LED Display - 10.5PSI@6000RPM=100% duty cycle

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CodingParadox

New member
I used tonight as a good opportunity to check the duty cycles. No one in the car, midnight, empty roads, and cold misty air. Did a 10.5(+/- 0.5psi) psi pull once after dropping my friend off, and when I looked down at the LED display as I shifted into third at 6500rpm, it was pegged out on the 100% LED. To verify, I then did another pull coming out of the next stoplight, and again, saw the LEDs peg out at 100% around 6000 RPMs.

(The LED display I'm using was identified by Chris D in the other thread by me a few days ago in the EFI board.)

So, as long as this thing's reading correctly, which I'm betting it is, we are, in fact, pegging out stock ecu/injectors by 6000rpm at 10.5-ish psi. So, to those of you worried about running high duty cycles... Well, um... Yer running 'em.

To summarize Chris' findings, this isn't a terrible thing, since the ECU runs so damn pig rich that even though it's 100% duty cycle, you're running rich as hell. The problem then becomes that as you go to higher PSI, you're just running fully open injectors, which isn't stabilizing an A:F ratio at all, you're just praying that it's holding a good number for you. Any blips in it are usually hidden by how pig rich you're running anyway, but if you're one of those running higher psis (I'd guess 14+ psi is starting to become a problem) on the stock ecu/injectors, you're going to hit a problem pretty damn quick if you don't already at lower pressures.

Just some more data for the rumor mill. Off to bed for me.
 
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Weasy2k

New member
Great find CodingParadox,

Yes we all thought this was going to happen and now we know. So people dont run your injectors so high for so long....even if it is pig rich it may be fine for the engine (knock/lean wise) but NOT for the injector life. You do not want one of those failing during a high RPM run just to have one cyl burn right up :cry:

For chrisd he can jsut use the SMT6 he is using to tune the A/F a little leaner to get a bit more power and to help the injectors a bit more (11-11.5:1 ish vs the 9-10:1 i see in some dynos).
:smokes:
 
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CodingParadox

New member
Yeah, yeah, I'm on the info waiting list for the SMT7 myself. :)

Yeah, I'm even a bit uncomfortable about hitting these high duty cycles at even this low psi... 100% duty cycles are terrible for injector life. And, as you said, I'd rather not have one go out on me on a high power pull and blow the hell out of a cylinder. :)
 
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Weasy2k

New member
CodingParadox":3jj0mae9 said:
Yeah, yeah, I'm on the info waiting list for the SMT7 myself. :)

Yeah, I'm even a bit uncomfortable about hitting these high duty cycles at even this low psi... 100% duty cycles are terrible for injector life. And, as you said, I'd rather not have one go out on me on a high power pull and blow the hell out of a cylinder. :)
Click to expand...

Yep im still waiting myself :( damnit....he said a couple weeks last week so that means 1 more week... :roll: I will wire it up the day i get it....time to order sensors in the meantime to prepair for the MR2 wire up...
 
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ChrisD

New member
AH HA!

I knew it. I have the same monitor that I just hooked up to my car, however I haven't had a chance to drive the car since hooking it up. Anyways, this confirms my findings and suspicions. I 100% expect to see the same thing on my car, with a CT20b running 12psi...I ran 14psi a few times, once at the track.

Good summary, spot on. I can't wait to do some tuning, get those duty cycles down to a safer level. Of course I'll correct the timing maps since they will be affected.

So anyways, this confirms my thread on celicatech: http://www.celicatech.com/forums/showthread.php?t=1892

And mathematically proves that the BSFC is ~0.60 as I expected, not the 0.52-0.54 that RickyB states here: http://www.mr2oc.com/showthread.php?t=8 ... light=BSFC

RickyB could have been diong his test with race gas or something like that, which would be more reasonable. Either that, or he was using a freak motor.

Regardless, the math doesn't lie. I won't try to argue this over there (mr2oc) again though, my ideas were very quickly shot down last time.

Good info, thanks!

Chris
 
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Mafix

New member
where sis you guys get those duty cycle moniters? i'm interested in getting one for myself.
 
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Zeus

New member
unless you run 10's / build motors / install tune ems' for a living its very difficult to be taken seriously on that board

dont worry chris we all have faith :)
 
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Weasy2k

New member
RedCelicaTRD":m4fp9dms said:
Zeus":m4fp9dms said:
unless you run 10's / build motors / install tune ems' for a living its very difficult to be taken seriously on that board
Click to expand...

No joke. Most of the MR2 owners are a bunch of sheep.
Click to expand...


Keep MOST in mind not all :)
But i agree on the whole
Big boost big turbo thing...thats why im going smaller turbo with high compression :smokes:
 
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