turbo - Page 3

Storm_X · #31 (**permalink**) 10-09-2009, 05:28 AM

ha sailsbury north.

na sorry no intercooler im still looking around.

i wouldnt have a clue about the plenum. i dont think it would be cheap to get some cut then all the holes cut etc then weld it. thats why im doing it my self

should speek on msn. my msn is fked tho atm.

gattia86 · #32 (**permalink**) 10-09-2009, 06:28 AM

A custom fabbed sheet-metal turbo plenum fabbed in aluminum is going to be EXPENSIVE! Here in the US, it would run around $1500 to over $2000. You could probably get a set of Hayabusa throttle bodies and an off-the-shelf Hayabusa turbo plenum for less than that. (But don't be fooled... an EFI conversion will cost a lot more than that by the time you're done with all the details!)

Make it out of steel.
It's not ideal, as steel is heavy and retains heat, which partly defeats your intercooler... but it'll work. If you like the design, you can always take it to a fabricator later and say "make this out of aluminum". It'll save you some money, since there won't be any design work to pay for.

Don't make it out of 3mm steel! That's way too heavy. .045" (whaterver that is in mm) is fine. Then don't get it powder coated, or the heat will warp it.

Be careful when welding that the flange that seals to the carbs doesn't warp, or you'll get all kinds of leaks. Make the flange out of heavy gauge stuff. Also, figure out some way to pressure test the thing when you're done welding; pump it up 5 or 10 psi of air and stick it in a bucket of water to look for air bubbles. Don't put, like 50 or 100 psi of air in it, or it'll blow up!

Even small pin-hole air leaks will loose boost pressure and make tuning difficult.

As far as attaching bolts(?) or studs to an aluminum plenum... you can get "nut-serts" or steel studs which attach kind of like rivets; drill a hole, insert the nut or stud, and press it in with the special tool. A sheet metal fab shop or race fab shop should be able to do this for you if you provide the aluminum part with the holes already drilled.

George

BradGTV · #33 (**permalink**) 10-09-2009, 04:02 PM

thanks for the info. at home i have a sheet metal bender,gilotien and roller so i will cut the sheets of steel and the fold to sides on the plenum. so it will only need two welds besides the back and the front if you get what i mean. that i way there will be les chance of leakidge. george i like your idea of testing it in water with pressure in it

.

do you suggest i use tubes (ram tubes) with bellmouths on them to go from the carbies into the plenum? (see pic on page 2)do i need to do this? or just put the plenum up againss the face of the carbies?
hey storm salisbury north is pretty clos do u drive ur alfa around much?
where 2 of my gtvs are is at my grandpas house in salisbury so even closer.
brad

Storm_X · #34 (**permalink**) 10-09-2009, 06:17 PM

Quote:

Originally Posted by BradGTV

thanks for the info. at home i have a sheet metal bender,gilotien and roller so i will cut the sheets of steel and the fold to sides on the plenum. so it will only need two welds besides the back and the front if you get what i mean. that i way there will be les chance of leakidge. george i like your idea of testing it in water with pressure in it

.

do you suggest i use tubes (ram tubes) with bellmouths on them to go from the carbies into the plenum? (see pic on page 2)do i need to do this? or just put the plenum up againss the face of the carbies?
hey storm salisbury north is pretty clos do u drive ur alfa around much?
where 2 of my gtvs are is at my grandpas house in salisbury so even closer.
brad

Storm_X · #35 (**permalink**) 10-09-2009, 06:25 PM

oh and u will need to cut holes into the plenum for the top hats and also i think for vacume for map sensor etc. im not %100 sure

BradGTV · #36 (**permalink**) 10-09-2009, 07:58 PM

my gilo is 40 inch, but my mate has a extremly large one.
yer i was thinking of putting it face to face and then on lathe make 4 of these (pic) what do u guys think?

Storm_X · #37 (**permalink**) 10-09-2009, 08:19 PM

im not even sure what that is.

the gilo i used when i was welding was huge like 3m.
still 40inch better then nothing

gattia86 · #38 (**permalink**) 10-10-2009, 01:03 AM

Quote:

Originally Posted by BradGTV

i was thinking of putting it face to face and then on lathe make 4 of these (pic) what do u guys think?

Storm_X · #39 (**permalink**) 10-10-2009, 01:26 AM

Quote:

Originally Posted by gattia86

The hardest part will be figuring out how to screw the things onto the carbs with the plenum on... but I suppose you'll have to figure out how to screw the plenum to the carbs anyway.

George

OzMidnight · #40 (**permalink**) 10-11-2009, 12:26 AM

Some guys have been known to use alloy bullbar material to make their plenum....more than strong enough to hold boost...and cuts down on fabrication time.

Duk · #41 (**permalink**) 10-11-2009, 03:23 AM

Quote:

Originally Posted by gattia86

A radiused carb bell-mouth is important on a NA carb. I'm not sure how important it is on a forced-induction engine, although all high-end racing plenums have these inside. It'll run either way... I'm not sure how much you could feel the difference.

gattia86 · #42 (**permalink**) 10-11-2009, 10:24 AM

On the topic of attaching the plenum to the carbs, here's a fabbed plenum that bolts to a Weber IDA carb (downdraft, but similar to the DCOE).

Aluminium Custom 12A/13B Turbo Plenum for IDA ITB/Weber - Polished

Instead of trying to make a flat plenum surface that bolts to the carb faces, you could build something similar to this with short, round runners sticking out of the plenum; the bolts are outside the runners, so you can bolt the assembly to the carbs without having to make any holes or through-studs in the plenum.

You can even buy the parts seperately, or you could even fab something like this in steel, using steel DCOE velocity stacks as a starting point.

Just an idea...

George

chelo · #43 (**permalink**) 10-11-2009, 11:48 PM

If your looking for a cheap and good intercooler, use one off an isuzu diesel truck. In the U.S it would be an NPR diesel. Works great and could be purchased for cheap. The volvo units work but over 17 psi they start to crack because almost all are made from plastic.
A log style manifold should work if your on a budget and not pushing high psi. For your application get a turbo with a smaller a/r housing. Yes you could use a bigger unit but boost will come in later in the rpm range and you would have to rev the engine higher. Building boost at a lower rpm is more fun than waiting for it to kick in hard. Well actually both are fun but it depends on the purpose of your car.
I don't know if you mentioned it but this will be your street cruiser? More of a daily driver vs a track car right? Keep it simple not too much boost and enjoy it. If your going to build your engine with forged internals and have a bigger budget than I would do things a bit different.

Storm_X · #44 (**permalink**) 10-11-2009, 11:50 PM

Quote:

Originally Posted by gattia86

On the topic of attaching the plenum to the carbs, here's a fabbed plenum that bolts to a Weber IDA carb (downdraft, but similar to the DCOE).

Aluminium Custom 12A/13B Turbo Plenum for IDA ITB/Weber - Polished

Instead of trying to make a flat plenum surface that bolts to the carb faces, you could build something similar to this with short, round runners sticking out of the plenum; the bolts are outside the runners, so you can bolt the assembly to the carbs without having to make any holes or through-studs in the plenum.

You can even buy the parts seperately, or you could even fab something like this in steel, using steel DCOE velocity stacks as a starting point.

Just an idea...

George

Storm_X · #45 (**permalink**) 10-11-2009, 11:57 PM

Quote:

Originally Posted by chelo

If your looking for a cheap and good intercooler, use one off an isuzu diesel truck. In the U.S it would be an NPR diesel. Works great and could be purchased for cheap. The volvo units work but over 17 psi they start to crack because almost all are made from plastic.
A log style manifold should work if your on a budget and not pushing high psi. For your application get a turbo with a smaller a/r housing. Yes you could use a bigger unit but boost will come in later in the rpm range and you would have to rev the engine higher. Building boost at a lower rpm is more fun than waiting for it to kick in hard. Well actually both are fun but it depends on the purpose of your car.
I don't know if you mentioned it but this will be your street cruiser? More of a daily driver vs a track car right? Keep it simple not too much boost and enjoy it. If your going to build your engine with forged internals and have a bigger budget than I would do things a bit different.