Couple of questions on rebuild

[Kyle97-clipse]

Okay so I finally decided I THINK what I'm going to do. I'm going to slowly start and rebulid the spare motor I have, heres what I've come up with so far please add suggestions

1. get machine work done on the block
2. Weisco 8:8:1 forged pistons
3. Eagle rods
4. new water pump and oil pump
5. APR head studs
6. possibly cams may run stock for now
7. possibly adjustable cam gears
8. as for the head port and polish???? Ive heard not to with turbo
9. and all gaskets and little stuff
10. some sort of turbo, biger fuel injectors I have 300 cc will they work?
11. FCD

 

[concept4g63]

Okay. The cam gears are good to mess with on a dyno. Then for your porting and polishing its good for the head and turbo, remember do the exhaust manifold to match the turbo. Get a downpipe and exhaust piping as well so the car can breath better. 300cc are tinnyy i dont thinl dsms have them. Stock is 450 for turbo ones. And get a front mount or a good side mount

 

[zatomz]

300 cc injectors will not work period. Are those non turbo injectors stock size? I could have sworn they were bigger. What block are you building all of this on by the way?
I would not worry about cam gears at this point in the build unless you just want to pay for looks. You should be more concerned with fuel, rebuild parts, airflow, and tuning modifications.
What's your budget/goal?

 

[Kyle97-clipse]

stock non turbo injector size is 190cc I beleive, I'm rebuilding on a stock block but I figure it should be good enough for my goals. The foal is about 300whp and somewhere in the 13's for a quarter mile. As for the budget this motor will be built over the course of a year its an extra motor I have so the car won't be down

 

[zatomz]

Ok I am assuming your talking about a 420 block then, right? either way if your running a smaller turbo say, 14b or 16g, I would go with some 550's to leave your self some room to tune your fuel settings. Obviously, your also going to need something to tune with like dsmlink and a wideband, you can add those to the list.

 

[Kyle97-clipse]

yes 420a block and dsmlink won't work with this being the 420a, however I will need to add the wideband to my list

 

[zatomz]

So I take it you'll be looking into getting some sort of piggy back system? I would recommend starting a build sheet and following some of the path of other 420a turbo builds and just altering to fit your needs and wants from there.

 

[Kyle97-clipse]

I'm having trouble deciding what compression piston to go with I like the 8:8:1 because the will prevent knock, but I feel like the car will be sluggish when out of boost, with the 10:5:1 I just feel like that will be to high for turbo I mean stock is only 9:6:1

 

[Locke]

Plenty of guys are running 10.5 on boost, you just have to make sure your tune is in check.

 

[zatomz]

I do not know the stock compression for the 420a motor but I dont see where you are getting that lower compression will prevent knock. The way to prevent knock is through tuning and making sure you have a system with no boost leaks and proper fuel delivery. A higher compression piston is not going to make a major noticeable difference on your setup being as your not talking about going with a high horsepower setup. If your running a higher amount of boost then a higher compression piston would help a little with combusting added airflow. The size difference in pistons is not going to help dramatically until you get to that point. The major differences would be the in the rod length and stroke of the motor.

**EDIT** Question for someone who knows: How, or can, you go from a higher compression piston to a lower compression piston? Wouldn't a lower compression piston have a smaller diameter or would it be in the depth of the surface area itself? Wouldn't the depth of a stock 9.6:1 piston have less surface depth than an aftermarket (forged) 8.8:1 piston?