ITB sizing for worked g180w

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Encyclopedia Ronnie
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Post by Encyclopedia Ronnie »

GeminiCoupe wrote:All im going to say is they definately arent GTiR items.... :lol:



well the onli other 6 i can think of factory with quads from the nissan gtir eara is welll godzillaaa :twisted: :twisted: :twisted: the gtir quads are useless as the ports are mega homo for gems i already looked lol
Yes, i do still own my coupe, Yes it is still registered and running and ATM driven daily.


oh and NO its not painted yet
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redzone (coxy)
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Post by redzone (coxy) »

E36 m3?
GARAGE REDZONE sunshine coast ph 07 54433507

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F3ARED
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Post by F3ARED »

coxy, M3 ones are hard to find and rrrrrrrrrrrriiiidddddiculously exxy [trust me, ive tried finding them :lol: ]

Well now that youve let the cat out of the bag i may aswell show you this...

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BAD 44u
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Post by BAD 44u »

like someone else said dont compare webers with throttle bodies since there is no venturi. i gained 10 hp by moving the injector further away from the port.
Also a ported G180W port is about 38mm so if you want to go much bigger in throttle body your better off with a tapered throttle body and runners on a slight angle to clear the shock tower with a raised port roof. also lots of bracing to stop the manifold cracking

What are guys doing for your bigger cams billets or regrinds?
elky
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Post by elky »

so i just wanna go bigger carbs for the drag gem......was thinkin 45's but seeing as drivability is not a concern would 48's work?

i got a monster head here i wanna use with some big cams that came with it, but first we need to establish clearences, and at this point i wanna keep it drivable as i am soon to go back to the track, so that means dropping a valve to measure things on the car

there is a mob in sydney that did some billet cams for a hillclimb gem up here, i will try to find out who did it

cheers
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BackToTheGem
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Post by BackToTheGem »

See boys Nissan's are good for something :D (just don't tell the clubman boys - they've damn nearly robbed the entire country of escort diffs, cortina uprights, 4age's and t50 gearboxes lol).

From what I've found out with carbs comparing to itbs is that yes you obviously have to take the chokes into account. 45mm webbers use a 42mm choke so I'd compre them to 42mm itbs and 48mm webbers use a 45mm choke so comparable to 45mm itbs. This really backs up Coxy's comment - 48mm itbs are going to flow heaps and at low throttle openings will probably be a bit of a pr!ck to drive. I'd ideally go 45mm but so far the itb's GeminiCoupe has found are the best suited I've seen and currently reasonably cheap. The fact that 2 sets will do 3 gems is also a big bonus.

Bad44u do you think you gained the extra 10hp through better atomisation when you moved the injectors? I've seen a fair few bike itbs that use tapered ports but was trying to stay away from them and their silicone joiners.

For my cams I'd like to go billet as I have absolutely no idea if my current cams are standard or have been reground already. My engine came from a rally car via Elky and was running on 3 cylinders when I got it. I'm yet to pull it down to find out why it was running on 3 cylinders (suspect a valve or ring) - being from a rally car I wouldn't be surprised to find it's received a bit of work but it's just as likely to be dead standard.
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orange_gem
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Post by orange_gem »

http://www.rawbrokerage.com/RB26DETT-In ... 26-itb.htm

So you would have to make all your own set up? To mount and everything? I would rather buy a set from efi hardware or injection perfection. Save alot of screwing around and ready for everything to rock and roll. Plus I got a g200z. 134hp atw. Going e85 and itb's and quad coil end of the year will let everyone know how it goes.
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F3ARED
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Post by F3ARED »

So you would have to make all your own set up? To mount and everything? I would rather buy a set from efi hardware or injection perfection. Save alot of screwing around and ready for everything to rock and roll. Plus I got a g200z. 134hp atw. Going e85 and itb's and quad coil end of the year will let everyone know how it goes.
Yes you would have to make your own setup but thats the price you pay with a DOHC. Im going to assume by your power output your running twin webers/dellortos in which case you would already have the manifold to suit the injection perfection/efi hardware throttles. That would also mean you wouldnt have to weld on injector bosses as the new throttle already has that.

Unfortunately, us DOHC guys dont have the same luxury, however we DO have some advantages [besides the head flowing better standard then most modded SOHC's].

Unlike the Z series the W does not have the thermostat or water running through the inlet. To adapt the GTR throttles on, all it would take is 4x flanges [2x gtr mounts, 2x DOHC head flange] and some pipe. There are no bends to worry about and the port spacing is paired [refer to diagram above]. All that would be left is to do the bosses for the injector and the linkages. Also note that weber manifolds for a DOHC dont fall out of trees, and most aim the carb smack back at the master cyl which is not something you really want.
like someone else said dont compare webers with throttle bodies since there is no venturi. i gained 10 hp by moving the injector further away from the port.
Also a ported G180W port is about 38mm so if you want to go much bigger in throttle body your better off with a tapered throttle body and runners on a slight angle to clear the shock tower with a raised port roof. also lots of bracing to stop the manifold cracking

What are guys doing for your bigger cams billets or regrinds?
You sure Tim? Mine measured @ 40mm and it hasnt been ported before [that or perhaps im blind?]. As for cam ill be going regrind, cdtpf60 [Paul] has found me someone that can grind em
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BackToTheGem
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Post by BackToTheGem »

orange_gem wrote:http://www.rawbrokerage.com/RB26DETT-In ... 26-itb.htm

So you would have to make all your own set up? To mount and everything? I would rather buy a set from efi hardware or injection perfection. Save alot of screwing around and ready for everything to rock and roll. Plus I got a g200z. 134hp atw. Going e85 and itb's and quad coil end of the year will let everyone know how it goes.
I reckon I can save over a grand going custom rather than efi hardware or injection perfection. If I can spend that money elsewhere I'd prefer too. As GeminiCoupe said though we've got it pretty easy when it comes to manifolds. Pretty much just 2 flanges and 4 straight pipes. The fact the GTR itbs have the exact same port spacing just makes it easier - we're going to have to mess with linkages and fuel rails though. One of the beauties of the bike itbs is that a lot of the gsxr ones are held together by 2 m5 rods. You can separate them and then space them however you like using some longer rods and a few nuts.
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BackToTheGem
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Post by BackToTheGem »

http://www.sportingfords.com/forums/vie ... 574#p19574

This is an example of the gsxr itbs on a zetec. So easy to mount! Such a shame those silicone joiners would hurt flow
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orange_gem
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Post by orange_gem »

Nah im running efi with a vr t/b (60mm) Only 30 degrees timing on 105 race fuel. Only had 118 on 95 octane. So its a 12 or so percent increase. Which is crazy for fuel only. Will be alot of fun if I get the tuner to play with my hand controller and add some timing :P can't wait for the e85 and everything else.

And btw it drifts pretty awesomely.
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