I currently have a 87/88 j-spec turbo motor that I am going to use for a datusn 510 rotary project I will be starting later this year. I was reading somewhere that the 89-91 Intake Manifolds flowed more air, hence producing more horsepower. Can anyone tell me if this is true and if it would be worth my time and money to change the intake manifold to the later style?

thanks
John

 

The 89-91 intakes manifolds do flow more air...slightly. The runners are ever so slightly larger and a very small amount longer. You are not going to get a noticable increase in power from just doing a swap. However if you already have the 89-91 style then use it. The real gain from 88 to 89 was in the turbo itself. It flowed better through the exhaust and the boost was electronically controlled and higher. The hp gain from the manifold was minimal.

 

thanks for the reply, I will stick with the 87-88 manifold that came with my motor.