Don't Shoot the Messanger

[gnxjester]

Okay, so here's the deal, i'm the technician not the tuner but still need help either way.
Big stroker engine, L92 heads, no knock sensors installed, no O2 sensors installed, no MAF installed (speed density), 90mm throttle body, Venom 48# injectors, equal length shorty SLP headers, no-cat straight pipe with mufflers, always tuned for open-loop.
The problem is when at WOT at the dragstrip or on the dyno, cylair mass goes up, car stumbles and falls flat on its face, only for a matter of .050 seconds, and then back to WOT. WTF We have filmed the throttle body on the chassis dyno in shop and it is not closing, the injectors are not loosing injector pulse, tested by pulling tach signal from all 8 on the dyno. This almost happens every time at the 1000' or around 5200rpm in 3rd gear. The other day at the strip we pulled 2degrees out and ran 10.80's, no stumble but car feels weak.
Next problem, Cold Fusion Fogger System. Also at the track, we tuned for the spray, pulling timing out, etc... and the car didn't make it 80' before falling worse.
Not that I want to let out all the secrets, but we have exceeded the max Torque Managment numbers. Don't get jumpy i'm talking at the flywheel numbers.
Is there any way that the computer can be tuned so that it only does what we want and not adjust itself. I've been reading other posts about stumbles and most of them are more Daily Drivers then this steetABLE,tagged and insured racecar.
Any and All help would be greatly appreciated.

I forgot 2004 Vette, 461ci, automatic w/ 2800stall

[WS6FirebirdTA00]

Need tunes and logs posted, sounds to me like a timing and fueling issue if it is nothing mechanical.

[gnxjester]

Attachment 14883

Attachment 14884

starts around frames 170/172 through 180+
there is a drop of injector pulse only for a brief second
the boss has been tuning for ten plus years and never had this happen before

[gnxjester]

air fuel stays at 12.8 except when hiccups happen

[WS6FirebirdTA00]

Yeah, it is cutting fuel. Prob need to adjust some DTC parameters and what not, I have not had a chance to go through the tune, or it may be an OS error (seen it before) what version of HPT do you have?

[69lt1bird]

Are you sure you posted the right tune? This thing has small injectors, the strangest timing map I have ever seen and a scary looking VE table for a car that is supposed to have the power you say it has. What gives?

[gnxjester]

9pm wednesday night, loaded up and heading to Memphis. Car runs smoother, no glitches or hiccups. Thanx for all your help. Post et, mph, 60' when we return. Thanx again.

[WS6FirebirdTA00]

Hopefully some low 9's

[Ben Diss]

Are you sure you posted the right tune? This thing has small injectors, the strangest timing map I have ever seen and a scary looking VE table for a car that is supposed to have the power you say it has. What gives?

I agree. That tune is whacked. If that's what's running the car it's no wonder its doing what it's doing.