Rollaboy

iTrader: (1)

My old rusty exhaust is leaking everywhere so i need a new one and im hell not buying one from lexus.

So why not make some upgrade while i'm add it :-)

I have searched but cant find any headers anymore for my 91' LS400 :-(

Anoyne can help on that? I want to install the new headers and exhaust and never think about leaking anymore so it needs to be a pro job on those headers.

Well i cant make my own headers but i know a guy who can help me weld the rest of the exhaust together with his TIG.

But i can buy everything we need so i'm thinking what sizes should the tubes be?

and i need new catalysators also. which ones can hold up to the horsepower for the engine. in a future not near i am dreaming of some kind of supercharger setup, so i might as well get this exhaust to widstand about 300horsepower i guess?

I have an example what i think i would use but im open for some other views on the case.

fromt the top. the catalysators and after that a flex tube and of course holes for the oxygen sensors.

after that comes a middle muffler that has a double entry and a single output. thats kindda how the original exhaust a made too.

then after the muffler the tube then goes to the middle of the car and then splits like the original and then i will make tubes back to a set of rear mufflers. one in each side. so i will not use another two middle mufflers like the original.

i'm looking for a little more sound and mabye a little horsepower gain. I dont want it to be too aggressive and rattle can noisy. i want the sound of a japanese v8 in action. not a american loudness v8 if you can get my point?

I dont want this to be a ricer sound. it should sound a little more serious like mercedes amg and so on. of course i now every engine has it own sound, but i hope it can get near of what i want.

right now i removed the two middle mufflers and else its stock. i think it sounds fine. not too much and not too stock.

What do you guys think?

Rollaboy

iTrader: (1)

bump

No one have something to say. Should i go with 2" or 2½" stainless tubes?

Bradster

2 1/4" is the way to go..

kuziwk

i would try to keep the exhaust as stock as possible, unlimited resources were spent on research for this one car, ive heard of people losing performance due to changed exhaust's. Unless your installing a turbo you dont need the extra airflow, if you want more sound do the rear muffler delete or remove some of the resonators.

RA40

iTrader: (6)

This discussion about the 1UZ exhaust thread in the 2-GS forum for some ideas:
https://www.clublexus.com/forums/per...ease-read.html

2-GS sound clips:
https://www.clublexus.com/forums/per...ollection.html

This is a nice sound too:
http://www.youtube.com/watch?v=I5ZIomet8Yk

Rollaboy

iTrader: (1)

Thanks for the links. Im looking and listening right now ;-)

The mercedes F1 car is NOT what i'm looking for 8-) but you know that. But it sure is a badass crazy F1 sound!

But the sound from the GS link you posted. The #3 reply by beaterKU sound just like how i want it :-)

I cant really find any 2 1/4 pipes over here in Denmark. The most common pipes the companies are selling is 2", 2,5" and 3". It would also be alot easier to find mufflers etc to match.

But if 2 1/4 is the best then i need to get it! i will search some more...

But i was thinking of 2,5" for the front end. Like to the cats and down to the y pipe and the resonator and then from the resonator, split it like the original with and y pipe convert to 2" and straight to the rear mufflers, dropping the middle resonators.

Down know yet what kind of mufflers i will be installing but the tips will be just like the original just a little but bigger. I sure dont want to have two 4" tips like HKS or anything racing like muffler tips.

PureDrifter

iTrader: (10)

2.25 is the best size for a stock 1uz, if you plan on serious power mods, be them cams or supercharger, 2.5 wont hurt.

Rollaboy

iTrader: (1)

Hmmm... I will be stock for know. It cost some serious money to do supercharging etc.

Right now i'm buying both supra tt calipers, ebc rotors and pads for the front and also bigger LS400 calipers in the rear, also with ebc rotors and pads so that costs some money, but i will rather start with bigger brakes than supercharge the engine and not be able to stop in time. Many people do it the other way and i think its stupid.

But for now the engine will be stock. i've only installed K&N air filter so thats nothing.

It would be nice later on to get the engine tuned, but it would be nice, not to go weld another exhaust again at that time. hmm...

im just thinking, if the front is 2,5" and the rear is 2", wouldnt it be ok? 8-)

I better measure what the stock exhaust is. I think its larger in the front or is it the same all the way?

i know the best thing would be to make a 2 1/4 now and later make it 2,5" when the engine gets tuned.

But right know my biggest concern is the leaking exhaust i have. So i have to do something now. And i sure gotta be ready for the summer ;-)

PureDrifter

iTrader: (10)

personally i would keep the same size all around, 2.25 all the way through, or 2.5.

3UZFTE

+1 for 2" to 2.5".... Your really only hurting the performance of an NA motor if you are running too big of a pipe. The 4.0L can breathe, but it's not a big block by any means.

PureDrifter

iTrader: (10)

yeah but imho 2" for a 4L that goes to 6500rpm is too much restriction on the top end.

LiCelsior

iTrader: (32)

mike the LS is missing 4 cylinders to compare it with that sound .

Rollaboy

iTrader: (1)

Well i've searched a little over here and its kind of impossible to find 2,25 pipes and matching resonators and mufflers.

i'm like hmmmm there isnt THAT much in difference from 2,25 to 2,5 is there?

I can get plenty of 2,5 pipes and resonators, so i think i will just go for it with 2,5 all the way and see how it goes.

3UZFTE

Sorry I didn't see this or respond sooner. It's ultimately up to the end user, but too me 2.5" is too big, and you will probably lose power.

I beg to differ 2" exhaust is too small for a 4.0L engine, as I am running a 93' 5.0L/302ci with 2" straight pipes, as well as a 62' 327/5.3L SBC that running factory ram horn manifolds, through 2" exhaust and magnaflows. I can promise you these high revving, pushrod motors put out more air than our 4.0L engines. That's just my 2 cents, I just think too often we go for bigger is better, but in reality, it's really not. Two 2" pipes have a larger circumference than a single 3" pipe, which is what I'm using on my turbo LS.

62' 327 SBC w/ ram horns into collectors, than 2" from there.

5.0L SBF headers into 3" collectors, into 3"-2" reducers, and 2" straight pipes


I'm building a 350/5.7L for my Toyota Pickup, and I'm running 2.5" exhaust, and even that is too big at times. The bigger the exhaust, the higher up on the power band you have to be to make power. You need to match the incoming air with the outgoing air, so by just upgrading the outgoing air. I would guess that you'd lose low-end torque, in favor for 2-3hp at the top-end.

PureDrifter

iTrader: (10)

-waits for jbrady-