Ok, i tried searching this but nothing is coming up.

I recently replaced my stock cats with catco's and now im planning on changing out my headers with some performance direct-fit ones. I have an opportunity to buy tube manifolds that look like they are from a 3UZ but are designed for the 1UZ for only $100. My car is a 1996 SC400 and i dont want to spend money on parts and labor for something that is not worth it. any help or advice would be greatly appreciated.


one last question, do you have to drop the motor to replace the headers?

thank you!

 

I hear IMF headers are good im not sure if they still make them but they are supposed to be a direct bolt on and then there are long tube headers at http://rushimports.com.au/store/inde...e5e6663c45fae0 you should email him first and ask if its in stock and if its a direct bolt on which i'm pretty sure it is.

 

ThANK yOU!

 

Why would you want to change them? You'll lose low end torque and no power gains by installing them. OEM looks busy, but aren't bad at all.
Save your money.

 

that is exactly what i needed to know. thank you. the guy selling the aftermarket ones was very adamant that i will get at least a 20hp gain.

 

well i am no guru by any means, however it is pretty hard to deny the poor design of the 1uz stock manifold. ive had lots of face to face time with them during my single turbo quest, and imo there would be noticable gains with a new fabricated header, or even better a long tube IMF. if you were to flow test a stock manifold side by side with a long tube imf(or any other properly designed header) that the stock one would show its restrictions.

 

20 is kind of a stretch with an NA car IF there are no other mods to your car. but there will definitely be a gain.

 

ok so the seller wants only $100 and this is what they look like


he says: "there not stock spec the stock manifolds are cast and these are tube. from what I have found these look like the tube manifolds for the 3uzfe but are designed for the 1uzfe. early 1uzfe have very poor designed manifolds" "1uzfe have very bad manifold stock very very poor flow these will def help" "have flanges for the cats but your stock cat will bolt right up"


does this sound legit? should i grab them? how much work is it to install new headers?

thank you for the input guys. i appreciate it

 

....looks like the stock SC header

 

no they are not bolt on, you will need to do some welding because these will extend all the way to the third cat (I think?) but you will definitely need to weld something

drawing on experience, NO WAY

that does not look one bit like the stock headers. the stock headers are quite tiny to be honest

OP, I went all out when I had my SC, rush long tubes, stainless steel true duals. All I got out of it was a very sad bank account and bragging rights. nothing else. You will not feel any difference. If you do, i'd say you're lying.

 

https://www.clublexus.com/forums/1510810-post4.html

So this isn't a stock header from a LS400? Yeah it is. So yes it's a stock header, and it won't clear our steering shafts.

Edit: Whoops, I noticed I put "SC" in my original post. Yes it's a stock LS header sorry.

 

That's just sad to hear from another SC400 owner. LOL!

 

It's probably cause you had true duals. You never had an X or H pipe to help with exhaust velocity.

With higher displacement motors you could probably get away with true duals depending on the diameter of the exhaust. However, it's been documented that a lot of cars (with v-styled motors) that have true duals end up losing power.

What you want to do is have exhaust gas hot as possible so it builds more velocity. We all know from High School science that hot gases move faster than cooler gases. So you want the exhaust gas to get hot, but what happens with guys that have too big of an exhaust is that the exhaust gas actually cools down in the pipe itself and thus loses it's velocity.

Another thing to is with true duals you virtually lose the effect to scavenge. Now I'm sure with a good enough designed header that was going to be made for true duals then you would probably have awesome scavenging, but with long tube headers, it's not really made for that.

Just my opinion

 

Installing any header is going to be a lot of work. If you had a supercharger it would be worth it.

 

Im in the middle of my r154 swap and decided to throw headers on as well, and the stock headers are a pita
Goodluck
Charley