So we replaced the exhaust on my gf's 96 ex starting with a cat-back from Magnaflow. Worked beautifully, then I ordered a random tech bolt on free flow cat and got a generic header cuz of the budget. We bolted on the header and random tech cat 2 nights ago and there are some issues I wanted to see if any of you had ideas for.

The issues are that the cat doesn't really seal well with the header though today I took the car to a vw performance shop local to my girls house in LI and they retightened the bolts and shortened them to pull the cat closer to the header. However, since we've changed the header and cat, it seems that the combination has pushed the cat-back further back and causes it to vibrate especially loud at 2k rpm's where it's apprantly hitting the heatshield. So, my options are-

1) The shop said I basically need to short my exhaust by 1in, and since the cat-back and cat are warrantied pieces, I asked them to do it on the header, the owner isn't sure if he can but on mon he's gonna take a look at it and see what he can do.

2) reinstall the factory header and just either run that or save and get a DC Sport or something.

Opinions?

I also noticed that the random tech unit does not have hangers welded on like the stock cat, is that a problem?

 

I have heard very good things about the stock F22 header, so I personally would switch back to stock on that, and see how it goes from there. As far as the cat no having hangers, either it just plain doesnt or they left it up to you to have some welded on there. If it hasnt been a problem yet, it might not be.

 

I'd suggest reinstalling the EX exhaust manifold. It's universally acknowledged to be an upgrade from the F22b2 manifold and will flow far more than you'll most likely need.
Clean it up real good, either Paint it with hi-temp Paint or Powder Coat and it will rival the tube header for appearance.
Have you ever wondered how DC or those other header manufacturers designed their units? Copied the 4x2x1 EX Manifold.

For instance:
4x2 (Manifold)



2x1 (Downpipe)



P

 

very true. ive seen a dyno graph or two of people actually LOSING power when switching from a b1 header to a DC header or whatever....this is on a b2 block however, if that makes a difference

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by fw190bvi &raquo;</TD></TR><TR><TD CLASS="quote">very true. I've seen a dyno graph or two of people actually LOSING power when switching from a b1 header to a DC header or whatever....this is on a b2* block however, if that makes a difference</TD></TR></TABLE>

True, I've run into discussion after discussion replete with observations that the "Collector" portion of the header is deficient. It necks down too quickly, and has often required modification to see any gains at all.

If he has some time on his hands (and doesn't ever want to hang the heatshield back on; he can grind off the mounting ears and clean it up even more b4 coating it. It's the way I'm going; I absolutely can NOT stand the ringing sound of tube type headers for everyday driving. Cast is OK by me.

P

* If he's got a '96 EX, isn't it a B1?

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by P_Adams &raquo;</TD></TR><TR><TD CLASS="quote">

True, I've run into discussion after discussion replete with observations that the "Collector" portion of the header is deficient. It necks down too quickly, and has often required modification to see any gains at all.

If he has some time on his hands (and doesn't ever want to hang the heatshield back on; he can grind off the mounting ears and clean it up even more b4 coating it. It's the way I'm going; I absolutely can NOT stand the ringing sound of tube type headers for everyday driving. Cast is OK by me.

P

* If he's got a '96 EX, isn't it a B1?</TD></TR></TABLE>

I'm gonna look into that, good thing I always keep salvagable stock parts when I modify lol. Yes, she has a F22b1 so that with a freeflow cat and the magnaflow should make it a pretty well rounded enjoyable drive with just the right amount of back pressure?

 

Absitively, Posilutely. The best of both worlds.

I suffered for a number of years with Hedman, Hooker and Blackjack Headers (domestic applications) on Small Block 350's from the incessant din coming from tube headers. Seems I was young and bought into the Noise begats Power theory (which it doesn't) so there I was, ruining my ears. What?

Slam the b1 manifold back on and enjoy your ride.

P

That set-up will work so well, you should be able to shoot giant spitballs from your exhaust with no problems.....

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by P_Adams &raquo;</TD></TR><TR><TD CLASS="quote">
That set-up will work so well, you should be able to shoot giant spitballs from your exhaust with no problems.....</TD></TR></TABLE>

that is key. freer flowing cat + 4500 rpm downshifts = giant fireballs

IMO, without spending TONS on a header, the best route to go is probaby a modified B1 header. if you could get a 60mm (~2.5") collector at the end where the 2-1, and mate that to an equal diameter cat and cat back with a good chambered exhaust. thats looking at some excellent flow for exhaust gases

 

Well, I don't think we should totally go to the conclusion that aftermarket header applications do not offer more power, after all, what it really does is move the prime power range from it's factory setting no? Also, different set-ups do yield either better power or worse power depending on the combination that one uses.

From my current set-up, the power range has been moved from low end to mid range/top end. I hope that by reverting to the stock header while keeping the rest of the free-flow applications will primarily resolve the issue of the cat-back rubbing against the rear heatshield and secondarily, move my power range back to low end/mid range. Thanks for all the constructive thought ppl, it's more than I can say that I've gotten from the other Honda boards. Keep them coming if you got em.

 

is the DC sports header still an option???

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by 03K24A4EX &raquo;</TD></TR><TR><TD CLASS="quote">is the DC sports header still an option???</TD></TR></TABLE>

In what sense? For you or me? DC Sport is def. still an option for anyone that wants to create a lil bit more power, but it's like the basics of aftermarket header. If you dig deeper, you'll see ppl that have really intense headers made for N/A applications that look nothing like the conventional DC header.

 

Tube style headers grew out if the realization that cast iron exhaust manifolds (of the time) were inherently inefficient as far as power development. At the time even h/p applications offered 4x1 log style manifolds. All it was meant to do was collect multiple exhaust ports into one outlet and send it out.
It wasn't until H/P enthusiasts (in conjunction with engineers specialized in fluid and sound dynamics) came up with the theory's which lead to <U>Equal Length </U>Tube headers. They learned the relationships involved in tube diameter, length and pairing which developed the best power at the best place in the power band.
So the exhaust manifold progressed from something just meant to handle exhaust gasses to a component which actually recovers power.

What you have to look at is the total effect of the exhaust system and how the header interacts with it. If you've got a 2 1/2" exhaust system, you'd better have a collector which necks down no smaller than 2 1/2" - it will act as a restriction if any smaller.

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by P_Adams &raquo;</TD></TR><TR><TD CLASS="quote">What you have to look at is the total effect of the exhaust system and how the header interacts with it. If you've got a 2 1/2" exhaust system, you'd better have a collector which necks down no smaller than 2 1/2" - it will act as a restriction if any smaller. </TD></TR></TABLE>

So going on this info, how do you think my car will react with a free flow cat and 2.25 cat-back and the stock header? Will the car be farting or will it be a nice constanst flow since the most restrictive part would essentially be the header.

 

The cast manifold will take care of whatever under-hood noise that the tube steel headers would have radiated.
The Magnaflow system is one of the deepest tone sets out there; and it has a resonator too boot! (Co-incidentally, I've got one on my '97 SE)
The only thing that would possibly be considered problematic is the "Free Flow" Catalytic Converter. If you can't see directly through the converter (an element is in the way), most likely you'll be ok. If there's nothing between your eyeball and your hand at the other end while looking thru; you're the proud owner of a test pipe. The one single component responsible for AutoFarts.

P

 

Lol, no it's a Random Tech unit, there is a honey comb in there but it's just less retrictive.