i'm going to do xf conversion shortly and want to get max flow from tb to plenum. however you will all know that while the width of the plenum is sufficient to handle the 68mm diameter of the xf tb, the height of the hole even when cut, ported etc in the plenum is only about 63mm on the outside, so inside diameter would be less than 60. so i was thinking of using a piece of pipe 68mm internal diameter and shaping it from perfect circular at one end (to fit xf tb) and oval shape the other end (to fit plenum). This in my opinion would allow max flow from the xf tb. Otherwise if you just weld up suitable flange (say that from an xf) to the plenum you're trying to squeeze 68mm of airflow into a hole that is much smaller in terms of cm2, and you're not getting max efficiency from the modification. has anyone else tried / thought of this? will the tb extend too far over the end the top of the engine so that vacuum lines etc can no longer be fitted??? also i've got a concern when looking at the plenum the end runners are shorter than the middle, so this must be how airflow is supposedly directed to each cylinder evenly. however with larger tb and hole in plenum is this going to direct more air down the runners towards the centre of the plenum (directly adjacent from tb)??? there is no baffle inside the plenum so me thinks there was not much thought or money put into design of the na or turbo plenum. any help, suggestions or whatever would be appreciated. Thanks in advance!

i have seen a few xf tb's and none of the xf butterfly's seem to seal up well. if you compare it to a vl tb you can see that the xf butterfly was made with little precision. adjusting it will likely acheive slightly better results, but they are just not made well, they don't even seal around the sides. I would highly recommend a new butterfly be made up for any xf tb conversion. get a fitter to do this for you if you know one, cos workshops will charge you heaps. there is a good 3 or 4hrs work to get it precision.

I got lucky and got a XF TB that does actully seal good. and in regards to the pipe bending idea, you would be better off getting the area behind the TB flange on the plenum all filled in with weld, then porting that out. On the top and bottom you might have to tapper it in to fit, but on the sides, you would tapper it outwards. Basicly the same as what you want to do with your pipe, flatten the top of the pipe, and have wider sides. Some original photos have not been recovered yet.

thanks for the suggestion, pastical i'll take it on board. anyone else? Quote: Originally Posted by Pastical I got lucky and got a XF TB that does actully seal good. and in regards to the pipe bending idea, you would be better off getting the area behind the TB flange on the plenum all filled in with weld, then porting that out. On the top and bottom you might have to tapper it in to fit, but on the sides, you would tapper it outwards. Basicly the same as what you want to do with your pipe, flatten the top of the pipe, and have wider sides. Some original photos have not been recovered yet.

will this work on turbos?

yes. XF TB works good on turbos

Quote: Originally Posted by 87BOOSTA will this work on turbos? You'll get slightly better throttle response but lose fine throttle control. I seriously doubt it will add anything to your power figures, though it depends on your turbo setup.

it takes the flat spot out on n/a's. although its a good mod it isnt as effective on turbos as to n/a's but still give's some performance

Quote: Originally Posted by Pastical I got lucky and got a XF TB that does actully seal good. and in regards to the pipe bending idea, you would be better off getting the area behind the TB flange on the plenum all filled in with weld, then porting that out. On the top and bottom you might have to tapper it in to fit, but on the sides, you would tapper it outwards. Basicly the same as what you want to do with your pipe, flatten the top of the pipe, and have wider sides. hey pastical, we tried your idea of making the intake as oval as possible using weld but the weld kept cracking. anyway still looks good! Some original photos have not been recovered yet.

Quote: Originally Posted by joel Mate, That sounds like your TPS. It's obviously not sitting tight enough on the throttle blade and is giving you different readings. Mine did exactly what yours is doing before I got it fixed by Chiptorque. They welded some dag onto the end of the XF shaft so the VL TPS sits in nice and tight. If you do this you will have no more probs. Regards, Joel Has anyone got pics of how they adapted the tps to the XF tb, and how they modded the end of the shaft??

just use the xf tps then you won't have this problem, the re-wiring was covered in the techincal thread section on this forum.

Quote: Originally Posted by DasBlitz Has anyone got pics of how they adapted the tps to the XF tb, and how they modded the end of the shaft?? yeah i do but cant post pics. And to fix my problem i sorta took joels advice and put a bit of silicone on the tip of the trottle body shaft and it fixed the problem. The problem was that it had a slight bit of play in between the tps and the shaft.

i just made up a little bracket thing so i could bolt the vl tps straight to the xf tb kind of like a washer. also guys it all hooked up and running, (goes heaps better) but... when i am just crusing down the road on like 1500rpm with my foot just touching the accel pedal it kinda like cuts out then goes again?? as if it was missing or something anyone got some ideas??

maybe the tps is a little bit out.. or has some play

Quote: Originally Posted by Calais 902 when i am just crusing down the road on like 1500rpm with my foot just touching the accel pedal it kinda like cuts out then goes again?? as if it was missing or something anyone got some ideas?? Your TPS is set too high so the computer's shutting down the injectors too early - In theory it should go open circuit at 900rpm but you'll be able to adjust it up without a tacho; just set the smallest gap you can get on the pulley stop. Fiddley little buggers.

smallest gap on the pulley stop?? wats that?

adjust the TPS so that the smallest movment of the thottle will open the TPS. You should be able to hear it click. You want to make sure when the throttle returns to close that it also clicks again Some original photos have not been recovered yet.

ok then saweet ill do it asap thx guys