Ok, I'm looking for input before I spend the money on new injectors. I've about hit the wall on upgrades before I dig into the motor.
I don't think I'm going to go nuts with the cam/head upgrade but was thinking about bigger injectors and possibly a bigger throttle body...

All imput will be appreciated

 

I am sure that your car is still running rich with what you have. A dyno test with Air Fuel Ratio info is required to know for sure. You WON'T need biger injectors until you change the cam, port the head, and port all the other important parts.
You can PM me, I know how to get there.
You can see at signature link.


Dave

 

There are also a number of NAM members who've confirmed that if you had a 19% pulley, you'd need larger injectors.

 

To get the most out of the smaller pulleys (17% and 19%), larger injectors will help. Also if you have cams, heads, etc...But DON'T get larger injectors unless you have an ECU specifically tuned for it. Either the GIAC or similar one that's done many dynos with the exact size injectors you'll be using. I wouldn't trust some of the ECUs out there like the MTH, for example, that is tuned more on "theory" than hard data.

 

Please, how has this been confirmed? All of the dyno results I have seen shows the Mini running rich even with the 19% pulley.

If you do deside to use larger injectors you WILL need something to adjust the A/F Ratio.

Dave

 

Sorry. I guess I should add the following: ... need larger injectors to MAXIMIZE performance with a 19% pulley. My bad.


For the specifics on this I defer to JLM. Please see post #45 in this thread:

https://www.northamericanmotoring.co...ighlight=apexi

where JLM recorded a net of 24whp with 440cc injectors & and Apexi fuel management with his 19% pulley.

Greatgro makes a good point. One needs an acurate means for controlling the fuel with larger injectors to really see any benefit.

 

I also believe the only reason why he ran that large of injector was....
it was what Hubie had on hand at the time. (440 is what he uses in the twincharge kit)

 

With stock injectors and the 19% pulley, the AFR peaks (gets leanest) at about 13/1. Whereas that is still richer than stoich (and thus safe for the motor), it's not rich enough for best power production. To make the most power with the 19%, you need bigger injectors, like the 380cc injectors. There's no need to go bigger: the 380s allow plenty of head room, and bigger injectors may not run smoothly for you over time. We now have German factory manufactured 380cc injectors for $300 per set. These are not cheap re-valves, which can puddle the fuel instead of atomizing it, but brand-new factory injectors.

 

D1JL, I just thought of another point... and believe its been cause for confusion in the past. If you read the 1000's of posts on pullies and fueling, you find people saying both... too rich and too lean.

Consider this. We know that the theoretical "ideal" a/f ratio is 14.7:1. A typical O2 plot on a pullied MCS has the ratio running all over the place, but generally richening up rpms rise. Some would indeed call this a "rich" condition, and I would agree in a normally aspirated engine. However, boosted engines have been proven (google Corky Bell) to require much higher than the "ideal" ratios to achieve maximum performance.

Ooops... I see Eric made this point too...

 

my apexi is throttling back the 440's about 35% for WOT running. assuming my A/F was as desired, and 15% headroom, that means 360cc would be right (80% of 440). I've had no idling or mid-throttle problems and can use the extra 20% if my rig gets built to be even stronger

 

My Apexi is throttling back my 380cc injectors using a 17% pulley, starting at 4,000rpm and about 25% at WOT. I still need to lean it out a bit. I do completely agree that richer is safer.

Dave

 

but the fact of the matter is::::

you still make more power at 12:1 than you do at 10:1
those differences in a/f ratios tends to be about 10whp from what we have seen on the dyno

yes... 12:1 is richer than 14.6 :1 but still not as pig rich as the mini will run if you don't control it.

 

Eric,

Are these the ones you've been testing for compatibility with the 19% & GIAC ECU? By chance are these the same as what Greatgro has?

Thanks,
AMPR

 

These are the SAME SIZE (380cc) as the ones I have. Unfortunately, these new, lower cost injectors were not available yet when I got mine done. But it was still worth it. Now at the $325 GIAC price and only $300 for injectors is even a better deal!

 

will there be a GIAC program for a 15% pulley and JCW/380cc injectors? only seems logical since the JCW 210 upgrade includes them.

 

What I'm getting is people are saying that I do NOT(?) need to go bigger with a 15% pulley?
Guess I'm still confused, my ECU is remapped from Ren-Tech and I can have them change it to reflect the bigger injectors. I'm looking at the M7s but I can't seem to get much feedback on how well they work.
Should I just spend the $$$ and go JCW?
Thanks to all...

 

Sorry for the confusion but this kind of topic brings out so many opinions. Many people are using 15% pulleys with stock injectors. I guess what most of us agree on is that as you go to smaller pulleys, larger injectors are a good thing. Most important is as you go to larger injectors; you need something to control them. The question seems to be; how big? I am using the JCW/380cc injectors with a 17% pulley and I am still running a little rich. I am pulling 210 WHP with this configuration but I don’t expect to get much more. Maybe just a little.


Dave

 

Thanks, Greatgro. Good to know since it means I'm now only a set of injectors away from GIAC nirvana. Goodbye 15% GIAC; hello 19% GIAC!

 

Although I it may seem logical, I believe GIAC's testing proved injectors aren't necessary with the 15% to make max power. Personally I want good bang for the buck. If it isn't helping (significantly), it won't be on my "rig" (just borrowing your term, jlm).

 

Discodan, Greatgro is correct. My MINI was used in part to test & tune the 15% GIAC and we found that injectors aren't necessary for the 15% & GIAC. They are, however, a must with a 19% or greater pulley & GIAC ECU.

 

Okay, but, will the 380's be enough if nitrous is thrown into the mix?

 

Aaaah! Now that's a completely different question!

 

As far as I know, there has never been 1 assertion here at NAM, that larger injectors were REQUIRED with a 15% pulley. Hell, I ran my 19% with factory injectors and unflashed ECU for the entire summer without a hint of detonation or problem. So, I have to conclude that larger injectors will not get you anything with a 15%, except maybe a higher gas bill.

Now, in spite of my 19% w/OEM injectors & w/OEM ECU, its been proven that fuel tuning which incorporates larger injectors on a 19% car, will net a substantial HP gain.

Ultimately, I believe that, how large you go with any injector upgrade, is a function of your engine building plans... how exotic your end product/goal is, should determine if, and how large your injectors should be.

I think I'm going to try Helix's 380's or perhaps wait a bit and see how Pilo's work out before deciding.

Cheers all!

 

True - I ran a 19% for 15 months with stock injectors/ECU.

 

This all started due to the fact that MINI flashed my ECU and set it back to stock. I lost so much HP I thought since I had to send it back to Ren-Tech I might as well squeeze a few more HP out of it.

Currently I'm, 15%, header w/high flow cat, Borla Sport, intake and a few other mods, thought that they could get me a few more with the bigger injectors...

Still debating for a few more days, this thread is becoming an interesting read.