Miata Turbo Forum - Boost cars, acquire cats. - Swapping just rods for 300hp

Hi my name is Josh I'm new to this group. Regarding this post. I have seen people running stock pistons with cheap H beam rods and having no issues at all pushing 300+. I have also done this myself and I'm still driving it on the street daily. Its all in the condition of the engine first of all make sure you have a nice healthy platform to start with. Go through it change the gaskets clean any carbon from the valves pistons and so on. Change the bearings there cheap enough. replace the head gasket with a good quality multi layer gasket I used ARP head studs same again cheap enough and worth it. File the ring end gaps so there's more room for expansion the rings get hot they expand if the ring end gap make contact you will shatter a piston and that might take out the cylinder. I did a quick home hone. I got some thermal tecline on top of the pistons to help with heat dissipation. The main things to keep the car safe and reliable is a GOOD tune by a pro or someone who really knows what there doing. Make sure you have lots of fuel and a good oiling system also make sure you can keep the engine cool the more power you make the more heat its going to make so a bigger rad is a good idea but not essential some good fans will still do a great job cooling. Intercooler you don't need a huge over sized monster intercooler a small to mid size will be perfect there cheap too you wont have to chop the car up loads to fit it ether. Plus an engine is like a big air pump its all well and good forcing all the boost in but it needs to be able to push it out or your going to have restriction issues a good exhaust system helps but that's why you need to make sure the valves are clean and working great you can also look at cams and valve work if you wanted but its expensive. I used my dremel to port and polish the cylinder head intake side and exhaust side out it helps flow and you get a quicker spool time but the main thing is your engine can breath it can expel all that boost. Good fuel is a must a good ECU is a must and a good tune is a must. retarding the timing will really help knock and pre detonation. A good fuel pump and lines get some bigger injectors you don't need to go crazy with injectors at all you don't need 1000cc injectors for 250/300hp at all. All the stuff I have mentioned there its all just supporting mods and all cheap some stuff and some free and it's simple to do on your own in your garage with basic tools. You don't have to do all of that but it all helps and it helps keeping it healthy and alive It's all elbow grease and time really. Get a wideband and a boost gauge so you can see the air fuel. I find is the best AFR making the most power for you NA will be the best AFR under boost your tuner will do that. Also when your making considerably more power it's a good idea to upgrade your brakes it's usually over looked but last thing you need is enjoying some power and then crashing because your brakes are not good enough. You may need a better clutch to handle that power I did my stock one was fine for a short time but it soon started slipping I hove a twin disk now it gives me room to grow in future.

That's just a ruff guide you don't need to do all that its not set in stone but it's what I found out to be a good recipe for a budget reliable 300hp daily driven car.

It all depends on what you want to do with the car also your budget if I were you I would just read everything I could to find out as much information as you can theirs people on hear who have all done different things in different ways with different results you'll learn loads if you look about and ask. Good luck with it it would be dope to see some pics when your done.