At what point in the mod process, do you really need larger injectors?

 

Ideally, you don't want to run your injectors at more than 80% of their duty cycle.
More boost /larger intake = more air in, which means you need to add more fuel to compensate (or go lean and hole your pistons)

If your running a WB O2, this will help tell you.
also you can ask who ever tuned your car/ecu what you injectors are running at during WOT.

HTH.

 

I've generally heard closer to 85%

 

Are you asking after I do this that and the other is that time for larger injectors?

I think JCW has laid a plan for us. They add a 380 injector with a pulley, head (sorta), Exhaust and CAI along with a tune that takes advantage of the new parts.

That being I'd think one would want to increase injector size when adding the MINI Trinity of CAI, Pulley, Exhaust. Then get a tune to make the most of it.

380's till a big valve head and header are added then 440's

Thats my take...

 

There is an injector calculator tool, http://www.injector.com/injectorselection.php

I'm not sure if these are accurated or not.

According to the calculation from the tool, I have to use the 440's instead of the JCW ones.

 

then it won't hurt. But really, if you go more than JCW (380s) you'll need an ECU tweak to use them If they're too big and you don't tune the ECU, two things will happen:
1) You'll throw rich codes because the adaptation values will hit the alowable limits in closed loop.
2) You'll run real rich in WOT untill you start hitting red line.

There's no hard and fast rule about what duty cycle is best. That said, the only way to know for sure where you're at is to log duty cycles vs RPM at WOT. Only one I've seen mention any data here is ryphile... (Ryan)

Matt

 

...until the ECU adapts with its long-term fuel trim. How much more fuel the injectors flow will depend on how long it takes for the ECU to trim. After that happens the fueling will be very close to stock assuming the new injectors have similar pulse volumes over their range versus stock. In general, once bigger injectors get scaled by the fuel trim then the system will run a whiff leaner in WOT. This is due to larger injectors having larger injection volumes at lower pulse-widths. The ECU scales open-loop pulse-width based on the relatively low-pulse-width closed-loop operation.

It's really easy to see when most MINI's are running out of fuel since almost all of us use injectors that are too small. We wait until the injectors go static [full on] and see the AFR rise as HP rises during our dyno pulls. Certainly not the best method, and if we ever endurance race all of our injectors will probably seize, but it does allow us to have smooth 750 RPM idles with our little 1.6L while still making over 300 gross HP [about 210wHP with an M45 setup].

 

I'm thinking about running 440s (in anticipation of a future head/header upgrade) with the basic mods like pulley, cai, and exhaust.

I'll be getting an RMW tune in May and was initially going to upgrade to the JCW 380s. Reading around a bit, including one of ryans posts on mmmc, it seems like jumping to 440's may be the way to go.

Will it be safe to drive on the 440's for a few days before the tune? Will the ecu trim them back enough to maintain smooth idle? Will Jan be able to tune for a smooth idle with 440's on a stock head?

 

Who is selling the 440's nowa days?

 

I got my 440's from Jan on the day that he tuned. Just have him bring you a set and you can change them before the tune. It took me about an hour to put them in having never changed them before. Now it would take me a half hour. It is pretty easy to do.

 

The thing is that I still run "rich" using stock injectors and the mods in my sig.

 

heres one for yas... im just starting to mod out the mini. i have a 15% Alta pulley an Alta CAI, a 2% crank pulley, my Alta exhaust is on the way as we speak. its an early production 03. i plan to uni chip it this summer. you think i need injectors? if i do get injectors, will the stock pump supply enough fuel?

 

OK. I have been contemplating injectors for a while now, and the more I read, the more I am starting to think that I may need them.
I have a 16% pulley, Alta CAI, OBX Header, Random Technologies High Flow Cat, Borla Race Cat-back, and GIAC flash: on an 06 MCSa.
Any opinions out there as to whether or not I need them yet, and, what size? 380cc, 400cc, 440cc?
Also, do larger injectors require modification to fit? I know that the JCW 380's are supposed to just plug right in. What about the others, such as M7 400's or 440's? Are there other alternatives?
A lot of questions, I apologize, just very curious. Thanks in advance!

 

O.k. Astro,
We have almost identical power mods.The man himself(Jan)said that the jcw's(380 cc) are sufficient.Soooo.... I ordered them,received and am thinking of installing myself.I have tune with him fri.
.

 

Thanks a lot!

Allow me to say...sweet. Looks like that will be my next purchase then.

Hey, I also plan on tackling the install, so here is a good how-to if you'd like to view it. Good luck with your install!

https://www.northamericanmotoring.co...ad.php?t=68954

 

find an injector cleaning house and send the old ones off for a cleaning/flow testing. You'll get before and after numbers, and it doesnt' cost much. My JCWs were down a bit on flow, and only matched to a bit worse than 4% after 12 months of driving, and after cleaning matched to 1.1% best to worst.

It's also possible that a good cleaning can recover the pooched injector that wasn't firing on #2, but maybe it's just cooked.

Anyway, I sent mine to Witch Hunter (www.witchhunter.com) and for $60 bucks they were cleaned and tested and back in about 4 days....

Matt

Sorry,, the pooched #2 referenced another thread.....

 

The original one are good up to 230-240 HP the JCW one are good for 270-280HP.

 

I'm curious to know the source for this

 

but if one comes at these numbers from the calculators, one has to remember the power lost on the SC. Sound like one could benefit from JCWs at a bit lower a peak HP. I haven't logged duty cycles yet, though. But it seems that injectors are dealing with higher duty cycles better than they used to!

Matt

 

No problem
-Thanks be to Doc Obnoxious.His pics are great, I printed them out this morning!
He's a smart fella.

 

For what it is worth, my middle of the pack engine runs fine on 400 cc/min injectors.

I originally installed them as a reliability hedge, as I tuned the engine for a little more power and a high percentage of track miles. In line with Ryan's comments, the ECU in my MINI has to be leaned out at maximum RPM's for maximum power. So, I guess I've got enough injector overhead. However, never actually measured the injector duty cycle. Just took it on faith that the duty cycle would be a lot less for the 400 cc/min units than the duty cycle of the injectors that came with the car.

John Petrich in Seattle

 

I would reconsider the UniChip - Today you can get a custom tune for about the same price. The difference is huge.

 

I heard similar about the stock injectors - that they could handle all bolt mods including head. Perhaps this statement was before the recent tuning developments made?

on one hand, I still run rich. On the other I'm running JCW level numbers and JCW uses 380s.

MATT - I think its time for a MC2 article on injectors

 

My car is making 231.5 whp w JCW 380s at safe AFRs...... Jan thinks I can get into the 240s with 440s.

At one point I had 440s and it ran very rich (before the RMW head)....

 

SpideyX - greetings !!! I was hoping that Jan would chime in on this thread and share his findings and commentary.

Do you recall - your "richest a/f ? I still drop below 10.8 when all out near redline.