studman

Newer information is located near the end of this thread. I will update this first post once I get my scanner/computer up and running again in my new house.

----- Original Message Is Below -----

Well, here's the deal:

http://maxima.theowensfamily.com/dyno.html

As you can probably see, I lost 1 peak HP and 8 peak ft/lbs of torque. Also, you can see the overall curve is lower. There will definitely be a call to Stillen to find out why I lost power.

The first dyno is the Best Run. This was after resetting the ECU, and then re-tuning the E-Manage. This was not the first run, but the best run.

The second dyno is the top 2 runs. These were the number 1 and number 2 runs compared, so you could see that it was not a dyno error. The tunings between the runs did not change either.

The third dyno is a comparison between the last dyno I did (which was right after I put on my rims). Between that run and the best run, you can see the losses.

I will say this... the car rows through the gears faster. It seems that it "spools up" faster than before.

As far as the loudness is concerned, it is still louder than a Y pipe and full cat-back, but if you have never had a Y pipe, these headers will be loud as anything. I am working on getting audio clips of before and after uploaded as soon as possible.

Please... slamming Stillen right now isn't gonna help this thread or the .org, but I can understand your (and my) hesisitation to persue this further. I will keep everyone updated as my pursuit to find out why this happens continues.

IceY2K1

iTrader: (3)

Do you have the Run Files by chance? Before/after?

I feel a surge of Cattman Y-pipes being ordered with a TS ECU instead.

Thanks for taking one for the TEAM!

808SE

good luck.

IceY2K1

iTrader: (3)

Also, I'd have added some fuel from 3.5K-5.5K.

Did you try going more rich to see what happened and then you leaned it out?

1BADMAX

I talked to him just a second ago and he said that he fooled with the managment system trying to do everything and nothing happened. Looks like Stillen has some explaning to do.

IceY2K1

iTrader: (3)

I was afraid of that.

1BADMAX

Hopefully WILLSE will have better results. If he doesn't fair any better then Stillen is going to have a real problem on there hands.

MaximaMan77

Will is still waiting on his mount. If all goes well we'll both be dynoing on Tues.

MaximaMan77

Wow, 17.5 is getting lean.

PearlRalizinG2k

this look like stillen has made their real name show again "stealing".
hope everything goes well jeremy! how does it sounds anyways?

03BlkSETE

iTrader: (3)

NO!! Say it isn't so!!

deezo

iTrader: (3)

hmmm.........

2k2-blk-6spd

hmmmmmm......

BigDogJonx

iTrader: (7)

studman, couple questions. Why are you comparing dyno run 13 with run 27? On your July 11, 2003 runs you show run 11 being the best run of almost 223.5whp and 235ft.lb. Also that run all the way to redline is creating power.

How come when you compare 13 and 27 the runs just lose major power after 6000rpm? Im just wondering why runs 11 and 12 made power to almost redline and 13 seems to lose power at 6000rpm? Something dont seem right with those runs.

Cause if you compare run 11 to 27, you are losing almost 7whp and 12ft.lbs.

Im not knocking on anything or calling you out, just wanted clarification unless im looking at something wrong.

Dixit

studman

Runs number 11 and 12 were done before I had my rims installed. Runs number 13 and 14 were done after the rims were installed, which showed a 4 HP loss. All 4 runs were done using the same programming in the E-Manage.

Run 13 was one of 2 runs that were made. The lines were the same on both runs, but a slight loss in power up top was noticed. I can only attribute this to the rims and the rotational force, as no E-Manage programming took place between runs 11 and 14.

I don't know why this is. I tuned the car everywhere from 17:1 to 11:1 and in between to try to regain the top end. It just isn't there. The other thing is that the runs 11-14 didn't go all the way to redline. The dyno tech stopped them early because he thought redline was at 6500 RPMs.

Agreed, but again, runs 11 and 12 were on the stock tires, not my aftermarket ones.

***

I didn't print out numbers 15 through 28, with the exception of 27 because they were tuning runs. Run number 28 was just a verification of the final settings. Run 28 was also run about 2 minutes after run 27, so the HP numbers were 2 HP lower due to heat soaking.

As far as the tuning, trust me when I say that the car is tuned. When I first installed the headers, I cleared the tables in the E-Manage completely. The car was running a 15.4:1 at idle, which is extremely rich for idle when compared to the stock ratio of 17:1 to 18:1. I tuned the car one range at a time, concentrating on a 1000 RPM range (minimum of 2 adjustments per 1000 RPMs). Once I found the peak air/fuel mixture for that range, I proceeded to the next range. I continued this all the way through the RPM band. Once each individual range was completed, I then compiled them into a "working starter file". I then loaded all those settings into one mapping, and uploaded it into the E-Manage.

From that upload, I started the process all over again, but this time I was going for peak HP/TQ in a 500 RPM range. I did this through the entire powerband again. I have found that different cars need different requirements. E55AMG2's car wanted more fuel after 6000 RPMs for peak HP. My car likes it lean. Once I had tuned each 500 RPM range, I put that into a second "working file" and uploaded it to the E-Manage. From there, I tweaked the settings while concentrating on the ranges that I saw a loss at (when compared to the pre-install dyno).

The car was on the dyno for over 2 hours being tuned. I even reset the ECU after a few runs to allow it to adjust to the new headers. The O2 simulators worked fine, and I even checked them with a digital ODB-II scanner that the shop had.

I am calling Stillen on Monday to see what they have to say about this. The only reason I can think that I lost HP/TQ is because of a loss of backpressure. I had the system checked for leaks by myself and 2 other technicians while the car was on the dyno (it's an above-ground dyno).

I am as confused as most of you are, but the numbers don't lie. I even went through the hassle of re-uploading my old settings (before the install) into the E-Manage and running a run with them. The dyno that I posted was the absolute best overall and peak dyno that I had that would accurately display the gains/losses of the header install. I could have posted others, but they were "tuning" dynos, which means that the curves were not correct and could not be considered accurate for comparison.

Remember that my car was tuned (before the install) on the exact same dyno in July 2003. I changed the rims/tires on the car and re-ran the car in August 2003. Since then, nothing has changed on the car other than the header install. I then re-tuned the car after the headers were installed and posted the results.

The results are based upon the "best" dyno before and after. Runs 11 and 12 don't count because they were created BEFORE the rims were installed.

Quicksilver

iTrader: (1)

Damn man...that sucks...

Headers on my truck made mad power. I can only hope (for Stillen's sake) that this is some kind of an isolated incident...

If not, screw them!

1BADMAX

Yeah I think that pretty much says it all.

BigDogJonx

iTrader: (7)

Gotcha studman. Just to clarify, 15.4:1 is lean actually, you did mean that right? Cause the lower the number the richer it is. 15:1 is dangerous territory for us boosted people.

Dixit

WILLSE

i have it aranged with All Star Performance to put the mount on tues so i can dyno tues at 4 with maximaman777. that is some **** to see . i hope that isnt the case with me. does ur ur car feel like its fast as hell or does it feel just a lil just a lil faster? ill be kinda ****ed if my dyno turns out like that. if mine does we might have to have a lil convo with stillen. im definately dynoing tues. ill let u guys know as soon as i get it done.

will

juice

iTrader: (6)

Studman - I am not in anyway questioning your dyno results however I have some of my own information I would like to share.

I took my 02 SE (auto) to the track with intake/udp/y-pipe and full exhaust on my 18's and ran consistent 14.7s with an average trap of 94.5 (4 runs).

A few weeks later I gutted both of my precats, reinstalled them and took the car to the track again...consistent 14.5s with an average trap of 96.5 (6 runs). As you can see I was a full 2 tenths quicker and 2mph higher in my traps.

So, the fact that the stillen headers remove the precats alone convinces me that power is to be gained. I am curious as to why you showed a loss of power?

I will be installing the headers on my car tom morning and taking it to the track sometime next week. Hopefully the headers will yield better results than just the gutted precats alone otherwise I have wasted some ca$h.

studman

Dixit: While 15:1 is normally considered lean, at idle the car's mixture is normally around 17:1 to 18:1 in order to save gas. Naturally, if you are boosted, your ratio should be alot lower. But since I'm still N/A, the car was running rich at idle (when compared to the pre-install mixture). I looked back over the post and see how you saw that, and I edited it to make a little better sense.

WillSE: The car feels faster. The track was closed for a private event last night, so I won't be able to get a timeslip for the next few weeks (I'm in the middle of moving). As far as a comparison, I can't say that it's fast as hell, but I do run through the RPM ranges much quicker than before. That could be a result of the loss of weight too. I would say that the car is more than just a little faster, but still could use some improvement. Please let me know when you get your dynos. If you need space to host them, let me know.

juice: Join the club. Myself, E55AMG2, 4 shop employees, and the shop owner are all confused as to why it lost power. The pre-cats alone should be good for around 5 HP.

The only explanation that we could come up with is the loss of back-pressure. Here's my current performance mods:

PR CAI, Timing Advance, Greddy E-Manage, Stillen Headers, (Stillen Y Pipe for the Headers), CarSound Cat, WSP 2.5" B pipe, Custom Fabricated 2.5" Muffler Pipe (goes over the rear axel), and a FlowMaster 60 Series Muffler.

As you can see, the exhaust is wide open. That would lead to a loss in backpressure. When I originally installed my WSP Y, Cat, and WSP B pipe, I also had a loss in backpressure. I corrected it by changing the muffler from the MagnaFlow to the FlowMaster and then re-tuning the car. I don't know if the muffler itself did it, or if it was a result of the ECU finally adjusting, or both.

That's the only explanation that I could come up with so far. If you've got a better one, by all means please share it with me.

SR20DEN

iTrader: (7)

I will wait and see results from other people before I draw any real conclusions here. As it stands I suspect your incident will be an isolated one and can be explained away.

NT2SHBBY

hmm...more evidence to the whole "I'll believe it when I see it" theory....

studman, as Icey said, thanks for "taking one for the team" on this one....

03BlkSETE

iTrader: (3)

I remember when the Altima guy (snolden ) installed the protoype hotshot headers on his Altima. Initially he thought the car felt a little bit more powerful but he wasn't to impressed.
He later posted that the car seemed more powerful everday and shortly thereafter he was very impressed with the power gains.
I'm not sure if the E-manage overrides the ECU learning process but it seems like it to a few days to adapt on snolden's car.

Juice - sent you an email.

02MaximizedVQ

Maybe we should consult with our Altima bretheren and see if the headers are making power for them?

mzmtg

iTrader: (11)

Nissan Performance Mag's Altima gained 17 whp with the hotshot headers...

http://www.nissanperformancemag.com/...ltima_headers/

Aquineas

I'm baffled by this... My HS headers will be here (hopefully) on Monday; I'll let you know what I find (although admittedly the results aren't directly comparable).

Good luck, and please keep us posted..

PrinzII

iTrader: (2)

Sounds like the concesus is that there is a loss of backpressure. However, what if someone decides to add a cat with a 2.5" inlet along with a Magnaflow 14615 muffler, would that cause a significant loss of backpressure since headers do reduce backpressure by their very nature.

KLOOGY

iTrader: (12)

Im puzzled , but I would like to see a second car dyno these. I truley didnt feel any gains when I had my Y pipe, but that was the Warspeed POS. I will keep a close eye on this. Just a word of caution to a lot of you guys who are ear - sensetive. There is no question that these headers will make your card LOUD ! My y pipe was loud enough.

03BlkSETE

iTrader: (3)

Here's snolden's initial impressions

http://www.nissantalk.com/forum/show...s&pagenumber=5

mzmtg

iTrader: (11)

How many times do we have to go over this?

Engeines DO NOT "need a certain amount of backpressure" to make good power.

Backpressure is always bad. Pipes that are too big cause loss of low end power due to the loss of exhaust stream velocity, not the loss of backpressure.

MaximaMan77

Another thing to think about is these headers left unwrapped with no heat sheild will increase the temp of the engine and underhood temp, while underhood won't matter during the dyno runs there will still be significant heat loss in the exhaust track. The header is much thinner than the stock manifold so more heat will be radiated out that is better kept in the piping. I'm was already thinking about putting header wrap on them right out of the box when I buy'em and seeing if the sheilds will still fit.

Also the "loss of back Pressure" would mean not only a lower temp in the combustion chamber but less unbrunt fuel staying in the CC. Also given the info from TS that Nissan has the car set to run rich up high what do you think about doing a few runs with the E-manage removed and seeing what you get from the stock map. I have a feeling you will see more power with more fuel.

Lastly what did the timing look like during the runs?

JayMax00

It seems to me that from the results on gains from aftermarket parts on the 2k2=2k3's is that nissan did all the work for you from the factory and trying to make the car faster from simple boltons doesn't work that well. I don't know maybe I'm wrong. But sorry to here that about those headers.

WILLSE

guys before we jump down stillens throat saying there things dont do **** let me get my dyno and compare the results.. dont want a negative view on the headers with only 1 dyno sheet. if mine proves to be abnormally low as well then we will definately get to the bottom of this!

will

Quicksilver

iTrader: (1)

Man, you couldn't be further from the truth. Please keep your ignorant comments to yourself, as it is obvious that you know nothing about the 3.5L ECU/engine/exhaust...

And mzmtg and maximaman777, you guys are both correct in that less backpressure in the exhaust system is ALWAYS a good thing for any N/A engine. Sure you might lose some TQ/HP from idle to 1000-1200 RPM, but it will not have a significant effect on the overall low end performance (as you're not really making THAT much usable power there anyway). And besides, we're talking about a FWD platform that has enough difficulty keeping traction as it is, so this might actually help our launches in the long run.

Properly designed headers on any N/A car have a significant improvement over the entire range of power. Your area under the curve will be significantly increased (as long as the Stillen headers were correctly designed). I can only hope that it's the ECU and "maybe" some excess heat in the engine bay that is causing this current performance loss...if not this, it's a bad header design (and that I find hard to believe).

Dave B

Studman's numbers don't lie, fellas. It appears that's he's done an excellent job of reducing bias by using the same dyno and trying multiple runs with different A/F ratios. It's pretty clear to me that these headers are worthless. You could wrap the headers and/or coat them in Jet Hot, but it's not going to change much (maybe 3hp at best). A lack of backpressure is not the cause. Like MZMTG pointed out, it's the EXHAUST VELOCITY that makes power. Too much area in the pipe will slow velocity and the air gets turbulent. Studman is running a 2.5" exhaust which is perfect for an NA VQ. He doesn't have an exhaust velocity issue due to too large of exhaust. As for NissanPerformanceMags numbers on the Altima, I don't trust any dyno that comes from that mag. Somehow every product they test seems to make 2X-3X as much power as private party will see on their dyno. I don't trust them one bit.


Dave

02MaximizedVQ

I'm going to have to agree with Dave B. on this one. Unless there is an underlying problem with Studman's tuning equipment (and I hope that is the case) these headers are worthless. If worse comes to worse I would buy a y-pipe and gut the precats. Would be much cheaper anyway!

I guess what we need now is someone who is not tuning their ECU
to install the headers, dyno, and let the ECU adjust for a few months and then redyno.

Jesse

PS- any word on the supercharger kit from Alpine??

MaximaMan77

Thank you for your insight, you have really contributed to this thread and gone against what Studman asked in his 1st post. If you have any thing else that you would like to share please feel free to continue to contribute your wonderfully enlightening thoughts.

Quicksilver

iTrader: (1)

Quote:
--------------------------------------------------------------------------------
Originally Posted by Dave B
Studman's numbers don't lie, fellas. It appears that's he's done an excellent job of reducing bias by using the same dyno and trying multiple runs with different A/F ratios. It's pretty clear to me that these headers are worthless. You could wrap the headers and/or coat them in Jet Hot, but it's not going to change much (maybe 3hp at best). A lack of backpressure is not the cause. Like MZMTG pointed out, it's the EXHAUST VELOCITY that makes power. Too much area in the pipe will slow velocity and the air gets turbulent. Studman is running a 2.5" exhaust which is perfect for an NA VQ. He doesn't have an exhaust velocity issue due to too large of exhaust. As for NissanPerformanceMags numbers on the Altima, I don't trust any dyno that comes from that mag. Somehow every product they test seems to make 2X-3X as much power as private party will see on their dyno. I don't trust them one bit.


Dave
--------------------------------------------------------------------------------

Thank you for your insight, you have really contributed to this thread and gone against what Studman asked in his 1st post. If you have any thing else that you would like to share please feel free to continue to contribute your wonderfully enlightening thoughts.





Useful posts only from this point forward...

MaximaMan77

Here we go again. 1 set of numbers on 1 car proves to all of us that the product sucks and we shouldn't look any further and focus on another product that no one has any info on.