Hi All…

I’m pretty new to the whole ‘Cosworth’ thing, so please bear with me whilst I ask what might seem like pretty basic questions!
I’m not about to purchase a sierra Cosworth, but am seriously looking into using a YB_ for powering my next road/drag racing project. I’m therefore after a ‘crash course’ in the facts and to dispel some dubious rumours I’ve heard about these great engines.

Firstly, what are the ‘official’ power outputs of the 2wd and 4wd sierra YB_ engines, and at what boost level was these power levels achieved? Also, what is the correct designation for the 2wd, 4wd and Escort Cosworth engines? I know they are the YB_ range, but just for interests sake, what is the last letter for each one!

Was the turbocharger, ex. Manifold, and inlet manifold the same on the 2wd and 4wd versions – if not, what were the differences, and were they all basically interchangeable?

Do all the 2wd and 4wd engines have valves / valve seats and ECU’s that mean they will run ok on Unleaded (Optimax) Fuel?

I understand the loom and ECU is different between the 2wd and 4wd. Why is this? Is the 4wd ECU more refined, is the 2wd ECU more easily tuned? Are the looms the same? Will the looms and ECU interchange (I assume they are all Weber/Marelli based???)

I hear the 4wd head is different from the 2wd. Is it a huge difference, is it better porting, larger valves, better cooling, thicker deck, etc? Is any better or more suited to bigger power outputs?

Block: what is the ‘205’ block that I keep hearing mentioned? Are all the blocks pretty robust for moderate power increases anyway?

Aside from fitting a ‘chip’ is there anything else that needs doing to achieve a reliable 280-300 hp – eg, rod bolts, head gasket, improving cooling, plugs, etc… Intercooling will not be an issue by the way, it’ll be much better than standard…

Finally, if I was to scour the small ads, how much do you reckon I could find a fully dressed engine in reasonable health for (i.e. turbo, inlet, plenum / fuel rail, flywheel, loom, ECU, etc)???

Many thanks, and apologies if it is stuff you’ve been asked a million times before!
Dave

 

Official std power outputs :

YBB 2wd 3dr / Sapph 204bhp
YBD RS500 224bhp
YBG / YBJ 4x4 Sapph 220bhp
YBT T34 Escort 227bhp
YBP T25 Escort 220bhp

Power made at std boost approx 8 psi

4x4 manifold is a single piece item - quite compact.
This gives good response and low down torque on lower power cars, i.e. if you are aiming at 300 ish bhp.
2wd is a better flowing design and comes in multiple pieces - better for higher power cars.

Different ECU's are as follows:

Level1 3dr & very early 2wd Sapph
Level6 2wd Sapph
Level8 4x4 Sapph
P8 T34 Escort
Ford EEC-IV T25 Escort

std 205 block is found std on std 3dr and 2wd Sapph
Modified 205 block with thicker walls, smaller core plugs etc is RS500
More than 1 type of 200 block but these are all 4x4 blocks.

The power you will make will depend on the fitment of the other ancilliaries but a live mapped chip, T34 turbo with a .48 a/r exhaust housing and "dk green" 803 injectors would be your best bet for a solid 300+ bhp without spending too much cash.

HTH

Edd

 

hi

just interested in the torque thing u mentioned..am i right in thinking the 4X4 sapp has mor elow down torque than a 2wd or is this variable depending on mods etc?

tia
dave

 

The 4x4 head is a true hemi head, and has better cooling properties. Apparently the cams that come stock also allow smoother running. Also it is tuned to work with US emission regulations (despite the fact the engine was NEVER offered in America)

The 2WD 2-piece exhaust manifold is MUCH better than the one on the 4x4. So many Cosworth 4x4 owners swap to the 2WD exhaust manifold for a cheap power boost.

The L8 ECU (4x4) is more advanced and is set to run to US emission specs. It is said to run smoother in a 2WD car as well. Better than the L6 (2WD) and the 3 door Cosworth (L1) in the fact that it offers more memory.

That's what I know. Anyone willing to fill in any blanks?

 

Cheers guys,
I'm left a little curious however; there must be quite a difference in the heads / cams or injection system if (on the same boost level) there is over a 20hp difference between the 2wd and 4wd?

I assume the 0.48A/R isn't on the Sierras as standard then? If this is the only change, i assume the trim on the compressor is good, but the power was 'held back' with the restrictive exhaust turbine? As nitrous isn't out of the question for an easy, cheap power boost in the future for the strip, a larger exhaust housing would probably be a good point to start from...

To clarify further - will both sierra ECU's swap with both looms? Is any ECU particually better, or cheaper to modify / get more power from than another?
And are both / neither looms integral with the main sierra wiring loom - ie will the loom come with a load of redundant wires, or will it be just the Engine loom?

Cheers!
D

 

i'm interested in ecu swapping. i was originally after a L6 instead of my L1. however i was told by another 3 dr owner there was no difference felt on the road. ie not any smother??

also read on this board that although the L6 has more memory it doesn't use any more than the L1. something to do with the memory chip(s) in the L1 being obsolete - only larger capacity ones availble. but i don't know this for 100%. only read/heard?

cheers
Rob.

 

you can put a L8 ecu into a L1 or L6 loom but you will also need to change the Throttle Position Sensor.

the engine loom is separate and just connected to the main loom with a multiplug with 5 or 6 wires for power, temp gauge, oil pressure light and stuff. it's dead easy to use in another vehicle.

 

Can I use a L6 on a L1 loom without modification?

 

The YBG 4X4 head was also the basis for the YBM head which Cosworth California sold in kit form to customers.
270 hp @ 8750 with 50's
Kit comprised of ported N/A head runing solid lifters, cams, verniers and larger inlet valves.

 

Yes hard to find, yet well worth it - YBM - M stands for Motorsport as it was sold via Ford Motorsport catalog (listed in the 1988 year for example).

 

Only minor improvments to the 4x4 head including cooling passages and combustion chamber size to improve emissions. Cams have the same profile. Power difference is down to the bigger intercooler, larger compressor trim and a touch more boost.

.48 A/R is standard on all Cossies apart from the RS500 and Escorts. This exhaust housing is good for over 300bhp (more if a cut back wheel is used).

Both ECUs?? There are L1, L6, L8, P8 and EEC IV. Worst (relativley) is the L1. Best is P8(but get your wallet out). Don't get hung up on what ECU as all can be sorted to have a properly running engine.

I believe all the Weber Marelli looms are separate but not 100% sure on the later cars.

 

Somebody asked diffirence between L1 and L6 ECU. They can be chanced together w.o. any problems. Only reallife problem with L1 is it can melt its earthwires inside of ECU. And other one is C0% adjust -potentiometer in ECU; it`s too small in movement-> can "wear" easily and can loose its setting, specially in well used ECUs. In here Ford importer chanced (in warranty terms) L6 for many threedoors due mentioned problems.
Sorry for bad english; too old person to learn anything...

 

hey,
i found a book called how to power tune ur ford SOHC pinto and sierra cosworth DOHC engines this book has helped me very much. so good luck!

 

the 4x4 looms are much more integral to the car than early looms
early loom joined with just 1 plug containing about 5 wires
4x4 engine looms don't have the ecu plug and have i think 3 8-way plugs or thereabouts