whats everyones views on ITB's

[WABIT]

has anyone thought about building a set??

if so what for what type of engine, of fuelling

and what badies were you going to use??

im thinking about ITB's for the k-jet 16v using GSXR 750 throttles with custom tunnels and a custom plenum joined to the airbox/fuel distributor

would it be worth it??

cheers

wabit

[GoLfMan]

ITB's are definately worth it in my opinion, i friggin love em!
thats would be a cool set up, hows it all going to work with the K-Jet system though?
my next engine for the mk1 is a 16v on ITB's

[gldgti]

you might be able to.... i dont know how you'd make it cold start properly though. also, i don't know how you'd tune the thing. the metering head is designed to run with all of the downwind piping in mind. you would be changing all that. it might still work ok - its all a matter of what kind of pressure drop you end up with across the metering head.

my guess would be to start with, that you make the runners the same length as the old ones on the k-jet manifold, and the same diameter too.

[velly_16v_cab]

there is a few threads on the clubgti forum about this but no-one are running on k-jet tho (i cant see how it will work!) they are using a stand alone engine management system (megasquirt / dta etc...)

but like anything its not just put them on and bang 200 bhp here we come.

personally I would look at fitting twin 40's or 45's, it will be easier to fit, easier to get tuned and much cheaper.

but before fitting any ITB's or carbs i would work on the engine first. Gas flowed head, cams etc.

[Peter Jones]

I'm not sure there will be any advantage without getting rid of the K-Jet sysytem. You're still going to be limited by the air flow through the air metering setup. Besides if you you stick all those ITBs in a box you don't get that wonderful induction noise!

Pete

[DubSteve]

I am considering running ITB's on my vr6 in the future I would love the fact to have my car screaming like it does with ITB's however I would also upgrade the cams and do the bottom end at the same time.

[Preen59]

Go for carbies. Less jerking around, cheaper, you can tune them yourself (If you are game :) ) and you don't need outrageous fuel line pressure.

Much better on carbs for cold start too. Because even if you don't have the chokes hooked up you atleast have those lovely throttle pumps that could drown a small family.

ITB's would be OK if it was a race engine only.

[h100vw]

You can make over 200 crank horse power with K-jet, so the move to ITBs/carbs or management wouldn't be on my list of priorities unless you have money to burn.

In fact, having messed with several 16Vs in my time the ignition system is more of a limiting factor.

Gavin

[Valver.]

Been there done that with my Cupra - $15,000-$20,000 for a built engine with 200hp and no bottom end vs 16vT with tonnes of torque and power for similar money means no competition in my book!!

You need a close ratio 6spd to keep a proper NA 16v on the boil anyway (another $7,000), whereas forced induction can bridge the torque gaps, even off boost (as don't have aggressive cam profiles and timing). Yes you can drop the final drive on a 5spd, but no ones want to rev at 5k on the motorway if it isn't a race car.

You can do it on a budget for sure, but there are not many gains (beyond throttle response and sound) as you can't spec the head to pass all the available air. They do go well with 285+ cams, but it's $3000 in head work to get a reasonably driveable engine from such a setup.

The stock 16v compression (even advertised 9a is 10.8, but actually 10.3!) is far too low aswell. 11.5 is more realistic for ITBs

I could go on about all this for ages, but the main point here is that go ahead with ITBs if you're on a budget and want looks and sound, but to get the motor to go like a VWM race car, you need a hell of a lot of money and it isn't worth it ;) Take it from me, as I was there a few years ago :)

[Valver.]

You can make over 200 crank horse power with K-jet, so the move to ITBs/carbs or management wouldn't be on my list of priorities unless you have money to burn.

In fact, having messed with several 16Vs in my time the ignition system is more of a limiting factor.

Gavin

I agree. In fact, Preen is right too, if you want the noise and cool factor, just fit some Webers, as the EFI conversion isn't cheap either. ITBs are for race engines (and race team budgets!!).

[twin eng, twin turbs]

ITB's would be OK if it was a race engine only.[/QUOTE]

I agree on both counts, twin carbies and turbocharging are great ways to extract the power your after, but ITB's on a race engine only? In this era of after market engine management systems you can most certainly tune ITB's on a road car mapping both your fuel and ignition to make it smooth and very drivable in daily driving conditions and with the better computers on the market offering multiple fuel and ignition maps you can switch maps having aggresive ignition advance and fueling for top end performance. Carbies are a far cheaper option though I would like to see someone get more power and better drivability from twin carbies of equivilent throttle diameter to well tuned ITB's. I would not bother with K-Jet though having done an 8v turbo setup with it and having no end of drama tuning it. ;)

[pepperwhite]

yeah its a lot of hard work.. especially if you are on a budget.

but still i learn the hard way. should have built a 20v ae86 then i could have had the sound and the sideways action...