Manifold Vacuum Patch - 2bar Enhanced OS Results

[10_SS]

Just wanted to throw this out there for someone like me that couldn't find much info about the "Manifold Vacuum Patch" and how it works or how it would affect fueling if you applied it AFTER you dialed in your 2bar Speed Density OS on a 2010 LS3 E38...

I had a stock FP and Whipple 9psi, Boost a Pump, bigger injectors. I drop considerable amount of fuel pressure at WOT, high RPM. So this caused rich low RPM WOT but OK/perfect higher RPM AFR's, this is because I had more fuel pressure down low than I did up high, and the stock 2bar OS Injector flow rate table doesn't reference fuel pressure in boost (or delta FP above 90-95kpa MAP).. running MAF there was no easy way to fix this... other than run SD mode that I didn't want to do.. SD still wouldnt fix the problem, it would only alleviate the problem, if pressure every changed, or dropped more It would throw AFR off...

So I applied the patch, and now can reference boost... but now with no other changes my "boost" AFR's are rich during WOT everywhere, as expected... I was about 10% rich above MAF 5500hz, and 95kpa in the VE tables.. so I simply removed 10% from all cells above 5500hz and 95kpa in the VE tables, smoothed the transition before and after those cells, and now I have rock solid and correct AFR down low and up high even with considerable loss of fuel pressure (~15psi loss from low to high RPM).

So I'm very happy! One datalog after applying the patch was all it took to fix the AFR problems I was having... and I thought I would have to redesign my entire fuel system to get rid of this problem... thanks HPT!

[10_SS]

OK... so I decided to play with the stock build in "Supercharger fitted" switch... instead of using the OS Patch "Manifold Vacuum Patch" to make the Injector Flow rate table reference boost.

I'm finding switching the Supercharger switch to "FITTED" appears to do the same thing as the "Manifold Patch", however I'm having better results using my bench simulator... meaning the injectors are not cutting out at high MAP readings (180kpa+), like they would with just the Manifold Patch applied. They still cut out at 1100rpm, but I have no TPS so that's prob why. With "Supercharger Fitted" enabled, I can go all the way to 255kpa MAP and injector PW still shows pulses on the injector pins and HPTuners... so now wondering if I should just switch that on in the real car tune... seems to be working fine even though I dont have TPS or other sensors... now worried the "Manifold Vacuum Patch" will actually carry these problems over, or manifest in some other way... Any guess as to which to use? I'll continue this over at the Bench Simulator thread... http://www.hptuners.com/forum/showth...U-really/page3

[griffincox]

Your bench simulator thread is great. I have always suspected IVT in the rich after flash 'whodunnit'. The simulator is great way to sleuth it out

I have an E67 (TBSS) with TVS1900 on LS2 (With GM/Bosch 3 Bar MAP). I have not enabled the Manifold Vacuum Patch or "Supercharger Fitted". I assume this means that above 103 kPa, the injector PW is no longer compensating for MAP?

Is this true? If so, any more insight into which may make more sense to use. I don't think I would ever fully integrate inter-cooler pump, other sensors, etc like a E67 on LSA. But certainly need to have injectors providing correct fuel...

Thanks for any insight you can provide.

[10_SS]

I ended up just applying all the patches and leaving Supercharger Fitted disabled, since i have an E38 LS3 I didnt want to chance it, find something else wrong. I did have to retune a bit after enabling the patches though. Not much.