Ideas for size TB I need?

DarkAngelGSR

*JDM Approved*
I'm tryin to get skunk2 TB and IM. I don't know what size TB I need though.

Basically, B18C1, full Type-R conversion just about. Skunk2 springs/retainers,cam gears, type-r cams, pistons, rings, valves, s200, msd wires, ngk plugs, new cam seal, ARP head bolt set. DCRH, Greddy SP2 full exhaust, omni test pipe.

Any ideas? Anyone wanna explain to a TB noob the difference in sizes, how much it effects the rest of the system?


I was told to go Edelbrock instead of Skunk2 by a few. That's a first I've heard.
 
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JDMxDB8

Raceline USA
I'd go with a Skunk2 60mm TB. I wouldn't go over 60mm if I'm not racing it on the track.
 

TegSox

Super Duper Moderator
OEM ITR TB is 62mm. Looks like by your list of mods that 63mm would be a good choice to go with, since the Skunk2 IM is a little larger than an OEM ITR IM, and your header/exhaust is larger than OEM ITR, shifting your powerband up in the RPM range, requiring more air to enter the IM/head in the upper RPM's.
Stepping up to a 2.5 inch cat-back exhaust would help you out a bit too. Doesn't the DC race header have a 2.5 inch collector?
 

JimmyRos.

07 BMW 328Xi
TegSox said:
OEM ITR TB is 62mm. Looks like by your list of mods that 63mm would be a good choice to go with, since the Skunk2 IM is a little larger than an OEM ITR IM, and your header/exhaust is larger than OEM ITR, shifting your powerband up in the RPM range, requiring more air to enter the IM/head in the upper RPM's.
Stepping up to a 2.5 inch cat-back exhaust would help you out a bit too. Doesn't the DC race header have a 2.5 inch collector?
Click to expand...
yes sir it's 2.5.
 


mteg

Automatic Lover
The IM comes from Skunk2 at just under 64mm. I would go with the matching 64mm TB and IM.
 

DarkAngelGSR

*JDM Approved*
Thanks for the feedback guys, but I'm still wondering which is best for my setup.


So whats it all about with the Skunk2 TB/IM vs. Edel TB/IM?
 

mteg

Automatic Lover
The skunk 2 is probably going to be a better choice for NA. A good rule of thumb with IM's is the longer the runners, the more low end power. THe bigger the plenum, the more top end power. The edlbrock intake doesn't start to make power till around 7,000 rpm I think. The Skunk 2 produces good results across the board. Just remember, If you go with a larger throttle body than say 64mm inlet on a skunk2 IM, your going to have to hone out that inlet hole. Just take it to a toolshop-yhour best bet to have it match your throttle body.
 


mteg

Automatic Lover
I would go with the IM which has a 64 mm inlet and either a skunk2 64mm tb or a ITR tb thats been bored from 62-64mm. Shop around a bit. a skunk 2 tb costs about $250. I picked up a bored out ITR tb for $150 froma friend and it bolted up oem.
 

Aussie

Zoom-Zoom
I would go with a 64mm, it might be more than you need but it will work fine and leaves room for improvement. Stock GSR is 59mm if that gives you an idea, you don't want to go over 66mm. The bigger the throttle body the more throttle response your going to loose. So no bigger than 66mm for no less than 62mm. I would go with 64. Your really not going to see that much of a difference in hp anyway.
 

mteg

Automatic Lover
Get some cams in there and that intake manifold and 64mm throttle body are going to be very noticable.
 

Aussie

Zoom-Zoom
Oh it will be noticable, I meant that the diffence in the 64 and 66 won't be that noticable.
 

mteg

Automatic Lover
Yeah, going from a 59mm to 64 will be noticable but ussually the tb and im add very noticble gains when adding cams.
 
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