Sportmachines 3 bolt vs JSM Style 4 bolt 3" stock turbo downpipe? ---

alwayscode390

alwayscode390

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Im looking into keeping my stock turbo and getting a 3" stock d.p. , but I am ignorant on the differences in the styles offered by Sportmachines.

I have never seen a stock turbo unbolted .

I messaged Tom about what he has, and he said " We have two versions. 3 bolt stock flange style, and JSM style flange 4 bolt with open WG puck area ".

I always thought the stock turbo was 3 bolt, and the aftermarket turbo's were 4 bolt. Do the 4 bolt setups use a 3 to 4 bolt adapter?

Maybe he was saying they have a 3 bolt ( stock turbo ) and 4 bolt ( aftermarket turbo ) 3" downpipe available, and I just took it as they were both stock turbo options?

If they ARE both stock turbo options, what are the differences in going with either choice?

I think both are internal wastegates. I currently have a new 3" ATR downpipe w/ the external wastegate but am not sure if I want to go with a new turbo yet or not.

I'm trying to keep my build basic for once, so I can keep the truck and not sell it.

Thanks! ---
 
Slyclone

Slyclone

Well-known member
Re: Sportmachines 3 bolt vs JSM Style 4 bolt 3" stock turbo downpipe? ---

Keep it simple

Stock 3 Bolt

4 Bolt jsm back turbo puck hogged out special Pipe cut in half on a angle to connect from back to section of down Pipe. Allows more boost?

You want to keep it simple go for the stock 3 inch for stock turbo
Just my thought.
 
alwayscode390

alwayscode390

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Re: Sportmachines 3 bolt vs JSM Style 4 bolt 3" stock turbo downpipe? ---

OK, thanks for the advice. This is my 4th build combo LOL. I hope to actually put this one in effect this summer though.

Right now my truck is stock besides a 3" cat-back and suspension/brake/steering mods (75k miles).

This is what I am thinking so far:

*Turbo Tweak chip
*60# injectors
*Accufab Adj fuel regulator
*255 walbro pump/ racetronix hotwire (is this necessary for a small build like this?)
*Razor alky
*Stock turbo 3" Downpipe
*Wideband / boost gauge
*Electric Fans ( I just hate the clutch fan sound )

Then call it a day, looking for around 350 whp and high 12s? ( I couldn't get the truck to cooperate on the Dyno , but the most consistant run was 241/340 rwhp/rwtq ) ---
 
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JSM

JSM

Active member
Re: Sportmachines 3 bolt vs JSM Style 4 bolt 3" stock turbo downpipe? ---

The 4th bolt is added in addition to the stock 3 bolts. By opening up the WG you get much improved boost control and a much better flow through the exhaust to take advantage of the 3" pipe. It does requires some cutting of exhaust housing, and drill tap the 4th bolt hole.

IMO opening it up is WAY worth the effort, unless you want a stock appearance which a 3" dp won't have anyways.
 
alwayscode390

alwayscode390

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Re: Sportmachines 3 bolt vs JSM Style 4 bolt 3" stock turbo downpipe? ---

I appreciate the link, and the explanation of the JSM differences guys :) ---
 
alwayscode390

alwayscode390

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Re: Sportmachines 3 bolt vs JSM Style 4 bolt 3" stock turbo downpipe? ---

Is the walbro 255lph pump, and Racetronix hotwire just good security ... or is it pretty much necessary for any kind of mods (especially when meth is involved) ? ---
 
It's just a six

It's just a six

Super Member
Re: Sportmachines 3 bolt vs JSM Style 4 bolt 3" stock turbo downpipe? ---

alwayscode390 said:
Is the walbro 255lph pump, and Racetronix hotwire just good security ... or is it pretty much necessary for any kind of mods (especially when meth is involved) ? ---
Click to expand...

The stock pump is not enough volume. It is just OK up to 14-15 psi, after that it cannot keep up.:2cents:

When you add a meth kit, it adds fuel, which will make it richer.

My Sy used to go lean when running 18 psi & stock fuel pump.
 
alwayscode390

alwayscode390

pppssssshhhhhtttttttttttt
Re: Sportmachines 3 bolt vs JSM Style 4 bolt 3" stock turbo downpipe? ---

Ok, well that is enough for me to hear where I will be doing it for sure now.

Thanks for the input It's Just a Six.

I didn't realize that was the issue, I thought the AFPR would compensate for added boost.

I'm sure the TT chip will keep me around 18psi. ---
 
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