The MGF Register Forums

Hoya, on evil bay there is a 56mm throttle body for sale, anyone tried/got one of these??

Im affraid all of the advert on one of the 56mm bodies on ebay is bull poo.

For starters, they are hands down shown to loose power, the pressure post throttle is incorrect and the K series does not like it.

Then the ebay add.... was a good laugh to read.

"A second gent bought one for his MGTF 1800VVC to replace the plastic 48 TB" - The TF has a Alloy 52mm body on it (which is the one you want btw)

Id go on, but alas its not worth the time. A simple google search will yield results showing the negative effect of the 56mm body, it was never fitted to a K Series either, they are usually modified GM parts...

The 52mm does not add power either. What actually happens is that for the same % throttle (aka foot down) you get slightly more air which means the car rev's a tad higher than you expected, giving the illusion of increased performance. Rolling road gains are not noticeable. A 10bhp gain from a throttle is pure bullshine, direct to head bodies dont gain that much on a K Series.

Ta very much, I must confess I was sceptical especially after the vvc comment lol but just thought I would ask. I am considering a 52mm but need to actually check what I have first as the 52 is not visable as I believe it's on the back edge when in place??
Cheers for the reply though, much appreciated

TF135 and 160 models had a 52mm TB as standard. TF120 and 115 models use the 48mm version

Rob Bell wrote:TF135 and 160 models had a 52mm TB as standard. TF120 and 115 models use the 48mm version

Is that a fact Rob? Well blow me lol how come so many go on about changing to a 52mm then? Maybe I should get the old dentists mirror out and check lol you sure that's right? Flippin good if it is lol

Other than the MGF Trophy 160, all MGFs got the 52mm - and hence this became quite a popular retro-fit. I have one on mine too - although a 1 bhp gain of power is essentially neglible on my 1.8MPi. The throttle response is sharper though - as you'd expect with a larger throttle area - so I've never reverted back!

From about a decade ago (!) - red line is with the original 48mm TB; the green with the 52mm TB. I haven't tested a 145PS VVC with a 52mm TB - and on this car, there might be a little more to gain

The 56mm TB is found on the V6 K series, AKA the KV6.

Personally I found the 52mm TB on my mk1 VVC (143) gave a noticeably sharper response than the O/E 48mm TB.
And it took longer to remove the engine cover to find the location of the breather hose than it did to swap the TB's over.

Would be interested to see the data showing they lose (peak) power... My experience is they will give you a little more at the top end, but at the (quite drastic) expense of mid-range (on an engine with no/mild tuning)