Header question 2.5 2002-06 Altima

[Darius]

I have searched and searched on NICO but haven't come up with anything that is definitive. My gf is about to buy a 2005 2.5 Altima and I want to get a header for it to get rid of the pre-cat BS. I know the Altima and SpecV Sentra run the same engine, but do they use the same "downpipe"?

The reason why I'm asking is because DC Sports has a header and downpipe for the Sentra that is 4-2-1 and about $125 less than the Altima header by Stillen. Will the sentra header/downpipe line up with the Altima exhaust?

Sorry if this is a bit of a repost, but I couldn't find any info on it.

[SHIFT_COUPE]

My first inclination is to say "Yes" because of the QR25 being used in both vehicles. However there might be some differences in the downpipe location because of the Altima being a different sized vehicle. I wish I could give you a 100% positive answer but I can't. My recommendation with things like this is if it hasn't been specifically produced to fit your vehicle than chances are it probably wont. Whose to say some sort of fabrication might get the job done. Hard to say really. Thats what guinea pigs are for

[SHIFT_COUPE]

On second thought. I'd say go for it. It must man with a little finagling.

[adidas2go]

also check to see that the cat is the same on both cars. if the cats arent then theres a chance the fitting to the header is not going to be the same. and check on the o2 sensor position. If your car comes with an o2 sensor in header then you'll need a header with an o2 port. if not and you want to fabricate you can always buy a universal o2 sensor simulator. so your car thinks theres still an o2 signal and it doesnt throw a light

http://www.o2simulator.com/ind..._id=9

[Darius]

Good idea on checking to see if they share the same cat part numbers. I'll look into that.

As far as O2 simulators, I have read on other <ahem> Nissan boards that say the 05+ models have wideband O2 sensors and that an O2 simulator will not work because the sensor is not your standard stoich/not-stoich sensor. I have seen the solution to this being an O2 spacer bung that screws into the existing (or new) bung to set the sensor out of the exhaust stream. BUT if you have an earlier 2.5, the O2 simulator works great because they still had standard O2 sensors.

My question is, if the 2.5 has REAL wideband sensors, I want to be able to tune this beast to get my gf like 35 mpg. Just lean the crap out of it . I would really like to have someone confirm this though!

[SHIFT_COUPE]

I believe 02-03 models in Auto Trans only have the wideband o2. This is the case with the Sentra QR so I don't see why it would differ much in the Altima.

*Edit 02-03 models sorry. What year is your girls?

[Darius]

She hasn't actually bought one yet, but the one we might get a sweet deal on is a low mileage 2005. We're going to check it out tomorrow.

[adidas2go]

My question is, if the 2.5 has REAL wideband sensors, I want to be able to tune this beast to get my gf like 35 mpg. Just lean the crap out of it . I would really like to have someone confirm this though!

Be careful not to lean it out to much as to cause knock (pre ignition of the pistons). Just curious what are you going to use to program your air/fuel ratio?

looks like its a narrow band o2 sensor. It lists your car as using a 4 wire setup. 4 wire is narrow band.

wide bands used a 6 wire setup. 1 Heater power, 1 ground, 1 Reference high, 1 low, and 2 wires for current.

[Darius]

Thanks for doing the research for me! I'm still kinda new to Altimas so it helps when you guys can chime in when I get stumped on stuff like that.

haha yeah I know how to tune. I do my own datalogging and tuning on the RB so I know all about knock. Damned physics and chemistry butting heads!!

Anyway, I think the cheapest way to tune it would be to get an HKS AVR ($125) and simply knock off an AFR point across the entire map. However, I would definitely do that on the dyno with a wideband to make sure the AFRs were still healthy and that the engine wasn't knocking at all.

[adidas2go]

sounds good let us know how it goes. good luck!

[Darius]

Alright, so I bought the Stillen header from Sport Compact Only and it took foooooorever to arrive. I think I ordered it from them before Thanksgiving and I just got it today (so about a month wait). SUCKED! I went with the Stillen because of the name and with hotshot being out of the business now. SCO had the best price ($511 shipped) that I could find so I figured that it was worth the money.

I was wrong! When I loooked at the welds on the header collector, it looked like they were done by a 5-year old working on his first welding project. The cone welded in the center of the four runners honestly looked like a piece of $hit on end. I have pics to add to this but I will have to post them later. Also, the head flange appeared only to be welded partially on the exterior side but entirely on the interior side of the runner. I'm not sure about the design theory behind that but I would think a full weld around the outside of the runner pipe would be better and not much more work.

The race pipe/cat delete pipe looks amazing though. The welds on that thing are nearly picture perfect! I just wish that for $500, the collector wouldn't have looked like it was made in China. I'll post pics later tonight.

[adidas2go]

sorry man that sucks about the welds. You get what you pay for sometimes. You should have told us you were getting hotshots im sure more than one of us would have warned you about those guys. Sounds like you did alright with the install tho. Good going, cant wait to see the pics

[Darius]

haha I don't think you read that very closely.

I got the Stillen so I should have gotten a better quality product, and I haven't installed it yet. I'll definitely post pics and video up after I finish it though.

[Darius]

Here are the pics. It is kind of hard to tell what I'm talking about but maybe you can see that the ends of the runners are all uneven lengths (+/- 3/8") and so on...











Wooops! (had to sneak this one in there too) Don't get too excited. Its not for the Alti.

[generic808]

sorry man that sucks about the welds. You get what you pay for sometimes. You should have told us you were getting hotshots im sure more than one of us would have warned you about those guys. Sounds like you did alright with the install tho. Good going, cant wait to see the pics

Hotshot makes one of the BEST headers! I think they went under, but they did have one of the best headers out there! I ran their ceramic one on my old SE-R and it was pure quality. I just wish they were still around to make for the new Altima's. I'd take the Hotshot over Stillen any day!

[Darius]

I searched high and low for a hotshot because everybody loved them and they had decent gains with good longevity. Just sucks that they quit making them. I could have gotten ahold of a used one, but who knows how hard it had been run and how long it would have lasted. It is for my gf's car so it needs to be reliable for her too. I truly wish they would have sent it to me without the coating so I could take a grinder to those welds and smooth them out. Oh well.

Prospective Stillen customers beware, their products are not all the inflated price makes them out to be.

[Darius]

Got the header installed. The fitment was great, but the O2 sensor simulator didn't work. The header sounds like an empty tin can until about 4000 rpms and then starts to sound better, deeper and more throaty. You can feel the added power up top which is nice, but still unimpressed with the sound and fabrication.

Here's a short video clip of the interior sound:http://www.youtube.com/watch?v=fcppK1vD3OI

I made an intake for it so I'm going to install that and see if the header sound changes or resonates less. I'll keep you all updated.

[generic808]

After a break-in period, I'm sure the sound will get a little better. I was disappointed with my Hotshot at first (sounded a little tinny), but the sound improved after a few hundred miles.

[spike228]

I have searched and searched on NICO but haven't come up with anything that is definitive. My gf is about to buy a 2005 2.5 Altima and I want to get a header for it to get rid of the pre-cat BS. I know the Altima and SpecV Sentra run the same engine, but do they use the same "downpipe"?

The reason why I'm asking is because DC Sports has a header and downpipe for the Sentra that is 4-2-1 and about $125 less than the Altima header by Stillen. Will the sentra header/downpipe line up with the Altima exhaust?

Sorry if this is a bit of a repost, but I couldn't find any info on it.

No, the spec-V does not have the same down pipe as the Altima 2.5. However, the standalone headers are swap-able between the sentra and altima. In other words, anything without a down pipe will work. Stay away from XS power. They have clearance issues.

You are pretty much left with the nismo headers and OBX.

Good luck.

edit: guess i am a little late.

[TheBourneAltimatum]

Got the header installed. The fitment was great, but the O2 sensor simulator didn't work. The header sounds like an empty tin can until about 4000 rpms and then starts to sound better, deeper and more throaty. You can feel the added power up top which is nice, but still unimpressed with the sound and fabrication.

Here's a short video clip of the interior sound:http://www.youtube.com/watch?v=fcppK1vD3OI

I made an intake for it so I'm going to install that and see if the header sound changes or resonates less. I'll keep you all updated.

you made an intake? how? what materials did you use? if you can make an intake, i am moving my battery and making CAI :

[Darius]

Thanks for the encouraging news generic. I really hope the "tinniness" goes away.

Making an intake is not that tough. I mean it takes a little effort to source the right parts, but I just pieced it together. I will try to finish the install today and get pictures up. Note that this is for a 2005 2.5 and not a 2007. I would imagine that there's room to squeeze something in the 2007 next to the battery though.

[Darius]

I installed the intake today (for the most part) and it sounds much better IMO. I have a couple of things to do like reconnect the PCV line from the valve cover and trim the MAF adapter plate.

There is still a little of the raspy sound from the header but it doesn't sound as high pitched anymore. Here's a video:

http://s118.photobucket.com/al...1.flv

And a pic of the engine bay: