BEGi-S w/ GT2860RS + Divorced DP
 

I was always drawn to the Greddy because you could spend x-amount of dollars, bolt on and go, and upgrade as desired. What I didn't like about the Greddy was every single part in the kit. Enter the BEGi-S. This thing is like a dream. It's customizable from the get-go and is totally forward compatible as far as you want to go. It's inexpensive and comes with everything you need to get going with the turbo.

Well I want to start off with my dead stock Miata, with my MS from Brain and the default 1.6L maps he gave me, bolt the BEGi-S on and go. I want to do the fuel, intercooler and etc. later after I've had some fun with the money I've already spent. Catch is I want the GT2860RS option from the get-go, along with the divorced DP and a bypass valve. I'll have the BEGi AFPR and total control over timing so I should be able to get a safe tune out of it. I figure BEGi wouldn't sell the kit with that turbo if it wasn't workable.

Can anyone see any potential issues?

As long as you keep your intake temps in check it doesnt matter what turbo you run. Larger turbo will spool slower, but wont heat up the air as much as a smaller turbo. So in reality it would be a tad safer then the 25xx, at least in my mind.

Its workable. just dont expect to run bigger boost until you get an intercooler and your fueling figured out. But you should have a great base with potential for later on.

You bought a standalone ECU specifically to avoid crap like AFPRs. Delete that from the kit and order a big set of injectors.

+1.

I agree, and that'd be the eventual plan.

But I also subscribe to the philosophy of changing as few things at a time as possible. The MS is supposed to run like stock. The BEGi-S is supposed to run on a stock car. It makes sense to me that I'd get the turbo kit working like it should on a stock car and upgrade like I would if I didn't already have the MS. I like to take things slow and get things working well and then upgrade one thing, get that working well, and etc.

IMHO that is a very complicated approach you are taking. Start with larger injector and a megasquirt before you install any turbo or perform any other modification. That will be taking it slow and properly. The other way around will just cause you unnecessary complication when you try to tune your fuel curve to compensate for the increasing fuel pressure.

yeah but the FMU is a band-aid, why limit yourself in the fueling department if you don't have to....you'll eventually sell the FMU for a fraction of the original cost and end up with larger injectors anyway. Get it running good now with 460cc injectors then once the turbo goes on, you'd only have to tune the boosted rows....

+1

Do the MS first, with the new injectors. Get the non-boosted parts of the table reasonably sorted out- you don't have to book dyno time for this, just some patience and a laptop. Once you're comfortable with that, plop the turbo on.

I respect your approach, alot of us here started with AFPR's, The BEGI AFPR is a great unit.

You'll want to add a WBO2 once you start to tune outside of 14.7:1 w/ the MS.

Also the AFPR works best with an O2 clamp to trick the stock ECU into thinking its still running stoich (or a tad lean)under boost. Esp w/ the later models that stay in closed loop longer (not sure of your yr though).

I'm not sure if you want to trick the MS O2 sensor signal, it's a little smarter than the miata ECU, and might cut out...Has anyone tried it???

Never thought of getting the bigger injectors first and tuning the car without boost.

I've been away for awhile. I started messing around with aquariums and haven't had much time for cars, my head's not in it. I haven't even installed the MS yet. Weather is getting nicer though so it's time for cars and motorcycles again.

Not needed. With the MS, you can tell it when to be open-loop and when to be closed-loop. Additionally, with a WBO2 you can run closed-loop at any AFR.

No, because nobody else with an MS is fucking around with FPRs and O2 clamps. Get big injectors and do it right.

+1 again. I am installing a BeGI-S with the 2560 turbo and a megasquirt in my '99. Based on input form someone else with the same setup, you can get at least 5-6 psi boost with the stock injectors and the MS with no AFPR (not sure if that is true for a '92). I installed the MS, got it running (well idling anyway) and then started the turbo installation.

When you want to crank up the boost, get bigger injectors. I have a set of RX-7 550cc injectors, cleaned and tested by witch hunter, ready to go for when I want to increase boost above that. Bought used and cleaned all for less than $150.

Simply put, take the time and money you would put into the AFPR and put it towards the MS instead.

Ok, I will get larger injectors (and a WB obviously) before the turbo and save money by not getting the AFPR at all. That makes more sense, I think.

I love threads like this.

Awesome knowledge transfer in a nice compact package. 2 hours start to finish, a dozen or so posts, and open minded OP.

Way to go you guys.

C

*Disclosure* I only skimmed through the thread, but it's long, I'm sick, and frankly I don't give a damn

Now, here's my $.02
If you think you need a 2860, you need to take a serious look at the 2871r. It's going to spool the same, but be more efficient up top.

Ben, how do you think the 2871 and the 3071 compare? Jeremy at FM has said the spool difference is minimal (not sure how he defines minimal) but the 3071 is much more efficient.

think we'd need to define which 2871 vs which 3071, but in general I'd expect the 2871 to spool about 400 rpm sooner. Also, you'd need to define your goals. The 2871 would be pleasant on the street, but if it's a track only car that's always at high engine speeds, then the 3071 would be the ticket...