DOHC 2.0 Conversion; What Do You Think?

[rachaeljf]

Your best bet is to search for Fiat Coupe 16V turbo or non-turbo heads.

 

[fiatfactory]

The thing with even the 16v engine and injection is camshaft selection with any form of inlet manifolding that uses a common plenum (which all the stock Fiat / Lancia 16v manifolding does) ... is that it limits the amount of cam duration that can be used.... to help the engine breathe at revs, additional duration is just one of the things you need.

Same with hoping to use a set of stock NA cams... your severely limiting the output, and isn't that the whole reason for doing an engine swap... to get above the level that is possible with the SOHC (which is up around 135 at the wheels with a very good 1600, and maybe a little more with a 1870) and / or move to a transmission that will handle the torque produced.

I think the 16v 2000 engine is up around 150 at the crank... and there's not a lot of scope for simple improvements if your thinking of using stock manifolds and cams as the engines are already quite well developed...given the lack of VVT and also being close to 25 years old .... 16 valve performance cams for NA applications are not cheap, not plentiful (so limited used market) and necessary if you want to get anywhere up near (or over) 200hp.

ITB's would be the only way to go if you wanted to go down the injection route...and I doubt the LH2.4 will handle that application...so think cams, manifolding, ITB's and engine management, and the usual suspects (pistons/rods) of sufficient quality to handle the revs required.

I stuck with an 8 valve and carbs... cams/manifolds are far simpler to find and far cheaper than bespoke 16 v parts.

SteveC

 

[lookforjoe]

ITB's would be the only way to go if you wanted to go down the injection route...and I doubt the LH2.4 will handle that application...so think cams, manifolding, ITB's and engine management, and the usual suspects (pistons/rods) of sufficient quality to handle the revs required.

I stuck with an 8 valve and carbs... cams/manifolds are far simpler to find and far cheaper than bespoke 16 v parts.

SteveC

Why couldn't you make a decent sized plenum? Plenty of 16V Volvos using LH2.4 without flow issues. Not seeing the picture here. Mind you, I've never seen the stock manifolds.

 

[fiatfactory]

Short answer, Wave interference... it's because we are chasing more power than stock to the tune of about 50% if we aim for 220hp... to get there you need to take advantage of the "ram effect" to improve the Volumetric efficiency

Sure plenty of all sorts of cars use a single plenum and it works well... BUT... they don't have camshafts with a long duration. It's just physics, air/water/electrons always take the path of least resistance..when you increase the valve open duration your going to have more than one inlet valve open for a considerable amount of crank rotation, it confuses the simple ECU which is "batch" firing all the injectors at once.

if you were to turbo charge, it wouldn't matter... but for a NA application it will... just like the stock efi on an X19 wont idle or perform well with a long duration cam, same problem with the stock manifolding on any engine if the runners meet in a single plenum and a single throttle body.

To get above that 200hp threshold, ITB's and a clever enough ECU that can sequentially fire the injectors... if your aiming under 200hp, then a built 8v and carbs would get you there.

SteveC

 

[kmead]

Here are some pics of a Integrale 8v reverse intake and exhaust flow, reverse coolant flow turbo’d head. This is on an ‘88 model imported from Japan. Around 180hp.

The block has a pair of balance shafts which are not hooked up.

If anyone wants more detailed pics of this car let me know as I know the owner quite well and he would be happy to show it off a bit more. He is an old time Fiat guy in his 70s who is a real hoot and drives them as they should and can be driven.

 

[Ulix]

And here is an Integrale 16V in an X.
Used a block without balance shafts.
Power was turned back from 240 to 220hp when I got a ride in it.
Quite the experience.

 

[kmead]

View attachment 14728 And here is an Integrale 16V in an X.
Used a block without balance shafts.
Power was turned back from 240 to 220hp when I got a ride in it.
Quite the experience.

Quite the packaging job. The Integrale is packed as it is and I think overall it is a larger bay than an X by quite a bit. Thanks for the image and a bit of the experience.

 

[elderair]

Put a 1.9 turbo stroker Punto block with 8.5:1 Wosner pistons in it and Uno turbo ecu and controls. Run a cable shift Uno transaxle and it all bolts in with minor mods. 200 plus hp at the wheel and all sohc Fiat. Quite pleased with the 136whp im getting but I have almost all parts to go turbo and fuel injected.

 

[dcioccarelli]

https://petrolicious.com/articles/what-do-you-think-of-automobili-amos-lancia-delta-futurista

So now we know we can get 330 HP from the Lampredi DOHC