I have a 1997 miata 1.8L & I plan to get a Garrett GT2860 from BEGI, I plan to run it at it's full potential (12psi) but talking to a specialist he mentioned that the turbo is a bit too big so there would be some turbo lag & I was thinking of purchasing CP forged pistons 84mm 9:1 compression set, I already bought a lightweight flywheel & lightweight crank pulley, what do you guys think? Is CP forged pistons a good brand? (Btw this is gonna be my daily car I plan to race it at least 20% of the time) Is increasing the bore size gonna help? Any other ways to reduce turbo lag?

 

I think you have no idea what you're doing.


but I'll be nice and help you anyway:
to reduce turbo lag you want to run a properly sized turbo and have the least amount of restriction in the exhaust and charge air path. Properly sized turbo is the smallest turbo that will reach your hp and tq goals, and least restriction means good hotside parts and good charge side path, intercooler flow, and IM flow.

Before you make n00b mistakes with a build/setup, I suggest doing way more research.

PS: sure, overboring and running bigger pistons will get you to 1.9L, and will help, but not nearly as much as what I mentioned above.

 

It's all in your plans and how much power you want. You mentioned a GT2860 at 12psi, which should be around 250whp. If that's your power goal, you'd be better off with a GT2560 that's easily capable of that power and will spool a good bit faster.

If you want to push the power a little higher, toward 300whp, then the GT2860 or GT2871 and a built motor is probably a better option.

 

Also, these are death to miatas. Make sure you research real well before you put it on and destroy your oil pump.

 

Man, you guys are getting soft in your old age! Giving good advice, with no insults?

OP, you hit the jackpot of people in a good mood for some reason... take their advice as a gift from the gods!

Keith

 

It'll do more than that on a BP, sir.

Too big for... what? Turbo is fine.

Not much.

Replace with Supertech 8.6:1 for pump gas goodness.

Good!

Bad.


Yes. Buy Supertechs anyways.

Not really.

Good tune. Good hot side. Efficient intercooler setup. Picking the correct turbo for your goals/needs, etc etc etc

 

lol @ "full potential" of a 2860 being 12 psi.

You sir need a 2554 or 2560.

 

I'd say those are both too big to be limited at 12psi on a BP.

 

 

Somewhere, Corky and StealthNB are jizzing over that wastegate reference port.

 

yes yes and yes to concealer's answer, much props

 

Eh the turbo on my Fiesta isn't much bigger than that and it hits 21psi. 1.0L FTW

 

waitwaitwait... the stock 1.0 ecoboost 3 cyl is at 21 psi?

That's idiotic. lol

 

Yup I think it is limited to 18 or so in 1st through 3rd gears and 21 in 4th and 5th.

Just waiting for the warranty to run out so I can strap on a GT2554 and swap it into a Miata!

 

I second Ed. What are you talking about? Proof plz.

This thread is now about 21 psi tiny turbos, not a noob that is going "ALLOFIT" 12 psi 2860.

 

Did the OP ever state his peak power goals? Without that we can't give a real answer on turbo sizing.

Or, he could mention his high load [4th and 5th gear] boost threshold RPM requests, and then from there end up with whatever power at the top end.

 

The new 1.0 Ecoboost motor that's an option in the Fiesta. Runs lots 'o' boosto.

New cars run lots of boost. I think even the new Elantra Turbo is knocking on the door to 20psi.

 

http://www.nytimes.com/2014/08/03/au...view.html?_r=0

20psi, sorry, it appears I was incorrect.

 

I need this for my leaf blower

 

Here's the Fiesta turbo with a quarter on the compressor for comparison: