I thought the restricted one just didn't open all the way?

 

52mm throttle body usually has a 52 in a circle on it somewhere. Easiest way is from the part number though.

MHB000261 is the 52mm part number.

 

There should be a part number stamped onto the outer edge of the flange at the inlet manifold end. You can cross reference this with the parts listing on http://www.rimmerbros.co.uk/.

The throttle body fitted to the ZR 105 and 120 is the same 48mm throttle body as is fitted to the unrestricted (103ps) versions of the Rover 25 1.4.

The (84ps) versions of the 25 have a similar 48mm throttle body, but it has a restiction which only allows it to open halfway.

The 52mm throttle body was only fitted to the 160 VVC version of the 1.8 engine in the ZR - some made by Delorto do have '52' in a circle cast on the flange, but early 52mm TBs don't have this.

 

Hi I have a 1.4 and assume that my throttle housing is a 48mm as I can find no markings apart from made in Italy and what looks like 20 so my question is if this is the case what would a 52mm throttle body do and what would be involved in doing this change over would I need the air filter box would it have to be mapped to the ECU or could i just put the the 52mm on and start the engine? Im sure people have done this but not sure and what about the Injectors any upgrades out there thanks in advance

 

Thanks all, that clears that up for me

 

As long as you keep the Cat (or sports cat) then yes you are correct.

 

Yes indeed, we must, unless we shall be in big trouble for the French version of the MOT.

 

Bigger is better comes from the turbo engine world where it is often true. Unfortunately many just take that as being applicable to all engines including NASP.

Its people like this who are dangerous in advising anyone on anything. A little knowledge is dangerous.

All of the analysis was done by a whole group of us independently and together many years ago. Like 10+ years ago and its all on here, rovertech, xpower etc if you search for it. Many of the images were externally hosted though an will have probably gone y now. I probably have most of them on previous hard disks I have stored away, but would be a pain to find now.

 

Both TB's are the same size externally, it just the Throttle butterfly inside that is different so no need to change the airbox. They are just plug and play, and all thats needed is to swap it over, refit the the throttle cable and plug it in. It won't give much more power (maybe 2-3bhp if your lucky) but will make the engine slightly more responsive. To really get the benefit from the 52mm TB you are better changing the air intake system to a cold air feed cone filter rather then the standard box air filter, Cold air is more dense (more oxygen) so burns better giving more power and the cone filter's are generally freer flowing which gets the air in quicker.

I got the 52mm...into the 1.4...135 cams.... Smoothed airbox..... The ribbs were all flatted out. Works fine