What is the 2016 Zo6 maximum boost on a stock cam/fuel system and .....

[mowton]

.....when will the fuel system start to drop off. SC757 package and 15% overdrive is pushing 17 lbs of boost (1.7+ g/cyl) and HP pump is dropping to <1000 psi almost instantly on a pull....

Ed M

[Higgs Boson]

low 700's hp

what is your ipw?

what is your SOI at WOT?

what are you commanding at WOT for rail pressure?

stock cam or what are the valve events?

[mowton]

[QUOTE=Higgs Boson;501188]low 700's hp

what is your ipw? goes to 11+ms before we get out at around 4800 rpm (scared :-))

what is your SOI at WOT? 376 (1.36/6400) even though our cylinder charge is hitting 1.8 g/cyl...could adjust the axis

what are you commanding at WOT for rail pressure? we started with the stock 2901 psi and even tried setting it to like 4000 psi but had no effect on rail pressure

stock cam or what are the valve events? Stock Cam but again has the Callaway 2.3 blower

Thanks Higgs, here is the info above....

Ed M

[Higgs Boson]

IPW over 6ms means you are out of fuel and draining the rails/puddling fuel, washing down walls, etc. That sounds alarmist on purpose. My preference is to keep IPW at a stock like 4.8 - 5ms. I also dont like to start injection before about 355 or somewhere on the downstroke of the piston.

you need meth or a supplemental port injection system and leave the MAF curve (assuming it is correct) and take fuel out of PE table (yes you have to hack the PE when adding an outside fuel source).

what is your spark lead/knock retard pid doing?

[mowton]

I think we may have caught the dogs tail (been chasing it for 3 days now...)...

Our initial issue began when our power numbers on the customers initial Callaway install were low which was confirmed by Callaway (boost was a bit off as well)...this lead the owner to want a set of headers which of course bled down about 2 more lbs of boost...to compensate we installed a 15% overdrive pulley to recover the lost boost. All during this adventure, we were also fight belt slip which further exacerbated the low power and drove us to install mods to recapture the lost boost. And if that wasn't enough, all during the same adventure, in parallel, the Bleed valve stop screw, which wasn't loctitied (not sure if that's a real word :-)) correctly began working its way loose as well until finally, concurrent with the final belt change, we found kicking aroung the supercharger....it had worked its way completely out.

So install a TVS 2300 blower, correct the belt problem, fix the stop screw so the bleeder closes all the way and add a 15% overdrive lower and develop 16 lbs of boost....which from what we can see exceeds the stock cam/fuel system specifications. This is a case of 3 wrongs making a tuning disaster.....

Proposed fix is remove the 15% pulley and replace with a 5% one and then adjust bleeder if we are still a bit too high. I agree with you Higgs that we want to stay withing the 5 ms IPW. Thank you for the look and input.

Ed M

[jc052685]

Post the tune file please

[GHuggins]

ED, I glanced at your tune - I think some things you might want to try to change is your soi, split pulse settings and some of your main and hpfp settings - You can advance your soi in the higher loads lower rpms more than your running by 30 or so degrees to help with that initial fueling, you can also set your split to 5 degrees instead of 10, then change some of the DC settings for your main pump and some of the hp settings for it... Probably still won't fix the problem, but should help... I like cams with more lift on 700+ setups for the hpfp's - otherwise they take a lot of compromising...

[Higgs Boson]

ED, I glanced at your tune - I think some things you might want to try to change is your soi, split pulse settings and some of your main and hpfp settings - You can advance your soi in the higher loads lower rpms more than your running by 30 or so degrees to help with that initial fueling, you can also set your split to 5 degrees instead of 10, then change some of the DC settings for your main pump and some of the hp settings for it... Probably still won't fix the problem, but should help... I like cams with more lift on 700+ setups for the hpfp's - otherwise they take a lot of compromising...

in the settings, split pulse is only enabled during cranking, are you finding changing split pulse eoi tables is changing anything?

[GHuggins]

Sorry Higgs - your right - what I meant to say was change pulse gap min to 5 instead of it's 10 degrees...

[mowton]

I didn't forget about the thread, will get back to this setup tomorrow with the set screw fixed and the 5% overdrive as well as trying the changes from above.....

Ed M

[mowton]

OK, so we finished up the tune on this project. Appears that 16/17 pounds of boost exceeds the fuel systems capability by a lot. We replace the 15% overdrive with a 5% and reduced the boost to around 14sh and now in the mid pull we get about a 800 psi drop on the HPFP but increased the maximum to 3099 to help compensate and our IPW don't exceed 6 ms during that drop. All other places the IPW is 5 ms or less.

Final numbers were good at 622.7 rwhp @5400 and 729 ft lb @3600 at 14.4 pounds of boost. Next time would definitely go with an increased HPFP cam or keep boost down to 13 pounds.

Thank you Higgs and Greg for the help....

Ed M