A Grand National engine is a 3.8 litre V6 and uses a 1800 stall torque converter with the A/R of .63 on the exhaust housing. Its spools up damn near quick with factory setup. If you were to brake torque a stock GN with the 1800 stall coverter you can make6-10 boost just standing on foot brake. With the 4.0 motor it will be easier to spool up. If you are only lookig to make 6-8 psi you should be just fine. What stall is your converter? if its just around 1000 rpm stall then it might be a little slow to spool up just off the line but when you're rolling around 20 mph or so it will spool up ok. Also use a good size wastegate to control the boost down to 6-7 pounds.

HTH
Prasad

 

Thanks for the info. My jeep is a 5 speed so no converter stall issue to worry about. Any insight on my plotted line on the compressor map? (About 3 post back)

 

I can't see anything, can you sent me a link to wikedv6@hotmail.com.

Thanks
Prasad