LLY frontpipe options

[Lonnie]

Anyone have any info on a 5" front pipe?

I see Magnaflow is making one that steps up after the 90deg bend, but what size is the rear section? Does anyone have one?

I'm asuming it does not have a big effect on power, but looks cool. Anyone have experience with power outputs using a bigger pipe over 4"?

Since I'm building one from scratch for my Duramax conversion, the different tubing size will not effect the price much.

Any recommendations???? Possibly a 4" elbow, then a step, up to 5". Not sure I can or should use a 5" elbow as the larger radius may make it hang too low. My downpipe is still stock, but I may save this for a future project.

Any advice is appreciated.

 

[paint94979]

Anyone have any info on a 5" front pipe?

I see Magnaflow is making one that steps up after the 90deg bend, but what size is the rear section? Does anyone have one?

I'm asuming it does not have a big effect on power, but looks cool. Anyone have experience with power outputs using a bigger pipe over 4"?

Since I'm building one from scratch for my Duramax conversion, the different tubing size will not effect the price much.

Any recommendations???? Possibly a 4" elbow, then a step, up to 5". Not sure I can or should use a 5" elbow as the larger radius may make it hang too low. My downpipe is still stock, but I may save this for a future project.

Any advice is appreciated.

Diamond Eye is IIRC 3inch.... It is going to be hard to get one that big unless you custom fab it yourself. The PPE GT42 Downpipe is 4inch I believe but it won't bolt up to your stock VVT turbo. The Diamond Eye might be your best bet.

 

[Lonnie]

Sorry, I accidently labeled the post "downpipe", but I posted my question about the front pipe.....

Looking to build exhaust from the downpipe back. One of these days, I may do a different turbo/downpipe, but for now it will stay stock.

Just looking for exhaust options. Seems odd for me to build 5" exhaust with a 4" front pipe.

 

[Noreaster]

Diamond Eye is IIRC 3inch.... It is going to be hard to get one that big unless you custom fab it yourself. The PPE GT42 Downpipe is 4inch I believe but it won't bolt up to your stock VVT turbo. The Diamond Eye might be your best bet.

3.5"

 

[sweetdiesel]

Sorry, I accidently labeled the post "downpipe", but I posted my question about the front pipe.....

Looking to build exhaust from the downpipe back. One of these days, I may do a different turbo/downpipe, but for now it will stay stock.

Just looking for exhaust options. Seems odd for me to build 5" exhaust with a 4" front pipe.

I renamed your thread Lonnie
MBRP probably a good bet or just build your own

The Diamond eye down pipe is pretty nice too How much clearance do you have inbetween the fire wall and your motor....more than a stock lly

 

[Josh2002cc]

I have a tts front pipe that I am willing to part with. It is stainless steel I believe.

 

[Lonnie]

Simon, thanks for renaming the post.

As for all normally available front pipes, arent they only 4"?

I figured I would stay away from a downpipe for the time being. I know eventually there will be a turbo swap in my future & then I'll build a custom matching downpipe. I have to have something to do when I get bored with it.

 

[Kat]

Does this mean you have found time to work on the truck again?

 

[sweetdiesel]

Simon, thanks for renaming the post.

As for all normally available front pipes, arent they only 4"?

I figured I would stay away from a downpipe for the time being. I know eventually there will be a turbo swap in my future & then I'll build a custom matching downpipe. I have to have something to do when I get bored with it.Smart

You can get a lb7 frontpipe ( cat delete ) IIRC they are 3.5"
It is pretty cheap to build your own 4" or 5" or maybe try GrandRock?
http://www.grpipes.com/search.asp

 

[Lonnie]

Kat,
I'm just strategizing for my Christmas vacation.
I need to get a radiator so I can start mounting it & the intercooler, as well as I'm planning to start the front exhaust.

There is still a pile of Camaro & Corvette fuel pumps, fuel tanks & lines sitting in front of & under it, so I'm trying to clear a path over the next 2 weeks.


Simon,
I'm thinking of building a 304 SS setup out of a 4" elbow, then expanding up to a 5" straight piece. I seem to have a straight shot straight through the crossmsmber, so hopefully I can make it work by adding a small muffler (not sure I can tolerate a straight pipe) & either a 5" D-max or Dodge 5" tailpipe.
I had dodge diesel tailpipes on my other 82 truck & it fit pretty well.

 

[mytmousemalibu]

I made my own! BUT mines 6"

It has the stock 3.5" elbow but imidiatly opens into the merge cone up to 6" and runs from there back! I noticed no power loss with pipe this big. It spools faster and egts lower and when i idle it to cool it off before i shut it down it it really drops fast! I love it!
It will soon be a single stack instead of side exit. The cone i made from sheet steel I had around, the pipe was a 10' stick of aluminized from trucker store for $200ish and i did the bends buy compound miter cuts and welding it and made my own mounts. I did cut out and rebuild the right side of the driveshaft crossmember to run the pipe straighter and keep ground clearance. The new stack setup i have a 2' piece of flex for $12. The Chrome stack was $130 and one 90* mandrel bend was $100 bucks! Just FYI if anyone wanted to know! :hug:

 

[sweetdiesel]

I made my own! BUT mines 6"

It has the stock 3.5" elbow but imidiatly opens into the merge cone up to 6" and runs from there back! I noticed no power loss with pipe this big. It spools faster and egts lower and when i idle it to cool it off before i shut it down it it really drops fast! I love it!
It will soon be a single stack instead of side exit. The cone i made from sheet steel I had around, the pipe was a 10' stick of aluminized from trucker store for $200ish and i did the bends buy compound miter cuts and welding it and made my own mounts. I did cut out and rebuild the right side of the driveshaft crossmember to run the pipe straighter and keep ground clearance. The new stack setup i have a 2' piece of flex for $12. The Chrome stack was $130 and one 90* mandrel bend was $100 bucks! Just FYI if anyone wanted to know! :hug:

Flex didnt work to well for me And it was suppose to be the good stuff

 

[mytmousemalibu]

Flex didnt work to well for me And it was suppose to be the good stuff

This stuff seems pretty robust! I dont really like the stuff but im going to mount the stack fairly solidly to the bed and it needs a way to compensate for thermal expansion and vibration. I mounted the old system too solidly and it cracked the hanger mount a time or two and i dont like that crap! So I hope the flex works, ita be farily straight run for it and i bought a nice 90* bend to transition to the stack.

 

[LBZ]

FWIW Lonnie, I would install a 3" Diamond Eye Downpipe now while your still putting it together. I guarantee you will be doing it in the future anyhow and at this stage of your build, it is likely easier.

As far as 5" from the downpipe back, I can't see why Stainless Steel flexpipe would not work. It seems to last on the Big Rigs just fine. But a custom built solid piece looks nicer!!
Just remember, your going from 3" so I don't know if there would be any advantage with going to 5" as it is much heavier than 4"! Plus MBRP sells 4" downpipe back kits so they are readily available and cheaper.