bigger exhaust on the 81
- Thread starter gowyn
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From what I understand there is no power difference with a biggher exhaust.
All it does is help keep the temps down.
But it would probably allow you turbo up your fuel, which would add more power.
Cheers,
Nick
All it does is help keep the temps down.
But it would probably allow you turbo up your fuel, which would add more power.
Cheers,
Nick
here is what you "should" expect:
-cooler EGTs across the board
-quicker spool up (not really an improvement for towing)
-louder (depending on the muffler and resonator)
- no increase in actual power
-might be a decrease in fuel economy
cheers
-cooler EGTs across the board
-quicker spool up (not really an improvement for towing)
-louder (depending on the muffler and resonator)
- no increase in actual power
-might be a decrease in fuel economy
cheers
crushers said:
I notice you put might decrease the MPG.
I wonder why?
I should of just let you answer.
You have way more experience on these things.
Cheers,
Nick
- Thread starter
- #5
cooler EGT's - good, might allow me to better utilise the power I already have before going with PIcrushers said:
louder - why not, no resonator just a big muffler
Was quoted $900 for SS system, turbo back, mandrel bends, 3" system, just a bis ass muffler, maybe I should put a Cherry Bomb on there...hehe. Reminds me of my BMW r1150gs, had a LOUD pipe on it, boy she barked, set alarms off too....hehe
I like the idea of letting the diesel breathe better, makes a lot of sense
crushers said:
I don't believe those two for a minute Wayne.
Anything...read "Anything" that reduces restriction on the intake and exhaust side, over something in stock trim, will result in an increase in efficency. This naturally will free up more ponies.
This will also result in a more efficent motor, which will translate into increase economy, for the same given workload.
The only reason to notice a decrease in fuel economy would be from having ones foot in all the time.
Cooler EGTs and faster spoolup are a great benefit, for sure.
gb
My friend Dave's HDJ81 has a full 3" stainless system done by ATEB. Actually, completed by Ateb would be more correct as it came from Japan with about the last 2/3 of the system with 3" stainless and the first part stock. Unfortunately, we don't have a baseline to work with, but he gets a pretty consistent 26.5 mp imperial gal with his truck, and I'm starting to think the 3" exhaust is part of the reason. He says it might be a touch louder now that it's full 3", but he certainly hasn't noticed any decrease in fuel economy since the whole system was finished. He's also now thinking of a pyro.
all i can say is give Alamo a call and have a chat, they are the ones that i chatted with back when i first got my BJ74 (seems like decades ago now) and i was looking at finding more free hp... they said that ON THE DYNO there is no increase in actual hp. i don't know, does that actual sound like "hot air"?Greg_B said:
the larger exhaust, they told me, allows the turbo to spool up quicker which "feels" like more hp. they don't sell exhaust systems so i can't say why they woudl want to BS me. now a place that sells exhaust might be tempted to exagerate the benefits of the product they are selling...
has anyone acurately tested their fuel economy before and after the huge exhaust has been installed to see what, if any, improvement in milage was found?
cheers, off for the weekend...
crushers said:
Fuel economy: Likely, in the real world where these engines are worked, any increase in efficiency will probably be used by going faster and harder. The only way to actually gauge it would be on a dyno, with set fuel being metered, over a set distance, with the same workload placed at the rear wheels. If someone was quite consistent with their foot, it might show up.
People port and polish to increase airflow efficiency. Part of that proces is looking after the air before it goes in, and after it comes out. Anything that increases efficiency, reduces pumping losses, or evacuation restrictions, has to show up somewhere. Remember, I am talking about stock trim (intake air restrictions and exhaust air restrictions) for our factory diesels.
This difference in power if one has not played with the fuel or air to take advantage of the air movement efficiency may well be of a minor nature, but it will be there imo. Certainly one will feel more, sooner, as the turbo can spool up faster too.
That's my uneducated opinion anyway...
hth's
made a difference for me. cooler egt's, more power, basically improved everything. only downside, is 3" exhaust is difficult to route under a 40 series, and its freakin loud next to the passenger door now.
( kinda fun starting it up tho, when someone is talking to you through the passenger side window....big blast of hot air on the shins makes them step back in a hurry
)
cheers,
r
( kinda fun starting it up tho, when someone is talking to you through the passenger side window....big blast of hot air on the shins makes them step back in a hurry
)cheers,
r
Just to second the other posts here, I've spent quite a bit of time at Ateb and my buddy Dave has had his exhaust finished there in stainless. They do superb work. The welds are works of art, and it's an overall extremely high quality effort. I've done some welding myself, long ago, and a friend of mine is an aircraft mechanic who does a lot of welding, so I have a good idea of what to look for.