throttle bodies?

[chris CORRADO 0]

What kind of prices am I looking at if I want to change the inlet manifold system to throttle bodies...?

 

I have heard that driving a car with throttle bodies is like driving a 5L V8 on petrol consumption... LOL what other disadvantages is there

 

Also if you change the fuelling system what happens to the metering head and stuff like that???

 

I’m new to this but I heard with this mod it can bring the power up to as much a 170-200bhp when tuned properly?

 

Cheers any comments appreciated

[Kevin Bacon 5]

Throttle bodies are well expensive! Bill Brockbank (Badger5) used slide throttle bodies many moons ago and got good results, he's probably the best person to speak to about them.

 

Most TB sets I've seen use a fuel rail, so the K jet will be junked. So you'll need a DTA, Emerald, or Motech standalone to run them - sequentially if you like, unlike the K jet which is CIS (constant injection system).

 

I've only seen a handful of genuine 200 bhp 16Vs and they were fully lightened, balanaced, cam'd, flowed and solid lifter headed to extended the RPM range past 7000rpm. A properly built 2.0 (non long throw type) with solid lifters and titanium valve springs is good for 9000rpm, and that's where your power comes from, at the expense of torque.

 

Main disadvantages are:-

 

Expense

Fuel consumption as you've already mentioned

Noise

Loss of bottom end torque

 

Advantages are:-

 

Reduced air flow restriction

More power

sharper throttle response

Highly tunable

 

I wouldn't bother personally, I'd put the money towards forced induction instead.

 

K

[andycowuk 0]

Kev...you seem to have your noise in the wrong list!

 

That is deffinately a good thing!!!

 

will get a clip of a rally prepared 2l 16 onto fast purple asap for all to hear!

[chris CORRADO 0]

cheers for the responces... what made me turn towards this system is the fact my mate in his MK1 golf GTi 16v has this setup and when he took me for a spin OMG :shock: the pure kinda areoplane take off feeling kicked in it was truly fast mind you he has every thing done.... also sound OMG :shock: sounds like an F1 car LOL

 

cheers for your views i will stick now for the turbo conversion :mrgreen: :mrgreen:

[Timo. 0]

kev, whats sequential fuel injection all about? Haven't really been able to get my head round what that means. I know the vr6 has it.

 

cheers

 

timo

[Kevin Bacon 5]

Sequential means one after the other, like true sequential gearboxes, i.e. you HAVE to go through the box, unlike swapping from 5th to 3rd on pseudo seq' boxes......anyway, CIS injection, ala K Jet simply lifts 4 plungers attached to the air flow flap....all 4 lift at the same time and in doing so sends fuel to all 4 injectors simultaneously. This is very inefficient.

 

Sequential injection injects fuel at the precise moment of firing order, so injector 1 fires, then 3, then 4, then 2. I don't know what the VR firing order is, but I think you get the picture?

 

The net result of this finer metering is much better fuel efficiency since only the cylinder that's about to fire gets the fuel, unlike CIS where all the cylinders get fuel regardless, but that's not as bad as it sounds as the exhaust and inlet valves control the burning still. Some clever boffin just questioned the need to inject fuel into cylinders that aren't on the firing stroke.....simple but effective.

 

On top of that, the VR6 also has independant 'per cylinder' ignition with variable timing per cylinder, aka 'Wasted spark', which is the term used for modern distributor-less ignition.

 

K

[andycowuk 0]

on the g60 the injectors all fire at once (grouped injection), this means that sometimes the injector fires when the inlet valve in closed, although this improves torque and economy lower in the rev range, and is the reason it is done. In sequential injection, the injectors are fired in order, one by one. This improves the peak torque and power for the engine. It also means that feuling can be altered or tailored for each cyl, althoiugh i dont know if motronic does this, giving optimum pwer from each cyl.

[Timo. 0]

sounds sweet!! No wonder its soooooo smooth.

 

cheers kev

 

timo

[Kevin Bacon 5]

It also means that feuling can be altered or tailored for each cyl, althoiugh i dont know if motronic does this, giving optimum pwer from each cyl.

 

Yes I believe Motronic controls the open and shut times for each injector.

[Kevin Bacon 5]

Do you remember that science program some years ago called "The secret life of " ? On one episode, fuel injection was explained in great detail and the nutter connected a manifold with sequential injectors up to a petrol pump and set light to it, LOL! It was a good demonstration though because you saw 4 mini flame throwers timed to perfection, 1, 3, 4, then 2. The CIS manifold just had 4 flame throwers going continuously!

 

Oh and flow rate is an interesting sight too! Just bung each injector into a litre tube, bypass the pump really and open the throttle to full. Then you do a volume over time and hopefully all 4 tubes will have the same amount in them after say, 30 seconds.

 

I think my 16V Turbo filled 4 x 1 litre tubes in about 15 seconds at WOT!! That would explain my single figure MPGs when hammering it then!

[andycowuk 0]

i thougt that the vr had a cam position or phase sensor? if so, why does it run wasted spark?

[Kevin Bacon 5]

Well don't you still need a hall sender to create data for 2 and 3d ignition maps, regardless if it's wasted or non-wasted spark? I dunno, you tell me?

[andycowuk 0]

i just typed loads, but have deleted it cos i was on a rant!

 

not sure if i am being pedantic here (apollogies if I am), or if I am answering a question....but never the less.....

 

i thougt that the vr had a cam position or phase sensor? if so, why does it run wasted spark?

 

'Wasted spark', which is the term used for modern distributor-less ignition.

 

if it has a cam phase sensor, it doesnt run wasted spark. If it only has a crank phase sensor it does.

 

Well don't you still need a hall sender to create data for 2 and 3d ignition maps, regardless if it's wasted or non-wasted spark? I dunno, you tell me?

 

no, u need some phase sensor on either the crank or the cam, not always a hall effect one, so the ECU knows the stroke phase of at least each pair of cylinders.

 

agreed?...anyone!

[vr6storm 0]

cheers for the responces... what made me turn towards this system is the fact my mate in his MK1 golf GTi 16v has this setup and when he took me for a spin OMG :shock: the pure kinda areoplane take off feeling kicked in it was truly fast mind you he has every thing done.... also sound OMG :shock: sounds like an F1 car LOL

 

cheers for your views i will stick now for the turbo conversion :mrgreen: :mrgreen:

 

you've also got to remember too that your mate's Mk1 will be a fair bit lighter than your C :wink:

[Kevin Bacon 5]

no, u need some phase sensor on either the crank or the cam, not always a hall effect one, so the ECU knows the stroke phase of at least each pair of cylinders.

 

OK thanks for the explanation. Like I say, you tell me, I'm no expert :lol:

[flusted 0]

it doesnt always use more fuel.its supposed to be quite economical on light throttle.

 

Bloody expensive tho

[Bobbywhacker 0]

what sorta power would a VR get with some TB's then??

[Kevin Bacon 5]

Take a look at this:- http://www.grantmotorsport.com/heads.asp

 

Is that horny or what?

 

Dunno what power you'd get, lots probably, but probably with a sacrifice in bottom end torque.

 

If you add a lightened flywheel and pulleys to the TB'd VR, you'll get one hell of a screamer. The perfect track weapon.

 

Not so sure it'd be suitable for road use though!

 

K

[Bobbywhacker 0]

the flywheel and pulleys are already in the 'mod queue' ... jesus that head looks fit!!!!