Race Engine Forum UK

Hello,

I have a Fiat 131 1585cc TOHC engine fitted to my Dutton Phaeton S2 kitcar, it is all standard apart from a Pipercross air filter. At present on the rolling road it is producing around 84bhp. I would like to increase the power output from the engine and wonder what the best route would be ie change to twin carbs or change to race cams etc.

I know this is a bit of an open question, like how long a piece of string, but just wonder where to start as I'm on a bit of a budget.

If it's a good motor - decent oil pressure and holds temperature, doesn't burn oil (ie: no more than 1000miles to pint), then she is tuneable in situ I'd say.
I'd recommend pair of sidedraft 40DCOE with Weber linkage. Check out Weber's site at:
http://www.webcon.co.uk/weber/performance_carbs.htm

The cost of the carbs is very modest - they cost way more years ago than they do now, well done Webcon. You can buy them from any Weber agent but they come with standard jets and chokes and you'll need to refer to me for alterations and be prepared to spend some more to get the calibration. Setting them up is straightforward - idle mixture and balance and is an essential user skill you need to learn, after that you can go back to the RR and see the difference. Best to get a new fuel pump too. That's the brush strokes for now.

I make offset sidedraft inlet manifolds for that motor but I won't have fully machined stock for a month or so. See prices in GC V/W.

GC

How far out from the engine would one of your inlet manifolds protrude. Space to each side of the engine is a bit tight so I need to work out the over distance the new carbs/manifold will stick out to make sure they will fit.

Bob,

you'd best publish a semi-plan view photo of the inlet side of the engine bay and let me examine that out in the first instance. Include some means of gauging distance in the photo.

GC

The pics might be a bit small so from the engine to the frame reads 315mm

Good photos Bob, I'll have a look at the sidedraft setup tomorrow and see if it will fit.

GC

Bob, hi

here is a photo of a sidedraft setup, only one carb shown of course, the manifold is an GC 131 offset sidedraft unmachined blank and will be a fraction shorter when finished, price is in GC V/W.

Looks like this or something like it might be the way to go. Looks like you will have enough room for a K&N twin or ITG one piece filter too.

GC

Would pair of 40 dellorto's fit the GC inlet manifold and work as well as the webbers??

Yes, DHLA and DCOE 40 and 45 all have common length and mountings.

GC

Well got a set of twin 40 dhla dellorto's, both of which will be stripped down and fully rebuilt. Therefore what setup is required to suit the engine ie jet size chokes etc.

Bob, hi

remind me by e mail to answer jetting once you've stripped and cleaned thoroughly, got the overhaul kits from Dellorto.

GC