Headers

[Tony95sc400]

Tony, I live in Santa Monica and there is a shop on Lincoln Blvd in the city of Santa Monica, called A+ Auto repair...The garage owner is Leo and he can install the S&S Headers for you, relocate the 02 sensors, create the the two down pipes with correct flange bolt patterns, and delete the two small cats all for $500... You will need to leave your car there for two days...

Leo is a nice guy but is busy, so call first and make an appointment....It's a small shop and doesn't look like much but they do outstanding work...

Leo - 310 314-3104 A+ Auto repair....

kool! Will deleting the cats make the caar really loud? im trying to keep it as quiet as possible

 

[jibbby]

Deletion of the two small cats and the Header install really doesn't effect noise levels at all if you can believe that or not...

The center and back section mods of the exhaust system is what creates the noise levels too increase...Mufflers, and center main cat changes is what causes the exhaust to get really loud...

Staight thru mufflers is what you do not want.. Stick to Ovals...

 

[Tony95sc400]

There's some interesting things I just read on this thread. I was wondering if instead of X piping you go with a Y and what would you recomended to keep the flow well and keeping a smooth powerband through out the rpm range? For example what size piping would suit both the pipes flowing into it to the end of the exhaust?

i had put a y pipe on mine. 2.25 pipe from the center cat on to magnaflow 14829's. Gave the car a nice lil rumble now, as far as off the line pwer i didnt really notice a difference. Mid range is a quicker. Should i change to x pipe or will it be a waste of money?

 

[JBrady]

Deletion of the two small cats and the Header install really doesn't effect noise levels at all if you can believe that or not...

The center and back section mods of the exhaust system is what creates the noise levels too increase...Mufflers, and center main cat changes is what causes the exhaust to get really loud...

Staight thru mufflers is what you do not want.. Stick to Ovals...

This is Jibbby's experience but it surprises me. All others that I am aware of say their was a noise increase by deleting the cats. If you want a quiet car (as reasonable anyway) I suggest keeping cats. Jibbby is correct about straight through style mufflers being louder than non straight through type mufflers.

There are a few choices to keep the cats.

Option 1: Move the stock cats under the car. I honestly have not done this and cannot vouch for how much clearance the stock cats have under the car. This would require creating downpipes from the header outlets (use 2.25" mandrel or even 2" mandrel) to the cat inlets and then creating a Y pipe from the outlets of the 2 cats.

Option 2: Same as the above but using aftermarket cats. I suggest the round very high flow metal subtrate cats that are available for $60-$150each.
Here is one source http://www.rpmoutlet.com/powercat.htm I would suggest creating heat shields for them.

Option 3: Use the above style cats in the stock location. This would require cutting the flanges off the stock cats and cutting/fitting/welding the new cats to fit in the stock location.

Which ever above option is used there is still the EGR situation. Some simply delete the EGR. I would keep it for emissions reasons. Simply install a 2 bolt flange (buy from S&S) in either the downpipe or the inlet side of the passenger catalyst. You will need a section of 1/2" stainless flex line to connnect to the stock EGR plumbing. I do NOT mean braided line. I mean the corrugated accordian type line found in some stock EGR systems. Obviously you want someone that is capable to make this installation. Should not take much over an hour for someone that is capable and has the tools and materials before starting.

For the rest of the system use no larger than 2.25" pipes and some have reported EXCELLENT results with stock sized 50mm (1.97") pipes and others with 2.00" pipes. No reason whatsovever to increase sound, weight and loose clearance using larger pipe. Not to mention larger pipe will reduce overall performance.

 

[jibbby]

Well I must say I drove my SC400 the same day after deleting my small cats and installing the S&S shorty headers... I was expecting a big increase in noise levels after the header install and deletion of the two small cats...I drove it after and noticed there was just a very little increase in exhaust noises after the fact..I noticed just a slightly greater little rumble noise and maybe a 10% increase at best...I was pleasantly suprised...

The high flowing straight thru circular mufflers is what really made my SC400 scream at high rpms, infact I needed to install 4 high flowing circular resonators to keep it somewhat quite and that still didn't work that well..The high flowing Magnaflow main center install also increased noise levels which I forgot to mention ... So in the end I would suggest using oval mufflers and or oval resonators to reduce exhaust noise if you're not satisfied...

As JBrady stated that is my experience with my SC400, but I really don't see how that could be any different with any other SC400 but maybe I am wrong.....

 

[JBrady]

Well I must say I drove my SC400 the same day after deleting my small cats and installing the S&S shorty headers... I was expecting a big increase in noise levels after the header install and deletion of the two small cats...I drove it after and noticed there was just a very little increase in exhaust noises after the fact..I noticed just a slightly greater little rumble noise and maybe a 10% increase at best...I was pleasantly suprised...

The high flowing straight thru circular mufflers is what really made my SC400 scream at high rpms, infact I needed to install 4 high flowing circular resonators to keep it somewhat quite and that still didn't work that well..The high flowing Magnaflow main center install also increased noise levels which I forgot to mention ... So in the end I would suggest using oval mufflers and or oval resonators to reduce exhaust noise if you're not satisfied...

As JBrady stated that is my experience with my SC400, but I really don't see how that could be any different with any other SC400 but maybe I am wrong.....

Yes, I am also surprised that this is your experience.

Now, be careful about the "shape" of the mufflers. The Magnaflow are OVAL but are also straight through. It is the straight through that is the loudest style. Now, an oval shape will be slightly quieter than a round shape but the real difference is in the internal shape. Turbo style mufflers are reverse flow with internal expansion and absorbsion and flow redirection. This creates more opportunity to reduce noise at the expense of reduction in flow. Different brands will sound slightly differently and flow differently. The best flowing "turbo" muffler will not loose much additional power over a staight through design and will definitely be quieter.