Where is the "sweet spot" for a TA-49....

[Lee_Burough]

I've heard people report a range where a turbo will be most efficient. If My memory is correct, the Ta-49 (Garrett housing) performs best (the sweet spot) between 23 and 26-27 PSI....Right?

TIA

 

[Geoff87]

I have mine set at 25#, both on the street (18 deg timing/alky) and at the track (26 deg/C-16).

 

[XLR8]

My TE-44 won't blow any more air than 24# up here, but it seems to like 24#.

 

[Lee_Burough]

Thanks for the help. My car still had the original fuel pump when I planned to shoot for 22 PSI with a TT chip designed for that goal. I got nervous about that old pump, so, I changed it out last week (or, better said, my mechanic did ).

I did get the boost up to 20 PSI with the old pump and stock injectors, but now, I'm not limited by the stock fuel pump. (the car is just starting to 'wake up' at the 20 PSI level). As soon as I get the larger puck in there, I'll be able to go over 20 PSI (somebody had ported the exhaust housing, and the stock puck doesn't seal correctly).

Eric, at turbo tweak, had programmed the chip for 91 octane and 22 PSI and progressive Alchy, so I should be able to get the boost up to 23-24 PSI and change timing if I need to. I'm rewiring the audible knock detector today to enable early warning if I should get into knock retard in the process. I'll use Turbo-Link too....

I'll stop on the conservative side of the sweet spot, so that when I'm on the road at lower elevation, it won't be necessary to change the setup because of overboosting (I get one to two PSI more boost while driving through Denver than when at home, because of the altitude difference -1,000 to 1500 feet lower in elevation, and plan trips to near sea level -4500 miles since May this year).

Thanks again,

 

[Pronto]

I would be concerned about stock injectors. New pump is good. Do you have a hotwire kit too? Dont' want to go lean.

 

[Lee_Burough]

I would be concerned about stock injectors. New pump is good. Do you have a hotwire kit too? Dont' want to go lean.

I'm not lean yet Pronto. Thanks for the heads up, I've been keeping an eye on it....Not close yet. With 18PSI I still had o-2's in the mid-to-high 800's.....No KR today @ 19PSI. I have a set of 50's on the work bench.

No hotwire. With a TTA, its not as big a deal because the fuel pump wire is supposed to be a heavier, stranded copper. I have a hotwire kit (for a TR) on the bench too, but prolly won't install it. The new pump (W340) flows more fuel at less voltage than the W307.... Its coasting at my WOT hp. When I get to the sweet spot for the turbo (3 or 4 PSI more), I'm done.

leeb

 

[Pronto]

My friend Big Al is running 36s in his TTA with excellent results. Very low 12s with stock turbo and alkycontrol threw the stock exhaust. He's running a race chip with the alky. Seems to work out ok.