AlexM

Hi,

I am starting to think about upgrades when my MY98 UK car is out of warranty..

I am contemplating an ECU upgrade (Link), turbo upgrade (VF23), and various exhaust bits.

Given that my car has 380cc injectors and that I know that running 1.15bar on a similar car (with a factory TD04L) will give injector duty cycles of 85%+, I am assuming that bigger injectors would be advisable to maintain a good margin of safety.

I would be grateful for advice about which injectors should be considered... I would like them to have the following characteristics:

1) compatible with the standard fuel rails (drop-in replacement).
2) 440cc or bigger (what size would be optimum).
3) Compatible with Possumlink ECU.
4) Less than outrageously expensive.

Any information regarding suppliers, prices etc gratefully received.

Regards,

Alex

P.S. would my JECS ECU be able to cope with 440cc injectors, or would it just overfuel massively on boost?


[This message has been edited by AlexM (edited 27 July 2001).]

AndyMc

Hi Alex

For info.I have a MY98(standard engine wise) and a multimeter that measures duty cycle.At high revs in fourth gear the duty cycle reaches 85% believe it or not and thats with standard boost.

As I'm sure you know theory says that you shouldn't drive injectors over 85% duty cycle so it would seem that there is very little scope for improvement with the standard injectors,however something to bear in mind is that when you increase the level of boost the fuel regulator automatically increases the fuel pressure.
So long as the fuel system can supply enough fuel at the higher pressure the duty cycle will not need to increase by nearly as much as you would think.I think this is the reason that UK cars can be made to produce 50-60hp more than stock even though the duty cycle runs high when completely standard.
What I'm trying to say is that it may not be necessary to replace the standard injector to produce 300hp so long as the rest of the fuel system is healthy.

Andy

AlexM

Andy,

Thanks for your reply, which makes perfect sense.

I forsee two possible problems - if boost pressure is not increased greatly but airflow is due to a bigger turbo then the FPR may not increase the fuel pressure sufficiently for duty cycles to stay acceptable.

Secondly the fuel pump may not be able to flow enough fuel at the increased pressure to keep up. I would imagine that fuel system headroom is ultimately limited by the pump - Am I likely to need to upgrade this too?

Either insufficient fuel scenario would obviously spell trouble.. .

Can someone tell me about injector options for the Phase 1 and give an indication of prices?.

Also, if anyone is running a VF23/4 or similar on a Phase 1 UK car with the link and 380cc injectors... what duty cycles are you seeing?

Thanks in advance.

Alex