ITB's for 1jz

**Robbos_Toyotas** · 17-03-2006, 05:39 PM

if i ended up buying a 1jz, i was going to make a manifold with a custom plenum and a 75mm XF falcon tb...damn sure thatd make 300rwkw easy as piss.

on that note, good luck getting 300rwkw on stock turbos.

**gianttomato** · 18-03-2006, 01:42 AM

Originally Posted by ReQuieM

Pretty keen on building it my self but on the subject can you pm me with some prices of throttle bodies? Could aslo do with some advice on ITB's in general.

Is this going to be a dedicated track car? Why do you think you need such crisp throttle response? It's in a 70 series Supra? My gut instinct tells me you should just use a couple of nicely sized roller bearings with nice intake and exhaust manifolds to achieve what you are after.

This is going to be painfully expensive. You'll need to make a manifold (you can't use Ed's because it won't bolt up to your 1JZ). Then you'll need to buy 6 ITBs (or 3 pairs) and associated linkages. Then you'll still need to make some sort of "plenum" or sealed airbox.

There are plenty of throttle body options out there.

The cheapest and most ghetto spec would be finding some dead 45mm Webers, seal them off and use them. This works very well. If you are a little inventive, then you could mill off the throttle section from some SU carbs and use those as throttle plates, or the throttle section from those old shitty single barrel carbs can also work fine.

Simplest would be the GTR 45mm throttle plates - you can bore them out if need be and get larger throttle plates put in them but then that negates how cheap they are. Meridian Motorsport also sell throttle plates - probably best to get a price from them. The easy thing about throttle plates is that they are very compact.

Glenn sells 20V style throttle bodies in a range of sizes up to 52mm. Quite a good price considering what you get for them. Best to PM him or see what stuff he has for sale in the For Sale section.

Then there are a range of proprietary DCOE style throttle bodies that you buy as kits from Speed Technology or Injection Perfection. Both have websites - google is your friend.

**JZA70 R** · 18-03-2006, 05:16 PM

Originally Posted by ReQuieM

I guess the way to judge the real differnce between response would to ask a skyliner thats drivin a GTS-T and a GTR. I off to the skyline forums!

I'm not so sure you will get much of a comparison with 2 different motors.

**ReQuieM** · 19-03-2006, 10:30 PM

Sorry worded badly, some one thats upgraded their GTS-T to GTR ITBs.

Well I've got my GTR Throttle plates. their not to far off being the right spacing. I've got some shots I'll up load when i get a chance,

Thanx for the responses some of them are really helpful. Basicaly i've decided F it i'm just gonna do it and see. It'll be a while coming but it'll get there eventualy. as for cost its been pretty cheap so far, it'll get more expensive tho but i can see coming out of this for under 600 so thats not too bad.

Nah its not gonna be just a track car. I dont need chrisp response but i want it! just like every thing else when it comes to modifing cars!

Any way more comments are welcome and I'll attemp to keep every one posted on how it turns out.

**ReQuieM** · 20-03-2006, 10:12 PM

For thos interested.

**Draven** · 20-03-2006, 10:14 PM

1jz = teh tiny inlets

ed · 21-03-2006, 12:23 AM

meh, too easy

plate + round tube + crush + cut + weld + beer + money = too easy

**ReQuieM** · 21-03-2006, 08:13 AM

Haha Thats what i'm hoping for! once the throttles are mated up its just a matter of making a set of runners and plennum.

Then off to the dyno so see if it makes any recardable difference...

**ReQuieM** · 21-03-2006, 04:43 PM

With just some quick measurements and math the surface area of the 45mm GTR ITB's is 4996.5 mm2 and the surface area of the 1jz injector boss port is 3120.7 mm2. Nice little ram air effect jut before the valve. Larger runners then too.