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Old 04-13-2007, 12:33 AM   #1
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Default Turning up the boost?

A buddy of mine works for a shop with a dyno and told me I can make some pulls after hours for cheap! So, haven't messed with the boost at all still 5psi and haven't really wanted to since I don't have a wideband to watch and tune off of. Since on the dyno will be using the exhaust clip I feel confident in turning it up a little with the right upgrades. Was curious what all I need to go past 5psi possibly shooting for running 10psi if the a/f allows.

Current Setup:
Greddy Manifold/Turbo/FMU
Bipes ACU
o2 Clamp
FM Intercooler

What else is needed to do what I want correctly? (Manual Boost Controller, Fuel Pump, 1.8L Injectors, etc?!?!?!)
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Old 04-13-2007, 12:45 AM   #2
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Even with 1.8 Injestors alone won't take you far. Likely you are missing an AFPR or an FMU.
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Old 04-13-2007, 09:11 AM   #3
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A walboro 190 HP fp probably a slightly smaller disk on your fmu say 10-1 or so the 12-1 will work but will most likely cost you some HP up top. For the same money i would put in some supra 300CC injectors and just pretension your afm some more, With that and the bipes + FMIC Andy floyd hit almost 300whp (well 297 is close enough for me :gay at 15-16 psi (on a bigger motor and turbo to though) and DD'ed 12-13 psi on a bigger motor for a few years. So yeah just get some 300's and a Walboro HP fp, and you should be ok.
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Old 04-13-2007, 09:15 AM   #4
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Your limiting factor now is the stock fuel pump. It's only capable of around 80psi. Go to the FAQ in the DIY section and use the formulas there to calculate what kind of power you can make based on how much fuel pressure the stock pump can deliver on the stock injectors. YOU WILL ABSOLUTELY NEED A FUEL PRESSURE GAUGE!!! A Walbro 190hp is around $90 and I've seen mine push more that 140psi of pressure. I asked Corky one afternoon about the dangers of injector lock at those pressures, and he basically laughed... told me something along the lines of blowing the injector o-rings before they'd lock up, so don't worry about the pressure.

Directly from the FAQ: at 96psi a 265cc (1.8) injector will supply the needed 360cc (and a little extra breathing room) to reach 200 HP (165rwhp). You have the stock 1.6's and can only make 80psi... do the math.

What about a BOV? You can get away without one at the low boost you're running now, but higher will absolutely require one. If you go with a Bosch, definitely recirculate it.

The standard eBay brass MBC has worked extremely well for me. It's got great adjustability and can dial in whatever you want. http://cgi.ebay.com/ebaymotors/Voodo...02007686QQrdZ1

The rest of your setup has proven capable of well into the 200rwhp range... except for the clutch. If stock, your clutch is at it's limits. You'll want to replace it with a much stronger aftermarket one... ACT/RPS/SPEC/EXEDY/etc.
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Old 04-13-2007, 09:38 AM   #5
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Thanks for the responses guys. I do have some other mods that I didn't post cause I though they were unimportant on what I want to do but I have a BOV, ACT Streetlight Flywheel (1.8L), and ACT Street Clutch (1.8L).

So i'll need a Walbro, and Supra 300cc Injectors. Do I need to replace the disc in the FMU using those two with the modified AFM? Do i need to replace the FMU with an anjustable fuel pressure regulator/gauge?
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Old 04-13-2007, 09:39 AM   #6
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i keep hereing people say at high boost you need a bov and i am still waiting on the need. i dont see it. no just put a smaller rate disk in it simple and cost effective go to ebay or begi and they can hook you up.
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Old 04-13-2007, 10:07 AM   #7
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If you just get 1.8l injectors, you should be able to fuel about 170rwp, if the stock pump is up to it.

That's about the most I could make.

So then, you need a HP pump to pump the pressure up a bit.

Take it to 100psi in the rail and you should have enough (with 1.8l injectors) to fuel 190rwhp.

which will take a good 7-8-9psi or so.

that means with your current fmu disk (12:1), you'll have too much fuel.

12 x 8psi + 50 = 146psi, something most pumps can't even produce.

so along with the pump you need to recalibrate the FMU.....lets try a 8:1 disc

8 x 8 + 50 = 114psi, a bit high but gives you wiggle room....7:1?
7 x 8 + 50 = 104psi, closer to what you want....


If you go to a bigger injector you'll need less, FWIW, a 305cc injector should only need a 3:1 or 4:1 disc.

I'd stick with going with 1.8L injectors / 190 HP / 7:1 disc, untill you're ready to break 200rwhp, then go with engine management of some sorts.

Also FWIW, the package of disc (4:1, 6:1, 7:1, 8:1, 10:1) is $50, one disc, $35.....
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Old 04-13-2007, 10:14 AM   #8
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also you can plumb the boost line of the FMU with a MBC for 5 bucks and adjust the rate's begining point and some of the rise.
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Old 04-13-2007, 01:22 PM   #9
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Looks like everybody chimed in with enough to get you there.
Put all those parts you've installed and aquired in your sig so our responses can be properly tailored. Also, your avatar is a great picture. Take some more and put them up in your vbGarage.
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Old 04-13-2007, 01:47 PM   #10
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You guys keep the thread going. Thanks for the input. I am learning stuff here. I am in a similar point in my turbo set-up as the original poster, danscreations, so I don't think I am hijacking the thread when I post the following information and questions.

I had the following installed when I last went to the dyno back in August:

Greddy manifold
Greddy turbo
Greddy downpipe
High flow cat
OBX stainless dual exhaust
Vortech FPR 12:1
RX-7 intercooler with custom piping
Mitsubishi Eclipse recirculated BOV
Custom cold air intake
Tightened wastegate
Loosened AFM spring 4 clicks to richen the A/F
93 octane and 5-6psi

With this set-up I got 146.5 rwhp and 144.8 rwtq on a hot August day.

Since then I have installed:

New fuel filter
Bipes unit pulling 4 degrees starting at 3000rpm
VooDoo MBC on the minimum setting

I have sitting in the garage waiting to go on this weekend:

NGK 7E plugs [One step colder]
Olderguy's O2 Clamp
Walbro 190 hp fuel pump
1.8 Miata injectors

It sounds like the only thing I need is either a 7:1 or 8:1 recalibration disk for the Vortech or either another VooDoo MBC spliced into the vacuum line feeding the Vortech and I should have all of the goodies in place to shoot for this side of 200hp. Am I right?

Honestly, I kind of like the idea of the MBC controlling boost pressure to the VOrtech is would almost make it into a cheap adjustable FPR. then you could tweak the fuel slightly with the Voodoo hooked to the Vortech and a little by fine tuning the clock spring on the AFM. And you can adjust the timing with the Bipes. Does that sound reasonable? Am I on the right track in my thinking? Thanks for any replies or suggestions.
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Old 04-13-2007, 02:41 PM   #11
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^^^ Ditto ^^^

Well thats eazy enough....anyone know if you can get a package of disc's. Not sure where we're taking the boost to yet so not sure what disk I'll need. Be nice to have them there and change them according to boost if need be. I'd like to shoot for 8-10psi and since I have no base rwhp now I'd guess 170-190rwhp I'd like to be at figuring I'm at 140-145 now. Thats sound right and reasonable?

samnavy: (don't have new pics w/oem front lip and FMIC yet)
http://www.radicalride.com/temp/photoshoot_01.jpg
http://www.radicalride.com/temp/photoshoot_02.jpg
http://www.radicalride.com/temp/photoshoot_03.jpg
http://www.radicalride.com/temp/photoshoot_04.jpg
http://www.radicalride.com/temp/photoshoot_05.jpg
http://www.radicalride.com/temp/photoshoot_06.jpg
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Old 04-13-2007, 03:18 PM   #12
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http://store.summitracing.com/egnsea...s=false&N=+115

B&T, sounds like you are in the same boat.


FWIW, going from 140rwhp to 170rwhp was night and day. even 170 to 200.

you'll enjoy it for a bit, slap in some 305s, lower the ratio a bit more, and enjoy 10-12psi.
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Old 04-13-2007, 03:18 PM   #13
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Quote:
Originally Posted by danscreations View Post
^^^ Ditto ^^^

Well thats eazy enough....anyone know if you can get a package of disc's. Not sure where we're taking the boost to yet so not sure what disk I'll need. Be nice to have them there and change them according to boost if need be. I'd like to shoot for 8-10psi and since I have no base rwhp now I'd guess 170-190rwhp I'd like to be at figuring I'm at 140-145 now. Thats sound right and reasonable?

samnavy: (don't have new pics w/oem front lip and FMIC yet)
http://www.radicalride.com/temp/photoshoot_01.jpg
http://www.radicalride.com/temp/photoshoot_02.jpg
http://www.radicalride.com/temp/photoshoot_03.jpg
http://www.radicalride.com/temp/photoshoot_04.jpg
http://www.radicalride.com/temp/photoshoot_05.jpg
http://www.radicalride.com/temp/photoshoot_06.jpg
Nice Ride Dan. Love the paint. Is that original or a repaint? I sold my number 3 Miata last year. It was a Mariner also... See pic below. [I bought ti for $800 and sold it for $3450 after a bunch of elbow grease, cleaning, tuning, and about $200 worth of parts.] I still have my other two though and I'm not selling either of them. The red one below is my 1993 turbo, autocross, track car and general hell raiser.

I think you can go to www.summitracing.com and get the disk kit for about $50.

I am very interested in following this thread. Let's keep it up.
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Old 04-13-2007, 03:53 PM   #14
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92 b&t you are spot on mbc makes for a poor mans arrfpr
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Old 04-13-2007, 03:55 PM   #15
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Quote:
Originally Posted by magnamx-5 View Post
also you can plumb the boost line of the FMU with a MBC for 5 bucks and adjust the rate's begining point and some of the rise.
Can you just use a brass aquarium bleeder valve to do this? I mean, all we are trying to do here is adjust the fuel a little leaner by bleeding off some of the pressure to the FPR... Right?
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Old 04-13-2007, 03:58 PM   #16
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Quote:
Originally Posted by magnamx-5 View Post
92 b&t you are spot on mbc makes for a poor mans arrfpr
You can say that again... "Poor Man's" is right. I am trying to make a car that will perform with a Porsche or Vette for less than $5000 and I am almost there.
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Old 04-13-2007, 04:19 PM   #17
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Since we've totally threadjacked this, I'll play:
I've never heard of using and MBC for an AFPR... but the theory is sound. Since my dyno graphs showed that as soon as the O2 Clamp kicked in I ran fairly rich down to about 10:1 or so in the low RPM's, then leaned out through the middle and ran fat rich up high. I know this is a standard curve.

Question: Wouldn't simply varying the voltage on the O2 clamp so it doesn't clamp down so rich be better than delaying the onset of the fuel rise? I think that would be a better way to control the richness down low. Am I understanding correctly? It seems like it would require A LOT of tuning to get the MBC setting just right.

Damn, I really need to save up for the LM-1/AuxBox!

Dan, fill out your SIGNATURE man... it really helps us out getting you the right information if we don't have to look back through all your posts just to figure out what you're running.
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Old 04-13-2007, 04:20 PM   #18
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tune the o2 clamp voltage and you wont have the dip.
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Old 04-13-2007, 09:25 PM   #19
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Seems like a nice idea, but i think the boost is going to rise the fp, when hooking to the vacuum line.
The begi unit has another exit hole where it adjust the boost.
A small valve on top of the afpr...(youll need a check valve to have no vacuum leak)

I don't think the position is a problem only finding a small needle valve.
You can make your own begi afpr...
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Old 04-13-2007, 09:47 PM   #20
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Change out those down pipes and you will see more power just from that. My car spools much, much quicker and the boost also feels more linear instead of all at once like it was. That will be the first thing that I recommend to people with the greddy from now on is addressing the exhaust.
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