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Fast305 · 04-22-2008, 11:06 PM

Just want to show you'll how important a proper tune can be, especially when working with a OBDI vehicle running speed density. This is a TPI Vortec 305 built up some, but none the less, I picked up over 30 RWHP from fine tweaking on the dyno. I started out at 322 RWHP @ 4,700 from tuning without the dyno. My biggest power gain surprisingly was changing the WOT air/fuel ratio from the mid 12 down to 11.6:1. E10 does some weird things to the Air Fuel Ratio and engine wants. WOT TCC lockup was worth 9 HP, but I lost 8 ft/lbs in the process. Messing with the timing resulted in power loss, so I left it the way I had it.

04-22-2008, 11:06 PM	#1
Fast305 Registered User Join Date: Jul 2005 Location: Texas Posts: 3,839	Importance of a proper tune. Just want to show you'll how important a proper tune can be, especially when working with a OBDI vehicle running speed density. This is a TPI Vortec 305 built up some, but none the less, I picked up over 30 RWHP from fine tweaking on the dyno. I started out at 322 RWHP @ 4,700 from tuning without the dyno. My biggest power gain surprisingly was changing the WOT air/fuel ratio from the mid 12 down to 11.6:1. E10 does some weird things to the Air Fuel Ratio and engine wants. WOT TCC lockup was worth 9 HP, but I lost 8 ft/lbs in the process. Messing with the timing resulted in power loss, so I left it the way I had it. __________________ 1983 G20 Conversion Van, 383 TPI, 10.5:1 compression, Custom Reed Roller cam, Ported 906 Vortecs, Doug Thorley Tri-Y headers, dual 2 1/2" exhaust, 4L60E, 3.08 gears. 7427 PCM in MPFI Mode Last edited by Fast305; 04-22-2008 at 11:07 PM.