So Ive got this super nice 60-1 on my car now and good god is it fast. Its a big change from the stock HT-18. Going from almost no lag to low-moderate lag is a change, but now its like the car is a whole different beast ( and thats at only 10psi! ). Its like after 4000rpms, Satan himself came up and just smacked the car on the ***.



But to get back on topic, how much will porting my engine help spool? Ive got a T04S 60-1 undivided tangential with .70A/R cold and .96A/R hot. Im definitely going to port the intake but should I port the exhaust too? Ive heard about people doing it but never really seen any emphasis put on it.



Just curious about things I can do to get some of that quick spool back. Although Im more than happy to part with the instant spool for the gobs of power the car can have now.

 

depends on the port (how big you go) but my slightly laggy hybrid on a stock port was like stock on a ported engine

 

You must do the exhaust! Probably take off about 500rpms faster with a nice streetport.

 

look at it this way, the stock port was designed for the airflow requirements of the stock turbo. You have increased the size of the turbo, which in turn has increased the cubic feet per minute of flow output of the turbo (CFM). Now at 10 psi, both turbos could handle that with no problem, but you have increased the CFM into the motor, and given it a small area to get rid of the increased input. It would be like putting a fully ported motor on stock downpipe and exhaust, there will be a bottleneck. The recipe for power is getting as much air in...and back out as you can. A properly sized exhaust port will increase your boost response and lower the lag by allowing more air at the turbo. I know this is a general statement, but I do not have the mathmatical figures to give you scientifically proven facts at this point.



You did not specify if what manifold you are using either, a small runner will bottleneck as well.



I would look at Judge ITO's exhaust porting thread, he has some great tips and explanations about the importance of exhaust port porting. The thread is a sticky in the Rotary building and porting forum



Good Luck

 

HKS cast manifold.

 

Adam, i know the feeling, i have the same turbo. I plan to keep my motor stock now but will like to experiement with the rear turbine and go down like .82 or .76 to get a little smack action at lower rpm.



But the feeling of the .96 at top end is awesome, it will put a smile on your face when at the last second you car jumps forward over a car will less top end.



C