wfd1739

Thinking of putting ARH headers on my Grand Sport.

I'm going to order long tubes with no cats with emission fittings. I Will be mating these up to a corsa system. My main concern is drone since the center resonators will have to be removed. Another concern is the ecm throwing codes since I'll be running no cats.

If anyone is running this set up and can give me your thoughts I'd appreciate it.

thegame

I have them on my car but I don't think that will help you. I can tell you they are a great high quality product though and do sound great though.

kmillar

I have them 1 7/8"on my '90 coupe with a 421.
I had to use a header spacer to get clearance on my road race pan
The headers are good quality and you shouldn't have any issues there. If you are running a stock pan I think you shouldn't have fitment issues.
Get a heated O2 sensor, perhaps that'll solve your code problem
I have a corsa exhaust on my car with no cats, the system is loud at WOT and you're noticed driving around as it's not that quiet.

grandspt

I have the ARH 1 3/4" headers on my GrandSport but I have the cats and stock mufflers. Absolutely no drone and no codes thrown. Beutiful header construction!
If you are not running cats then you will not be using the rear O2 sensors which means that you will have to tune the ECM to ignore the after cat O2 sensors.
Personally I would install the cats as they are very high flowing and will eliminate the exhaust smell but that is just my opinion.
Good luck!

thegame

Also on the later models it sounds better WITH cats. Without sounds a little louder but too raspy. Is it the same with the C4?

grandspt

I have to say the cats are very small and are metal matrix so I don't think they would impede the exhaust flow.
I never ran the headers without the cats so I couldn't respond about the rasp. I did start the car with just the headers during my installation just for fun and it was loud and throaty

thegame

hell yea

Boss Lady

I recently installed the ARH Long Tubes on my 1993 automatic and I could definitely feel a SOP difference! I ordered them with the cats and emission fittings deleted. The piping and EGR were removed and the Air Pump disconnected. The block off plates are readily available. TPiS is one source. I did leave the EGR Solenoid connected, as suggested by another member, and to date there haven't been any codes set. I have the Magnaflow Mufflers and there's no drone at any speed. This set up is just about as quiet as before until you mash on it! They sound great under heavy acceleration. The only other real mod I have is 3:54 gears, and the headers were a super compliment in felt acceleration.

wfd1739

Thank you all for your comments. I've decided to go with the cats.

grandspt

I will recommend that you install a heat barrier on the fiberglass in the area directly above where the cats will be located. I had posted issues with my ARH header installation and what I did to make it work correctly. If you do a search you should be able to find it. ARH provided no instructions and left some parts out like spacers, header bolts, O2 sensor extension cable on passenger side (they were great about sending out parts after telling them what was needed). But the headers are great and go in pretty easy from below the car. Removing the OEM components was the hardest part.

wfd1739

Grandspt, thanks I read your post and it is very informative. I'll be sure to ask AHR for the parts needed. I saw you clamped a heat shield to the top of the cats. Where did you get them from?

Thanks again.

grandspt

I got them from Summit Racing (I think Amazon has them as well) and they were Thermotec part #11600. I bought smaller stainless clamps from Home Depot because the ones that come from Thermotec were too large in diameter. They have been working great and I made sure that they would hold up by calling Thermotec tech support and explained that they would be used on a catalytic converter. They told me it should be fine.

9T3VETTE

Just got done doing an ARH install on my 93 6-speed. The header construction is very nice and the headers fit with no major clearance issues. The drivers side o2 sensor could be better placed, it's very close the underbody of the car. I wired in heated DENSO o2 sensors, but they have quite a large body. If I were to do it over again, I'd look at a universal Bosch unit becuase the o2 sensor body is a bit shorter.

The x-pipe and cat fit left me feeling disappointed. The cats were placed far back in the x-pipe which put them too close to the underbody for my taste (less than 1/2"). To compensate I had to cut off about 1/2" from the header collector which pulled the x-pipe and cats forward to the front of the car. It's still close, but I used heat barrier on the underbody of the car for protection. For the price of these headers I expect a perfect fit.

However, the spark plug and header bolt access is excellent in comparison to the previous headers I had. Mated up to a magnaflow 3" system with no resonator it sounds great with minimal drone.

The heat protection I used is this. Very happy with it.
http://www.summitracing.com/parts/the-13575

grandspt

I used that heat barrier and stuck it onto the fiberglass above the cats. I also used a bead of high temp RTV (orange/red color) around the perimeter of the heat barriers just in case the sticky adhesive decided to fail.
I did not have to cut the collectors at all, that fit fine. I agree the cats are too close to the floor hence all the heat barriers I installed.
Also 96 cars had heated O2 sensors so no issues there other than an extension was needed on passenger side.
I agree for the price of the headers it should have been bolt on easy without me having to chase parts and purchase additional components but I have been through this before with my 83 Z28 I modified and raced occasionally. Nothing aftermarket bolts in perfectly only OEM stuff fits and even then there are exceptions to the rule!

9T3VETTE

Grandspt, totally agree that nothing aftermarket fits perfect that's why I'm not mad, just a bit disappointed.
Here is one picture I snapped of the passenger side cat, you can see how close it is. By cutting the collector flange it's moved the entire x pipe forward (to the left in the picture) and the cats further away from the underbody.

grandspt

I agree completely with you disappointed but not mad. And my cat was in the approximate location as yours.
I just didn't even think to cut the collectors to get the cats further away from the floor.
Absolutely no regrets though on the install it looks real nice under the hood and the car runs real strong now with absolutely no issues. I still think ARH makes one of the best fitting headers for the later C4s.

TorchTarga94

How much did the Magnaflow system's sound change when you removed the resonator? I'm sure it became louder but what about the note?

9T3VETTE

It sounds ALOT better without it. It's a bit raspier with a bit of a crackle, but still has that nice deep tone.

h.d.fire

I installed a ARH long tube system in my '89, 1-5/8" primaries with cat delete, 3" X pipe into Borla mufflers. I had to add a Bosch heated O2 sensor to satisfy the ECM. Like others, my only complaint was the fitment of the X pipe. It was off enough that the collectors would not line up without significant effort. The headers themselves fit perfectly (after eliminating the factory oil cooler adapter) and are very well made.
My car does have a notable drone at low speeds but the clears out to a nice low rumble at speed.
Overall I'd recommend the product.

thegame

Did you have to get a tune ?