MR2 4age internals - Toyota Nation Forum : Toyota Car and Truck Forums

4AC = AE71 · 10-10-2006, 02:10 PM

i did a search alrdy and came up with nothing. i want to build this motor to maybe about 200, MAYBE. i wanna do these upgrades to the internals:

1. port and polish the head
2. knife edge the crankshaft
3. higher comp pistons
4. mild cams without doing under bucket shims
5. some really good connecting rods (shot pinned and H-beam)

now note that i'm not a pro at tuning but have done my fair share. if any body has any feedback on these upgrades weather it be PRO or CON. plz i need opioions on these gentlemen...

meoggi · 10-14-2006, 03:14 PM

well now that all sounds nice. but just remember do not get hyperutectic any thing. they will break. i gaurantee

te51levin · 10-28-2006, 08:21 PM

I suggest you do a little research on other forums (club4ag, hachiroku.net, dorikaze, mr2oc) and learn more about the weak points and strength of a 4AGE. You've suggested some parts that will do absolutely nothing for power, and you've neglacted quite a few ideas that are necessary to make power.

Where does that 200bhp figure come from? It takes a hell of a lot more than bolt-ons to support that kind of output.

KensMR2Parts · 10-28-2006, 11:27 PM

OK, you want 200 HP by:
1. port and polish the head ... porting works, but the bigger the ports the more cam you need and the higher up (RPM) you will need to run the engine ... smaller ports flow more air (higher velocity at lower engine speed) ... polishing is passe; you get more air flow with an air barrier (rougher than polished ports)
2. knife edge the crankshaft ... good for a short term use engine (racing) but very high maintenance
3. higher comp pistons ... good move toward more power ... higher octane fuel and valve clearance issues
4. mild cams without doing under bucket shims ... if you remove and reinstall the same cams, reshimming would be a good idea ... a must with cam replacement ... if your can handle the emissions issues; go big (radical) or don't go at all
5. some really good connecting rods (shot pinned and H-beam) ... a lesser concern with the 4AG engine ...
Do as te51levin suggests and check those other sources ... also check Sports Car Club of America (www.scca.com) Formula Atlantic (they get tons out of the 4AG) ... remember; Speed Costs; How Fast Do You Want To Go? ... big power engines are made of unobtainium that sells for cubic money ... also, there is no substitute for cubic inches (except for turbos) ... Good Luck!