How much Boost?

[osargeant]

Hi Guys,

I have a turbocharged Mazda MX3 running around 7/8psi of boost for a couple of months now and am very keen to know how much boost I can actually run on this vehicle safely.

Here is my setup
- 1994 Mazda MX 1.6 DOHC
- GTX Manifold
- VJ5 (MX6) Turbo
- 1.8 Miata Injectors
- Walbro 255 Fuel Pump
- Vortech FMU
- Autometer A/F,Boost and Oil Pressure Gauges
- 2.25" exhaust without cat
- Sports filter
- TurboXS BOV
- TurboXS Manual Boost Controller (Not Installed)
- MSD Boost Timing Master

My a/f gauge reads rich even on idle and I have never see it dip below Stoich. How much boost can I run on this vehicle.

Please advise.

Web Site: http://www.cardomain.com/member_pages/view_page.pl?page_id=310985

[OsoSlo z28]

to say how much boost you can run isn't possible. people are under the misconception that all motors react the same way. it varies depending on mileage, care of the motor, etc. another factor is degree of tuning. i can sit here and say you can run 10psi, but the next guys motor might blow at 6, and another guy runs 14 all day long. your best bet is to throw it on a dyno and tune it to a safe level.

[cjthor]

How many miles you have on your car?

[xXx_OTEP_xXx]

I see 127,000kms on the cluster.. is that accurate?

[osargeant]

The vehicle has around 130,000kms or 80,000miles

Hope this will help.

[cjthor]

Well.... On MY 94 DOHC with 114k I run 10 pounds every day with no problem. One thing though...IT is not my daily driver anymore.

[mazda20]

racing mazda is tuning mine for about 15psi as we speak, but we will see if we can get all that Ric seems to think we can and for what he has done with SOHC it might just happen.

[Steeb]

are you both of guys running nonintercooled at that psi? how much power are you guys making?

[Josh]

i was hitting 9 psi and blew my engine. it had under 40K origional miles on it. and i was taking it real easy on the car. the only thing that me and several other people can figure out why it blew, is the cams that im running, its the only thing that iv done differently than everyone else running the same setup. too much power for the stock engine, its a shame i didnt get to dyno it. oh well the new built up engine will be arriving next week.

[The_Great_Tonge]

what kinda cams were you running?

[Josh]

there made by INTEGRAL CAMS. and there stage 3 Miata cams at 260 seat duration and 9.52MM lift. with thies cams and some other little custom stuff, my auto was keeping up with or doing better than stock Integra's and the mx V6. the only thing i need is some adjustable cam gears and they will be perfect. the powerban is awsome, it kicks in at about 4 gran. the ATX had trouble with having the power to fully bennifit the cams. but with the turbo its quite insane.
the only thing with the cams is on the mx the dist is on the exaust cam and on the miata its on the intake. so it takes some playing around to get the timing perfect, thats why i need adj. cam grars.

[osargeant]

Just to give you guys an update on my car.

I forget to mention that I am using the stock 323 GTX Intercooler and I have installed the TurboXS Manual Boost Controller and have been running 9/10 psi for a couple weeks now.

The engine internals are completely stock at this point.

I am looking at changing from the Vortech FMU to a Cartech fully adjustable FMU unit shortly though.

Will try to get some new pictures for you guys to see shortly.

<small>[ December 07, 2003, 08:24 AM: Message edited by: mx3dohc16 ]</small>

[osargeant]

Latest update.

The Cartech/BEGI Adjustable Rising Rate FPR has been installed and I have been running 9psi for the last couple of weeks now.

The car is moving very good at this point and I am very satisifed with the performance. The difference between the car when it was NA and now is amazing.

I want to do some 1/4mile runs to get an idea of what times the car is doing.

Will try to get some pictures for you guys shortly.