Hello everyone. I've decided to step into the boosted world and purchased a used turbo kit(GT2871r w/BEGi manifold and downpipe, RX-7 550cc injectors) for my car. It also came with an AEM wideband and I have a MSPNP on the way. I'm about to start installing the kit but I have a few questions that I need to clear up.

1997 Miata 1.8(stock internals)

-The previous owner stated that the internal actuator puts out 12-13psi. On stock internals I would much rather be boosting at a lower psi. 7-8psi is what I'm thinking. Will I have to purchase a new actuator or can I adjust the arm to put out lesser psi?

-I'm feeling that I need to take it to a dyno in order to get whp numbers for a reliable setup, but I would also like to start slow and tune the setup myself(street tune) in order to gain experience and be more in tuned with my car. I'm currently reading the Megamanual and as much online info as I can. My question is..will I be okay with boosting a GT2871r at 7-8psi on factory 1.8 internals? I'm aware that different turbos flow at different rates and I don't want to exceed 250whp. I don't think that I can achieve that much with the amount of boost I plan on boosting but I would still like to make sure.

 

Yup

 

What type of actuator is compatible? Any Garrett actuators or is there a specific type/length?

 

If the rod of the actuator is threaded, you can adjust it.

 

if the can is set up for 12psi, loosening it will only make him spool slower and he'd still creep at high load and likely blow his engine.

OP - you need EWG. that kind of turbo on a stock motor with iwg is just asking for trouble.

 

That's such bad news...sigh. I tore down the car today and prepped it for boost. The manifold has to be modified and so does the turbo for EWG..the downpipe as well I'm assuming. So...I just purchased a kit that I can't really use. Sad. Any other methods? Can I possibly purchase an 8psi actuator and replace it??

 

why don't you just buy a low-psi wastegate, set agressive overboost protection and see how it handles?

 

This is what needs to be done. You want to run 7-10 psi or so through that turbo. Anything more then that and you will be in the bending rods territory. With my GT2871 I made about 225hp at 9psi on my built motor.

 

Is this what you are referring to?
Wastegate Actuator, GT28 Stock Unit- TREADSTONE PERFORMANCE

Also for Overboost Protection I'm looking for set the limit to 152kpa(default). Should be okay there right? This will be mostly daily driven.

 

I've found I need to set it a psi or two higher than my target boost as it'll hunt around a bit with temperature and the like.

An EWG is the most expensive suggestion and not required at all. A lower psi can is what you need, try calling FM and tell them the turbo you have, I'm sure they have a 7-8psi can that'll work. It might even be on their site.

 

Believe I've found it!
https://www.flyinmiata.com/index.php...umber=02-70576
But to be sure I'll give them a call today.

Also editing my previous kPa limit to 162..which should come out to about 9psi.

 

Measure the rod. Study the mounting bracket design. Go on ebay. Buy a lower psi Act Chew Waiter that has the correct length rod range adjustment and a compatible bracket design configuration. Some brackets can be removed from the actuators so you might be able to reuse the one on your turbo.

 

Sorry, but that's downright stupid.
I've ported the iwg port extensively as well as ran a 7psi can before, and with 3" exhaust on a long high load pull it would still creep.

I've experienced this with numerous turbos with very similar results. So have many others over the years. So has FM and BEGi. This isn't something new.

Have you any 1st hand experience with exactly what OP is asking about? If you did, you wouldn't say silly things like this.

 

Dont be a wuss. Attain greatness. I rant this on a larger turbo with a stock bottom end with a 145k+ miles on it and never blew it. 8psi LOL pppfffffttt

 

That right there. Loosening the rod will only make the wastegate flapper not close fully so you'll always be losing pressure that should go into the turbo while at redline the wastegate wont open fully until that 12psi mark.

 

18psi, yes, I have experience running any number between 7 and 10psi with 3" exhaust without issues on an IWG.

I never said they were perfect, and EWG is certainly the better technology, but saying such an expensive option is THE required fix without even mentioning the $60 option is poor form.

 

I'm saying its THE required fix because it actually is.
Porting and using low pressure can is NOT a fix, it is a band aid, or work around.

Congrats if it worked for you, maybe its the higher elevation or whatever else (perhaps much smaller turbo?) that helped you, but like I said: I and many others (in fact most others) have experienced the exact opposite results.

But if OP wants to try to the low pressure can + porting and it works for him, that's great. I'm all for people achieving good results with less investment. If it doesn't though, he will have wasted time and money for nothing, and will still end up needing a "real" solution.

 

if porting fixes creep, then porting is a fix.

 

yeah IF

And IF it doesn't then he wasted money and time.


Whatever, lol, OP can decide for himself.

 

I probably had some of the worst creep around after I ported my head and fit a 3" exhaust. porting the wastegate *fixed* the creep.

this was my 6psi wastegate: