Builds 1988 BJ74 “Number 1” (4 Viewers)

[theglobb]

Did you by chance come into or already know any information on how much flow a straight pipe vs a muffled engine is. In other terms how restrictive is a muffler on average? Btw I'm loving all the info and numbers, about everything with this turbo upgrade!

 

[coldtaco]

Short stack out the top of the hood is probably most efficient

 

[FJBen]

Did you by chance come into or already know any information on how much flow a straight pipe vs a muffled engine is. In other terms how restrictive is a muffler on average? Btw I'm loving all the info and numbers, about everything with this turbo upgrade!

Short answer:
it depends.

Longer answer:
Mufflers have different CFM flow rates depending on how they are made, the style, size, and sound level.
Muffler companies also measure differently using CFM or SCFM.

CFM - Cubic Feet per Minute
SCFM - Standard Cubic Feet per Minute

CFM is the flow rate at unknown conditions, while SCFM is flow rate at a give temp and pressure (if it's given to you) flow rate changes dependent on temp/pressure which is why it's not very specific without actually measuring using equipment while testing. Manufacturers will make all sorts of claims that their race muffler can flow up to 2000SCFM and support 2000HP (Dynomax Race) on a 2.5" inlet/outlet.


So a muffler will cause more of a disruption over just straight pipe, but it really depends on all the factors to how much it can actually flow. If you want a muffler, you just want to be able to flow as much as the pipe or more.

More info from a Garrett Turbo Engineer: As for 2.5" vs. 3.0", the "best" turboback exhaust depends on the amount of flow, or horsepower. At 250 hp, 2.5" is fine. Going to 3" at this power level won't get you much, if anything, other than a louder exhaust note. 300 hp and you're definitely suboptimal with 2.5". For 400-450 hp, even 3" is on the small side.”

 

[FJBen]

Got in the new downpipe.

As you can see it's pretty compact. It's a 2.5" cast downpipe from Denco. They use it on a couple of their kits. There isn't a lot of room with the 13BT to put a different downpipe on without some good fab. I'm not good enough at all to fab something like that up. 90 degrees aren't the best, but quite a few factory setups use them. Hopefully this won't be restrictive.

You can also see that it's wider and more of a "cobra-head" design. The widened area is supposed to help with flow in tight/compact spaces. Ford Engineers on the 6.7L have put out documents on the tons of hours in fluid dynamic testing they did using a cobrahead design on that exhaust and say it flows better than a regular downpipe. Whether thats marketing speak or the fact the didn't have room, I don't know but they claim a ton of work went into it.

This Denco piece isn't as exaggerated as the Ford piece. Cummins also has a cobrahead design as well, but it's a 4" piece and wouldn't fit my turbo.




Matches up perfectly with the Holset V-band outlet, something that the cheapie ebay unit didn't do.

Nice and compact.

Quite a bit of difference. Even have an EGT port if I want to do POST EGT...

 

[badusmaximus]

Man what a beauty setup. Can't wait to see how it performs. I think you're going to be happy with the post ct26 swap efficiency that the 13BT is capable of. I drove 200 very hilly miles yesterday at 70 mph and returned ~24 MPG, non intercooled.

Aren't your digital egt/boost displays pretty programmable? I've considered running a signal from EGT >1200f through the built in relay in the display to a digital inline boost controller to increase airflow at high turbo RPMS. Would be cool to take an average EGT reading for that. I'm sure an intercooler would negate most need for it.

Are you considering intercooling? Cheers

 

[FJBen]

Man what a beauty setup. Can't wait to see how it performs. I think you're going to be happy with the post ct26 swap efficiency that the 13BT is capable of. I drove 200 very hilly miles yesterday at 70 mph and returned ~24 MPG, non intercooled.

Aren't your digital egt/boost displays pretty programmable? I've considered running a signal from EGT >1200f through the built in relay in the display to a digital inline boost controller to increase airflow at high turbo RPMS. Would be cool to take an average EGT reading for that. I'm sure an intercooler would negate most need for it.

Are you considering intercooling? Cheers

Yeah, I'm getting a little antsy and want to get this thing slapped on. It should be quite the upgrade considering how wrong the factory CT26 is for it. 24 is great mileage. The best I've gotten is 23.9 so I would be thrilled if it got better than that.

Yes, those auber displays are pretty programmable. People have used them to kick off fans, alerts basically anything controllable. That would be a good idea with increased flow. I was also thinking you could rig up a meth-injection kit when it hits 1200F to cool it off.

I am looking to intercool it, we will see how it all mounts up then decide the best route for an intercooler after the turbo is mounted. Front mounts are pretty tight on these.

 

[badusmaximus]

Those FRP scooped hoods from Australia are sure looking tempting...

 

[FJBen]

Those FRP scooped hoods from Australia are sure looking tempting...

Yeah those are sweet for sure but definitely not in the needed budget lol

 

[coldtaco]

"I am looking to intercool it, we will see how it all mounts up then decide the best route for an intercooler after the turbo is mounted. Front mounts are pretty tight on these."
I put a front mount into the 13BT swapped in BJ70 I had in the past. I used a generic 2.5" wide one. Of course I didn't have AC. I would think it still could be done, there are other style of grills that could be easily modified to make more room if needed.

 

[FJBen]

Another piece in. 1FZ-FE air filter top.

Why the 1FZ lid? Here's a 1FZ lid vs 70 series diesel lid.

.

The diesel lid is like 2.5" I believe.

So from my exhaust venture sizes,
2.5" intake = 564cmf
3.5" intake = 1106cfm

Thats quite the difference. However, thats just that one outlet. You have to know all the other variables, bends, snorkel tops, filter restriction, etc to know what your intake is actually flowing.

The turbo inlet on the HE221W is 3" I figure it's better to size down to 3" than size up from 2.5"

 

[FJBen]

"I am looking to intercool it, we will see how it all mounts up then decide the best route for an intercooler after the turbo is mounted. Front mounts are pretty tight on these."
I put a front mount into the 13BT swapped in BJ70 I had in the past. I used a generic 2.5" wide one. Of course I didn't have AC. I would think it still could be done, there are other style of grills that could be easily modified to make more room if needed.

I'm thinking water to air might be the easiest solution because of the space. I saw how yours was setup and like that, although I would like to keep ac.

 

[badusmaximus]

I'm thinking water to air might be the easiest solution because of the space. I saw how yours was setup and like that, although I would like to keep ac.

Also what about the space taken up by the fan shroud?

 

[FJBen]

Should be a good fit. I Have some fittings on the way to finish the intake portion.

90 degree an10 to barb fitting for the block side of the drain. The other piece hasn’t shown up yet.

I’m waiting on 2 more pieces before I can install and those should be in this week.

 

[FJBen]

New chalice for my Purple Drank...

Nice piece of machine work.

The Holset HE221W has this V-band 1/2 marmon connector on the compressor outlet. Some people use factory pieces to fit, some grind them off, some weld to it and some people just try to squeeze a silicon hose over it and clamp it down. Benzforce makes a cool adapter so you can weld to it or use a silicon coupler. Has an O-ring seal in it and V-bands on then goes to 2.5" . Factory on that side is 55mm or 2.2" For now I will have an adapter/reducer, but in the future this gets me 2.5" for an intercooler.

 

[FJBen]

In today’s episode of “Tales From The Drivethrough!”

The workers are taking orders walking in the drive through.

Worker: oh cool. Don’t see many of these around.
Me: (anticipating enthusiast conversation) No, no you don’t.
Worker: so you like bought this from like the post office?

Me:

No, no it’s from Australia....





Drive around to get my order and new worker is handing food out. She looks and goes wow and is seemingly excited at the cruiser

Worker: COOL! So you like deliver mail?

Me:

Me: (reluctantly) from Australia

Worker: awesome, well welcome to the country

Me:

 

[coldtaco]

What I did for the air cleaner top.

 

[FJBen]

What I did for the air cleaner top.

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THats nice work on there. The only issue I wonder about is that you are still using the smaller opening on the air filter lid.

 

[coldtaco]

THats nice work on there. The only issue I wonder about is that you are still using the smaller opening on the air filter lid.

that's because it matches the 12HT intake

 

[FJBen]

Never know who you’ll see out and about.

@PabloCruise in his sweet 40.

 

[FJBen]

Yet more little pieces.

Here is basically all the parts needed. Well you don’t “need” the 1FZ lid or the compressor outlet.