hey guys I would like to upgrade to bigger injectors 740cc jecs , just need some advice could I fit them in and drive it un tuned for a few days until I get it tuned ? I have booked in with toshi on the 16th on this month other mods are HKS side mount intercoolers greedy pro spec 2 cat back exhaust
It's more that you will be dumping more than double the amount of fuel into the mix than the ECU thinks you are. I'll be surprised if the car starts...
What ecu are you running? I'm assuming Nistune. You should be able to get a base 740cc tune from Nistune and/or search on how to adjust the K value (from memory). It'll then run but I wouldn't give it many revs until it's tuned or unless you have an wideband guage to monitor afr's.
im getting nistune on the 16th just wanted to know when I had to fit them in . I don't think the tuner would replaced the injectors himself
Or just ask Toshi if he will fix up the nistune board and set for 740s so you can install and drive it to him. But yeah, wouldn't be risking too much driving until you have a proper tune, injector flow is only nominal and differences in dead time and spray pattern will affect how it runs, may end up a bit lean or cause exhaust temp to spike. It will be just as important to avoid labouring it up hills at low revs as it is to not run it through to redline.
Just upgraded the injectors in a friends s13 from stock 370's to 740's. AFR was around 10:1 at idle before adjusting the tune.
You mean before setting the k-value or with adjusted k before a dyno tune? I guess doubling the metered fuel when duty is at 1% isn't going to be crippling but I would expect it to flatten and stall if you tried to drive it anywhere. Was it warm weather when you started it? over fueling to the point you have liquid petrol in the cylinders isn't great for an engine
That's because the wideband saturates at 10:1. The actual O2 would have been richer than this. As a guide the K-value needs to be 145 and the Latency set to 970. You will also need to adjust the TTP Min in the lower ranges from 600-2000 RPM to values of around 6-7. These values will get you going and by no means is this a flag to drive your car like you stole it. Toshi will sort it from there.
thanks for the info guys ,90ttz that's what I wanted to know as long as I can drive it to toshi keep the revs low so he can tune it , also just wanted to confirm if in the 1994 zeds the injectors come off without the pulling the plenum ?
