Re: My 1.2 3 door Stilo
Ok well I've came across an old thread where my exact question was asked - with a definate answer.
https://www.fiatforum.com/punto/245290-stilo-20v-throttlebody-questions.html
It makes sense what it says about the whole design of the TB being based on the intake systems design and injector positions and so on. I take that fully on board and wouldn't like to mess that up by fitting a huge TB (though from the previous comparison it only looks like a 10 - 15mm difference).
Suppose it's like a well thought out formula - and the TB is one of the values and when you go changing that value your whole formula will be out!
What also interests me is where it goes on to describe the TB design a bit more with regards to diameter and the effects that actually changing this has, "A larger bore leads to lower flow resistance, but obeying the laws of diminishing returns.". What would these "diminishing returns" be? Less BHP and torque? I would have thought a larger TB would allow more air in at high RPM thus moving the power band up higher in the rev range but with the adverse effect of having less control over the extra incoming air in a lower rev band?
It also says, "A smaller bore leads to better throttle control and response (never underestimate) and improved fuel mixing.". So obviously with my 1.2 I've already got a comparably small TB, but when I'm planning on doing improvements such as a free flowing exhaust manifold and an upgraded induction system - where the breathing of the intake and the exhaust have hopefuly improved afterwards - should fitting an even smaller TB improve things further by - like this person quoted - "improving throttle control and response...and improved fuel mixing". When I say a smaller TB I'm talking a few mm - if there is one smaller than mine made for fiat that would work on mine?
Would this also have the effect of moving the torque/power band into a lower rev range based on the fact that a smaller TB won't allow as much air through at high RPM? If so then this sort of setup might well be ideal for the practical everyday town/city sort of driver like me who doesn't rev the tits off their engine all the time!
I prefer a car that feels urgent rather than outright powerful lol (never going to get that in a 1.2 anyway lol)
Once again your feedback is much appreciated, I do ramble on a bit I know but I like to lay my thoughts out in full so as I can get a full, unbiased opinion on the topics that I bring up
That's whats this forum's best at right?