360demonRT

iTrader: (1)

***disclaimer: my Microsoft Paint skills are terrible***
***disclaimerII: I did do a search***

first off, I'm working on a 78 Malibu twin turbo build and want to run a header or log setup as opposed to a stock manifold setup. one reason for this is that in forward and down configuration, I don't think any fit, and I don't like the look of the up and forward so much. That being said I have sketched a couple ideas and would like to know some info on if anyone has done anything like this before.


-first one-
I know this is a common setup for log manifolds.






-second one-
Wondering if something like this (similar to a stepped header idea) would keep velocity up more (quicker spool etc), of if it would even amount to a damn.



edit* perhaps change the 1.75" primary tubes to 1.625(1 5/8)"?

I have a tig welder and am getting decently handy with it so the fab shouldn't be an issue so much.

Which would perform better or am i wasting my time?

Thanks

Ping King

iTrader: (20)

Do yourself a favor and do the manifold with sch 40 or sch 10 pipe elbows.

A 1.5 primary will have almost a 2 inch od. The main section of the log should be 2 inch pipe which I believe will have an od of 2.5 inch. You can get a really nice deep weld on the manifolds and they'll last forever.

4000 years from now when archaeologists are digging through the ruins of your garage the manifold will still be intact.

Cleenenhaus

I did a log manifold with a taper. Not sure if it bought me anything but it was more complicated and harder to make so it must be better.

360demonRT

iTrader: (1)

I get the longevity standpoint, but will 2" ID support enough hp to run 8.50's @3300lbs? .25" seems really damn thick for a tubing wall

360demonRT

iTrader: (1)

the logic of my life lol

Ping King

iTrader: (20)

Truck manifolds have the same dimensions and have been taken to that time. Most of your restriction will be in the turbine housing anyway.

You also have sch 10 and even sch 80 pipe if needed.

shawnc16

Here ya go. This question gets asked a ton. I made a set and pics are in the following thread
https://ls1tech.com/forums/forced-in...-question.html

TrickPerformanceProducts

iTrader: (11)

No need for the step log.
Your first design is fine.
I would use weld L's sch 40 and call it good.

360demonRT

iTrader: (1)

Shawnc16 - can I get some more pics of your manifolds? Since I don't need the step design for my goals, that's actually the exact design I had in mind lol. So I need what? Hate to pick your brain that hard, but I'm still new to fabbing stuff. Looks like 10 els (1.5"?) And some 2"id sch10/40?

Thanks everyone

stevieturbo

Are none of the factory cast manifolds suitable for you ?


They would make life a lot easier, and they do work.

LT1PWRD

iTrader: (2)

I had the exact same problems with my single T4 Chevelle build, no OE manifolds would clear forward and down. And I too really didn't want up and over exhaust pipes, don't like the look at all. Not knocking anyone else's setup just don't want that look. I made the exact logs in pic 1, worked out perfectly. Ill try to post some pics for ya.

360demonRT

iTrader: (1)

None clear foreward and down. Only up and forward I like are the Obx or whatever brand headers that I'm not paying for. I really hoped truck manifolds would work. But really, just got a new tig and want to play factors into this as well.

shawnc16

Its Sch. 10 1.5" short radius elbows, 2" log and a 2" to 1.5" reducer. Pretty simple.

360demonRT

iTrader: (1)

Thanks man, looks pretty straight forward.

FrankSS

iTrader: (18)

shawnc16, how much in supplies it run you to set that up? do you think that design would clear the 4th gen shock tower/fender on a 4th gen?

shawnc16

Honestly I don't remember exactly how much.
10 short radius 1.5" els.
2 2" to 1.5" reducers
4' of 2" pipe
2' of 1.5" pipe
1/2" SS flanges
2.25" V Bands

I don't see why they wouldn't fit. Here is a pic in my 3rd gen chassis. I'm not running power steering so, I couldn't tell you if it would clear or not.

LT1PWRD

iTrader: (2)

Here's a pic of the ones i made

turbotater1

just for reference truck manifolds can be modified for down and forward and have power steering. this pic is pre wastegate

LT1PWRD

iTrader: (2)

[QUOTE=turbotater1;18172756]just for reference truck manifolds can be modified for down and forward and have power steering. this pic is pre wastegate

What type of welding did you use for the v-bands,mig,tig/stainless,stick/cast rod?

turbotater1

i used stick welding on modifying the bottom of the passenger side and then tig welding the v bands on