Ford Sierra (The European One)

[Pythagorus]

Someone wrote long ago " when I drive downhill and not giving gas it backfires," if this is the Jahn's pistoned engine spoken of earlier...timing is likely to be a problem.

The unfortunate thing about these engine mods is there is so much crap talked and so little knowledge of how one change affects another action by owners, forums, magazines and "speed shops" . The guy who proposed head porting and oversize and Jahns and boring etc...seems to have said little about ignition curve, advance specifications and mechanical and ignition timing and carburretion (I seem to recall it being mnormally aspirated) These guys recommend compression increases as though it is like buying more grapes..but!..its how you achieve it that counts...and will you need more expensive fuel and a different range of spark plugs...probabaly!..almost certainly. A very different combustion chamber shape and performance emerges fro using domed pistons over flat tops or in changing the dome.

Incorrect carburettor settings CAN cause the problem even though. even a catalitic converter or someone has disabled the "pollution" gear. All these affect performance and predictability. I'd suspect the timing at the outset ...but all of this should have been sorted out before the car was on the street..in fact before the engine went into the car...on an engine dyno.

Alll that expense for you to get less reliability, more engine temperature and a small increase in performance....as compared with noise...re-states profoundly and sagely ..."better to buy a car which performs at the outset..from the factory"...Your contribution to knowledge and performance by what you are doing to your car is non existant..it sounds as though in fact you have been led up the garden path...an excited young man obsessed with spending money without a clue as to how the car will respond or feel and unprepared for the inevitable unreliability. maybe you don't see that yet, still starry eyed and vulnerable to the crap engine mod's sellers talk. No personal attack, it's the type of sucker these engine speed shops feed to and from.

A very important question is "where does this "high performance" range exist in the rev range and under what conditions of car weight? is it actually going to add something to a better drive in your normal restriction of driving on the road?

I have lightened pistons cranks flywheels and done every conceivable thing to engines...an improvement in acceleration, yes a little but in traffic..more revs and more clutch wear and more fuel usage. Such engie mods are for high rev track work...don't you think the manufacturers would do all these things if cost sensible and better performing over the car's use? They simply lighten body parts, using plastics for example. A lot of what is done today by young or young at heart speed demons ws done back in the 1920's....and we have moved on from there to highly competent theories put into practice and tested and offered as a package in new cars...and still a few decent cars, rear wheel drive, exist as very high performance cars, Nissan, Benz, BMW, older Lexus' Porsche even Holden and Falcon if you can put them amongst high quality cars...and all these cars are set up and ready to go as V6's and 8's and turbos and can be bought with a few years on.

A 1600 beetle with twin carbs might blow this car of yours off because of it's flat 4 characteristics and its lightweight..power to weight ratio. .

You see all that work you have done adds little power might even reduce torque...if you got 20hp increase you'd be doing really well..but in mentally winding it up to 150 to 200Hp.....hey, give yourself an imagination break old feller..the standard cosworth goes 220 turb'd. If it was all as easy as a few bits and pieces a similar option would have been offered by the single cam manufacturer very possibly...

The simple fact is that increased compression (overbored and/or Jahns high compression pistons ) and a tiny increase in capacity (one or two mms in diameter over say 75 original) and a head port and valves is of little value..however increasing the compression affects the bearings more than it increases performance. I wanted to increase a Lotus Escort performance once...I didn't mess around with pathetic mods like boring and porting... I stroked it. The performance increase was noticable but my SAAB 2.3 Turbo would perform as well, maybe better, a better car all around.

Back to yours and....I am also aiming at everyone else who goes on with this half baked "speed shop" stuff with some sort of orgasmic fantasy on a promise. It the piston profile is different..swirl and ignition change...the same happens with porting and larger valves...you can go backwards in torque/power or little forwards for a lot of money spent. Many argue that the rough manifold and ports work better than polish and port, just as one example.

"Buy the right car in the first place" is advice I scoffed-at when I was young but I'd have been financially better off by possibly 200 to 300 times after such restorations and modifications and in happiness and advancement much more than that. I did alterations you may not dream of including having mates make manifolds for carbie changes..one had 6 Amyl carbies on my FJ Holden

I'f I'd done what the wise told me I would have been a millionnaire by 35 just on wages and the investments which kept me from going under over rebuilding cars...and where are all those hundreds of thousands today?..."rotting somewhere" is the answer. The knowledge and experience ??...unappreciated no doubt when trying to offer my hard-earned wisdom to others.

The environment of "hotting-up" cars is mostly dreamtime and self delusion time money and environmentally sacrifical. When you own a fast car, standard, if you have any maturity at all, you use that power less than guys spend flogging their expensive often tin pot and inclomplete, sometimes deleterious, sometimes idiotic and ignorently devised sometimes reactive, engine modifications in cars often with idiotic suspensions and brakes which would be vastly more deserving of vastly less expensive attention.

So..have your engine dyno'd...let them fix the problem at a tuning shop with a rolling road. Spend no more on it unless on properly engineered suspension and brakes by a technician who can prove he knows about what happens when things are changed..some suspension improvements such as castor /camber plates can be a godsend. My advice...fix it and get rid of it and buy a decent car with all the engineering done as a system and under warranty or at least with the advantage of standard answers. If you want to play cars...do an engineering course.

Cheers

[mrgixxer]

I've got an 86 XR4Ti...A little tuning and the Turbo 4 will put out some decent power...

[Cosworth7188]

what up guys and maybe some badass girls, im new to this website and usually deal strictly with Imports, mostly Honda/Acura but i just bought a 91 ford cosworth 4x4 wolf edition(lip kit, all leather interior, is that all the special edition comes with? lol) with a garrett T 25, i dont know too much about the cossies yet. There wouldnt happen to be a doctor in the house by any chance........