Increasing Injector Size L67

[ev351]

Hi all,

I am looking at using larger injectors on my L67 SC as I want to take the boost higher. I have searched around on here, but have not come up with the exact answer, so maybe someone can answer this for me....

If I increase the injector size, up to I think the recommended is 60 - 65 lb from stock, do I have to adjust the entire map for fuel? or is this done with the Injector Offset that I keep reading about?

I guess what im getting at is: Am I biting off more than I can chew here? I mean if its a case of just bringing the injector into the correct range by way of changing an offset and checking AF ratios, then OK, but if I need to change the entire fuel map, that may be a little out of my league.

Thanks in advance.

Ev.

[antus]

you just need to change the injector rate to fix it up for larger injectors, but you will probably need to run one of the1s enhanced bins and/or change the MAF to meter the extra boost airflow. Depending how far you go you might be able to retain the stock maf, which will be fine for the existing parts of the map, then you 'just' need to come up with something sensible for the spark and fuel at the higher boost levels. wideband will help. Im not sure if the1 has pre-populated those bins with a good starting point for x amount of boost, he can probably advise.

[The1]

whats your duty cycle now at WOT Redline? Usually you will need 16psi @ LIM to max the stock injectors to around 80% on stock engine, going upto the 968 Bosch Green XR6T Injectors will drop that back down to 50% Duty Cycle, can run smallest pulley on stock engine with those or perhaps rockers, If your going to do headwork, camshaft etc then definatlly go for 60 or 80lb dekka's, can go upto 60lb dekkas even if not doing it, a larger injector will give you room to play with EOI.

As Antus stated you'l need to use enhanced mod bins and a larger MAF to read higher, Stock MAF will only get you around 10PSI. You will need to for a start change the base injector rate to suit and input the data for the injectors your using, pulse offsets, battery offsets etc, then retune spark/fuel and all usuals.

[ev351]

Thanks for the replies.

I will have to look at the duty cycle once I fit the new pulley on the weekend.
Currently I have:

3.2 inch Pulley
indicating 9 psi at redline
water injection
headers
dual cat free flowing exhaust

Before I did the two cats headers and exhaust I was showing about 11 psi at redline.
My aim was to bump the boost back up as apparently 2.8 inch pulley is the smallest you can go without machining the snout of the m90 - but that's off topic.
So from what you are saying I should not really worry too much about the injectors at this point, more likely the MAF sensor? Can anyone suggest a vehicle to source a suitable MAF sensor from?

Thanks again... Ev.

[The1]

have a read of the enhanced mod general information PDF.

http://pcmhacking.net/forums/viewtopic.php?f=27&t=2518

[ev351]

Wow, OK thanks for that, I will start learning, and then get back here with some hopefully sensible questions, but nice work...

Thank You!!

Ev.