420A Which pistons for my setup?

[lilbayz311]

I bought the Hahn stage 2 turbo kit with FMIC about 4 months ago. About a month later my engine stuck a ring and I lost all compression. Since then I have spent literally 6k in parts alone I just haven't had time to sit down and write all my mods down on this website.

Well anywayz I purchased Wiseco 8:8:1forged pistons to replace my stock ones. We got my engine all bak together with pretty much ALL new parts and started it. After we fixed all the bugs such as vacuum leaks from my new intake manifold and figured out both the MSD ignition system and SAFC Neo, it ran like a champ for 2 dayz.

Next thing we know the car kills going 60mph. The cause: the power steering belt came off for some ### reason, it somehow got threw the alternator belt which was still in perfect shape and interfered with my timing belt big time. The next day we took a better look at it and discovered that what was left from the powersteering belt was wrapped tightly around the crankshaft. I know we were pretty dumb not to have the timing belt cover on but it had gotten broken when we pulled the motor and when it was finally to the point to put it back together we didn't want to wait another week for a plastic cover to ship and we just spaced it.

So anywayz we replaced all my new 16 bent stainless valves with new stainless ones and put it back together and started it. It made a loud knocking noise and rattled. Last night we pulled the head and oil pan once again and checked all the pistons. every skirt on every piston was collapsed. :'( now I am broke and need new pistons once again.

My main friend that is helpin me with the project for free labor mentioned maybe we should just go with the 10:5:1 compression pistons this time, since my drag race stage 3 Crower cams run better with higher compression. I want to do this due to the power that could be gained but would anybody recommend higher compression on a turboed car? I am planning on running 15 psi daily boost. And my last question, which brand pistons should i go with? links to any websites with standard size forged pistons with fast shipping would be ideal.

Thanx for input

 

[dr1665]

First of all, why are you running standard bore pistons? Did you guys mic out the bores and find them to be within spec and perfectly concentric all the way down? Second, Crower 3s are a bad choice for a turbo application. They have too much overlap (as they are designed for naturally aspirated applications) and your turbo will simply boost right through the head with them. You're better off with stockers. You are, very seriously, going to be losing power with these cams. They are positively horrible for a boosted 2GNT. Consider this "private forum" information which I can't link you to, but want to be sure to share with you, given your investment in this project.

Third, I would strongly advise you stick with the 8.8:1CR shelf piston from the likes of JE. Venolia can also build you any compression piston you want. Expect to pay only slightly more for custom pistons. You're looking at $450-$500 any way you cut it for pistons. You do not have the tuning capabilities to run high compression turbo on your engine. Which brings me to my next point.

Your tuning set up is nearly useless to you at this point. Delicately remove your SAFC, put it neatly back in the box, and sell that piece of shit on eBay. All an AFC can do for your MAP-based car is lean out the fuel mixture, mostly around idle. You can not add fuel at all. When the SAFC is used in conjunction with a MAF-based system, such as the factory turbocharged DSMs, it is able to alter that signal in a way which gets the ECU adding fuel. Doesn't work the same for our cars. Sorry. The good news is, a near stand alone with strong 2GNT community support is the Megasquirt and you can have one controlling your fuel beyond what any SAFC could do on any car for right about $450.

If you're coming up short on funds to get your car running, I would highly recommend selling that pointless SAFC, the Crowers, and what I suspect is a proven worthless OBX or Venom intake manifold. Given the demand in the market for the Neo, the practically unused condition of the Crowers, and the shininess of the manifold, you could easily bring in a grand on eBay with them. That gets you a proven tuning system with a wealth of community support (visit 2gnt.com's performance engine forum), the new pistons you need, maybe even the right cams (Crower 2-Turbo grinds), and the best manifold available for our engines until Paul (Velocita) brings his design to market later this spring (the lightly massaged stock unit).

Good luck to you. Let me know if you want me to put you in touch with an experienced boosted 2GNTer in the SLC area who might be able to offer advice first hand.

Latz

 

[Blitzeclips]

Wow, man. That sucks. Some little mistake of not putting that cover on cost you pretty much the motor and drivetrain. I am sorry.

If I may add to Brian's great post on why 10:5:1 would be a bad choice if you plan on going turbo... Your motor will become much more prone to knock. Once you increase displacement you create more load on the motor as it functions. Theres an increase in the stroke within your cylinders, and under boost this can create serious damage. This is why most people choose lower compression for turbo applications. Most guys around here with forged internals, and a turbo, opt with 8:8:1 or 8:6:1. For reliability purposes, and to allow more boost.

 

[4UH8ERS]

Your tuning set up is nearly useless to you at this point. Delicately remove your SAFC, put it neatly back in the box, and sell that piece of shit on eBay.

I always feel like saying something like that, but i just can't do it. I would feel bad.

and the best manifold available for our engines until Paul (Velocita) brings his design to market later this spring (the lightly massaged stock unit).
Latz

Paul, I told you 6 months ago i wanted one. Hurry up now .


Please do stick with 8.8:1. If you cant seem to comprehend Megasquirt then you can always spend twice the $ and get a portfueler with the software for your home pc, Which BTW cant do 1/10th of what MSNS can provide with the right tools, but is the second best fuel management out there for our cars.