My Miata + rb20 turbo

[messiahx]

Hello all,

As listed in the topic, I'm going to be turboing my Miata and I've purchased an rb20 turbo from a friend (has an S13, RB20 swap, RB25 turbo, Silvia conversion). This seems to be THE place to go on the net if you have a Nissan related question. So, I'm wondering, can anyone tell me about the stock rb20 turbo? Specifically, I need to know what the stock wastegate spring is set at. Any other info would be cool, too. I'm only looking to run 6psi to start out with (I'm on a tight budget). Thanks for your help! Please don't flame me too much for asking a Mazda question on a Nissan forum.

[Eikon]

Stock rb20det turbo wastegate spring should be set at 10psi.

You are not the only person I know looking to put a rb20 turbo on a Miata.

[S13FX]

OK,

I am the man with your answer.

First off we all know the RB20 turbo Is a ceramic ball bearing turbo, thats water and oil cooled.

The turbo is slightly larger then a standard T25 trubo, but it is ported and has a T3 Flange which helps it greatly.

Now I don't know if you have the 1.6 or the 1.8 Miata.

But on a 1.8 Miata a standard T25 turbo pulls all the way to red line very nicely and on about 8psi you will net 200-210 rwhp.

So now, just imagine what a Rb20 Turbo can do. And having water and oil lines ran in a Miata is very very simple. Especially since the water jackets on the RB20 turbo are BI Directional.

If you got any more questions let me know.

[messiahx]

Thanks for the info S13FX! I have a '97 1.8, btw. I have an ebay T3 manifold on the way (well, hopefully, the guy sent me the wrong mani the first time). It's good to know that the water jacket can go both ways. That should help a lot when running lines to it. The only issue I think I'll run in to is the 10psi wastegate spring. I wasn't planning on having this much power right from the start. I'm trying to do this on a small budget (less than $1500) and I wasn't planning on new injectors right away, not to mention I still have stock suspension, and with 200whp, I'd probably grenade my lsd within a week with my driving style. Any ideas on putting a different spring in? I'm still learning as I go with this stuff, so I don't even know if that's possible. Thanks for your help! At least I know I've got a good turbo for the job.

[Carl H]

trade the stock 10psi wg for a 25 actuator they only hold 6psi.

[JPsNissans]

trade the stock 10psi wg for a 25 actuator they only hold 6psi.

Good idea.

I run 8psi on a Jackson Racing s/c on my 99 1.8 (I dont know how many similiarities there are between our cars, such as transmission and LSD strength), but mine holds up great. I'm probably around 200whp or so from looking at other peoples numbers. Im on a stage 3 CM clutch also, so it is very violent and hard on the transmission and LSD. No problems as of yet.

Are you planning on running an FMIC? If not, better start looking into some water/alky injection. We might be trying a water/air intercooler setup on mine soon along with the alky injection.

[l0nestar]

I would gladly help you out with that trade..

[themadscientist]

The RB20 turbo should be just about right for your needs

[DJButton]

Good question, good responses, I love seeing forums used properly!

[themadscientist]

We are a bit more friendly here than some places.

Give the OP some of the credit. Had he wrote I gotz this stoopid fazt miyata yo! Iz gettin a dope azz RB20 turbo biatch, tyte? I think the responses would have been less than helpful.

[messiahx]

Oh, but my Miyata is mad tyte fast jdm drifto, yo!

Just kidding. It got a lot of "it's so cute" comments from the ladies at a party last night, actually. 'Course that's not such a bad thing...

Anyways, yes, I will be running an FMIC. My concern with running 10psi is that, first off, I gotta buy new injectors and this turbo project has already eaten a lot of my limited funds, but new injectors are still definitely an option. Secondly, while I do have an upgraded clutch and LSD, and the transmission should be good for ~300whp, I'm not sure the stock suspension will handle the power so well (wheel hop?). I want to start out conservative with my first turbo project. My aforementioned friend with the s13 said he'll swap actuators (he has an rb25 turbo) with me once he gets a few problems worked out with his setup, but 200whp is very alluring...I'll keep you guys updated.

[themadscientist]

You might want to look at this carhttp://www.sdsefi.com/features/july03miata.htmI beat him with a stock Skyline at this stage but he quickly got too fast for me to ever do it again He was blowing diffs left and right, I am not sure about the transmission. They eventually swapped out the 1.6 stuff for the 1.8 and it helped. The car has gone through many incarnations and is now rocking a 500hp SR20. I have heard third-hand that an FC k-member will bolt into a Miata but I have never confirmed it myself but you might want to look into that.

How do you plan on tuning for the larger injectors?

[messiahx]

That's a pretty nice setup! An sr20 miata would be pretty insane. There's a guy on the miata.net forums currently doing that swap. There's another guy running a built 1.8 bp turbo that is pushing 600whp+ on the forum as well, but I think it's mostly just a drag car.

I'll be running an emanage blue for fuel and timing. I have a lead on some 440cc injectors from a late gen FC I hope to get. The thought of freaking out Mustang GTs and the like sure makes me want to get this turbo project done!

[themadscientist]

Do you need top feed or sidefeed? I never really noticed what Miatas use.

[messiahx]

On the injectors, honestly, I have no idea. Only thing I've researched as far as injectors is what I can directly swap in. I also found out that 440cc injectors would make for a really poor idle without a full replacement ecu, so it looks like I'll be buying some used mx-6 turbo injectors (330cc) and a walbro hp 190lph. Quick question: Does anyone know if the rb20 turbo needs an oil restrictor? Or is it built in? Thanks!