Ok, here's the plan for my car in the upcoming months. I'm definitely going up to 9-9.5 pounds of boost and adding water/meth injection. My goal is to have 380-390 rwhp on a very conservative tune. Because I've seen a lot of guys on the Thundercoupe and Supercoupe forums making 30-40 rwhp less than this with the same setup as me, I've decided to go a step further to ensure I meet my goals.
While cams would probably provide a nice gain, I've ruled them out because I don't want any loss in fuel mileage, and I want to keep the car as subtle as possible. This leads me to heads.
Choice A.) Buy a set of PI heads and send the blower off to Steigemeier for a port and polish (including port-matching the runners to PI head specs). This would up the compression to a level that I don't feel particularly comfortable with, although my tuner is assuring me that it would be perfectly fine with the use of the methanol injection, and that I'd easily reach my goal this way.
Choice B.) Port my NPI heads. I'd also at least upgrade to PI valves, or maybe something else if someone knowledgeable about the subject thinks I'd benefit from a larger valve. It would be optimal if the ported NPI head flowed the same or slightly better than a stock PI head; that way, I wouldn't have the higher compression problem that I'd have with the PI heads.
Both options cost roughly the same, so I'm planning on going with whichever one will get me to (or close to) my goals all-the-while being as safe as possible.
Nick at MHS, if you see this, I'd love for you to chime in with your opinions. If I go with Option B, I'll almost definitely send them to you. I'd like to see the flow numbers on your NPI heads, as well as what kind of gains you think I'd see with my setup. I'd also like to know if you think it would be worth it to upgrade to larger valves.
What says Stangnet?
While cams would probably provide a nice gain, I've ruled them out because I don't want any loss in fuel mileage, and I want to keep the car as subtle as possible. This leads me to heads.
Choice A.) Buy a set of PI heads and send the blower off to Steigemeier for a port and polish (including port-matching the runners to PI head specs). This would up the compression to a level that I don't feel particularly comfortable with, although my tuner is assuring me that it would be perfectly fine with the use of the methanol injection, and that I'd easily reach my goal this way.
Choice B.) Port my NPI heads. I'd also at least upgrade to PI valves, or maybe something else if someone knowledgeable about the subject thinks I'd benefit from a larger valve. It would be optimal if the ported NPI head flowed the same or slightly better than a stock PI head; that way, I wouldn't have the higher compression problem that I'd have with the PI heads.
Both options cost roughly the same, so I'm planning on going with whichever one will get me to (or close to) my goals all-the-while being as safe as possible.
Nick at MHS, if you see this, I'd love for you to chime in with your opinions. If I go with Option B, I'll almost definitely send them to you. I'd like to see the flow numbers on your NPI heads, as well as what kind of gains you think I'd see with my setup. I'd also like to know if you think it would be worth it to upgrade to larger valves.
What says Stangnet?
do not swap to pi heads when your goin FI. you DO NOT want a high compression motor with any type of FI. also there not many options for aftermarket cams when you do the swap. PnP your npi heads (checkout 98cobras stuff very nice) go with a blower cam. (cushmen motorsports has some nice ones, along with crower.) ive seen charts that if done right that ported npi heads flow way better then pi heads and could flow as much as 4v heads.
