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Sierra V6 - EFi or Weber 500?
jimmyjoebob - 4/2/06 at 11:29 AM

Although not for my locost, I am wondering whether I would be better off using a weber 500 on a 2.9 V6 rather than the EFi that Ford used. I have all the ECU wiring (car is now a wreck but never mind!) ready to install, but was recommended weber for an old essex v6 engine. Any advice?


froggy - 4/2/06 at 11:31 AM

i think they meant a weber 38 dgas as fitted to the essex capri, the 500 cfm will be too big for the cologne engine


jon_boy - 4/2/06 at 11:38 AM

holly 500 is apparently the best carbs for quick essex V6's although thats generally when they are bored out to 3.4/3.5 litre so i dont know for yours but that may give you some comparison


jimmyjoebob - 4/2/06 at 11:41 AM

38 dgas was standard for essex engine. These are often fitted to the 2.8 cologne engines as an improvement on the Pierburg-Solex. Fitting a holley to an essex is quite popular for 30hp power increase. However, a specialist recommended the weber as a better alternative. Since the 2.9 cologne breathes much better than an essex surely this would be alright if jetted appropriately?


mark chandler - 4/2/06 at 12:30 PM

I had a 350cfm holley with vacuum secondary fitted to a 3.1 Essex V6 years ago, 500cfm is way to large, the are for 5.7 litre engines.

My preference these days would always be EFI, better off fitting what you have.

If you want the look of a carb then gut a holley and just leave the throttle bodies, insert some injectors & megasquirt it.

Regards Mark


jon_boy - 4/2/06 at 12:33 PM

the 500 Holley - probably the best single carb for race engines
Car Clinic produced double manifold for two 38 DGAS carbs gives budget power
At £300 on an exchange basis - including the linkage - the manifolld is a lot cheaper than a triple-Weber one.
A lot of people use the Weber IDF in Group I racing, but Martin finds a Holley 500 gives better fuel atomisation- lDFs seem to give wet plugs a lot.
For the Capri, they homologated the Weber 40 DF15, quite good for racing but no good on the road, as they don't have a power value and give a very rich partial throttle running - washing your bores out quickly.
Four barrel carbs don't seem to give good results either, a 390 Holley is just too big.
The 500 Holley has a flow rate of 500 cfm at three inches of water pressure drop. Four-barrels like the 390 are tested at 1.5 inches pressure drop, and if the 500 two barrel is tested at the same pressure as the four barrel, it flows at 353 cfm - smaller holes give higher air speed which encourages better fuel atomisation.
Thats essex v6's anyway.

[Edited on 4/2/06 by jon_boy]