low RPM surging issues I'm having. Jeff really seems to know his stuff. I was very impressed with his demeanor and knowledge. The downside to Jeff is it is a royal PITA to get ahold of him. He also charges $500 for a 'lifetime' tune, paying just dyno costs after.

I'd consider Jeff or Brett. If you plan to stay just very mile boltons, then I'd say Brett due to the ease of getting in touch with him. If you plan to go big later, it's probabaly worth puttin gup with Jeff's availability issues.

Finally I'm sure there have to be some good tuners in NoVa, but I don't know any.

-Chris