Engine Choie and Carbs Or Throttle Bodies

[rowle1p]

Hi,

I have just joined the club and have ordered an sei kit from Westfield.  I intend driving the car 3-4k miles per year with a couple of track days.  I could do with some advice re selection of engine, shortlist at the moment is zetec 2 litre  or a vauxhall 2 litre.  Does anyone have a preference ?

Secondly is the choice of carbs or throttlebodies.  Some swear by carbs , others by throttlebodies.  Some say by the time you have got all your bits for te carb setup you might as well have gone for TB cos of the improved performance and fuel economy ?

It was also mentioned that due to Weber being taken over, they are in trouble and may cease to exist ? so is this likely if so can u recommend another carb route if this is chosen over throttle bodies.

I realise there are loads of questions but would appreciate some guidance as I have to specify to Westfield which route I want to go for the loom and chassis setup.

Thanks v much

Phil

Thanks v much.  

[Blatman]

Go for the Vx. Better power as standard, better ultimate potential, loads of 'em around, and no cat required for SVA. DON'T get an ecotec version......unless it's the 1.6.

Throttle bodies every time. It's a no brainer....

[Nick M]

I'd second everything Blatman just said.

[SteveC]

I'll jump on the "hear, hear" bandwagon. You can get some very competative (priced) throttle bodies from the likes of Jenvey, with no messing around retuning or rejetting.

Steve

[gee_fin]

Alternatively Lumenition have just released some roller throttles that apparantly fit any DCOE inlet.      

[Nick M]

But a DCOE (carb) inlet will have a nasty kink in it that will negate any gains from the roller barrel throbble botties....

[gee_fin]

So you're saying you wouldn't like a set? Anyways, direct to head it is, saves any worries about 0.00001bhp losses.....

[Nick M]

Not if I had to have a crappy manifold in the way.  Yes, they look cool, but what good is cool when you're losing power ??

DTH is OK, but I still think there's more than a bit of merit in the individual taper throbble botties that have a manifold which lines the inlet tract up with the inlet port in the head - there's still quite an angle to get round on the VX heads if you go DTH.

[gee_fin]

From what I've read (can't say I've measured it) it appears that the losses between the options, be they individual tapered, slide throttle, roller barrels, DTH, DCOE mounted etc. are so minimal as to be negligible. Barely a bhp in it, at least until you start getting up to BTCC states of tune. From what I've read that is  

However, SBD swear blindly this isn't the case but then they sell lots of individual tapered throttle bodies.......

[Nick M]

The main benefit of the tapered throbble botties is that you get more mid-range torque - doesn't really show up as a peak bhp gain though, which is where roller-barrels, etc. come into their own, i.e. at WOT.

[rowle1p]

so are we settled then that it is the VX with emerald ignition and jenvey throttle bodies.  I am still undecided re the zetec or VX, as the zetec seems more available ?, also for someone starting off like myself, first build, the vauxhaul will be harder to understand and put together ?

[Fat Arnie]

Jenvey SF taper throttle bodies with 90mm trumpets and a decent ign map will give about a 7% increase in peak power over twin 48 webbers or DCOE style TB's on a kinked inlet manifold.

Swindon twin roller bodies are slightly better still (maybe a further 1 or 2 percent, but they are much more expensive.

Any form of 3d management will give cleaner crisper throttle response  in the midrange.