Project Thread SC470TT (VVTi) Twin Turbo Lexus SC400 with 4.7L Toyota Tundra Engine

[bobadrift]

You should do some research over at supraforums. This has been discussed in great detail where two individuals in Australia tried the two different sized turbos idea.
Also for sequential turbos the only successful attempt by an aftermarket company has been RPS aka turboclutch.com
There's was supposed to cost $10 g's with an AEM EMS integrated into it. He never went public with it and there is only one in existance as of right now. I know he said if someone was really interested you could contact Rob from RPS and have one custom made from his jigs. Of course this was for a 2JZ-GTE motor though.
I think you should forgoe the sequential setup unless you just happen to have a roll of $100's as toilet paper. You can simply have a built auto tranny with TC of course and a high stall for when you want to drag. And for roll-on racing simply brake boost it according to the speed you're traveling.
Either way goodluck with your choice and keep us all informed.

Chris

 

[Lextreme II]

Here is a design i drew up. The Turbo # 1 (right side) will dump part of its exhaust gas into the second turbo for pre-spooling.. What do u think?

 

[WDoherty]

So what are the stats on your new built motor?

 

[Lextreme II]

working on the pistons right now with Chevy rods....

 

[WDoherty]

but, i thought you already had the motor built and in you car?

 

[Lextreme II]

The LS400T yes, not the SC470TT.....

 

[cowboy bebop]

Lex, from the diagram above, the excess exhaust airflow causes a cylinder imbalance because your exhaust energy would sooner exit out of the left turbo exhaust pipe, then turn heavy turbine blades. Essentially, when you run a dual turbo set-up, what you do to one side, you have to do to the other. Cylinder balance is key.

Eric

 

[Lextreme II]

Gents,

Finally got some time to do some work. Here are some welding i did today. They are 1.5" mild steel. I am still waiting for the 1.75" to come in. These are tac weld. Remember I dont have any training on welding. I learned by myself so dont judge me like a pro. Took me about 45 minutes to do the below. I am sure the pro can do it alot faster. However, I still need to wait for more pipes to come in. I will put V Band on it. 2" up and 2.5" down. Once everything is done, i will take it to a pro for tig weld.

 

[Toysrme]

Looks good! Don't worry about the welds. You can grind them somewhat to clean up anything that is horrible nasty. Past that... It's just asthetics.

Good work!

 

[Lextreme II]

Just would like to update you guys with the progress. I got some high temperature heavy duty industrial 1/2" hose along with some fittings. I market the anterior portion of the oil and tapped a hole to mate with a 1/2" npt. I think this is the best place to oil return lines. Its high enough to clear the oil and at the same time its close enough. Due to the configuration of the SC400 oil pan (rear sump) I have to do 90 degree return. The return lines are 1/2" or around 8-AN. 8-AN is little small for single turbo, but should be ok with twin. I was going to thread the oil pickup pan, but couldnt fint my die. I will finish this once i get a 1/2" npt die. Here some pictures.

 

[Toysrme]

Tada. Oil lines!


You linked me to the bottom of this thread so I never read most of the posts. I'm sure you will get it to work, but I am not a fan of this idea.
True multi-charged setup = +++
Blow a turbo with another turbo, or take a turbo & blow it through a large S/C. In the case of the latter, keep the majority of the boost off the S/C provided that you use an Eaton (M112).

 

[Toysrme]

Aaaand I just realized that those were old plans & not what he's actually doing.

 

[Lextreme II]

Ok,

Thursday is my best day. I only work 3 hours in the morning. Anyway, while I am still waiting for more pipes and bends to come in. I started the passenger side. The process is pretty much the same. Here are some pictures of today's accomplishment.

 

[Lextreme II]

Here are few pictures side by side. Still waiting for more pipes....

 

[Lextreme II]

Here is some progress of the project. Its looking like a header now. I added the 1.75" pipe this morning and still need more parts... Here are some pictures. The secondary Y will too large for the 2" pipe. I will do some minor trimming to make it work The last picture is the indication of the cuts.

 

[Lextreme II]

I thread the oil pickup. Its pretty thin so becareful when u r doing it.

 

[stevechumo]

David,

Your manifold design is very efficient with heat elimination to its max. However, I have an idea to make the manifolds much more simpler in a tight area as you see in my pic. It's not as efficient as yours but it's still way too good. This design is actually used on many cars. The material used should be thick mild steel for plumbing like in the picture. Your T-304 steel might not stand the heat with my design. But if you like using your design, then why not.

 

[Pro]

if it's braced correctly the thin material should be fine.

and those inside seams that you have filled with weld there David will crack.

i would make a piece of material to cover the weld that wraps around to the other side of the join and then weld THAT in place.

like this.

 

[Lextreme II]

Thanks Pro,

I will take your advice.....

 

[Pro]

no worries dude - but do it where all the pipes join in the same way too.