Motor Build Questions

[240sxOwner]

Ok...i am starting up the process of building my motor to turbo it...i am leaning toward BRC Pistons 9.0:1 comp, stock bore....I want to know you guys feelings on the coatings for the pistons. It significantly lowers bottom end temp...but is it worth it for an extra 100/ set? I will also be doing the timing chain since i will have the motor apart, as well as putting in a metal head gasket. What is a good quality head gasket, and where can i get it? Is there anything else that i should replace whil i have it open?

What should i use to run fuel...I will be driving daily at about 7-10 psi....should i get the SAFC II, E-manage...do i even need anything at this low of boost (im sure i do).

When removing the head....what do i use to get the two middle bolts out? It is between a 1/2 drive and a 3/8 drive?

Thanks for the help guys...i really appreciate it

[Ubernoober]

Stick with the Fel-Pro "print-o-seal" head gaasket that comes with the engine kit. Unless you are blowing over 15 PSI I just cannot justify the cost. I would be willing to bet the Fel-Pro will seal the water passages better also.Fuel: upgraded pump, better flowing filter, larger injectors for 7-10.Control: Your choice. JWT, SAFC, E-manage. Just buy the one with the options that you want. If you don't plan to screw around, just get a JWT. Its fire and forget. Total control would come from a standalone, a-la the AEM.

[240sxOwner]

I am just looking to get this thing running like 250 daily for now...then when i get more money i will upgrade to a standalone and all of that. I have the walbro fuel pump and a 300zx filter already. I think i am going to go with the safc II because i like to be able to see what my engine is doing. The only thing is that it can't control timing...but is this really necessary? Does timing need to be adjusted while driving? What injectors should i use?

Thanks

[MarkEmark]

I am just looking to get this thing running like 250 daily for now...then when i get more money i will upgrade to a standalone and all of that. I have the walbro fuel pump and a 300zx filter already. I think i am going to go with the safc II because i like to be able to see what my engine is doing. The only thing is that it can't control timing...but is this really necessary? Does timing need to be adjusted while driving? What injectors should i use?

Thanks

If you're only looking for 7-10 psi, why bother re-building the engine? The KA can handle 7-10 psi daily NO problems so long as it's tuned right. I think you have the right idea though, because like all of us, once you get 7 psi, you'll want 8 psi, then 9, then 10, then 11, then 12, all the way up to as much as you feel necessary. I thought I'd be satisfied with 9 psi, but here I am saving my money to rebuild the engine to run about 17 psi.

At 7 psi it's not *that* important to have a timing control system, but the timing still needs to be retarded from stock 20 deg btdc, especially when you near 10 psi. To control timing you could get a MSD BTM, which can adjusts timing per psi of boost...Most people suggest around 1/2 deg. retard per psi of boost...which would be 5 deg of timing retard at 10 psi, but this seems rather conservative...if you don't have the money you could always just adjust the timing at the distributor to around 16 deg btdc which should be plenty safe for around 7-10 psi...the only problem with this is that you'll lose off-boost driveability and lose quite a bit of power when not in boost...might have some low rpm stumble too...it's amazing what advancing 2 degrees did to my car...got rid of all low rpm hesitation (my timing is controlled by the JWT ECU, btw).

For 7-10 psi, 370 cc SR fuel injectors are adequate and they drop right in the fuel rail and can be had for cheap. 370 cc injectors "max out" at around 250 or so RWHP...which, depending on your turbo and tuning, can come as early as 8 psi....If you're running a smaller turbo like me (T3 super 60, .48 a/r turbine, .60 a/r compressor), even at 9 psi my max duty cycle for my 370 cc injectors is 87% so 10 psi could be run w/o maxing them out, but I'm not planning on running more boost until all of the fuel system is upgraded. All that you'll need to control the 370 cc injectors is the S-AFC II, but if you buy a JWT ECU to control the 370 cc fuel injectors, it will also take care of all your timing needs, and can be upgraded as your power grows for $100 per re-tune.

If you're rebuilding the engine with forged, lower compression internals, it will be able to handle quite a bit more than 7-10 psi of boost...and believe you me, you WILL want more boost. So you may as well start off with a fuel system that gives you plenty of room to grow...I suggest 550 cc fuel injectors or MSD 50 lb/hr fuel injectors, which are top-feed and will require a new, top feed fuel rail (~$100). If you're running more than 10 psi or so of boost you will most likely need a larger MAFS as well (Z32), so a popular fuel/timing management system is the JWT ECU tuned for 50 lb/hr fuel injectors and a Z32 MAFS, which will be able to handle well over 350 rwhp (I will be going with this system). The drawback is that JWT ECu's are very expensive unless you get them used, which usually you can, in which case they only cost $100 to upgrade to a completely different program.

However, you say you just want to get things running...so for now, 370 cc fuel injectors and a S-AFC II will be perfectly adequate for 7-10 psi...you can always upgrade later to 550 cc fuel injectors, a Z32 MAFS and the stock ECU if you're strapped for cash but don't want to go standalone or the JWT route, but you'll need something to control timing once you're running quite a bit of boost. Structure240sx is running the 550cc/min fuel injector + S-AFC II setup and is making impressive power.

Hope that helped.

Marc

[240sxOwner]

Yes that definately helps....so the only problem with what i have planned is that i will need 550cc injectors in the future if i want more power....I have seen the msd injectors...do they make a custom fuel rail or would i have to have one fabricated? I would like to run about 12 psi @ 300hp. Thanks for the help

[MarkEmark]

Yes that definately helps....so the only problem with what i have planned is that i will need 550cc injectors in the future if i want more power....I have seen the msd injectors...do they make a custom fuel rail or would i have to have one fabricated? I would like to run about 12 psi @ 300hp. Thanks for the help

Yes, for anything more than 250 whp, you're going to need to upgrade to larger injectors...you could run 440 cc fuel injectors (I think they come in this size) that drop right in the KA fuel rail if you're only looking for 300 whp, but having some room to increase boost/power is always a good idea.

There's three companies that make a fuel rail that fits the top feed MSD fuel injectors that I can think of off the top of my head:

http://boostdesigns.com/store/...id=98h ... x/fuel.htm