Got a set of hedman headers that I'm going to get installed later this month. How much HP can I expect from just the headers?


As well, what else can I do to improve my stock exhaust system? Where should I go next and what product is the best?


Thanks.

 

#s wise who knows it should pick up some torque across the board;as you add mods the headers will compliment everything. Catless or not a simple true dual 2.5" system and a low restriction muffler youll notice it.
Any muffler shop can do this no need to spend crazy money

C4s have a short exhaust system why they cost more than most cars is beyond me.

Renegade intake is proven piece, heads/cam the usual can get you moving pretty good. Ask lots of questions, plan research and do it once


Many Xfire guys here been at it for yrs will get you pointed straight the first time.

 

Thanks for that.


I'll look into the 2.5 true dual system for starters. Wish our dollar was good. For me to buy the Renegade right now I'm looking at $750.00.

 

Assuming that you don't have to deal with emissions testing for your '84, a true dual exhaust using 2.5" pipe will compliment the headers adding some more HP and torque. Don't know what Canadian laws are regarding the removal of a working catalytic converter, but you may want to remove all of the old exhaust first then take the car to a muffler shop. Driving with open headers will be LOUD but you should be OK.

Add an X-pipe just behind the trans (about where the old cat would be located) and a good set of performance mufflers like DynoMax UltraFlo or Flowmaster Super 40's. Other mufflers that will work are MagnaFlow or Corsa. More expensive but nice sound.

 

Thank for the info. Cars from 1988 or older don't need to have what we call an "e-test." So I don't need to worry about that. As for taking my cat's off. I would face a fine if I was pulled over by someone working with Ontario emissions. What most guys do here is punch out their cats. That way if they get pulled over, the cats are present on the car and there is nothing they can do.

 

James,

With your XFire, the biggest bang for your buck is the Regengade.

The XFire is choked (badly) in the intake side. If you put headers on your car (without the Renegede) you will see negligible performance increases-if at all.

Now, if you put the Renegede on your engine along with the headers you will see a HUGE improvement in your engine- 50HP ish which is pretty good on a 200HP stock motor with just bolt ons.

Don't waste money on a true dual and get yourself a upgraded ignition. I advanced my to 14 and my totally stock car loved it.

So...
1) Renegede (+30hp)
2) headers (+20 with Renegede)
3) ingition (and advance the snot out of it and pick up 7-10hp)

1000 bucks (US) and you have gotten as much as you can get out of it without heads and cam ($$$)

 

Thank you. Think I'll go that way. As you said, seems to be the best bang for your buck.

 

Definitely agree that the Xfire was choked on the intake side in stock form. However I feel these numbers are a bit optimistic. I like my Renegade & recommend it, but with your currency conversion & shipping costs, porting your stock intake would be a much more budget friendly way to start making power. Many on the forum have done this and could walk you through it I'm sure.

The +30hp number for the Renegade was achieved with a 383 I believe, so unless you're adding cubes I wouldn't get your hopes up quite that high. I personally did not notice much if any of a SOTP increase when my only mod was the intake. Adding headers to the combo did help...and true dual is far from a waste over the restrictive stock exhaust.

Factory 6 deg advance is conservative, sure, but 14 deg seems a tad ham-handed. I could be wrong. It really depends on the knock count...you can advance it til the pings start showing up, which will cause the computer to pull timing electronically.

Your biggest gains will be with heads & cam (both are super conservative smoggers), but it all works as a combo--keep that in mind, and keep your goals budget-realistic, and you will have a really fun build project!

 

 

I used the Melrose long tube and full exhaust back with the X pipe. I can't begin to tell you what a huge difference it made. I have not had it at a dyno but without opening up the engine its HUGE.

I know the HP number may sound big but if its measured at the Crank and take in consideration how bad the original 80's junk was.....

I probably uncorked 30+ HP removed 3 Cats and the horrid ports of the factory shorties....


Brian

 

Good info so far! We would agree that freeing things up on the intake side will help yield better results overall. If there is a kink in the hose, it wont matter how big you make the nozzle, after all.

We would recommend keeping your stock cats in place, unless you have reason to believe that they are failing. There is minimal power gains from deleting them, and opens up the issue of legality. A well-made catback system with straight-through mufflers like ours will help increase power even further, and improve your engines efficiency. If we can assist you with choosing the correct muffler, please feel free to shoot us a PM!