I am curious of what people have tried..... and the results..... butt dyno OK..... I have had stock, Milltek and Megan.... this is a category that is heating up and I'm curious..... do you have a head? is it loud? where have you found the most increase.....what catback do you have?

 

Bob,

Got your voicemail.

I'm willing to offer that header on the mod altar.

 

I had a Milltek cat-back and Milltek header. Nice increase, but it was too loud for my tastes and I didn't like the sound. I had it taken off and had the stock header put back on. Sound and volume were perfect. I still wanted more performance, though, so I had Helix install a JetHot coated OBX with my stock cat. Although the sound is still nice, loudness increased more than either of us thought it would and it is still a bit too loud for my taste, but far more tolerable (IMO) than with the Milltek header. It's growing on me though... and since I don't have a intact OEM header anymore it's a bit more difficult to go back. I noticed an increase with each header but my butt dyno is not so finely calibrated that I could compare them.

 

I installed a Milltek header about year and half ago.
The cat is now shot (its rattling around and throwing P0420 code).
It only gained a couple of ponies on the dyno when new. But, it did help on the top end at the track (butt dyno).

What do you mean "...this is a category that is heating up..."?

 

Bob,

Not new info to you but for the thread . I have the OBX with stock cat and found SOP TQ improvement( w/stock ecu). My Gtech indicates that peak TQ comes on about 300-500 rpm sooner than when stock. Top end HP - can't say my butt dyno really picked anything up but the car was not slower.

Originally, I hooked the OBX up to a 1-ball and found that the header made the car just slighly louder and clearly deeper in tone. Then I mated it up to an OBX exhaust - and well its loud but can't seperate the loudness contribution.

Recently I added GIAC software that seems to tie in all of my mod contributions.

My opinion is unchanged -

1) A header is great mod (as 4th or 5th mod) particularly for street driving do to the TQ mid range gain.
2) OBX is an excellent header option and should be seriously considered. The price (200 bucks delivered) makes the TQ and Hp gains reasonable (i.e. cost per).
3) Re-using stock cat is a good way go for it is a quality cat, why throw it away/spend money and I'm not aware of anyone who has done this having code problems or fitment issues. I believe the cat "flows" just fine unless you are making a living racing the car. When it goes I will then consider a different cat.

 

Bahama,

Doesn't using the stock cat bring back the restriction and limit the effectiveness of the header in the first place?

 

I am pretty sure that the most restictive part of the stock header is the pre-cat.

 

There are the experts here that clearly feel that a "high flow" cat is BETTER. I'm no expert and I don't necessarily disagree but lets just say I don't think or feel that the stock cat is undersized.

Bear in mind that -

1) I look at it from a enthusiast perspective not a race expert. For 400 bucks appr. (header + install), I improved the HP & TQ. Could I have added more if I had spent 1,200 - proabably but those would have been very expensive TQ/HP additions.

2) if we are talking purely performance - the word cat isn't/ shouldn't be part of the discussion.

 

stock cat is pretty good actually. Or so i hear. I use the stock cat with OBX and oneball

 

I have a Magnaflow exhaust and just added a Larini header and cat. It looks very nice and the fitment is perfect. The sound did get louder and the car now sounds like a F1. It also uses no pre-cat and has a 200cell cat. I noticed i gained a tiny bit of power. I was dead even with my buddy's MCS and now I pull him by one car length, but only from 20mph to 50mph. The header should really shine with the new Head and Cam installation

 

I consider your exhaust set-up to the best bang for the buck exhaust system - not loud, stealthy with clear daily driver gains for very little $.

The ultimate budget enthusiast system.

 

well i didn't want to spend too much on a header system, cos no-one made a true performance header, and even if there was one, i wouldn't it on until i had a performance head and cam. Catback, i thought, was unnecessary, as not much power to be had, and my stock exhaust sounded brilliant already. Only problem is, my car doesn't burble as much :(

Also, stealth is very important to me, as i'm a 19yo, so cops tend to target us. Thus i have what looks like a stock exhaust

 

What I meant by "this category is heating" up is that there are several companies developing headers at the same time...

 

I've noticed that several header manufacturers place the first O2 sensor bung in a lower position than the stock manifold. Have people had to lengthen the wires to the first O2 sensor, or does the stock wiring have enough length to reach the header bung?

 

I use a megan header with the stock cat along with a custom stainless dual three chambered 2 1/4 magnaflow mufflers that collect in the rear just like the magnaflow system. I also run two 16" magnaflow resonators inline before that. It is still anoying loud when you cruise at about 60 to 70mph and vibrates at 2000 rpms. It has been trial and error to cancel out sound since I installed the header. In my opinion the header is hard to tame!!!! I wish it was as quiet as it was with the stock header! It also makes a tin pinging sound in the header area which is not a leak. Has anyone thought about modifying the stock header? Wrapping the Header tubes? Anyone?

 

here is the one we have been installing :




Also this is what Larini has to say about the factory header compared to theirs.

The Mini O.E.M. header incorporates four short, varying length, 1.25-inch primary pipes attached to a tiny, restrictive collector and flexible pipe section. This is followed by two 400-cell ceramic catalytic converters in tandem, offering an approximate 45% flow area, connected by 2.25-inch pipe work. This arrangement, in terms of performance, is inefficient.

Unlocking power from the Mini involves carefully tuning the header to work with the Cooper’s lively engine and the brutal Eaton supercharger of the ‘S’. The Larini Systems Mini Manifold and ‘GT’ Cat incorporates four equal length, 1.50-inch primary pipes, mated to a collector of increased length, followed by a high performance flexible bellow. Attached is a single, 200-cell, METALLIC super performance ’GT’ sports Cat, offering a flow area of approximately 85%, coupled to 2.50-inch pipe work. This arrangement is the performance ideal.

The two original lambda probes are retained in their correct positions for the proper operation of the OBD II (On Board Diagnostics II) system.

Victor

 

full alta here; quite loud inside but not too bad with windows down . my wife takes it occasionally and it's not bad as she pulls away.(it's what she's doing down the road.....) .....easy now be kind.

 

I have the London Stainless header, dimensionally the same as the Milltek, but the LS cat is different. This has been mated to a custom cat back, the first part being the Superstrint non resonator pipe. I have tried several (5) mufflers, starting with a 4" disc Supertrapp and finally ending up with a 5" disc Supertrapp, with a Borla a Coast Fab. and an Aero Turbine in between. By far the quietest and best sound quality came from the 5" disc Supertrapp and this with more discs and power than the 4" disc ST.

Just adding the header to the stock cat back did seem to add power above 4-4.5k and with the complete exhaust the car pulls harder further into the rpm's. Now with the JCW 210 kit my power, on the dyno is still going up when I hit the fuel cutoff, no dips anywhere.

I would like to see a STX legal header from Stahl, which I think can be done by putting the flex connection behind the cat and shortening the primaries just a little. STX is limited to moving the cat no more than 6" and I think this would be a good match up to any JCW or 15% pulley car.

 

SpiderX - you refernce that you felt the Milteck was holding the m62 back - have you considered the Stahl for it offers various size tubings?