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MG MGF Technical - Swapping Throttle Bodies
|Well, we did it. Yesterday I fitted the 52mm TB and the Trophy/TF airbox to my '01 MGF VVC. Did it with a friend who has a red '98 MPI. Without any sophisticated tools I expected it to be really difficult. It wasn’t. One of the bolts was, as expected, difficult to tackle, but we accessed it from the cockpit, back through the rear window (removed the headrests on the seats). |
After we'd done mine, we did his. Now he’s doing his Articles so can’t afford to spend any money on his car, and I decided to give him my 48mm alloy TB, and the ’01 airbox (which is, after all, bigger and better than the older item). We tackled the TB all right, as a matter of fact the diameter of alloy item seems definitely bigger, it looks a good 1 or 2 mm bigger. The airbox was more difficult, it just wouldn’t fit in the same clips as the old item. In the end we decided to keep the standard ’98 item, disconnect it from the resonator box, and run a flexipipe from it to the side air vent.
Results? Given a few hundred miles for the ECU to cope with the new setup, the difference is, as expected, considerable. My VVC feels really torquey at low revs, and really gets going from 6000 –7200. It feels like I’ve swapped a 1.8 for a 2.0 .
On the ’98 MPI, which has 80,000 km on the clock, the difference just as perceptible, almost more. It’s torquier at any revs and there’s no fall in power at 5,500. It just revs freely up to the limiter, almost like a VVC. The extra miles on this engine help, I think, too.
Took 2 pics of the engine bays from above – it’s an interesting comparison. Note the different shape of the airbox, the extra cover over the exhaust manifold, and the different plastic engine cover. (copy and paste link below)
Anyway in the MPI’s case it’s a really simple mod and for my friend the cost was zero… : the better breathing helps of course but I’m positive the 48mm alloy TB helps too. I know I felt a power difference when the dealer swapped my 48mm plastic TB for an 48mm allow item.
|> In the end we decided to keep the standard ’98 item, disconnect it from the resonator box, and run a flexipipe from it to the side air vent.|
Anthony, you got any pics of the routed pipe from the airbox to the side intake as I'm considering doing this on my '98 VVC.
I split the two bits of pipe that go between the air filter box & the resonator below, and ran a piece of pipe from the LHS air intake upto the 90 deg piece of pipe coming out of the air box.
I have a piece of 62mm flexy in the garage if you want it to try. (this was on a 1.8)
|Alistair, that's rather similar to what we did. |
I haven't taken pictures of our system yet, but I've taken pictures of the parts and made a small sketch (link below).
We used the pipe from the airbox I had ordered from the MGF Centre. It’s the pipe that runs along the rear of the engine bay, about 60 cm long, and at the point where it is attached to the MY 2001 airbox, there is a plastic part with a 90-degree elbow , ending inside the airbox. This is the part we used to connect the tube to the ’98 car’s airbox.
We disengaged the old airbox from its resonance box by removing one item of piping. We then opened the side air vent and passed the pipe through. It emerged inside the engine bay, parallel to the ground, directly below the airbox. We placed the plastic elbowed part at the end to see where arrived. Sure enough it jutted up in the airbox area, but was a bit long, so we sawed off about 10 cm. It then fitted perfectly into the pipe leading into the back of the ’98 airbox.
I hope to take pics of the whole system tomorrow night. We’re opening the Red ’98 MPI again to fit a Green panel filter.
|I've just uploaded photos of the intake pipe|
|>>I decided to give him my 48mm alloy TB, and the ’01 airbox (which is, after all, bigger and better than the older item). We tackled the TB all right, as a matter of fact the diameter of alloy item seems definitely bigger, it looks a good 1 or 2 mm bigger.<<|
I have both a plastic and an alloy 48mm throttle body at home, and will measure these up - I suspect that they are the same - but perhaps the Dell'Oroto flows better than the plastic SU TB?
>>The airbox was more difficult, it just wouldn’t fit in the same clips as the old item.<<
That's a pitty :o( The later cars must use a different mounting bracket? Useful to know for future reference though.
>>In the end we decided to keep the standard ’98 item, disconnect it from the resonator box, and run a flexipipe from it to the side air vent.<<
This is the famous Roger/ Bruno airbox mod! :o)
I suspect that the majority of the gains are through the improved airbox/ cold air intake you've now got (pre-2000 cars have a very restricted air intake as standard - and this may be why the MPi responded to the work better than your later car Anthony).
The 52mm TB is great Anthony - but is only good for a couple of bhp. But throttle response is electric - and for that reason alone is worth doing! :o)
Well done guys! :o)
I'm the happy owner of the famous red flame MGF with the new Anthony's throttle body and our home-made air box system (with my dear friend Anthony Braham...a great Mister). He is absolutely right, I don't have the same car!!! that's like a small Ferrari! and now I have problems with tyres...my car drives too fast...and furious! (I will have problems with police soon). So do this easy motor tuning and you won't recognize your MGF!
Cédric (sorry for my "frenchy english")
|Hi Cédric - no need for apologies - I completely understand what you are saying (enthusiasm like that always communicates well!)|
I might add that neither of us had ever done anything as complex as changing a throttlebody.
Thank you to all those who posted on the subject - the instructions were really helpful and gave us the confidence we needed to do the job.
I think you're right - the brackets on the later boxes are different. When I fitted my ITG Magogen (which had just come off Gerry's "Golden Wheels") I had to fabricate a bracket extension to make it fit. One other thing. I'm sure someone said that later Fs and new TFs have two pipes going into the air box. My 2001 car only had one pipe into the "Trophy" style box. I suspect that it might only be TFs that have two pipes. Unless anyone knows different.
|I believe that the Trophy 160 may have a dual intake David - but will have to be guided by those with this car as to whether this assumption is correct or not!|
|Hi Rob! perhabs a stupid question...(some say that there's no stupid questions but only stupid answers!) are you the Scarlet Fever's owner??? if that's correct, I'm really happy to know you and what a pity to your poor MGF after this accident.|
(My MGF is also a red flame one) and I tuned it with the Newton Commercial black full tonneau cover and some other accessories...
Not a silly question at all! Probably a bit confusing because I wrote the introductions to a number of the sections of the "SF Forever" SOS site. But no - I am not 'Scarlet's keeper' - that honour belongs to Andrew Philips :o)
I'm sure that Andy will be along shortly - but from what I can gather, the Scarlet Phoenix project is continuing a-pace :o) Looking forward to seeing the completed car on the 17th! :o)
My car is a BRG 1.8i with a great white dot on the side of the doors! :o) :o)
|>My car is a BRG 1.8i with a great white dot on the side of the doors! :o) :o)|
And a smart front splitter :-) I got one from the MGF centre (the Trophy one) and will be installing it shortly.
Rob, did you measure the throttle bodies? I'm curious. My "48mm" alloy item has number on it: 000090 (where the 52mm item has 000261). This is different from what someone else (Per I think) reported in the archives ona similar item, IIRC.
I confirm the Trophy has the dual intake pipes on the airbox. I just checked it out at the dealers. Which would seem logical because it has the extra power. IMO the airbox mod adds as much if not more towards torque and power than the throttle body.
Hi there from Essex, near Stansted airport using airport transfers tonbridge. :-)
Thanks for the kind words regarding the accident, but it is all looking a lot better now (there is a new gallery on the SOS site as of this morning showing Scarlet with a new front end!) :-)
Sounds like you have a nice F there Cdric, but then i am a bit biased (Fs look great in red!) :-) I thought about the Newton Commercial full tonneau cover myself recently and came close to getting one (but the accident got in the way).
Rob has his own website too:
>> http://www.mgf.ultimatemg.com <<
...and there are loads of useful tips, hints, facts and figures on there, well worth checking out (i use it all the time!) :-)
Scarlet should be ready for August 17th and there will be loads of stuff on the web about her shortly afterwards!! In the meantime, keep watching >> http://www.sfforever.co.uk << as there will be a lot of activity during next week - i'm off to Wolverhampton to re-fit the interior...
|>>Rob, did you measure the throttle bodies? I'm curious. My "48mm" alloy item has number on it: 000090 (where the 52mm item has 000261). This is different from what someone else (Per I think) reported in the archives ona similar item, IIRC.<<|
oops - I forgot! I'll have a look at this tonight for you Anthony :o) And I'll check those numbers too.
>>I confirm the Trophy has the dual intake pipes on the airbox. I just checked it out at the dealers. Which would seem logical because it has the extra power. IMO the airbox mod adds as much if not more towards torque and power than the throttle body. <<
From the RR tests, I'd certainly agree with that Anthony! :o)
Great new pix Andy - and look forward to seeing the new galleries as the interior is fitted up... :o))
This thread was discussed between 27/07/2003 and 05/08/2003
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