hi all, i am learning new things everyday, and thought i would share it with you all

fiat coupe 20vt

first things first, for every 90 degree bend on your inlet pipework.turbo to inlet manifold decreases horsepower by 5%
3 x 30 degree bends = 90 degrees so keep in mind

next thing, if your intercooler is working so hard to keep charge temperatures down, why fit a dump valve after the intercooler and loose already cooled air, less work for the cooler if u fit it before,,

inlet duct diametres,

pipe outer diametre (in) horsepower

2 255
2 1/4 345
2 1/2 450

AIR FILTERS

1% hp decrease for every 7 degree rise intake air temp
so if its 25 degrees outside and the (iat) is 75 degs your loosing
20 hp in a 300 hp engine,
they really dont work on these engines unless u shield them from the under bonnet temps extremely well, and even then, not great,

AIR FLOW metres

removing the mesh screen from both sides may give a 2 +/- power gain at max revs.

Throttle bodies,
size HP
50mm 250
56mm 310

these figures are only for turbo versions

any input always welcome, il be posting different tuning topics for the 20vt every now and then,
regards jason

Makes sense. I knew aftermarket air filters on the coupe suck unless you running big upgrades. The common thing seems to be to drill the bottom of the air box to get more noise my car had already been drilled when I bought it

makes me laugh all the marketing hype that induction kits gain u 20 bhp and that stuff haha, on a skyline maybe and thats only coz it raises boost pressure 0.3 bar due to being more free flowing,

I think some of your statements may be flawed - lets go one at a time

1) I have a total of seven 90-degree bends in my inlet tract - are you telling me I've lost over a third of my bhp? You might want to know that I have over 400bhp at the wheels

2) The dumpvalve doesn't 'loose' the already-cooled air, as the Coupe has a recirculating DV - it simply puts the dumped air back into the system (so you could argue that it's even more efficient, as dumped air is cooled twice)

3) Rubbish - I was producing 400+ bhp on the standard diameter inlet piping

4) partly correct - an increase in inlet temps has a corresponding decrease in power. However, to state that under-bonnet temps affect power is wrong. Once the car is moving, the amount of air circulating though the engine bay is massive. The underbonnet temps will only be a couple of degrees higher than ambient, and that's only because the majority of the air under the bonnet will have come through a radiator. I have tested this extensively, in order to prove the effectiveness of a Pace chargecooler. I agree that underbonnet temps are a problem when the car is stationary, but power isn't usually an issue when you're sat in traffic. The only consideration is that you shouldn't use maximum boost immediately after sitting in traffic on a hot day. Just to add that your figures are also wrong - the Coupe ECU retards the ignition once charge temps hit 70 degrees, so you would be losing a LOT more than 20bhp on a 300bhp car

5) Air flow meter - removing the filter gauze just ahead of the air flow sensor will cause all sorts of problems - DON'T DO IT (unless you're willing to have the car re-mapped)

6) Not sure here - what's the size of the stock throttle body? Either way, there's an inaccuracy, because I'm running 457bhp on the stock throttle body and there are several cars more powerful than mine that are also stock

Well said Nigel
It seems to me that unless you are certain of the facts you state,best not to say anything.

Where have you got this info from? I'd suggest a rethink.