MazdaRx7Racer4Life

Well, right now I have enough money to send my turbo to bnr and have it upgraded to the stage IV. ITs money left over from the rebuild at the rotary specialist shop, the guy that is rebuilding it is also streetporting the engine and told me that if I get the turbo before he finishes, he will install it at no charge, my question is, can I set my boost controller to about 6 or 7 psi and keep my stock fuel mods until I can afford an injector/pump/computer upgrade. Right now the only fuel mod I have is an HKS FCON which can be tuned to run rich. I also have a greddy profec b spec II to control the boost.

Basically, I wanna get the big stuff on already, and add the injectors, pump and standalone later, can I do tat as long as I mellow down the boost......way down?

bryantho

Yeah, that sounds reasonable.

Different compressor maps might tweak the tune a bit, but as long as you have enough fueling for 6-7psi, you should be fine.

Rxmfn7

iTrader: (4)

Id think you should be ok if you only run stock boost levels. Be aware though that you cant turn boost down with the boost controller, only up. Meaning, if you have a free flowing exhaust , and intake, your boost levels will be much above stock levels, necessitating more fuel. If you put the stock intake and exhaust back on, you should be ok. Be aware though that the stage4 turbo at 7psi is flowing more air than the stock turbo at 7psi, so I would advise at least getting an upgraded pump to start off.

bryantho

Huh? Okay, that's confusing.

1. The BNR turbo's have larger waste-gates. They can divert more exhaust gas around the compressor, thus they have better control over "boost creep."

2. If he has a manual boost controler, he can set it to turn on at 7psi. Meaning, the boost controller will see 7psi in the manifold, and vacuum actuate the waste-gates. So you can turn the boost “down.” Since the BNR turbos have better waste-gates, this should work better than stock.

3. Yes, the stage4 is a different compressor, and may flow denser air at 7psi. But isn't that what the AFM and air temp are for? The ECU will compensate for air charge temperature and mass.

Did I miss something?

Rxmfn7

iTrader: (4)

Yes, you are correct. I wasnt arguing with you. A few things though, BNR does port the stock wastegate larger. However, with intake and exhaust mods, I still highly doubt that it is sufficient to hold 6-7psi of boost, with a open exhaust and intake. I remember reading about a forum member who had even ran an aftermarket 35mm wastegate off the BNR stage4, and still couldnt hold boost under 12psi. Thats a huge *** compressor

bryantho

Ahh, okay.

Revised:
Stock vs. BNR. The BNR wastegates can and will divert more gas around the compressor. But whether or not that's enough to keep him from creeping past 7psi is another question.

On the other hand, I think it might be safe to assume that if he's not creeping now, then he shouldn’t be creeping more just by changing to the turbo.

MazdaRx7Racer4Life

so theres no way to hold the boost at 6-7 psi except putting stock intake/exhaust back on. Hmm.....those are long gone, guess ill be paying a visit to the rex junkyard for some stock echaust/airbox parts. Thanks for your help guys.

MazdaRx7Racer4Life

so theres no way to hold the boost at 6-7 psi except putting stock intake/exhaust back on. Hmm.....those are long gone, guess ill be paying a visit to the rex junkyard for some stock echaust/airbox parts. Thanks for your help guys.

Rxmfn7

iTrader: (4)

You could always just drive lightly...try not to boost much until you get your fuel system taken care of..

Digi7ech

iTrader: (1)

BTW don't foget that 6-7 psi on a larger CFM compressor is more than 6-7 psi on a stock hitachi.

Silverfc88

iTrader: (7)

I'm running a BNR stage 1 and I'm running about 10psi of boost on it with 720's on top and on the wideband I'm running maybe 11.5-11.8's for A/R's and if I turn the boost up to 11-11.8 I can see it blipping to 12.1 for A/R's at higher rpms and thats with the injectors turned up to almost +25%. I'm looking at more fuel now to run 12 safely. Maybe adding a single 550 with an AIC at around 10psi of boost and more.

Something to think about when you do your fuel setup, maybe 2x680 and 2x720 or 4x720 should be good for that hybrid.

NZConvertible

You're going to run a heavily modified turbo with the stock pump?! That's just plain nuts man. The chances you being able to keep boost that low are slim to none (you can't just "turn boost down" to whatever you want), and no fuel controller in the world will help you once the stock pump reaches its safe limits. If you can afford to have your engine and turbo rebuild and modified, then you should at least be able to afford to put a decent pump in as well to hopefully keep it alive.

MtnRacer

This a terrible aweful bad idea. Fuel first. Always.

Steve

MazdaRx7Racer4Life

ok ok, so fuel first then, what is the recommended setup, maybe a walbro 255 pump, what else do i need?

MtnRacer

Injectors, an SAFC or something like that, and a good tuner!

Steve

iluvrx7z

A boost controller can not lower boost, only raise it. Do a search, there are plenty of explanations why.

Dan

deltr0n`

its common sence to get fuel first! its NOT very smart to upgrade a turbo without already having fuel mods, matter of fact thats the stupidest thing ive ever heard. but thats just me, if you want, go ahead and do it, but why cant you just use that money to go all out on your fuel mods, and then worry about the turbo later, you can push a reasonable amount of power with a ported motor, and upgraded fuel!

i hit 15 pounds with my mods, and once i get my fuel pump and rising rate regulator, im pretty sure ill have somewhere near the 250rwhp range if not more at 15lbs.

im gonna go with a comp pump from teamfc3s store, and a bell regulator from Bell Engineering (only the best) that right there will get you enough for plenty of power, then im going to redo the fuel lines and make the rails parallel.

MazdaRx7Racer4Life

So, let me get this straight, I have a portd wastegate and a stock turbo. If I do a streetport on my engine and upgrae my pump and injectors, I can safely run 15 psi on my stock turbo? Will I really be making that kinda of power? Deltr0n, you also said a bell regulator from BEGI, Im not too sure what that is for, would I still need a fuel computer? Is my HKS FCON enough or do I nee an SAFC?

deltr0n`

well if you got the 720's you need a way to manage them, and thats even MORE power, actually i forgot to mention this, i will also be running 720 secondaries. of course the stock injectors might max out, thats why you need 720's but once you get the 720's you HAVE TO have something to control them (SAFC or standalone)

the bell regulator is a rising rate fuel pressure regulator, meaning as boost levels go up, so does your fuel! letting you boost more. but im pretty sure with just the regulator and pump, you can support 15lbs, cause i know our cars stock can handle 10, and with that pump and RRFPR, that should be PLENTY fuel.

MazdaRx7Racer4Life

so the pump, the regulator, the 720 injectors (4 of them right?) and an safc. Hmmmm............probably gonna go with the fmic as well, so that all I have left to upgrae it the turbo, alright man, perfect. Thanks alot for your help

Bukwild

fuel first for a rotary

sub9lulu

iTrader: (7)

2 of them 720's in the secondary u should be good
if u got $ u can get all 4
get the Rtek7 too , built in FCD sounds pretty good for 100 bucks

MazdaRx7Racer4Life

so stock injectors and secondary 720's? is this enogh for 380-400rwhp?

Digi7ech

iTrader: (1)

Umm I don't know about keeping the 550's for primaries.

It might not be enough for a 400rwhp set up.

J-Rat is getting the BNR and he is goin 720 Primaries(I think) and 890 secondaries.

Anyways. It's better to run rich than lean. Too lean == new engine go bye bye.

MazdaRx7Racer4Life

So 720 primaries, 890 secondaries, comp tech fuel pump, rtek7 chip, bell engineering regulator......safc?? I don't think I can control 890's with the safc, I think it has to be 720's all around. What do you think