FCD fitting, do I need more fuel?

[mattsavage]

1991 Turbo II.
Hi. I have been advised that I need to fit an FCD to stop the ECU from cutting the fuel at high boost.
The car (which I\'ve only recently bought) has a full stainless steel exhaust with cat replacement pipe, the engine was rebuilt 6,000 miles ago, it also has had some \'mild\' porting work done. So I guess all this helps the turbo spin/boost even more than normal, great!
But, when I fit the FCD (today\'s job) do I also somehow need to increase the fuelling so the extra boost has some extra fuel to go with it?!
 
I don\'t want to shorten the life of the engine by running it too lean at high revs. Also, I intend to do a few track days so it needs to be right.
But, I don\'t want tons of BHP and I can\'t afford to spend tons of money!
 
Please let me know what I need to do.
 
Cheers,
Matt Savage
 

[Prof]

1991 Turbo II.
Hi. I have been advised that I need to fit an FCD to stop the ECU from cutting the fuel at high boost.
The car (which I\'ve only recently bought) has a full stainless steel exhaust with cat replacement pipe, the engine was rebuilt 6,000 miles ago, it also has had some \'mild\' porting work done. So I guess all this helps the turbo spin/boost even more than normal, great!
But, when I fit the FCD (today\'s job) do I also somehow need to increase the fuelling so the extra boost has some extra fuel to go with it?!
 
I don\'t want to shorten the life of the engine by running it too lean at high revs. Also, I intend to do a few track days so it needs to be right.
But, I don\'t want tons of BHP and I can\'t afford to spend tons of money!
 
Please let me know what I need to do.
 
Cheers,
Matt Savage
 

Depends a great deal on what type of FCD and what other mods are on the car - basically the FCD, if it\'s an external \'cludge\' is lying to the ECU about the amount of boost - so the ECU will only be fuelling to the level of boost the FCD is reporting.  Ther rear rotor fuel cut normally kicks in about 8.8/9 psi, so the FCD are usually set for about 8 - any boost beyond that therefore has no extra fuel for it.
 
The upside is that the stock maps are pretty rich - but the more boost over the cut point the more risky it is (mixture leans out rapidly).
 
Try and find an aftermarket chipped ECU that has the FCD function built in, as these normally have adjusted fuel maps to take advantage of the additional boost available from aftermarket exhaust and intakes.
 
An ebay search for Blitz Access, Knightsports, Redom, Panspeed etc, should find you what your looking for.  You will have to run the car on super (99 RON) fuel as the Jap ECU\'s are tuned for that.
 
Failing that, go for a full after market ECU or piggy back and enjoy thje potential for huge power gains (appropriate mods of course )
 
Prof.

[grinder]

in run similar to what you have ( apart from the porting )

i run with a FCD and on the A/F gauge i see VERY rich right thru the rev range

im 99.9% sure you will be fine with this

the TII stock map is VERY VERY rich ( hence the naff all MPG )

[mattsavage]

Thanks for your replies.
I\'ve fitted my FCD and all is fine now. I also now realise that the factory boost gauge is reading a tiny bit lower than before, so I assume the gauge is reading the \'false\' modified signal that the ECU is getting! Cleaver!
Oh, I also spoke to someone at WGT auto developments, VERY helpful. He said (like you did) that the fuelling is on the rich side anyway, and the air flow meter should be able to keep up with the extra boost without any problems.
 
Thanks again for your help.
 
Cheers,
Matt

[grinder]

thats where i got my info from originally

glad that you are happy with it

[Brett]

I never had any fueling problems with mine  I\'d recommend replacing the fuel filters though :yes

[mattsavage]

filters, I thought there was only one?!

[Brett]

IIRC Theres one in the tank attatched to the pump (low pressure) and the high pressure one on the lower right hand side of the engine bay bulkhead. (As your facing the car)