mattrst90spec

Hi

I have a rebuilt engine for my s2, its a 1.8 zvh with low comp piston, ported head, newman cam with solid lifters, new stage 3 t3 .48, front mounted intercooler.
Its still running mfi, when i put on rolling road to get it set up it was bad news, it leans off when it comes up on boost, im being told this is because of the extra cc's the meetering unit cant keep up.
Im looking for a way to sort this with out spending loads more cash, some people are telling me to fit a mappable 5th injector, is that a good idea or is there another way?

Cheers Matt

Turbocabbie

I would personally change the management, im not a fan of 5th injector setups... although a 5th injector is a cheap way to obtain more fueling.

I personally do not understand why some people spend so much money on an engine to simply 'make do' with the management, get something which is right for the task required imho

matt p

As above really mate!

Better to get it done properly, 5th injectors are old hat now as there is so many other oprions avaliable

addiction

how much boost are you running? if your not running over 18 psi the metering unit should have no problem fuelling it.

105epwr

i run a pressure pipe of the manifold to the fuel press reg to give more press on boost as from factory this is not connected up Harvey gibbs told me to do this as a 5th inj is not needed with this mod i run mfi 1660cc a 5 second spike of 26psi and holds 22psi engine runs fine gear box hates it tho!

Rick

MF2 controlled 5th injector, very very good mod. Ignore people who say they are old etc, they clearly don't understand electronic or thermodynamic systems.

Turbocabbie

Im not for a moment suggesting that these 5th injectors do not work Rick but given the cost effective alternatives available these days such as OFAB/C EFI, DIY Cosworth, DIY Go-Tech, DIY Megasquirt and others it just seems false economy with regards to spending vast sums of money on an engine build and then skimping on something that is ultimately incredibly important, as I do not believe that a 5th injector setup is ultimately as capable as management suitable for the demands of the engine from the start

Do you not agree ?

im not suggesting your wrong, or that I have a greater understanding than yourself just curious regarding which way direction you would personally go in this situation...
I just personally think management is part of the engine build specification and budget

Rick

The problem with Efi, is that there there are few off the shelf chips available if any, and most so called tuners cannot map.

I'm not talking about full throttle, but driveability, part throttle transients etc. This takes many, many hours to do properly, and people are not willing to pay for this to be done. MF2;s can be sourced for under 200 quid, and can be mapped for heavy throttle in a day. You then retain the smoothness and driveability of KE JEtronic, and gain significant economy due to having the MF2 do all your on boost fuel, and the KE set to cruise at 15:1. Your engine lasts longer, and you don't use oil.

Most cossie's are badly mapped, never mind CVH's which didn't use efi from the factory. I mapped a Zetec turbo that someone had already paid 500 quid for to be mapped on the rolling road. It drove like a pig when i got it, and idled at 10:1. Gentle accelration in 5th, and it was as if u weren't pressing the throttle - it just didn't do anything. It took me about 11 hours to get the transient maps right, on the RR u cant feel these splutters, but even from the data logs it was obvious that there was waaay to much fuel going in. The guy thought he was driving a different car on the way home, not to mention using half the fuel!

Ultimately, if the customer is prepared to take the car to MSD for a week of mapping, and wants to spend the 2k ish it's going to cost for the mapping and conversion, then yes - Efi all the way. But for less than a 1/4 of that, u can have very similar results on the MF2.