MPLexus301

iTrader: (3)

Hey Guys,

I have been doing some research on headers and it seems that OBX is the preferred brand. I have a few questions though...

1) How do these affect power/performance?

2) What about gas mileage?

3) Is there a significant difference in noise in the cabin?

4) Any issues with CEL or other electronics?

5) Anything else I should know about?

Thanks

LeXaNoMicS

Check out lexbox's sticky...

1. I dont think anyones dynoed but lexbox has a review of this also , I think he said it pulled harder in first three gears , BUTT DYNO.

2. Not sure

3. Yes it gets louder, not sure how much

4.Yes , you need 02 sims for the CELs

5. you will get black soot on your tail pipes due to not having CATs.

MPLexus301

iTrader: (3)

Does this have an impact on emissions testing? What are sims?

And thanks for the reply

LeXaNoMicS

yes if your state requires you to pass emissions you wont pass without cats unless you got someone in your back pocket. The 02 sims are to trick your ecu into thinking you havent modified anything, sorry im not an expert tho lol

MPLexus301

iTrader: (3)

Thank you for the help

LeXaNoMicS

oh and if you read LEXBOX's post you will se he took them off after he had to clean his pipes more often , what does that tell you? if it was a big gain i doubt he would have minded the extra soot

mex lex

iTrader: (4)

You will see a gain from the header, the exact number will vary. Gains with that type of header will yield ~10rwhp. This outline breaks down the NA options and gains you will see from bolt ons for the VVTI GE.

http://my.is/forums/f88/im-new-want-...-is300-343378/

The IS guys recommend leaving your stock y-pipe with this type of header for these reasons:
1) If you are worried about sound, the stock y will help things keep quiet.
2) You will get very little or no black soot at all because you will still have a cat in place.
3) You will make more tq with the stock y than the aftermarket y. This will appeal especially to the guys worried about losing low end power.

The o2 sim is so you won't get the annoying CEL. The CEL will be from your Bank 1 sensor 2 and your bank 2 sensor 2, the two sensors that you will not plug into your exhaust. These don't affect afr, they just monitor the cats. The ECU calculates off the readings from both sensor 1s, that is why you only plug in two of your four oxygen sensors. You could drive your car without the o2 sim and it will run perfectly fine. Its just that it will get annoying having the CEL and sooner or later your traction control light will start to flash to further warn you. Also, if something else starts to go wrong, you might not realize it right away because the CEL will always be on. Not to mention, you won't pass OBDII emissions scan test.

Based off my personal experience, if you have a header, definately get fuel management. You guys with SRT intakes will work, but if you have the option of going with an safc or those who want to squeeze the most power out of your motor and have more dough to blow, get an emanage ult. I have a cat in my y-pipe but I still get the fuel smell when I run the car hard because it is running rich with no means of to adjusting the fuel whatsoever. The ecu will also learn around your header, unless you drive hard all the time and/or reset your ecu constantly.

Basically, it comes down to whether you will do it or not. Technically you 'shouldn't' change your header, but if all you will base your decision on is gains, you won't be too happy. This is where many guys will argue, just save your money and go turbo or buy a GS4. That is not as easy as it sounds, and besides, there are some of us that will never go turbo for one reason or another or be able to get rid of our GS3 and get a GS4. The nice thing about bolt ons is that you will see and feel and increase in performance if you do your research and pick your setup accordingly. For $1500, give or take, you will see gains. So, weigh your options, have a slow,stock car and spend $0, spend $1,500 and make your GS faster, or spend $10,000 have a fast GS.

SUPRA OWNER

If you are NOT planning to turbo this is the way to go if you can deal with the extra noise. I dynoed 207rwhp with SRT intake, OBX headers,ypipe and HKS rear section. Gas mileage was about the same since I didn't gas it every minute due to the extra noise. You need 02 sim for the cel.

Later, Jose

Chris4.3

iTrader: (32)

Thanks for your post mex lex. I kinda regret installing my header. Unless I install a/f controller, (have exhaust, intake) I might just swap back to the stock y-pipe to regain low end

mex lex

iTrader: (4)

No problem , why do you regret installing your header?

I am in the same about as you, I am unsure if I should do a/f. I have a emanage ult., I am thinking of installing it or selling it and just getting a safc. However, I promised myself that I wasn't going to put more $ into performance until I finish the rest of the little things I started on the car. Decisions, decisions .

sakataj

iTrader: (182)

funny when i was in the honda camp no1 would touch OBX headers but the ricers but they seem to be the preferred header on the gs300. always amazed me as to why!

mex lex

iTrader: (4)

Pretty much lack of options, or should I say the only option. There are tons of different brands on ebay, but they are all the same design. They are just branded under different names.

albalushi

HaY Sup,

It seems that you are well experianced in GS. I really would love you to give me some advices for my ride. In the beginning I am going to tell you the modufication which are allready installed in my car then you can advice for HP gain:

1- Tanabe Medalion Exhaust CatBack.
2- SRT AirFilter with ECU.
3- The mid Exhaust filter or what ever it is called has been removed( which come imediatly after the Header.
4- Tien Spring race which will be cutted soon for more lowering.

I want to add a HEADER and if necessery a DownPipe. what do you thing will be appropriate to add on my ride.

Please Advice and Regards,
Al-balushi

Chris4.3

iTrader: (32)

Those are pretty much the basic bolt-ons we add for a lil more hp and noise. I recently swapped my y-pipe back to stock for low end, since there was too much flow. It also got rid of the cel. I kept the header though. Drives a lot better now.

Alexus_300

iTrader: (4)

The test that was conducted over on my.is was done years back on my friends ride and mine prior to us going turbo. For those who wish to install headers without any sort of fuel management is a no no. You wonder why? Well, with the factory Maf sensor, it is programmed to see a certain amount of airflow and restriction which is calculated into the diameter of the intake tube. When you run a header, those restriction is less which will cause your AFR to be in the 14.8's-15.2s which is pretty lean at WOT. This is the main reason why a simple piggyback such as a SAFC is needed because you will need to add more fuel in the 4200-6300 rpm range to compensate for the extra flow. I have my dyno chart somewhere that I'll dig up to show you guys when I find it. With an K&N intake, header, stock Y-pipe, and L-tuned exhaust, I tuned my car for drivability in the midrange, I made 197.8 rwhp. If I was tunning for max whp, I made 209.3 rwhp at roughly above 6000 rpm.