I just did a fan swap on the turbo today,already did a swap on the 90'740 with a b234f motor,it had all kinds of room for most any after market 16" cooling fan,however the turbo was a different story all together,the turbo has only 3.5 inches between the water pump bolts and the radiator core(due to the intercooler)this narrows down the type of fan you can fit in there and still have the recommended 1" of clearance and still have enough cfm to cool the radiator down,the fan I used is rated at 1600 cfm at 0" of static pressure(average static pressure is around 0.2" for most radiators)and at 0.2 it is rated at 1390 cfm,The 89 turbo didn't appear to have a aux fan relay as on the 90 740 b234f,it appears that the 89' uses only the radiator switch to turn on and off the stock pusher fan,I will wire in a relay so the a/c will keep the fan on all the time when turned on as I did on the 90'.If anyone else has done this conversion I would like to swap notes and if anyone knows what a stock fan draws for cfm at idle and full throttle that would be interesting because the electric fans really make a diference in HP and fuel economy.