IHADAV8.com - Turbo Buick Tech, and Nonsense

Tech Area => General Buick Tech => Topic started by: Shimy87 on May 26 2011, 11:43:42 AM

Title: Boost drop
Post by: Shimy87 on May 26 2011, 11:43:42 AM

Was out goofing around yesterday and have a question. Car is running good but with a WOT run from a light it produces 16lbs. of boost through 1st and second but drops to 13-14ish in 3rd?? NO knock and 800 is my lowest reading at 75mph. If I increase boost I start to get a little knock in 1st. Have my TT chip set at 135 for WOT fuel in all gears, timing is base chip setting.

Also it shifts at about 5500, is that a bit to high? If so is there any way to correct it without a trip to the tranny shop. Its a new rebuild on the tranny maybe 2500 miles ago. Other than the question about the shift point it works fine.

Thanks guys!!

Title: Boost drop
Post by: Steve Wood on May 26 2011, 05:40:37 PM

I would take a bit out of the top gear fueling

for a stock cam, that is too much rpm...probably gonna have to talk to the tranny shop, but, it may take a governor recal to get it down to about 5200 on the wot shifts

Title: Re: Boost drop
Post by: Shimy87 on May 27 2011, 10:15:16 AM

Thanks Steve,

I'll back off the fuel and try it, when it was at the baseline setting  of 128 I was getting a bit of knock so jumped it up to 140 and got no knock but was at 830 so I dropped it to 135 and still no knock and lowered to 800, played it safe and thought that was a good place to be?? Scared of the knock :confused;

On the shifts I was looking at the stock tack ( I know, not the best gauge :redfaced; ) I'll make a run watching the SM and see exactly where it shifts now that I know 5200 is my mark.

Title: Boost drop
Post by: Steve Wood on May 27 2011, 12:59:35 PM

yeah...that should be accurate.

Stock they shifted 4900-5100 generally which is fine.  The factory turbo was out of breath by then.  A bigger turbo will continue to make power a bit higher up.