turbo124.com

Made a trip back to perth recently and took some happy snaps from the inside of my cobweb ridden garage - and noticed that i had enough engine components to build 2 pretty stout turbo engines - got me thinking about the best bang for buck way of producing a high quality 8v turbo engine with as much factory 'bolt on' equipment as possible...

Check out this head.

using standard inlet valves - but HUGE 40mm alfa romeo exhaust valves!!!!! bloody huge - check out how much destrouding the combustion chamber has had to reduce static compression - probably not the most ideal shaping but it would still be very effective at reducing compression - but good squish has probably been sacrificed...

the ports have also been taken out to the max - all in all a good head for a high HP 8v engine........ Probably a good start for a 8v turbo project.....

the next part of the equation would have to be a suitable exhaust manifold to mount the turbo onto....

the standard fiat headers - i think - are actually a very good base to work from - they are robust - heavy and will take the repeated heat cycles that will be dished out to it from a crazy turbo driving hooligan...

the turbo would be coupled to the standard headers via an adaptor plate bolting onto the header and outputting to the required turbo mounting flange - a custom flange will allow the turbo to be mounted closer to the block and possibly forward a little to make room for a decent dump pipe..

the standard manifold is rather compact and would mount the turbo down low and back towards the firewall... this may interfere with an appropriate exhaust dump pipe conflicting with the steering boxes in cars that are right hand drive... so rack and pinion or some tricky engineering may be required

the four standard bolts at the head base would be adequate at mounting the turbo flange - but may not appreciate the weight of a heavy turbo - the turbo may need some support mounting back onto the head directly...

Inlet manifolds can be sourced from a Croma

and we have essentially a long engine 8v engine practically built!!

add in some forged pistons or standard lancia integrale pistons along with modified 2litre con rods to take chevvy bearings and you have yourself a budget 8v engine!!

anyone add anything else?

maybe go for the oil re-routing rather than, or as well as the chev bearing conversion could be an idea, I plan to document this when I get some time to work on the engine (in a couple of months probably ). Also using the croma/thema/integrale ex. manifold is another option.

i've never seen a fiat factory exhaust manifold, but i could only imagine a 'log' style setup that wouldn't be very flow friendly - the beauty with the stock fiat NA headers is that they are a great configuration

the oil re-routing is a good ungrade - especially for track racing cars

The log manifold isn't perfect for all out power but it mounts the turbo at the front I think? (in a RWD fiat) it's another option using factory parts


(cheers for the pic steve)

Do those alfa exhaust vlaves have the same 8mm stem dia.? valve length?

check out a lancia beta exhaust manifold. dunno how it'll fit into the engine bay, but its different again. one piece 4 into 1, but with the outlet central, and down.

possibly nicer than fiat 2L two piece 4 > 2 > 1 (like you had the photos of) that are on my 131 engines. lancia engine had 120 hp, as opposed to 113/115 of the fiats.. but i dunno where they made this. different carb, maybe different cams.. someone'll know

I can get some photos (of it still on the engine), and perhaps some measurements, if you'd like.

p.s. least it'll look better than a 16v, dave

haha snooze - of COURSE it'll look better.

testament: yep the log style - great bolt on option and benefits of mounting forwards..

snooze: i'd love more info on the lancia manifold - i never heard of there being different headers thou - i know that this header came off a lancia (one in the picture) and it is still offset back...

if you have one (or anyone else for that matter) - can you take a pic and post it up here - would be nice to have the turbo as far forward as possible

Dave

forgot to answer testaments question on the valves.

i "think" they are stock width - but may have been cut down in length to suit the fiat valve train.

i'm thinking about rebuilding this head - would be very interested to see what this head could produce power wise - it came off Tony Lucente's 8v race engine just prior to him changing over to 16v so it must have been making at least 400bhp or there abouts

dave, just for you, i'll thro on some thongs and head out into the cold nite for that long walk (ok, 6m) to my shed. be back in 10

actually, engine is under some shit now..and i bet its facing the rong way! make that 15..

...

The factory turbo manifold is a little better than a log. Here are some more pics

http://www.geocities.com/sspiers/Turbo

Dave, the resulting compression ratio of that engine may be a bit low. Croma/Integrale pistons will lower the CR under 8:1 to start with. That head also looks very hemispherical i.e. larger chamber.

i think i've got this one laying around my dad's place doing nuthin since having had custom extractors built.

steve: is that a croma exhaust manifold in that link? looks like it would stick a bit too far forward to use in a RWD... ie. the turbo would be squished up hard against the raditator by hte look sof it, and thats before you worry about an air filter and piping... or am i wrong?
in fact, i'd really like it if i was wrong about this, but i'm not sure..

isn't this http://www.turbo124.com/images/fiatfans/har1/Mvc-019f.jpg AC coupe in the fiat fans section of the website (not forum) using a croma turbo setup with a non-reverse port head?

thats actually a 8v integrale engine...

i think the inlet manifold may be a croma type thou - don't have any pics of 8v integrale manifolds

The manifold on my Tipo will be the same as an 8V Integrale

This pic that Tom found says it all.

http://www.turbo124.com/images/fiatfans ... c-019f.jpg

yeah, but that has no radiator, and no air filter or piping to an air filter.... hrm...

still, its a very very nice idea...

the head is an old style one though?, with late camboxes and/or cam covers.

steve: yeh, there is a LOT of meat taken out of the combustion chamber there - i'd dare say the volume of the combustion chamber has been doubled!!!

i think the previous owner had intentions of 7:1 compression - next time i'm in perth i'll measure the volumes and report back

Dave

Interesting It must be an old head. It looks like the spark plugs are rear facing. AFAIK the camboxes are not interchangeable so he must have fitted the covers somehow.

The head is early - look at the coolant water outlet of the head. The late camboxes will bolt into the early head, but the gasket faces will not line up perfectly -> oil leaks with the certain types of cambox gaskets.

There are two different Alfa 40mm exhaust valves.
The one in the old Nord engines with 30 degree seats and 9mm stems, 105mm long one groove and the TwinSpark valve with 45 degree seats and 8mm stems, much longer but can probebly be cut down to size, I have no measurement on that one though.

what is standard fiat stem thickness?

from memory, these had to just be shortened.

8mm for the 8 valve, and 7mm for the 16 valve isn't it?

edit all fixed now

40mm that pretty damm big

yep, gone

looks like its repling to "flange"

keh?

there was some bot trying spam off something i think it was "carrer opportunities" and "women's products" carnt remeber there was a few more

ah

i've made a significant change to the forum software which should prevent anything like this happening again....... famous last words?

Sorry to drag up such an old thread, found it from the very front page of the site http://www.turbo124.com , but.

So what exhaust manifold do most people use when they do a turbo conversion????

Is there a huge problem with getting a custom manifold made up, so that you can put your turbo wherever you want it to be. It must be easier that trying to find turbo manifolds??? or is it just cost prohibitive if you are on a budget??? What sort of money should you expect to pay to get one made up ??????

Do the custom made ones suffer from cracking or weld failing???
Or does it just depend on who does the work????

They all crack eventually, even the cast manifolds. The cheap ones avaiable for common cars off ebay etc dont last well. A custom one with good steel should last fine.

In NZ you can get something good for about $600. I have seen some (well 1) cost $2000

If you can weld or know someone who can its not that hard to make one out of steel. I wouldn't use stainless, sure its looks pretty but functionally its not that much better and its alot more expensive and way harder to work with. Basically thick wall steel pipe e.g. schedule rated steam pipe is easy to make stuff out of and you can get various pre made bends in different angles and some choice of radius. also depending on your goals and mindset even a basic 'log' design (thats all the factory ones are) will work well. and since its thick wall you can port away at the insides as much as you like if you want to.

I thought i had seen that head before - Yeah Tony made a realiable 350RWHP and above with a T4 cheap turbo, before he moved to 16V i think he got an odd 400Horses out of it for a short time.

i'm a little wary, as they aren't exaclty turbo specialists, but street machine have started carrying on about log designs working better than equal length (etc) designs, partly based on a test they did with a ford strait 6... quicker spool and more boost (iirc).. /methinks bad equal length design, especially re: volume, but how much is there in it, really? or is it like with other things where if you're tuning for specific rpm you're best off with (well designed) tuned length manifold, if you're after wide-range street driveability an unequal/stepped type of setup will work better?

I'm not saying ultimately a "log" or other easy to make design is better. But they still work quite well, and one advantage they have over "some" equal length designs is the fact they are small and compact so not much heat is lost between the exhaust port and the turbo.