Wrench Pro
grimsby england
vectra cdx 2.5
Hi just wondering if any body can help me,i fitted a gas flowed throttlebody to my v6 veccy a few weeks agoevery thing was fine could feel the differance it pulled like mad then when i stopped the revs stayed about 15/2000 rpm so i turned tick screw down to normal to normal idle but now it seems to hold back and it does not feel that responsive no more have i done any thing wrong or could the idle control valve be on its way out hope some body can help its bugging me now thanks all:confused:
Hello mate and welcome to the site.

Right this sounds like a classic case of the throttle body not being done right. They shouldn't be gas flowed, they need to honed out to create the exact surface area. Then they take out the single butterfly action of the paddle, then replace it with a twin butterfly so instead of tilting like the original, the open like butterflie wings and come together.

Make sure the breather pipe is still ok and the icv has been cleaned and put in the right place.

They are very similar apart fromt he inlet manifold but I can show you my 3.0 if you wish. This has the enlarged throttle body but because it was done at Courtenay, its done to a very high standard.
Thats great thanks for reply i purchased it off a site on ebay and showed me what else he can do,the throttlebody itself has the outter edge tappered and the rast is all pollished,so mi take it i have wasted my money? Do you no of any body who does these bodys as coutenay i think are over priced and plus courtenay did some work on an old car of mine and well put it this way i would not go there again.i did noticed when i cleaned icv the flap was very loose should this be tight thanks for your help:bigsmile:
From what you describe, your thottle body has been polished rather than honed out. Polishing is good as it allows the airflow to be smoother, but you wont feel the difference that a fully enlarged throttle body has.

Yeh theres a couple of peeps on particular Vauxhall forums that do them. I think theres one on Vectra owners club that does the V6 throttle body for about £70 returned. But if you wish to buy a second hand one, thats no problem aslong as you make sure it's honed out rather than just polished like yours. Typically, this results in an increase in full throttle cross sectional area of between 10 and 20% and usually gain about 7mm diameter which on a standard car will see you anything from 4bhp up to about 12bhp on the bigger 3.0ltr and 3.2ltr. Well worth having done right.

The main thing is mate, you need to get a remap when you change characteristics like this. Which could be why your car doesn't idle correctly as your cars ECU has leanered the throttle body by itself rather than it being mapped for the correct settings.

So what I would do to start with. Put the original throttle body back on and see if it does it. If it does it sets you up for a couple of nice mods. Get the exhaust made straight through with uprated Miltek downpipes, panel filter and a Courtenay 4 bar FPR and a pair of 3.0 G Cams (this will give the same as the GSi vectra). Then get it remapped and with all that including the uparted throttle body will see you a nice 200-210bhp ;)
Thanks for that mate you certainly no your stuff would it be possible for you to take a pic of your throttlebody,i would be very interested in a set of 3.0 ltr cams and could do with my tb getting sorted my car at the mo does have a 4 bar reg,straight thro exhaust and a good filter its just a wanna make mine get up and go more also do you no of any body that has these bits i am after if so could you let me no many thanks:)
Keep your eye on Vectra clubs and other vauxhall sites. Theres always loads forsale for V6's. I know you dont like them but just try and give Courtnay a ring and talk to them on the phone. You will get alot further talking to someone rather than going from the website and you'll get parts cheaper than whats listed aswell. Or try Regal Autosport. They do good exhaust stuff and the Dbilas stuff on there is pretty good. And i'll get some piccies for you when it stops raining here lol ;) But to keep you going, heres a short vid of my V6. Doesn't show the internals but theres a couple of bits you could look at on there:-


Please watch this on my YouTube channel & Subscribe.