Oww. My head hurts looking at that.

Am I correct in assuming you don't have a boost gauge either? I'm only going off your "sub 6psi" comment, which sounds like you're not absolutely sure.

I'd highly suggest getting one. After installing it, change the boost signal for the waste gate. It's currently going from the turbo to the waste gate. Move it to directly pre throttle body. This will get rid of that boost drop off you're experiencing at 6000+rpms. This will also change your pressure, be very careful not to let it go above 6psi, adjust your waste gate to 5.5psi MAX! No more.

Then get a wideband. We reliably suggest another disc without you having one of these at your disposal. Currently you're barely hitting 12:1 at redline, which is probably the leanest we'll suggest you run.

If I'm not mistaken, a 10:1 or 8:1 disc will actually give you less fuel, no? Because after 6ish psi of turbo pressure, 12psi of fuel pressure/1 turbo psi is too much. Or am I confusing myself again.

 

The 10:1 or 8:1 disc will give you less fuel pressure then the 12:1 that you currently have. What you need is the BEGI rrfpr so you don't have to change discs, you can get a used one for like $100. http://www.bellengineering.net/produ...?products_id=4
The 255 fuel pump will work if you already have it.

 

That's what I thought. Your fueling should be richer if you add and turbo pressure right now, although that's only if your fuel pump can handle it. And although I think you should go richer by about half a point (11.5 vs. 12.0), some would argue otherwise and I think it would richen it up past that anyways.

 

I actually have one of the Jackson Racing Adjustable Rising Rate FPR's if you are at all interested. You can use Google to find the details and see if it will work with your set up. It's been in the tool box for about 4 years and was only on the car about 6 months. I was running 8psi with it, stock injectors and a Walbro 190LPH pump. If you want some added headroom I have a set of Supra Green Top injectors I will let go of too.

 

As you can see from my signature, I have been running "bandaids" for over 70K miles. Early on, I found that replacing the 1.6 injectors with 1.8 injectors on the stock fuel pump, a 12:1 Vortech disc and an intercooler ran a safe 8psi. The stock fuel pump needs to be in good shape and capable of putting out ~80 psi. You can throw a gauge in the line and crimp off the return to verify that it can.

If the stock FP will not handle ~80 psi, then you can put in a 190LHP and a 10:1 disc. You may run a little rich, but at least you will be safe.

 

Lol @ Tasty moron defending RWHP as a more relevant absolute hp number and then feeling all mighty.

 

honestly, that AFR plot from that dyno looks pretty good considering it's an FMU.

But it looks like most, lean until about 5K then rich. Right now the numbers are good, but if you start making boost/injector/FP changes, you'll have to figure it out again.

what are you planning?

 

Now that's what I'm talking about. Proper constructive advice. Thanks to all for taking the time to reply. Appreciated.

I do have a boost gauge. 6psi on the road. The dyno read 5.7 max. Thanks for the heads up on the boost signal. Wideband on the shopping list.

TNTUBA, I'll be in touch re the JR fpr. Thanks. I've got a set of green tops.

Olderguy, now there's a name that pops up on the UK forums now and again, your rep proceeds you sir. Thanks for the comments. I'll test the existing pump pressure as you say. Would the 255 pump I have do the job or is the HP pump a must in that situation?

Again, thankyou.

 

Clearly it is Glad you are getting some help.

 

i own 1.8 NA miata
currently running:
190lph walbro fuel pump
t28 turbo from s14a silvia @ 0.6bar boost
vortech FMU with 12:1 ratio
diy o2 clamp
2.5 straight pipe
and wideband gauge
--
AFR
14.2-15 under cruise
if i accelerate slow but letting it go into boost (boost gauge reads ~ 0.1-0.2bar)
AFR ~ 13
if i floor it (boost gauge reads 0.5-0.6bar)
AFR ~ 12 and goes to 11 in redline
running strong for about 5month
now in winter car sleeps in garage and waiting for megasquirt and more boost
---
btw i dont try that but if your car runs too rich you can put manual boost controller to FMU and let em see lower boost that you actually have

 

from my car:







BEGi FMU - 11psi 305cc injectors.




always ended up at 10:1 AFR...this is why I went megasquirt.

 

I've been getting told over here that I'm running way to lean. Dangerously so in fact. That's why I've come on to ask you guys directly as from what I've read from old CR and Miataturbo threads, that's not the case. Thanks for confirming that.

The AFRs were from a stock 1.6 with GReddy kit/downpipe, Vortech 12:1, 10 deg. I've since fitted a Bipes, 1.8 inj and an intercooler. I've got a new 255 FP sitting in its box. Haven't played with the boost yet.
Just looking to squeeze as much boost as the new 'bits' allow.

The car is getting used more on track now....every little helps.

 

you're in the high twelves below 5K and high 11s above 6K. that's not that bad considering the FMU.

if you do anything to rich the midrange, youll richen teh top end too much. the effect is worsened when you add boost. running 10:1 afr in boost is damaging.

Do you have an o2 clamp?

 

I was actually referring to being past a 'safe ceiling' with bandaids Alex. But hey, no arguments from me!? I'm quite humbled by the trouble folk are going to here.

Cheers fella.

 

The 255 pump is too large for the 1.6. There is a good chance you will run too rich even at idle. 190lhp is the preferred pump if you leave the stock pump. If the stock pump is putting out OK, I would personally think about larger injectors if you want to go even higher than 8psi and drop to smaller disc if need be.

 

No O2 clamp. Interesting point from Deff. Bandaid too far? I can see Tasty's eyes rolling from here.

 

The o2 clamp might help with the area below 5K, where the stock ecu will be tricked into thinking the AFRs are still lean, so it wont fight the FMU dumping in more fuel. at 5K is switches to open loop and just fuels arbitrarily.

Problem is you'll always have your midrange perfect, or top-end, it's really hard to have both, and the problem escalates with more boost/fuel pressure.

 

Ok....thanks. Larger injectors being the 265cc jobs? I've got green tops but i was under the impression they need management to idle properly.

 

my first test drive without o2 clamp was awful
didnt notice huge power gain and it was running lean

 

My '91 was able to idle 305's. Others have problems. If you have the green tops, try them, but the 12:1 will definitely start running rich when you hit any level of boost.

I went back to smaller(later 1.8) injectors at higher pressures when I went to the Emanage and Autotune.