Modifying Stock R33 Airbox/snorkel Or Entirely Custom

[sl33py]

I want to keep my intake similar to the stock setup (ie enclosed, fed from the front of the engine bay) but I don't want a pod. I hate the noise, and want to avoid the legal ramifications.

I've seen some made for V8/LS1 engines which look like I want.. big wide open mouth taking up as much space as possible where the bonnet meets the chassis, kinda like the stock air snorkel but much larger opening at the front. I'd also like to modify how the snorkel feeds into the airbox - if I've made the changes just explained, the join into the airbox will be the next bottleneck.

I'm going to buy a spare snorkel/top half of the aribox. Can someone tell me what I need to make these changes? I've heard of plastic welding... do I need to do that?

Thanks for any help in advance. Also open to going completely custom if I can get the materials and the know-how to do it fromt scratch, but would prefer to use the stock box and modify it, cos then at least it will look stock-ish. I'd like to use the same kind of material at the very least.

[dezz]

I like this idea...no one seems to have done it though...If I were to have it on my car, I'd want it done professionally so it looked factory, and not some cheapo hack job.

[sl33py]

I also spoke to a (/the) dude that was going to do that a while ago From memory, he ended up going pod lol

That's pretty much what I'd like to do though. I just realised a mate has done fibreglass work for audio installs - going to see if he can make something. And yeah: I want it looking like stock. Matt black and boring!

Edited February 13, 2008 by sl33py

[Adz2332]

Mare if you come up with anything plz show it off. As im trying to come up with something for my 33 GTR

[sl33py]

Will do! Mate says it'll take a few days.

But from previous reading, I think the GTR intake is better than the GTST... It's larger. In fact, I think the intake I end up with could look very similar to the stock GTR one. Anyway, we'll see.

[GTRgeoff]

The primary reason a GTR33 airbox has so much potential is there is an extra inlet to the airbox through the side inner guard. Mine currently makes 320rwkw on the stock airbox and I'll soon push that over 400rwkw. It can't be done the same with a stock RB25 box, but I've seen a large improvement in simply removing the top out of the airbox on the auto 33 I had and sealing it to allow frontal airfeed only. Unfortunately the lower area of the airbox is not particularly good so on my race car (33 GTS25t with RB26/30) I custom made the new airbox to be where the stock cooler is with a stock panel filter in the front, bellmouth pickup inside and a vented front on the bumper will follow to allow direct air intake.

[R338OY]

Great idea, worth the effort. With a high flow panel filter and this Julia Roberts mouth drawing in air you'll be able to drastically minimise restriction without getting a defect.

[sl33py]

Cool geoff. I think I saw a picture of that. Changing the filter must be a hassle though? So far I'm just thinking of modifying the top section of the airbox and the snorkel. Also... I'm not keen on having the air filter so low to the ground. I'm in Canberra lol In Brissie and on a race car I'm sure it's fine though!

Edited February 13, 2008 by sl33py

[ACTIV32]

pod=more air induction

jap cars are never stock to much potiential so why look it

alteritive ad a pod and make i cold box to cover it

[GTRgeoff]

I lived in Canberra for 5 years. I'd have it the same there but yes it is a race car, and I intend to make filter changes easier by making a louvered front panel held on with dzus fasteners http://www.my105.com/catalogue.asp?id=4558 or the like.

Pods though are not as good as people think.

I've used HKS pods and they let a lot of muck through in some designs plus filter poorly. A mate just had a turbo destroyed by a Blitz that let gravel in where he mounted it. About the only foolproof ones are Apexi and even then without a topnotch enclosure they are subject to too much hot air. Calculate how much air is taken in in eack cycle of the engine, then times that by RPM then wonder how much enters every minute. Compare that to the size of the engine bay and no surprise they will be sucking a massive amount of hot air.

I hate pods, but I'm only an engineer specialising in race setups and weapons systems.......

[Adz2332]

GTRgeoff do you have any pics of your set up would reali like to see it

[sl33py]

Read my original post ACTIVE32. Thanks anyway.

heheheh Geoff I'd be worried about the filter getting soaked when it p1sses down.. Mine's a daily driver.

One thing that came up yesterday - my mechanic said if I'm going to experiment with modifying the top half of the airbox and the snorkel, I don't need to get it retuned or anything afterwards. I asked cos I'm getting a new turbo (HKS GTRS) and all the other bits at once and want it all perfect.

If I muck about after the tune, will it be like when you add a better exhaust and don't do anything to the ECU - it'll adjust automatically to make use of the better flow (by extrapolation with load point data and using the AFM I guess)?

Adz, I found the pics here: http://www.skylinesaustralia.com/forums/Ai...gtrgeoff+filter post #14.

Edited February 13, 2008 by sl33py

[dezz]

Definitely interested to see what your mate comes up with...I'm interested in something like the pics I posted.

As for tuning, I had my car dynoed at my workshop in normal trim, and then straight after with the top of the airbox removed. There was a change in afr and some knocking, so to run like that it would have needed the tune adjusted.

[sl33py]

Woah... You're tune must have been cutting it close WRT fuel supply? I sort of expect the engine should have room to move (supply more fuel) if a mod like this is done to supply (what probably isn't a whole lot) more air, and to supply the extra fuel needed. Hmmm. I guess it would depend on how much room there is in the tune and how much more the fuel pump and injectors can give.

[GeeTR]

I guess it would depend on how much room there is in the tune and how much more the fuel pump and injectors can give.

Would depend on how "on the limit" it was the start off with too.

I wouldn't have thought a air box mod would change fuel requirements all that much, alas agree with you. Get it tuned after all your mods are done.

[sl33py]

OK, well after about 3 hours of bvggering about with cardboard and getting nowhere, I've come to the conclusion that it's probably easier to get hold of a spare airbox and snorkel and modify them, if only to come up with a mold to make fibreglass copies.

[dezz]

I've got a snorkel for sale if you need one.

[sl33py]

YGPM!

[sl33py]

Anyone think a soldering iron with digital control which can go up to ~300 deg C would do the job of a plastic welder? And anyone think that plastic plumbing pipe would work to make an airbox? If not, maybe I'll just make a mold using it. What I'm really after is a material easy enough to work with that I can easily make a mold out of, or cheap and sturdy enough that I can actually make a permanent airbox out from. Gonna go look at Bunnings etc this morning.

Edited February 16, 2008 by sl33py

[Craved]

i used a cheapie direct plug in soldering iron to plastic weld, so that adjustable one will work.

you'll need to try and get a hold of some filler rod for the plastic welding .. or use off cuts as filler.