The story of my coupe.
I already striped the interior, installed a custom magnaflow exhaust, fitted bigger brakes and better coilovers to my coupe but it is still very slow,
so I’m going to put an amr500 supercharger on it and after that I’m planning on putting a turbo from a 1.9jtd engine on it. The drive ratio will be 1to 2.5 and I’m keeping my engine limited to 6500 rpm, because that’s where the power should be max.

My idea for the twin charged setup is feeding power from the turbo into the supercharger to make it more compressed, or to use the supercharger to feed the turbo and have a bypass valve in between that will open at vacuum or boost pressure.
does anybody have any experience with this because I’m not sure if I should run it from turbo to supercharger or viceversa?

I'm no expert at this, but if you have a look at Norris Design's kit, they do a twin charged kit for the Mitsubishi Evo's with great success. From what I have seen of this, it is a turbo feeding the supercharger with a bypass valve that will stop the air from the supercharger and the engine to be powered by the turbo charger

I have no real experience, but from memory a supercharger boosts at lower engine speed where as a turbo charger boosts a higher engine speeds.
Think it was the Lancia 037 the ran a dual boost system

first of all.. few question

with what ecu u plan to control the system? (if stock, verify, that there are companies, who can tune Hitachi ecu.. u will find not many, if one., the u are in trouble and will have to fit some piggiback ecu..which is not ideal....)

what your HP goal? it coul be too overkill to twin charge 1.8 if you can simply bolt supercharger on and leave the rest, or turbocharger (novitec did kits for 1.8 and alfa TS , hwich is the same engine in the past, driven by piggyback ecu, but were not ideal..after removing it and proper mapping car get much better results....)

with turbo from JTD..u will be limited to around 200bhp... chceck the compressor and turbine map.. I think that its noit good and suitable.. even if u use from 1.8 TBI u will get aroun 200-260bhp if tuned properly, and what I know from my 159, it spools up at 1500rpm and dies around 5500..which is like diesel... and for this case, twincharge is nonesence...



what supporting mods to engine? (stock internal/forged ones, cams etc..)

gearbox..


how to twincharge.. look at lancia S4

I didn't think the Alfa 1.8 and the Coupe 1.8 share the same lineage? I understood that the Coupe 1.8 was a derivative of the 5 cylinder 20v motor

no,

alfa 1.8 16v TS and fiat 1.8 16v are same "architecture" engines..."patrola serra " https://en.wikipedia.org/wiki/Fiat_Pratola_Serra_modular_engines



1.8 in coupe:

82*82,7 bore*stroke, camshafts 9mm lift intake, 8,5mm exhaust, 1 spark per cyl, 6toot trigger wheel (hitachi/subaru pattern)


alfa 1.8 Twinspark (16v)

82*82,7 bore*stroke, camshafts 9,5mm lift intake, 9,5mm exhaust (the only real performance affecting difference in comparison to fiat), 2 sparks per cyl 60-2toot trigger wheel (bosh)

the 5cyl 2.0 is more like 1.6 Twin spark - exactly same bore/stroke, small ports in heads and same dimension valves... 2.4 20V one ist thanks to lower stroke "destroked" (same stroke as diesels) any by 1 cylinder extended 2l twinspark


so u can upgrade your fiat 1.8 with cams from any 1.8l and higher twinspark engine (best 2.0 JTS from GT/156), or rebore block to 83mm, put in 2l or diesel crank (with small mains) and u get 2l in 1.8 block without balance shafts.. which I did in the past to my stilo 1.8 (and I was also thinking about turbocharging by modyfiing some parts from 20VT/Stilo JTD etc..)

what makes various conversions litle bit toughter is one rod lenght and different compression height piston.. its not so easy like with old lampredi, where u had 1 compression height for all capacity variants and could easilly play with CR by simple swap eg. 1.6 pistons with 2l...



same family is 1.8 TBI engine, which its bottom end is interchangable with JTD/Multijet.. so u can get 2l TBI etc..

It was the Lancia Delta S4 that ran this set up . VW used the same set up on their 1.4petrol CAVE/CTHE with some sucess but discontinued this engine

I would just buy a 20VT - at least you know it works or live with the available performance, like me

It is a 20+ year old car. Driving it like you stole it will only end in tears, one way or another.

I will never get round to it but have thought that adding a supercharger would be amazing for torque fill before the turbo really kicks in!

With modern, fast spooling turbocharges, I personally see little point in twincharging. Also, remember that a supercharger is belt-driver so will eat torque and you have to be sure it is worth it. Again, personally I would fit a modern turbo - much simplier and easier to tune.

Already thank you all for the quick reply’s I will look into all the tips you gave me this is very helpful.

The hp I’m looking for is around the 180/200hp because the stock 1.8 only has 130hp.

Next to me is a tuning shop that told me they could help me with a custom ecu tune for when I have everything fitted

Upgraded pistons and internals are things I’m looking at for if this works because if it doesn’t it would just be a waste.
I am looking into tuning the head for better flow of air and indeed maybe a different cam but I will have to do some research for that.

The original plan for my coupe was 20vt swap it so if I somehow f*ck up in the progress of doing this and blow up the motor. I can replace it for the stronger 5cilinder version

Interesting manufactures are now calling it E-boosting instead of twin charging . https://www.youtube.com/watch?v=iEGisoOnewg
Cleetus supercharged his cobalt i his car and look at the power result https://www.youtube.com/watch?v=iEGisoOnewg

That turbo will not be suitable - it is a variable-vane geometry turbo, set up for a low-revving diesel engine - it doesn't have a wastegate - it will not cope with the exhaust gas temperatures of a petrol engine

Good luck, although I expect you will spend massively more on getting a 1.8 to 200bhp than the net spend you would incur if you sold the 1.8 and bought a 20VT

if u look just for only 180-200bhp

Its feasible even in ATMO way.... and maybe cheaper...

- when I look for the prices of supercharger kit from autodelta for Twin spark (which is same family engine).. it cost 4000pounds and u get around 170-200bhp (1.6 - 2.0 TS)
- similar cost turbo kit from Novitec in the past, aproximatelly 200bhp etc..

in atmo way:

- second hand TS cams, if u are able to get JTS, go for JTS (even higher lift) u can get them even for 30eur
- exhaust - you already did something, but the biggest bottleneck are headers.. tiny 34-5mm Primary pies are good for something like 1.3liter engine..no matter whats done after headers, if they are the bottleneck, the results will newer be good..... best u can (could) purchase is this.: https://www.alfaowner.com/threads/156-ts-manifold-by-wizrdovoz.174516/ forget supersprint one.. its only "slightly larger" copy of stock..)
-some headwork and raising compression to 11:1


regarding to mapping:

here is one example of 1.8 modified with TS cams, exhaust and remap with results around 145bhp.. the owner in discussion says, that even "famous" tuning companies refused to map this, as they don´t have suitable equipment for 1.8 Hitachi ecu...

https://www.facebook.com/Empeco/videos/pcb.3014466081901456/10156373914385899/?type=3&theater

(I was in same situation when did my stilo 2ltr conversion.. Asked many companies, and if I get some answer, it was usually "we can´t do that" ..which simply means we are only uploading unknown maps, or blindly modify some maps and if they se some increase on thyno, the result is good.... Im affraid that same is with the tuning shop close to you...)

As I mentioned at the top of the thread, Norris Design have been doing this for 10 years now:

http://www.norrisdesigns.com/proddetail.asp?prod=evo%2D032506

And to quote from their site:

Next update! fitted the manifold and the turbo on the car after Some changes to the manifold, and i now have a wastgate on the manifold. oil lines have been fitted from the oil filter. And the return line has been drilled into the block. Soon i Will have a first startup without all the piping to see if it works and then i am going to make a custom downpipe and fit the air pipes