Upgrading exhaust/need new safc for gs4
Thread Starter
Driver
Joined: Feb 2009
Posts: 136
Likes: 0
From: CA
I am just now getting back to this thread I made. I only wish there was a clear and cut answer as to what I should do, but, I guess I will find out! I placed an order for the headers a week ago. Luis at L-Tuned said that the Tanabe cat-back and headers combo should pack a good punch; I won't experience any power loss, instead, I should gain from 22 - 30 HP. Any thoughts??
Lexus Champion
Joined: Feb 2001
Posts: 3,124
Likes: 32
From: Texas
well i apriciate all the advice i would think the factory x pipe/resonator would be restrictive, it looks like it but after reading what you say i might just cut out the rear resonators and do rear sections. I do own a muffler shop but i dont own a dyno 
, so i cant just keep changing exhaust out and head to the dyno and pay $$$ every time. IT would be nice but i just have the time to do it work late hours all the time. Is there a picture of Burns style x pipe like cut open(exposed)? i was going to use an old style magnaflow, cuz i can buy one real cheap. But if can get an idea of how the Burns style is made i can duplicate it, if not i'm leaving the first resonator alone.
Edit: i can easily make something like this myself http://www.jegs.com/p/JEGS/JEGS-Narr...30498/10002/-1
, so i cant just keep changing exhaust out and head to the dyno and pay $$$ every time. IT would be nice but i just have the time to do it work late hours all the time. Is there a picture of Burns style x pipe like cut open(exposed)? i was going to use an old style magnaflow, cuz i can buy one real cheap. But if can get an idea of how the Burns style is made i can duplicate it, if not i'm leaving the first resonator alone.Edit: i can easily make something like this myself http://www.jegs.com/p/JEGS/JEGS-Narr...30498/10002/-1
The Burns is a 2-1 merge collector connected to a 1-2 merge collector. It accelerates the gasses through the X.
Creating an effective merge of whatever style is like any other exhaust exercise... test, test, test. Since the stock one works so well for the application; street car with low speed torque and throttle response while providing minimal restriction at peak RPM/power, the answer is either keep the stocker or be prepared to test multiple designs.
Here is a picture showing how smoothly the GS400 Y pipe joins the 2 50mm pipes into the single 60mm pipe. Each 50mm is stretched and formed into 1/2 the 60mm pipe. This is very nice as the 60mm is less area than the two 50mm. This would require an acceleration of the gas to make this transition. By doing it at the end of each 50mm pipe you get a one way check valve that flows just as much as the 60mm will allow. Like I said, a pretty darn good part at these power levels.
Lexus Champion
Joined: Feb 2001
Posts: 3,124
Likes: 32
From: Texas
I am just now getting back to this thread I made. I only wish there was a clear and cut answer as to what I should do, but, I guess I will find out! I placed an order for the headers a week ago. Luis at L-Tuned said that the Tanabe cat-back and headers combo should pack a good punch; I won't experience any power loss, instead, I should gain from 22 - 30 HP. Any thoughts??
...I think he is just saying that for the money the power increase is negligible. As with most (if not all) exhausts you are lucky to see 5whp gains on an N/A car from what I have researched.
Most of that is mid-range power that you can feel in real driving instances!
I saw gains of approx. 16whp (251whp--->267whp) after JUST the addition and tune of the Apexi Neo last year! With the addition of the headers and a re-tune I saw an additional 15whp (267--->282whp).
--------------Power history--------------
Assumed: Bone stock: 243whp
Fact: Addition of K&N intake, Borla Exhaust and TM Spark plugs: 251whp
Fact: Install and tune of Apexi Neo: 267whp
Fact: Addition of S&S headers and re-tune of the Apexi Neo: ~282whp
In the order from oldest to newest:
-Apexi SAFC (The original)
-Apexi SAFC II
-Apexi Neo
They all pretty much do the same thing but as the models progressed there is better (more detailed) tuning abilities and the screen display is full color on the NEO.
You can pick them up for around $250 almost anywhere. You can install it yourself. Pick a location and start running wires; I used the center ashtray for the unit itself (gutted it out with a dremel; ashtray opens and closes and looks great).
As for the hook up and the tuning I had a shop do it because I was afraid I was going to screw something up; it could cost you your engine if you don't know what you are doing. Hook up and tune (on the dyno) cost me $240. So the next year when I got a re-tune...it cost me another $240. Oh, and I bought a custom harness from boomslang.us (which I referred many members to) where you do NOT have to hardwire (solder) anything into the ECU; everything is plug 'n' play; expensive though...$225/shipped.
GL!
Lex,
Is there any reason the Neo/S-AFC couldn't be left out in the engine bay, and just run the required ECU wires into the passenger compartment?
I'm all for set it and forget it... as well as maintaining the stock/stealth factor without using a dremel.
Is there any reason the Neo/S-AFC couldn't be left out in the engine bay, and just run the required ECU wires into the passenger compartment?
I'm all for set it and forget it... as well as maintaining the stock/stealth factor without using a dremel.
hey all, i have some similar questions, (mostly for jbrady and rock alex), I have an sc'd gs4 with no third resonator/ cat and 3" pipes back from that to some large top speed cans. I'll be getting the S&S headers as soon as I can find some(rather not pay retail) and I was wondering if I should leave the cats/ colector area alone or change them to 3" is the s%S headers 3"? don't mean to thread jack, this hould get answered quick i hope
Last edited by gs400 civi; Jun 19, 2009 at 09:45 AM.