I get a lot of PM's about certain parts etc that I don't have on the top of my head. I would like to have a thread that I can refer people to instead of looking for the information every time.
Heads: KMperformance.com (friends of mine) specialize in SOHC cylinder heads. The head porter Ed just does it for fun so its a 500-600 dollar type job unless you get special stuff done like oversize valves etc. He can get more flow from stock valves then I did out of my big custom valve self ported head. Thats because he owns his own flowbench and ports SOHC heads for fun (he has a 6g72 minivan that he works on as well as his 2nd turbo sohc build (dumped a 4 cylinder engine from a turbo dodge and threw in our lovely motor). We are talking 220-250 CFM from a sohc head on stock valves. Those are DOHC type flow numbers. Try an oversize valve head. Ed also makes sure to take care of port velocity so the car isn't a dog in the low rpms or out of boost on turbo sohcs.
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Cams: I have some custom cams that only cost 200 bucks (i paid 160 since he decided to give me a "student discount") from a local cam guy. Talk to machine shops and see if they suggest a local cam guy (if one exists).
Or,
Crower Cam profile # E-27829
Crower Cams & Equipment - Camshaft Specification Card
This cam is similar to the RPW (Austrailia) Stage 2 12v SOHC cam.
This cam has stockish lift but MUCH more duration. Has a nice lope.
It was originally used in Rick Lozier's 12 second direct port nitrous 12 valve SOHC Daytona (previously fastest SOHC in the world).
This cam will still give good low end power if you are worried about street manners. Rick Lozier's motor made 250+hp off spray with this cam.
Sunmind with the "real" RPW stage 2 billet cam (not regrind like the crower) made 220whp on a brand new motor that had not been fully broken in yet.
Enought to make even the mightiest DOHC n/a cars shy.
Order that cam card, not some crap unproven cam or a crower regrind that is from another data set. Unless you talk with them and get one made that is based off this one but more aggressive.
This cam will make power to 7k rpms even with a stock cylinder head.
OR
The super mild upgrade is find a 1992-1995 12v diamante in the junkyard. They are 10:1 compression (same place we get the 10:1 pistons) and have a slightly hotter cam. No other OEM cam is an upgrade as the rest of the 12v's have the same compression pistons, even the trucks.
I have these in my Daily Driver now but I would like a set of the Crower regrinds.
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Pistons
Forged. Ross has made turbo dished 12v pistons before. So has Venolia (the ones in my expensive shortblock). I would get the Ross because they can be ordered with rings. I think Weisco also started offering 12v forged pistons.
For OEM cast stuff (which I am currently experimenting with to get info for everyone).
Quote:
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Originally Posted by Ondonti
I'll just do the work real quick so it can possibly be archived.
Framed website so this link just leads to the frame
Import Performance Parts - Mitsubishi Topline Pistons, Rings & Plugs
Part numbers at this website. They cross over with chrysler apps too for the 8.85 and 8.9 pistons
PAMI9 The 8.85:1 piston from early 6g72 12 valve. Best for boost. Top ring located farther from crown of piston. FULL SKIRT. Dished with valve reliefs. Non interference
1.5mm top ring, 1.5 mm 2nd
PAMI10 8.9:1 pistons. 2nd generation pistons for 6g72 12 valve. Slipper style (not full skirt). Lighter because of the lack of full skirt. Top ring closer. Dished with valve reliefs. Non interference
Better n/a piston then the 8.85 because its lighter and the thinner top ring will create less friction.
1.2mm top ring, 1.5mm 2nd.
I ran 11.5@125mph on this piston but the top rings butted on my 2nd pass (leaned out=HOT). Stock ring gaps are way too small for boost (file to make bigger) and kill ringlands.
PAMI9D 10:1 pistons from 1992-1996 12 valve 3.0 Diamantes. Top ring is much closer to the piston crown then the lower compression pistons. 10:1 motor comes with a hotter cam (about 10 degrees more duration, not much though).
Slipper style (not full skirt). Almost flat top. Has 2 tiny sets of valve reliefs that don't line up with the valves and are so shallow you can ignore their existence.
1.2mm top ring, 1.5mm 2nd.
Ive put down 445whp on this 10:1 piston with a big single turbo. Head flexed (coolant push) the moment I got full boost on 4th gear pull so numbers are way down from what i was expecting. Was expecting more like 550+ @ 6000 rpms on 18psi. You can see torque flatline but hp keep going up...just not as high as if torque was 100+ft/lb higher :P (EDIT, motor was taken apart, blew out 2 o rings that were helping seal my headgaskets. 10:1 pistons undamaged and still made 445whp on 4 cylinders).
I don't know when I will push the limits of this piston. I probably need to do a partial fill of my cylinder heads because I weakened the combustion chamber when I ported them.
I bet TT pistons would handle more abuses in DOHC apps if larger ring gaps were used along with a huge 2nd ring gap. |
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Valvetrain
G54B mitsubishi engine (Starion, Conquest, and some minivans and my first ever car, dodge aries) has the same valvetrain setup that we have. They use the same lifters. Starion guys actually use our Roller rockers as upgrades.
Starion valvesprings have double the seat pressure when installed and are shorter (but same install height).
If you need solid lifters (crazy high rpms), some of the 2.6L G54B dodge minivans had solid lifters. These can probably be bought at the dealership. Don't ask me how. Me and a few others might eventually be using them.
Titanium retainers (aftermarket) for the G54B can probably work and are cheap. Just remember that we need 12 springs, 12 valves, 12 lifters and those motors only have 8.
Valves. I got custom Ferrea valves (oversized +2 +1) and so did Sunmind (stock size). Another option is the GIANT valves of the Starion. They are slightly longer but this is actually okay. My custom valves are longer then stock in order to increase the install height and allow room for more cam. Those valves are huge, something like +4 +3. Its possible to turn down valves to a smaller size if your machinest things they won't quite fit. They can install larger valve seats for your larger valves ( I have larger seats, and they are cheap, like 2 bucks a pop when I did my heads years ago). They have fancy machines to pop them out and install new ones.
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Rods - Just never worry about these. Ever.
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Crank - The cast crank is not as junk as people would lead you to believe. If you try to make 500+hp I would suggest using the same tricks Ray Pampena and Matt Monett have figured out on the Forged cranks. Use the heavy stock flywheel and stock dampened crank pully. I would always use that pully but for lower hp setups I LOVE aluminum flywheels. The heavy parts will help reduce crankflex and probably increase HP though that seems backwards. Thats how ATI measures the success of their expensive crank pulleys. Dyno numbers, not math.
The only real cast crank failures are due to rare casting imperfections like a bubble in the iron creating a weak spot. In that case it can fail with only 100hp. I have a balanced cast crank that I am not using right now. Its very smooth.
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MISC stuff (more to be added?)
Try getting a set of chrysler cam gears. They are stamped steel instead of Cast iron and are half the weight. I posted this elsewhere along with proof of them on the scale.
Not really gonna gain much if any power but its a fun cheap mod for anyone wanting to learn more about their car. I know at least a few people here have tried this on my advice and not found it too intimidating of a project.
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Intake manifolds - I made my own and so did Mopar3.0. Mine is ghetto as far as fab goes because I used steel. He had someone good with welding aluminum do his work. He used a stock 3/S 12v intake and cut off the plenum to put a big plenum on and a big throttlebody. Also ported out the runners etc. I will try to get pics of both added later. Mine is a short runner ram style intake that is meanted for assisting high rpm breathing.
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Updates - I will try to edit this in the future to add stuff. Falling asleep but I am trying to get my PM box cleared out of unread stuff. I sorta hate looking for this info. If anyone thinks of anything I missed that I would know about, or has something else (part numbers etc) that would help, please share. I am not here to advertise overpriced parts people are trying to sell to SOHC guys so this is not the place to share that kind of stuff unless they are the only people to offer it.
BTW, the 12v distributor is really easy to run with Megasquirt. My car is now running on a full aftermarket EMS (Megasquirt II) just using the input from my distributor for RPM signal. Woot. Tuning this way is very fun.
SOHC "above and beyond" mod Bible
