My question concerns the sound level/quality - and BTW, I've already searched and haven't found this specific question answered:
Couple of years ago I got the Cattman Y-pipe and added it along with a Stillen muffler. I've since then changed the Stillen for a 5.5 Gen OEM muffler and much appreciate the closer-to-stock noise level (I don't need to try to impress anyone with how much noise my car can make, and prefer the "stealth" approach to performance).
My Question: If I were to replace my Cattman y-pipe with their full header setup (back only to the CAT and leaving CAT-back as is), what should I expect in the change of sound level/quality (idle, cruise, WOT)?
Since it's a long shot that anyone has done exactly this, knowledgable estimates are welcomed.

 

Volume wise, the increase is marginal if at all. Tone wise, IMO, it will sound better because of the equal length collectors of the headers vs just the y-pipe. Y-pipes tend to mess up the harmonics.

If you keep the stock 5.5 Gen muffler, you will barely notice any volume increase at idle, cruise, etc, and there is no drone .

 

So the only significant volume increase would be under acceleration or WOT?

 

if any at all, yes

 

Interesting. Another quick question on this topic...How much better would the full Cattman Header/Y-Pipe Setup compared to just a older Cattman Y-Pipe be performance wise? Would it be that much of a benefit to switch over to the complete setup? Thanks.

 

Headers in the VQ30 have been about a 7-10 HP increase. In terms of power to dollar ratio, it's not worth it. It's the main reason most replace just the y-pipe. i'm sure the car would sound sweeter with the header and y-pipe combo

 

It varies from car to car, depending on existing mods and a bunch of other factors, but I'd be slightly more conservative and say that a performance y-pipe will typically make 12-14whp (over stock) and the header set makes about 18-22 on a 95-99 VQ30DE. More like a 6-8whp difference. [There's a little more difference between the two with a 00/01 VQ30DE, and a LOT more on a VQ35DE.]

If you're measuring dollar:hp ratios, obviously you're paying more per hp with the headers than the y-pipe. OTOH, the difference in hp is power left on the table - no way to pick that up except with the headers. Consider that once you've done all of the obvious bolt-on mods, the last few hp you add will be more expensive than the first ones (law of diminishing return) and when you consider it on that basis, the hp you get from the headers aren't a bad deal.

Finally, yes, the headers aren't really any louder than a performance y-pipe, but the quality/character of the sound is a vast improvement.

Brian C Catts
Cattman Performance

 

Does any one else feel this should be sticky material?



This is good info for a FAQ and since Mr. Catts has answered it makes even more sense.

 

I realize that I'm a "bit" older than some of you, and I am honored by the respect, but please... call me Brian, or "Cattman" - no need for Mr. Catts.

BCC

 

Brian:
Appreciate the clarification. Expanding on the figures you give of 12-14whp for the y-pipe on the VQ30DE and 18-22whp for the header set (i.e., 6-8whp increase, and assuming you're talking about naturally aspirated), what would you expect the comparable figures to be (approximately) for that engine with a Stillen SC setup producing, say, 300fwhp with a stock y-pipe.
And BTW, I'm pretty much sold on your headers with money in-hand. When do you expect to be ready to sell?

 

I actually have a customer's dyno results (2 years old) from his supercharged '00 Maxima. He did before and after dyno runs when he installed a set of our NZ headers. I don't use or quote specific #s from them because it was all done while he was trying to get his fuel system just right - some included an auxiliary fuel pump, some didn't - there were too many variables and differences in run results due to the experimenting he was doing. The data includes AFR and some were a little lean, and some were a lot lean - none of the runs were ideal in terms of air:fuel.

To give this a little context, peak power across these runs ranged from 250-260 ft/lbs and 268-289whp. BTW, he did a series of before and after tests with a Cattman catback after he installed the headers, so note that these numbers were done with a stock catback. The Cattman catback added about 10hp to the peak results, but made quite a bit more than that over stock at various points in the upper rpm range.

So, even though his fuel issues made the results too variable to pull out specific hp/tq #s, several trends or patterns were apparent in every test, although they differed in degree. The results were very different from what we see on a normally aspirated car.

These are my observations from the raw data that I input on a spreadsheet (I had his tabular run data), emphasizing that the baseline tests included a Cattman y-pipe, not a stock unit:

1500-3200 rpm - No significant performance gain
3300-5100 rpm - moderate increases in hp (5-15+*), more substantial increases in torque (8-20+*)
5200-5500 rpm - a "soft" spot w/ smaller increases...
5600-redline - the power band flattens and declines on the y-pipe car but the headers take off, w/ typical power gains of 18-24+hp* and 15-25+ft/lbs* in this rpm band, going up to redline.

*these #s are my best attempt to "homogenize" the various test results

So there you go, still a bit ambiguous and subject to all of the caveats I mentioned, but at least an indication of how you can expect headers to behave on a s/c-equipped vehicle (compared with a performance y-pipe). VERY different than n/a.

Brian C Catts
Cattman Performance

 

Brian:
Thanx for the info, and if I'm correctly interpreting what you're saying, where the headers in a NA configuration yield about 6-8whp over the performance y-pipe, with a SC setup the headers should offer 2 to 3 times that gain in the upper end of the power band. And with the 00VI and JWT's 7200 RPM redline.............sweet!
Sign me up for a set of headers and let me know when you're ready to accept $$$$ and start shipping.
Curt

 

Hi Curt,

The only way to get locked into the header order queue is to give us a call and place the order. We don't want any money until we've got your header set in stock, ready to ship, so we don't run the CC transaction until that time comes.

Brian C Catts
Cattman Performance