Besides the numbers how did the car feel when you drove it. Alot faster? Or a little.

 

While the gains sound nice, I'll let you guys in on what some of us 4th geners have experienced when we've seen gains like this. The Cattman headers show a definite increase in power, no doubt, but look closely at where and how long that gain is sustained. Looking closely at the before and after HP plot, his car is actually LOOSING power from 2000-5500rpms. Not until the rpms span 5700-6300rpms are the headers actually making more power (peak 23fwhp).



Now think about this for a second, where does a car spend most of it's time accelerating at WOT? The answer is in the midrange from 4000-6000rpms. There is only a fraction of time you spend accelerating from 5700-6300rpms, especially when you're in gears 1, 2, and 3. Not until you hit 4th does the car actually take some time to run from 5700-6300rpms. Even with a peak gain of 23fwhp, I would bet that this car is actually no faster or possibly SLOWER in the 1/4 mile even though it technically has more peak power. How can this be? He's lost low and mid range power at the expense a quick blip in high rpm power.

Am I talking BS? Here's my experience with my very own car. As many of you know, the "MEVI" has become a very popular upgrade for the 4th gen Maxima. Naturally, I had to have one. Prior to getting my MEVI, my 4th gen made 183fwhp/192fwtq with a y-pipe, intake, UDP, and B-pipe. My best 1/4 was a 14.61@96.0mph with a 2.30 60'. I got my MEVI installed and dynoed. It made 189fwhp/184fwtq. I lost ~8-10fwhp/fwtq from 3800-5000rpms, but I gained a whopping 20-45fwhp/tq from 5700-6500rpms. How in the world could this be a bad thing? I was making HUGE gains and minimal losses. Here's my comparo plot:



To the track I went and I was severely disappointed. On my four track outings and 20 total passes, I was actually a slower on average. My best was a 14.63@95.5mph. It turns out that loosing just a small amount of power in the midrange cannot be overcome by huge power gains from 5700-6500rpms. The added power was in the wrong part of the powerband when teamed with the stock rev-limiter. Mnay other MEVI experienced the same exact performance. Fast forward a few months later and I got my JWT ECU with a 7000rpm limiter. The ECU gained me back my midrange power loss and gave me an extra 500rpms of rev which meant I entered each successive gear 500rpms higher and in a much fatter part of the powerband. With the ECU, I dropped an average .25 seconds and gained nearly 3mph plus making my car significantly faster after 80mph.

The truth of the matter is power under the curve is what dictates acceleration, not peak numbers.



Dave

 

Very well said Dave,how's your ECU working,any code??Well I got the MEVI on my 96 just like Dave got,I can said I lost midrange power and gain topend after 5500 rpm,but it doesn't make my car any faster in the ET.

 

What are you looking at that shows I'm losing power from 2000-5500rpms?

I have to disagree with you about the car not having more power in the lower rpms... but this is from my experience in driving the car...

Before the headers my car would burn the tires in first (for as long as i wanted ) once i shifted into second, I would get a little tire spin and a mean chirp... it would also chirp third...

After the headers, the car still burns first (still for as long as i want) however shifting into second now, continues the burn out for a good long while... third now gives a meaner chirper than before...

of course the butt dyno isn't always accurate... but lemme tell you, these headers ROCK!!...

Also as an FYI, the first and second runs of both dyno sessions show lower numbers because I'm running too rich...

The third run, of both dyno sessions, were run without the auxillary fuel pump working. The runs are too lean for everyday driving, but give a better representation of how the numbers will be when the fuel issue is addressed.

So the first pass of the first and second dyno sessions should be compared to each other. The second pass, of the first and second dyno sessions should be compared to each other and lastly, the third pass of the first and second dyno sessions should be compared against each other.

You can compare passes one and two, of the two dyno sessions, against each other, but the third pass of the two dyno sessions should only be compared against each other.

For the third dyno session on January 17th, I'll continue running the first and second passes with the aux fuel pump on and the third pass with it off.

 

Maybe I'm looking at it wrong, but isn't the darker line with the higher peak power the headers dyno and the other lines the pre-headers dyno? If so, then that darker line is showing the same and sometimes less power until ~5700rpms.



With just my MEVI installed, I was still able to roast the tires in 1st and spin 2nd gear just as hard, but that doesn't necessarily mean I was any quicker.


So true.

What's stated above is confusing to read, but if I'm reading this right then the car wasn't running optimally prior to the headers?


Dave

 

Do you need to get a new high flow cat if you put the heades on with a greddy evo cat back exhaust?

 

Dave how the heck can you even tell what line is what...there are 5 million freaking lines..haha.

Regardless I'm with dave on this one. I cant find Iron Lungs dyno plot with the headers and cams...but I know with the mevi.........his car is making hp all the way at redline...and correct me if I am wrong..his peak hp number was at redline. I dont remember him mentioning any losses.

I was reading a leignfetter book on building cars...I guess thats how you spell his last name. Regardless his idea was to make a car make the most power in the rpm range with which it stayed in the most. Using an rpm meter with timing it would output the amount of time spent in each rpm range.........similar to ours the corvettes that he makes stay in the 4k-6k range most of the time. So his goal was to make the most power in that area. He said anything after that was pointless as teh fraction of a second u were in that area wouldnt matter anyways. So looking thru the book his dynos...would make power starting around 3k...huge power rather..and up till about 6k with which they dropped off..

What good does a gain of 23hp at 6500 rpms do you if your never even near 6500 rpms going down the track.

Interesting that cattmans dyno plot showed the curve from low rpms up to redline all above the previous line.

Just my venting about this whole header thing. Intersting still though that a guy I know still has only gotten 2hp out of his headers.....from cattman..2hp over the y-pipe excuse me...and looses below 5500rpm. I told him at least it has teh fancy shiney ceramic something or other coating........looks so clean
Then again he wasnt boosted either so maybe that was a reason.

 

It's hard to read the overlay, without comparing the 2 other charts at the same time...

Just look at the chart from the 1st session and the individual chart from the 2nd session - not the combined chart with the 6 different lines.

Then you can see which lines, on the combined chart, are for which session.

Yeah, it's confusing... basically though, for both dyno sessions (without header & with header) the 1st and 2nd runs were done with the auxilliary fuel pump turned on. This causes an over-rich condition at the higher rpm levels, resulting in lower numbers at the top end.

The 3rd run, of both dyno sessions, are run with the auxilliary fuel pump turned off, which shows the peak numbers.

So to be accurate, you can't compare the 1st and 2nd runs, from either dyno session, with the 3rd runs.

Does that make sense?

 

I doubt it... IIRC, the stock cat only loses 2-4 hp over a high flow one...

someone correct me if they know different though...

 

The way I estimated the HP line was because it's dark and it's the one that peaks the highest. If you look for a dark line from 2000-5000rpms, you'll notice it's in the area making the same or lower power. It was purely a best guess

It sounds like the Lingenfelter book is something I should look into getting because make of what I've read probably comes from him. Too bad Mr. Lingenfelter passed away a few weeks back.


Dave

 

Yeah but I think his brother or his son cant remember which is taking over operations. Which is good cause he did a good bit of the design anyways. Yeah the book is super imformative.....I read it while sipping a starbucks in barnes and noble...Hope no one mines that whip cream stain.

 

Someone would have to make equal lenght headers to get back mid range hp and torque. The headers like cattmans just increase topend.

 

I didn't measure the headers with a tape measure, but I believe Cattman's headers DO have equal length tubing...

 

The headers are very close to equal length. When the design was being done he found he got no gain in power by having exactly equal length headers.

 

No comment.

 

There is no reason to get excited about this dyno unless you have a SC. I see a bunch of NA guys thinking they might see these types of gains, it ain't gonna happen.

Irong lungs dyno's are only good info if you got the headers and cams. His dyno's tell me nothing if I want one or the other.

What most of need to see is Infintiblast's friends dyno of an NA max y-pipe dyno and cattman header dyno.

 

I'll see what I can work up.....He just wont let me post it, to um.........well dissappointed that he spent so much money.
I agree with you if your supercharged maybe you can see these results...na..I'm not feeling it.

 

Damn, I want so hard to believe that headers will really do something for these cars, but the evidence sure is pointing in the direction of "svae your money for something else".


Dave

 

Like a $300 y-pipe and TS ECU(hopefully soon!).



My .02, which isn't worth jack, is that a FI dyno is irrelevant for NA guys, ie most of us.

My gut is telling me after seeing all the VQ35s lose power and peoples unwillingness to post VQ30 dynos that UNLESS you're flowing tons of air, ie FI, cams, N20 and *MAYBE* a 7000+ RPM limiter, you *MIGHT* benefit by going with headers over a y-pipe. However, this is all speculation, but UNTIL I see a few NA dynos, that's my feeling.

BTW, I'd gladly give up some 1/4-mile performance for those kind of gains up top.

 

based on the info in this thread, i really can't justify $750 for headers plus install over a $200 y-pipe and a prcai that you can install in your driveway.

 

Uh perhaps you are confused....750 for the headers includes the piping all the way to the cat. No y-pipe needed.

 

hmm..maybe i am confused. lets see:

$750 for a set of headers.

or

$400 for a y-pipe and intake for approx. the same
gains.

i'm going y-pipe and intake . not really much confusion unless you shell out $750 + install for the same gains as a y-pipe and intake.

22 hp for headers and intake
about the same for y-pipe and intake
1/2 the cost - same performance

i know people really want to believe this is a good idea, but i just don't see it

 

No point in wishing, mate, its not widely known but the Cattman headers fit your 02/03 VQ35DE. You'll need to make up extensions for your rear O2 sensor wires and mind one of your engine mount bolts for clearance.

Brian C Catts
Cattman Performance

 

No, under no circumstances can you get 18-20hp from the Budget pipe. I'll put the Cattman y-pipes up against the budget any day, but ours won't make that power by itself and theirs certainly won't.

I have seen the data behind that rediculous claim and those numbers are worthless. If anyone can provide the dyno chart I'll be happy to discredit it again, its one of those BS stories that take on a life of their own and you just can't drive a stake through it and kill it. As I recall the "before" stock numbers were completely sick -- way below any healthy engine -- and the "after" numbers were about where you'd expect them to normally be on a y-pipe equipped car.

Brian C Catts
Cattman Performance

 

I've got all the table data from the run, i.e. power readings about every 15 rpm, they go on for pages. I'm inputting this into excel as time allows, and have not gotten deep into it, but this is not a "add to peak and subtract from below" sort of deal, there is no pattern of power loss below 5500 rpm. In fact, I suspect that there will be wider margins between the before and after curves than 23hp. I'll summarize this and post later.

Brian C Catts
Cattman Performance

 

Actually disregard my post I read yours wrong. I thought you were thinking you had to get a y-pipe to go along with the headers. I've half dead about that time of day.

 

Brian,


I first want to say thanks for bringing products to the maxima community, no one can say you don't bring high quality products to the table. Second, I want to say thanks to those org members who have supplied us with cattman header dyno's. It's guys like you who are willing to spend the money on an unknown product that make maxima enthusiast and this site great.

But we still have no hard evidence of what gains these headers will give over a aftermarket y-pipe.

All you have to do is dyno an N/A max with a y-pipe then dyno the same max with your headers. Give us the results and if they are at least 10+ hp or more through most of the power band you will sell tons of them. I know I would buy a set.

 

I'll buy them too if you show me gains in the midrange, not just some blip of power that I can't use in the 1/4 mile. From the posted graphs, I don't see a quicker car. Take a look at the torque graph and you can clearly see the "headers" dyno plot because it's the one that has a surge in torque occuring at ~5700rpms which is the same exact time the HP curve blips (hp is derived from torque, so duh). The header torque curve sure doesn't appear to be owning the non-header curves at any point except from ~5900 tp 6300rpms. Please prove me wrong though and show me more average power because I want to believe.


Dave

 

*cough*Pick me!*cough*Pick me!*cough*

Someone will EVENTUALLY get some clean dynos, but of course everybody wants someone else to do it FIRST. Especially now after the $tealin fiasco.

 

As an aside I just though of - why don't you purchase all the y-pipes available (stillen, WSP, budget) and then send those three plus yours to an outside person (like ME) to do independent dynos of all of them. Then you could use that to hopefully show why yours is better. Of course I'd be a perfect candidate, since the only mod I have that I can't undo is a muffler which doesn't add power so I'd be perfect for stocker.

Ah, even if you don't pick me it'd still be a good idea. Heck, it'd be a good idea for the stillen and cattman headers too.

BTW, the 18-20 was a mistake someone made. everyone knows y-pipes don't make that except maybe at the crank if yer lucky.

 

I've taken the raw data from each of the three runs Roy made, pasted it into a spreadsheet and generated comparative tables and charts. I suppose it could be extracted and pasted into this email, but its late and I'm beat. If anyone would like a copy of the entire spreadsheet, I'll be happy to provide it on request (write to catt@cattman.com) and perhaps someone more adept than I will post the graphs. There is a lot of information, I encourage anyone thinking about these to review it thoroughly.

I wasn't sure what to expect from putting the headers on a s/c max because the flow dynamics are totally different from a n/a engine. The typical pattern from opening up the headers on a s/c car is simply gaining power at the top end because it doesn't get stuffed up till the upper rpms -- the increased pressure seems to overcome a lot of small exhaust issues in the low-to-mid-range.

So, no surprise, that is the pattern I see here, and others have pointed this out as well. The three runs are quite different, with the first two running quite rich in spots and the third being quite lean with a fair amount of the run between 14.5-14.8:1. It seems that in all cases the car would benefit enormously from some fuel mixture adjustment.

It is important to point out that this is NOT the power profile that the headers generate on a normally aspirated car, that is very different, with most of the gains in the mid-range and no power losses anywhere. Someone suggested that if the headers are properly tuned, there would be mid-range power appearing, there's no question that occurs on a normally aspirated engine, but that would not be the case in a supercharged application.

Brian C Catts
Cattman Performance

 

True we will just have to wait till someone gets these dynoed on a NA engine. But that will be hard since nobody wants to take the risk of buying $750.00 headers to find out they only make 5 more HP over your y-pipe. But it's a new product at it will take time.

 

I'd like to get this figure as well, but I still feel it was more important to initially benchmark the headers against a consistant baseline, i.e. the stock y-pipe. If anyone in Arizona (or wanting to visit Arizona) would like to put on set I will be happy to pay for the dyno work.

As a function of some recent experience sponsoring dynos at a distance and getting absolutely unusable data from crap machines run by incompetent technicians (doesn't apply in this case, you'll never see the worthless data I'm referring to), I'm not going to do that anymore. If I'm paying for the dyno, which I'm happy to do, it will be at one of the half dozen dyno shops in Arizona, so I can be on hand to oversee the process.

Brian C Catts
Cattman Performance

 

I realize the skepticism helps keep everyone honest, but what Steve mentions about the difference between equal length and "near equal length" headers is true in the case of this part.

My New Zealand developers/fabricators do some very upper-end work in that market. They were approached by a customer for whom they'd done a real nice Skyline R34 project, who had a Maxima that he wanted done up as a sleeper. The regular headers (similar to what we're selling now) were not good enough for this guy and he paid to have true equal length headers made, which they did (after warning him they didn't think it would be worth the extra money) -- each primary was within 3cc of the others when measured volumetrically. Beautiful part, absolutely gorgeous, and they had to dyno it to find out what the difference was over the production headers.

Sure enough, the equal length header made more power. Exactly 0.86% (yes, less than one percent) more and it cost twice as much. The customer didn't care, it was a vanity part for him, but I was quite surprised because I thought it would make a much bigger difference.

I know the fabricators, I know the customer, I held the part in my hands. I saw the data from the dyno runs and I know this to be the truth.

Brian C Catts
Cattman Performance

 

Cattman please post your dyno graph that you used in your header thread way back when. I wanted to review it to compare to the results of others. Also couldnt remember if it was a car that had a y-pipe before or not. Do inform. Thanks

 

Smart move


Dave

 

Of course I'd be willing(5spd, local, 28K miles, and stock), but I can't cough up $750 plus $200+ for the install anytime soon.

Maybe after summer.

 

I will as soon as I can, Cardomain.com seems to be down right now and the graphs are there.

Brian C Catts
Cattman Performance

 

12345678

 

Sure, I'd happy to. I'd search it up, but since I only send maxima.org about a $1000/year I don't have search capabilities.

As a reminder, the test was done on the Cattmobile, a 97 SE 5MT with an PR CAI and Cattman catback exhaust on it already. Of course the car had a y-pipe previously, but I had put on a stock y-pipe a few days prior to the baseline so the computer would readjust to it.



Obviously the results on this normally aspirated car are very different than the s/c tests, with much stronger low-to-mid range performance and a drop-off at upper rpms, but that's primarily the difference between the engines not the exhaust parts. The headers resemble a y-pipe curve, but stronger, with a fatter top end margin.

Brian C Catts
Cattman Performance