Ok I have had these for a while and now they are finally installed. These where my mods before the headers, SRT intake, Carson tuned exhaust, 3.76 non-lsd diff.

This is my 2nd day with them and I definatly noticed a large increse in response in the low to mid speed. I noticed the gains more that any of the other mods I have done so far. I can even break traction with part throttle now. There is and added smoothness to the accerlation but there is the neck snapping responsiveness on stand by. It's more of a fun car to drive from this mod. The car definately seems to be breathing a lot better, the high end gains are less noticable to me. I think it is because of the 3 cats and the y pipe, which is ok cause they are on the way out anyways with my custom ypipe with an X-flow muffler and no cats. I tried to get the header to cat flanges in town but no one had that type, so I had to order some from s&s instead. Once they are in them I will build the ypipe. Then I will dyno it. I also have new stock plugs to put in as well.

If people are not seeing the same gains I am, I use 94 octane which may be the difference.

 

would you consider showing a video clip.....I would love to hear it....PLEASSSEE!

 

I would except that one of my 2 gaskets on the stock y pipe is not sealing 100% so there is a minor exhaust farting sound currently.

Once I get the y pipe installed I will make a video for sure. But the car does sound throatier now than before. Also it changed the intake sounds as well, I can hear the jet noise more from my intake than I did before. When I say jet noise, for the SRT owners the noise the intake makes while the engine is still cold.

 

Congrats Hollywood The lowend and midrange response is indeed impressive with the S&S headers. I'm waiting for flanges, too, for my custom Y pipe/X pipe change. I believe this will further improve the 'breathing' of my GS430.

It's a biatch to change the headers, but the end result was certainly worth it for me. Glad to hear you got it done. Now enjoy and watch your gas mileage go down because you can't resist putting your foot into it.

 

Excellent!

Again, engine responsiveness is very important to an enjoyable street car.

I am starting to think the very mild camshafts may be the real top end power limitation but we shall see.

 

Congratulations Hollywood on the headers mod!!!

I wish I could do this myself, as the install cost is too prohibitive for me to consider it right now. I will have to wait till next year to do this mod.

 

Ya with the cats to be gone in the future, it will be a test of weather the cams are the hold up, but really cams are probly the hold up anyways.

 

Try this link and see if it helps. I have HKS mufflers and headers, no other exhaust changes.

A better video could be made for sure, but, i just figured I'd share. Overall, the change in sound is not that great. Only during the 50-80% throttle in mid-range can you really hear a lower tone than before the headers. It's a very cool, muscular sound at that point.
Other than that, it's very close to what the car sounded like beforehand.

 

Here is the muffler I am going to replace the 3 cats with. I just hope it will fit.

http://store.summitracing.com/egnsea...1&autoview=sku

Tech data.
http://www.dynomax.com/news/Downloads/X-MUFFLERNrv3.doc

 

Are you 100% positive you have 3 cats on your car?

I just replaced my exhaust with a custom setup (and I also live in Canada) and the GS400 has only two cats - the ones bolted to the headers.

See what I did here to replace my exhaust - scroll down towards the middle of the page (I did a very detailed write-up with pics and a video (start up, drive away and drive by):

https://www.clublexus.com/forums/sho...&page=46&pp=15

 

Ya I've seen your threa a while ago.

Well 2 cats plus a resonator/baffle/cat like piece. It greatly resembles a cat but there is no sensor so may not be technically considered a cat, but all in all its a restriction and a filter of flow. Once I pull it off and look at it I will be able to tell its function.

 

Sounds good....Also Congrats on the Mod....

 

Doggonit, I forgot to put up the link!!!



https://www.clublexus.com/forums/sho...d.php?t=201294

 

Mine actually sounds a bit different. Yours the intake still dominates the sound greatly, my sound is almost the same but more exhaust side, but still the intake still out noises my exhaust sound.

 

You're right. In that video it is like that. Of course, the engine is more towards the camera and my exhaust is pointing the other way too!

I've noticed that around 4000rpm and higher (like in that video), my exhaust noise is not as loud/low toned as it is taking off from a stoplight, or in 15mph - 50mph hard acceleration. that's where the good stuff is for my HKS.
PS. my intake is still completely stock.


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