Larger Throttle Body

[OoskylineoO]

hey guys, I recently came across an 80mm billet aluminium throttle body on ebay. It didn't say whether it would fit an N/A or not but just said fits rb25det. (i have a N/A r33)

My question is, would the throttle body from a rb25deT be the same as an rb25de one? in other words would that throttle body bolt up nice and clean? or would I need a large throttle body made specifically for an rb25de?

If it does, what other kind of modifications would need to be done? e.g, larger aftermarket plenum?, larger diametre intake pipe??

[unarmed_skyline]

80mm will fit but it will be way to big for a stock na and u will most likely lose power and responce, best to use an xf throttle body, it you do a search there was a big disscussion on it about 6 months ago

[OoskylineoO]

thanks for that, had a lot of useful info there. Just a quick question about the XF TB.

Can I get them off any Ford XE/XF EFI ????

something like this?

http://cgi.ebay.com/FORD-XE-XF-EFI-THROTTL...1QQcmdZViewItem

Also would an aftermarket plenum be essential? or would the stock one be adequate. Would I need a larger AFM as well?, if so what AFM would I require?

Edited February 12, 2008 by OoskylineoO

[SKiT_R31]

No, the stock plenum is fine, BUT you need to bore it out, with a dremel or something, or take it to a proper machine shop.

there are 2 types of XF throttle body, there is a 65 and a 68mm, both are easily big enough. It wont bolt straight on, you will need to drill into it to make the bolt holes line up, and you might have tps issues (best to use the xf tps and switch around the 2 end wires, thats for the 30e need to confirm for the 25...)

that said, what mods are on your 25? cam? higher compression? headwork? tune? if its only mild mods, like exhaust/pod etc, then try a 60mm TB from a KA24e it more the airflow increase thats suited to your motor, and it bolts straight on, but you do still have to bore out the plenum (to match the tb size) or you wont get a gain.

i put an xf tb (68mm) on my old 30e, with basic mods (mild cam, extractors, exhaust, cai pod, advanced base timing, remap, water plenum-bypass, GT40 coil pack, indexed over gapped plugs, etc) made heaps of difference, one of the most worthwhile bolt on n/a mods, but the engine would have benefited the same from a 60mm, as past a certain point, there was no more pickup.

stock afm is fine, 75mm int. diameter

you should pickup some info here, should be similar for the 25 as the 30e

http://wiki.r31skylineclub.com/index.php?t...F_Throttle_body

Edited February 12, 2008 by SKiT_R31