The "Official" 1HZ/1HD-T/1HD-FT Airbox/Intake Mod Thread (1 Viewer)

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i started my build tonight. going with a box sized to fit between my fender and intercooler heat exchanger. i’m using a duramax filter. ill have a 3 inch inlet from my snorkel and then a second 3 inch hole that i can cap off when i need it sealed up.

so far here’s what i have
View attachment 1701854 View attachment 1701855
Any reason the cappable inlet won't be 4"?
 
9.5 inches by 13 inches by 8.5 inches tall will be the final dimensions. the duramax filter is 9.5 x 12 itself. it should fit. my only worry is height. i might need to shorten it if my hood doesn’t clear
 
Any reason the cappable inlet won't be 4"?

only reason is that the out let will be 3 inches to match my tube diameter to the turbo. once i have 2 x 3 inch hole sucking in air the air flow volume will be more than enough id think. i have the 3 inch pipe so it’s really a matter of cost in materials vs what i need. do you think the extra inch would really add much?
 
only reason is that the out let will be 3 inches to match my tube diameter to the turbo. once i have 2 x 3 inch hole sucking in air the air flow volume will be more than enough id think. i have the 3 inch pipe so it’s really a matter of cost in materials vs what i need. do you think the extra inch would really add much?

I'm pretty sure there is a comment from 2017 in this thread from @torfab that they tried 4" inlet with 3" outlet and it still created a vaccum, but 4 and 4 did not. a comment i wish i'd remember before having my box made.
 
Heres that comment from Oct of last year

Yes, that lid will fit but it's only 3". With the 4" inlet mod to the box and a 3" 95-97 fzj80 airbox lid, you will be just over the vacuum threshold. With our testing it only went under the threshold after we welded a 4" inlet pipe into the top of that lid.
 
I'm pretty sure there is a comment from 2017 in this thread from @torfab that they tried 4" inlet with 3" outlet and it still created a vaccum, but 4 and 4 did not. a comment i wish i'd remember before having my box made.

This. Everything I've read is that this engine wants as much air as it can get. Moonlight recommends a 4" snorkel with a 4" box.
 
Yeah, i think i latched on to thebigboys comments that this wasn't true and completely overlooked the more recent comments from torfab, and i think i may be reaping the results of that now
 
So i'm curious, Theres been a lot of interest in getting one of these in the US to avoid the shipping and have a better price point, but despite all of the conversation, i still don't see one available.

I'm committed to getting this air box worked out come hell or high water. If i do, would any else be interested in buying them. I'm working out the issues in mild steel and if it works right, i have a friend who could make it in stainless (or mild steel) for anyone interested, and I think it would be at a reasonable price point. Wont know until he prices stainless and gives me a quote.
 
So i'm curious, Theres been a lot of interest in getting one of these in the US to avoid the shipping and have a better price point, but despite all of the conversation, i still don't see one available.

I'm committed to getting this air box worked out come hell or high water. If i do, would any else be interested in buying them. I'm working out the issues in mild steel and if it works right, i have a friend who could make it in stainless (or mild steel) for anyone interested, and I think it would be at a reasonable price point. Wont know until he prices stainless and gives me a quote.

Yeah, I'd be in 100%. I'd put a deposit down in the right circumstances. I'd also love it if someone would fab a 4" snorkel so I can just get this over with. If I had the skills, I'd be all over this. I just can stomach $1800 all in to get this to me stateside.
 
Yeah, I'd be in 100%. I'd put a deposit down in the right circumstances. I'd also love it if someone would fab a 4" snorkel so I can just get this over with. If I had the skills, I'd be all over this. I just can stomach $1800 all in to get this to me stateside.

Ya, that's IC money, for just an airbox.
 
ive read all that. i figured as i’m not running a big turbo and haven t boosted it too much a 3 inch would be ok. maybe i’ll get a 4 inch pipe and make sure i do it the best i can. ill have to figure out a reducer to my turbo then. i guess it make sense as resistance to any fluid/gas flow is a function of diameter and length of pipe. the longer it stays at 4 inches the less resistance there will be
 
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I'd also love it if someone would fab a 4" snorkel so I can just get this over with.

If there is enough interest, That could be included as well, but ultimately it will depend on the level of interest
 
This. Everything I've read is that this engine wants as much air as it can get. Moonlight recommends a 4" snorkel with a 4" box.

I think this idea needs some context.

You can upgrade power a lot with the stock air box with no problem.

If you have aftermarket, high flow turbo's and running at high PSI, then yes you will find the limitations of the OEM intake.

With a stock turbo, there's loads of low hanging fruit to grab if your chasing more power before the effort and dollars for a custom airbox is warranted.
 
I think this idea needs some context.

You can upgrade power a lot with the stock air box with no problem.

If you have aftermarket, high flow turbo's and running at high PSI, then yes you will find the limitations of the OEM intake.

With a stock turbo, there's loads of low hanging fruit to grab if your chasing more power before the effort and dollars for a custom airbox is warranted.
Cheers. I saw posting under the assumption that you're pushing 20psi and are pretty far from stock tuning. I'm sure the factory box is great if you're running a close to stock setup.
 
Cheers. I saw posting under the assumption that you're pushing 20psi and are pretty far from stock tuning. I'm sure the factory box is great if you're running a close to stock setup.

Yep, a simple comparison is the 1HD-T to 1HD-FTE, very similar air box, 1HD-FTE in stock form produces quite a bit more power that the 1HD-T, mostly due to improvements in turbo design, and higher flow from the turbo. You can make decent increases in power with a 1HD-FTE too before airbox is a problem.
 
my goal hasn't been to increase power. I'm wanting to increase airflow to lower egts and I was under the impression that this would help accomplish that
 

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