My new custom exhaust for my 98 SC430
07-02-11, 12:49 AM
#1
My new custom exhaust for my 98 SC430
Well this is gonna be my new setup. I cant wait to get it on, & get my bottom end torque back. PPE Headers, Magnaflow shorty high flow cats. Custom size piping. 2.5 radius 45 degree mandrel bends. Custom scavage Y pipe, Top Speed resonator, & custom rear Y pipe.
This is pretty much the perfect set up for the 400's. Thanks to 2 member's on here for helping me get this setup together.
This is pretty much the perfect set up for the 400's. Thanks to 2 member's on here for helping me get this setup together.
07-02-11, 12:52 AM
#2
Looks badass. Cant wait to see what kinda numbers its gonna put down. I've been bugging 'bcsc400' about his exhaust setup for a lil while now lol. I'm gonna start bugging you about it when it comes time to do mine..
07-02-11, 01:19 AM
#3
Thanks man. Yea out of respect for the designer, we've been keeping quiet on the exact spec's. But you might be able to get some help when its time. All I need is someone to buy my S&S from me to have my install money. Then I could get it done next Friday. There up for sale for $300 shipped. Kinda got one guy interested. But no one saying yes yet.
07-02-11, 02:46 AM
#6
Nice spdrcr771! I'm in for the video soundclips! I still have my 2.5 Magnaflow X-pipe in my trunk waiting to be custom fabricated with 2.5 piping exhaust piping to my Top Speed Pro 1 mufflers on my 99' SC4. Sticking with stock headers and cats for now...keep us posted!
07-02-11, 07:32 AM
#7
1. 2.5" is too big
2. X pipe is not as good as Y pipe.
Last edited by spdrcr771; 07-02-11 at 07:36 AM.
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07-02-11, 09:20 AM
#9
gte & na-t
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I really dont want to be the bearer of bad new's. But there is a big reason Im switching back from my 2.25" mandrel bent X pipe true dual cat to rear setup. When I went from stock exhaust to the 2.25 X set up, I lost bottem end torque. Then I added S&S headers & I lost even more bottom end torque. Oh I had this slammin midrange & top end power but before 4K when the vvt-i kicked in, slug. Just look @ my dyno #'s in my sig. 1st one 400 w/x pipe. 2nd one 430 w/headers & X pipe. I gained 31whp & only 10lbs of tq. bcsc400 on here has a 99SC400 & he did this exact same Y pipe setup im posting here & his dyno's were (& I know every dyno is different) 270whp & 270wtq, & he's not even 430. So that being said. This is my 5th 400, 1st vvti & ive done this same X pipe on all my cars & its the same result. These car's were designed with a Y pipe & w/only 4 liter's of displacement & a very short cam duration over lap, thats what they need. There are several GS400/430 guys on here that are making the same 260-280 whp on the stock Y pipe.
1. 2.5" is too big
2. X pipe is not as good as Y pipe.
1. 2.5" is too big
2. X pipe is not as good as Y pipe.
good stuff bro keep it up
07-07-11, 10:38 AM
#15
I really dont want to be the bearer of bad new's. But there is a big reason Im switching back from my 2.25" mandrel bent X pipe true dual cat to rear setup. When I went from stock exhaust to the 2.25 X set up, I lost bottem end torque. Then I added S&S headers & I lost even more bottom end torque. Oh I had this slammin midrange & top end power but before 4K when the vvt-i kicked in, slug. Just look @ my dyno #'s in my sig. 1st one 400 w/x pipe. 2nd one 430 w/headers & X pipe. I gained 31whp & only 10lbs of tq. bcsc400 on here has a 99SC400 & he did this exact same Y pipe setup im posting here & his dyno's were (& I know every dyno is different) 270whp & 270wtq, & he's not even 430. So that being said. This is my 5th 400, 1st vvti & ive done this same X pipe on all my cars & its the same result. These car's were designed with a Y pipe & w/only 4 liter's of displacement & a very short cam duration over lap, thats what they need. There are several GS400/430 guys on here that are making the same 260-280 whp on the stock Y pipe.
1. 2.5" is too big
2. X pipe is not as good as Y pipe.
1. 2.5" is too big
2. X pipe is not as good as Y pipe.
The first V in VVT stands for variable that is always on or always changing. It does not "kick in" like Honda's VTEC.
The factory exhaust uses a Y-pipe because California spec vehicles use a third sub catalytic convertor. For Federal spec vehicles there is a resonator in it's place. Clearly the y-pipe is for ease of manufacturing but it makes no sense in a car with a v-bank engine and dual exhausts.
Are you positive the factory piping is in fact 2.25"? I believe it's actually 2". The factory y-pipe and cat or resonator is 2.5" and about 28" long. By my math the total volume of the factory pipe should be around 137 ci while a true dual would increase that to 176 ci. A 40 ci difference is less than the volume of two 12oz soda cans.
You never stated what mufflers you have.
I believe the key mistakes you made were piping that was too large and removing the factory catalytic converter.
My personal opinion of the perfect exhaust would be headers with the factory cats into an x-pipe with non high flow mufflers such as offset/offset rectangular mufflers like the factory ones all with 2" piping.
Last edited by account2x; 07-07-11 at 11:10 AM.