jonboy

I think there was a bit of a loss in translation going on - I read that as he wants to keep the current GT2560R and put it on the rodded/arped engine and turn it up to 18-19PSI.

sixshooter

iTrader: (12)

He's already turbocharged on the 1.6, Ryan.

IDK why he wouldn't build the 1.8 while still enjoying driving the 1.6 and then swap it in when he's finished putting it together. That way he can take it slow and not spend a bunch of money at once.

ryansmoneypit

iTrader: (6)

crap. totally missed that. sorry op

EDIT: yep, i thought this was another thread, had a very similar build list. My apologies for interjecting without knowing.

Mazdaspeed_Miata

Finally I travelled 560 miles yesterday to pick up a BP engine:




So, you recommend opening a new Thread named "Recommendations for my forged rebuild of my BP engine" or shall we go on in this one?

Because now I need some advices for the build of this engine.

Thanks guys!

psyber_0ptix

iTrader: (4)

Isn't the recommendation pretty much the same?

Just run with appropriate pistons to accomodate your new block.

Savington

iTrader: (31)

PLOT TWIST

sixshooter

iTrader: (12)

One thread is good enough.

Mazdaspeed_Miata

I don't think so. The engine should be good for around 350rwhp.

So what parts would you recommend to purchase?

Manley rods should be ok.

But what pistons? Wisecos or Supertech? Go for 85,5mm bore? 9,5 or 9,0:1 ratio?

andyfloyd

Manley rods, Supertech or Wiseco pistons @ 83.5mm or 84mm bore size. ACL main and rod bearings, ARP head studs, ARP main studs, OEM Mazda Head gasket. If the head looks good just put new valve seals in it and plane it flat. Kraken manifold and downpipe with your GT2560R, MS3 w/ 640cc flow force EV14 injectors.

edit : Do 9.0 : 1 pistons because you want to run high boost on pumpgas. Also do not bore out past 84.5mm with boost, keep it ideally at 83.5 or 84mm

edit #2 : A boundary Oil pump wouldnt be a bad idea either, I went with one. Once you pass 250whp on a stock pump it gets a little too close for comfort if you know that I mean

concealer404

iTrader: (3)

Do not bore for power. Run smallest pistons you can. Pump gas = 8.6:1 pistons.

psyber_0ptix

iTrader: (4)

You don't think what? What do you mean the engine should be good for 350whp?

There is a formula to what a lot of people run with relative success. Choose one and run with it. I personally went with 84mm supertech 8.6:1. The rest is pretty standard miata turbo prescription. All the hard work has been done and is documented in past threads.

18psi

iTrader: (76)

step 1: ignore this bad advice

Savington

iTrader: (31)

Wrong

Right

sixshooter

iTrader: (12)

^What they said.

andyfloyd

lol, ok because 8.6 and 9.0 are VASTLY different. OP good luck with your build.

concealer404

iTrader: (3)

One lets you hit MBT on pump gas, the other doesn't. Pretty different.

andyfloyd

You all were telling him to run stock pistons previously in the thread, which are at least 9.0 CR most of them are north of 9.4:1. Why cant you hit MBT on 9.0:1 pistons? You would run slightly less boost and be able to achieve the same power numbers at the lower boost due to the higher static compression ratio with the same timing # you would have on the 8.6CR. With less boost you should be able to achieve MBT on either would you not?

concealer404

iTrader: (3)

Yes, because putting pistons in a 1.6 is stupid. Also: Different motor.

Timing is everything on a BP. Compression is not. This isn't like... a new thing.

sixshooter

iTrader: (12)

That's actually a significant misunderstanding of how it works.

andyfloyd

I understand how it works its Maximum brake torque, its when the engine makes maximum torque with a certain amount of ignition advance. Im not going to clutter up this OP's thread though, but it sounds like you guys have a lot of evidence suggesting that 8.6 is superior to 9.1 so Im not going to argue since Im probably wrong.