Injectors only going to 78% DC

[HoP]

Attached is a log and tune for this LS7.

Punisher Cam from WCC
Brodix heads custom port work 274cc
LSXR 102mm Intake w/ NW 102mm TB
2x3 Kooks long tubes with corsa cat back
Hurricane Intake.

I'm having a few problems.

1) The injector DC is maxing at 78% when the maf hits 67.7 lbs /min

2) every since the addition of the 102mm tb the car has a hanging idle when vss speed is 1mph or greater.


So since it is apparent that I'm pegging the maf at 67.7 / 512 gs at 5,200 rpm's I'm going to assume this is why my injector dc only goes to 78? So this means I have to run this car SD now?

Thanks for any help guys

[HoP]

Here is the log and tune

[Ben Charles]

So since it is apparent that I'm pegging the maf at 67.7 / 512 gs at 5,200 rpm's I'm going to assume this is why my injector dc only goes to 78? So this means I have to run this car SD now?

No you can scale the tune and keep the MAF.

every since the addition of the 102mm tb the car has a hanging idle when vss speed is 1mph or greater.

Thats b/c your getting to much air

[HoP]

I though that once you pegged 512 grams per second which is 67.7 it was time to go bigger. Scaling allowed for more hertz, your still governed by lbs/min

I think I had it back words, thanks for the help Ben.

[Sébast19X]

I though that once you pegged 512 grams per second which is 67.7 it was time to go bigger. Scaling allowed for more hertz, your still governed by lbs/min

I think I had it back words, thanks for the help Ben.

What kind of injectors ?
Something seems wrong ,It'S mostly rare to get 512 g/sec MAF and 1.51g/cyl for a N/A car even with you'Re setup.
Look AFR and fuel pressure and input the correct data for injectors. I know it's a good cam, but you seems to run with a lot of timing ...

Hope this help.
Seb

[Ben Charles]

I can see a modded Ls7 breaking the 512 limit no problem (especially from his mod list)

Scaling the tune will lower the G/sec, if you hitting a HZ limit then its time for a larger inlet.

[Sébast19X]

I can see a modded Ls7 breaking the 512 limit no problem (especially from his mod list)

Scaling the tune will lower the G/sec, if you hitting a HZ limit then its time for a larger inlet.

Personally I have tuned a couple of cammed and ported LS7, With proper injectors data. They cannot reach 512 g/sec N/A.His mod list are not too impressive. Just something to get around 600- 625 rwhp.

I know about scaling...

Seb

[Ben Charles]

LOL, well from my personal experience I usually hit the 512 MAF limit with mid 12 AFR around 500-550rwhp.

Look at the LOG, he hits the limit around 5,000 RPMs again which I could see VERY POSSIBLE, also notice the injector Msec at the point he hits the limit and after.

To each there own.

[Sébast19X]

LOL, well from my personal experience I usually hit the 512 MAF limit with mid 12 AFR around 500-550rwhp.

Look at the LOG, he hits the limit around 5,000 RPMs again which I could see VERY POSSIBLE, also notice the injector Msec at the point he hits the limit and after.

To each there own.

Pretty funny stuff I found from RWTD in corvette forum:


Just for comparison, one of my '08 Z customers with a Halltech KB system was right at 9300-9400 Hz and 462.21 g/sec at 563.3 rwhp Actual, and yet another '08 Z customer with the Callaway CAI was right at 9400-9500 Hz and right at the 512 g/sec limit with 608.20 rwhp Actual. These were perfectly tuned MAF transfers, FYI.

I don't tell you that is impossible to peg , but at 4800- 5000 RPM, a setup like described above, didn't flow as much airflow to hit the 512 g/sec MAF.

[Ben Charles]

Sébast19X what were the other mods to those Ls7's besides a CAI? stock LS7's make around 450Rwhp in factory form.

Just looked a Will Cooksey Z06 I did with CAI that shows 492g/sec at 9400Hz and it was around 12.6 AFR. Didn't have the dyno, but guessing around 475rwhp. Looked for the log, but everything 6 months and older gets deleted.

[Sébast19X]

Sébast19X what were the other mods to those Ls7's besides a CAI? stock LS7's make around 450Rwhp in factory form.

Just looked a Will Cooksey Z06 I did with CAI that shows 492g/sec at 9400Hz and it was around 12.6 AFR. Didn't have the dyno, but guessing around 475rwhp. Looked for the log, but everything 6 months and older gets deleted.

I could not find this info.
My LS7 car is 600 rwhp, trap 140 mp/h N/A and I have room in g/sec (far from 512 g/sec) with the vararam SC1R and I have stock LS7 42 pounders injectors at 90% DC. All calibration MAF transfer function was done with a NGK AFX wideband.

Seb

[Ben Charles]

Seb lets just agree to disagree.

BTW Love the vette pic in your avatar

[Sébast19X]

Seb lets just agree to disagree.

BTW Love the vette pic in your avatar

This vette are mine. 2008 C6 Z06 9.92 @ 140 mp/h

[Sébast19X]

HOP, what injectorsis this ?

[DSteck]

There's no way that thing should peg the airflow limit. You really need wideband data in that scan.

Do you really have LS9 injectors in it? Because that's the data entered for the injectors. That airflow information for idle control is pretty bad. I'd suspect this car has idle quirks.

You can apply the custom OS to get double the MAF airflow.

[LSxpwrdZ]

From experience as well that setup should be on edge with the 512g/sec limit. However the factory injectors are capable of supplying enough fuel for that limit as well...

Can't compare dyno numbers because my dyno dynamics is alot lower than a dynojet but heads cam headers and big cam C6Z I did runs 141mph and made 526 on mine and pulled in ~505g/sec also on stock injectors running ~90% duty.

[Sébast19X]

From experience as well that setup should be on edge with the 512g/sec limit. However the factory injectors are capable of supplying enough fuel for that limit as well...

Can't compare dyno numbers because my dyno dynamics is alot lower than a dynojet but heads cam headers and big cam C6Z I did runs 141mph and made 526 on mine and pulled in ~505g/sec also on stock injectors running ~90% duty.

James, you are perfectly right. dyno is just dyno and as soon the dynoload as come into a play, the number are off each others. I know that guys who running 141 mp/h , d'ont ask my how !!!! lollll

But in the OP the log of Hop, show that he reach the 512 g/sec limit as low as 4800 RPM. That N/A setup mentioned above could not see 512 g/sec at low rpm like that. IMO

Anyway good job on that black C6 Z06

Seb

[edmundu]

The MAF transfer curve just doesn't look right? IS it a smaller metering area, because I cannot see how it is hitting 512g reported on a NA LS7, and not even at peak power rpm range at that!

[LSxpwrdZ]

James, you are perfectly right. dyno is just dyno and as soon the dynoload as come into a play, the number are off each others. I know that guys who running 141 mp/h , d'ont ask my how !!!! lollll

But in the OP the log of Hop, show that he reach the 512 g/sec limit as low as 4800 RPM. That N/A setup mentioned above could not see 512 g/sec at low rpm like that. IMO

Anyway good job on that black C6 Z06

Seb

Thanks brother, I think you've got yourself a pretty quick running car also!

The problem I see with people maxing out the airflow on a setup is usually if they have the injector calibration data wrong. Having the wrong offsets, flow rate etc will directly scew the MAF calibration. I'm not on my tuning laptop at the moment to check out the injector data but what injectors are you running?

[Sébast19X]

Thanks brother, I think you've got yourself a pretty quick running car also!

The problem I see with people maxing out the airflow on a setup is usually if they have the injector calibration data wrong. Having the wrong offsets, flow rate etc will directly scew the MAF calibration. I'm not on my tuning laptop at the moment to check out the injector data but what injectors are you running?

The LS7 stock one.