grandspt

I am looking for some advice from members that have installed headers.
I have had my GrandSport for 15+ years. It runs great and is in excellent condition.
I was thinking about installing ARH headers with cats.
My car is fairly stock with a cold air intake, throttle body coolant bypass, and a lower coolant fan turn on temp.
If I don't reprogram the ECM will I still gain decent HP? If it is only a 10 HP increase than to me it is not worth it.
When I had a late 80's Z28, I installed headers and the car really woke up and even gained some gas mileage to boot. Can I expect the same from my LT4 engine?
Also will it take away from the originality of the car (lower the value, not that C4 values are rising)?
In general would you recommend doing it or not?

383vett

Every Corvette I have owned, I have put long tubes on. C3, C4, C5, C6. They will wake up any car. I can't say for sure, but I don't think you will have to retune your LT4 to appreciate the benefits although there will be hp to be gained. The torque increase under the curve will make you happy. ARH makes a good header and I am running them on my C4 and C6Z. If your worried about resale value, just keep your original manifolds.

lt4obsesses

I can only speak for myself, and am not giving advice.

If putting on the headers would improve my enjoyment of the car, sure why not. As long as in doing so, I did not have to make any alterations to the factory parts. If it meant cutting exhaust pipe, modifying brackets, or anything that could not be put back, I would not do it.

I would also have to look at why I want to do it. Bolt ons can and often do add more power/torque. But what this does is to increase the capabilities of the engine. Now, if I'm not maxing out those capabilities now, or often enough to be important, I would have to ask myself, "what's the point?"

If I had a low mile, excellent condition GrandSport, I personally would try to keep it as close to when it rolled outta Bowling Green as possible. but that's just me. All this to answer the question about originality. You have the one C4 that is holding value, and may actually see an increase. Given that were only 1000 made, and certainly year by year the number in existance diminishes by untimely demise.

If I wanted more power and all of that, I would then go find a decent high mile plain ol' LT4/LT1 and build the crap out of it.

If I could afford them, the ARH would be the ones I get. Will they provide a noticeable difference without a tune? Yes they will.

dizwiz24

Big shot dyno in stow, ohio has a c4 specific tune for arh headers on an otherwise stock c4.

I think that tune is what arh used on the car they published on their product release bulletin showing a power improvement w/ tneir product on a stock c4


I believe they are the majority stakeholder in brians (obd2) portion of pcmforless.

Look up those guys and talk to them

383vett

My cars stay stock for about one night.

T. Wayne Nelson

What takes you so long, sonny,

PLRX

Yo are not in California, and you wonder if you should install long tube headers.

Do you have any idea how many of us here would love to install LTH?


Do the long tubes, drive, and enjoy the Vette.

BlackHarleyMan

I ran EM long tubes on my LT4, but when I put GS #91 together, I went with the ARH setup. I also had my set ceramic coated inside and out along with all of the exhaust piping of my Power Effects catback. Needless to say, the ceramic coated ARH's IMHO are far superior to the EM's, fit better and being stainless, I expect them not to rust out like the EM's did. So here's a vote for ARH's on a GS!

Noland

aboatguy

grandspt

Thanks for all of your opinions I will probably get them.
Noland, is there any reason you got the ARH ceramic coated?
Is it necessary? Or a better question; do you recommend that I ceramic coat them? I plan on keeping the car for a long time (not that 16+ years is not already a long time).
I thought the ARH Stainless headers will not rust through. Also if not coated will the under hood temperatures be too high causing clutch and brake fluid boiling or other issues.
I had coated headers on my late 80's Z28 Camaro with a ZZ3 engine transplant. The underhood temps were higher with the coated headers vs the stock cast iron manifolds.
Lastly, what are you doing for spark plug wire looms. Do you just use the stock OEM setup? Or do you use the center bolt valve cover looms and run custom length wires? I should change the wires (stock red with plug numbers) while I have a little space to work with.

Thanks
Gary

88BlackZ-51

What size you thinking?

BlackHarleyMan

Gary,
I had my ARH's ceramic coated for aesthetics only, I did not like the idea of the stainless steel bronzing effect, so I decided to get them coated inside and out then polished. As far as getting your headers and exhaust piping coated, that's a personal and monetary decision. HOWEVER, For what I want it was a no-brainer.

My motor with the EM's



Ny Motor with the ARH's



ARH's should not rust through, you shouldn't have any issues with them like with the EM's, do to the material and type of coating. I had CAT's on the 96 which created a TON of heat which was a factor in the demise of my headers and extension pipes. I decided to go with the type of coating that the NASCAR guy's use (So I'm told), and I deleted my cats. I use O2 sims for my rear O2's, which i exspect this new setup, as recommended by Billy, to alleviate all of any heat/exhaust related issues I had before (Can you say, car fire?).

My spark plug wires and looms are ALL custom made by Clif Williams, Billy Williams is my engine builder.


Custom wire work







I took this route because of ALL the headache's I had with the previous wire setup on the motor. These are custom length, made to fit well and are completely out the way of everything.

grandspt

Noland, both headers EM and ARH look great in those pics as well as the AFR heads
But if I read your post correctly you said the cats caused too much heat which destroyed your headers and extension pipes and possible fire?
The set up I was looking at with ARH was part#C43434WC with cats.
I don't mean to offend anyone that has deleted the cats, but I personally hate the smell of the exhaust without the cats.
My old '80s Z28 that I used to take down the qtr. mile on weekends had no cat at first, it smelled so bad driving around town that I had to put a high flowing cat on it!

Noland this is good information for me, are you saying with the cats it would be alot hotter than the factory stock cast iron manifolds and could cause a fire?

383vett

Longtubes will always create more underhood heat that stock manifolds. If they are coated, they will be slightly cooler than uncoated headers. The heat is retained better within the tubes and travels throught the system rather than diffusing throught the engine compartment. There is not a night and day difference, but the engine compartment will be a few degrees cooler.

BlackHarleyMan

When it comes to Cat's, I was of the mindset that I HAD to have them, I know now that, THAT is just not true. Overcoming the issues that you had with your Z28 is handled with a proper tune these days. Not going into Cat's and Function, purpose, ect...BUT With a good tune, you'll run fine.

Also, I believe that ARH has their Cat's located further downstream than the EM's. The EM Cat location on the drivers side of the LT-4 does not lineup adjacent to any headshield. SO, In my car, radiant heat from the Cat's (And there was a TON of heat), basically went through the tunnel fiberglass and caught my insulation and carpet on fire. Luckily, I was in the car at the carwash and was able to get a garden hose quickly and put it out. I then had a Stainless Steel shield installed with washers as offsets which fixed that issue. Because of this, and the FACT that Cat's do not contribute to MY motor setup I chose to remove them. My setup does not suffer from the gas smell condition that you mentioned, but I can only speak from MY experience. Either way, good luck, I'm sure it'll be bad-*** however you go and keep us posted with Pics!


Noland