VIKING tuning

Post by **jif** » Wed Nov 15, 2006 9:49 pm

[started a new thread for this discussion]

Hi John

To help with your (lack of) low end power you could try a few things:
- big downpipe and exhaust. Reducing the backpressure behind the turbo makes it spool easier

- disconnecting the downpipe temporarily should help test this theory (earplugs optional!)
- free up the intake, see if running without filter/plumbing helps
- bigger injectors, programmable ECU (maybe a megasquirt or e-manage blue, both relatively inexpensive)

The AFPR is only going to help out with fueling when it senses boost. Ultimately you should get something to help with timing as well- if you've retarded your static timing for the turbo then this is hurting your non-boosted performance...

The equally small GTX turbo (VJ20) on the 1.8 engine starts spooling around 2000 rpm, and can do 12psi by ~3000rpm ...

-jeff

[Posted via External Email]

SLYDIT · Post by **SLYDIT** » Thu Nov 16, 2006 10:30 pm

If your still running standard injectors and no AFPR then the lack of low end performance is almost certainly due to being lean under 4000rpm. This is a typical characteristic of the MX5 which runs off the Oxygen sensor until 4000rpm which means it runs too lean a mixture to make power with the turbo. when you hit 4000 rpm it goes into open loop mode and puts a bit more fuel in causing the "rush " in power. its not boost or timing.... its fuel....you need an oxygen sensor clamp to cure this phenomenon. If you search the Miata.net and Miataturbo.net youll find lots on this under "lean tip in" and O2 clamp.

poison · Post by **poison** » Fri Nov 17, 2006 2:02 am

Oh God I have to ask what is a AFPR "Air Flow Pressure Regulator"??? Air Flow Something anyway. Is this the same as a piggyback ECU?? Sorry for the dumb question.

Gazza

[Posted via External Email]

Post by **jif** » Fri Nov 17, 2006 8:29 am

Adjustable Fuel Pressure Regulator. Also the Alliance of Foam Package Recyclers

,hehe...!

[Posted via External Email]

Grant · Post by **Grant** » Fri Nov 17, 2006 9:07 am

----- Original Message -----
From: "jif" <horsepower@mx5forum.co.nz>
To: <horsepower@mx5forum.co.nz>
Sent: Friday, November 17, 2006 8:30 AM
Subject: [MX5Power] Re: VIKING tuning

Adjustable Fuel Pressure Regulator. Also the Alliance of Foam Package
Recyclers ,hehe...!

And don't forget

AFPR : Association Française de Prototypage Rapide

[Posted via External Email]

poison · Post by **poison** » Fri Nov 17, 2006 9:10 am

Well it’s good to see that Foam Packers are taking the environment seriously with recycling J

There was some comment earlier about the NB being a non return system thus you can’ use an AFPR? Why not?

And wouldn’t raising the pressure than cause the car to run too rich down low? Or will the closed loop running section of the ECU take care of this?

If I install my wideband O2 setup I can then play with the boost - I also have an HDI Hybrid electronic boost sensor and controller now, cheap as chips
off TradeMe and found many good reviews on the web, the strange thing is these sell for over twice the price in the States. So does anyone know somewhere
I can buy an O2 socket (17mm I think) from? So I can have it welded into my exhaust. Do you need one as well Jeff?

Gazza

[Posted via External Email]

Fletch · Post by **Fletch** » Fri Nov 17, 2006 10:23 am

Gazza,

an AFPR adjust the fuel pressure, relitive to manifold boost pressure.... no boost, no raise in the pressure...= standard fuel delivery when turbo not spooled or low throttle positions....

The AFPR sits after the normal fuel pressure regulator, in the return line to the tank. Thus, no return line in an NB = AFPR no worky

An AFPR is a simple/mechanical method to add more fuel under boost... it removes the requirement for an aftermarket ECU. If you have a Link or similar programmable ECU, you dont need or want and AFPR.

Fletch.

Post by **jif** » Fri Nov 17, 2006 11:02 am

The AFPR works by blocking some of the fuel return to raise the pressure in the fuel rail. Without a fuel return (NB mx5's) this isn't possible, altho they say you can convert it easily enough. The pressure is only raised when it senses boost and it raises it by some ratio - eg 6:1 ratio means 43psi base pressure + 6x (5psi manifold ) = 73psi.

Correct me if I'm wrong

The wideband bung takes standrard sparkplug threads, exhaust places should have these? Found something here:
------------
The 02 thread size is 18 mm x 1.5.
Stephanie

Stephanie Turner
Office Manager
BEGi / Bell Engineering
phone: 830-438-2890
fax: 830-438-8361
www.bellengineering.net
------------

[Posted via External Email]

poison · Post by **poison** » Fri Nov 17, 2006 12:11 pm

Hey Jeff

Thanks for that, from this I would assume that the fuel pressure on the NB is the Fuel pump pressure or they have a FPR somewhere in the line, I’ll have a look on my parts book.

I tried a couple of exhaust places, not too clued up. I would have thought they must have them for when the make exhaust sections that need an O2 sensor fitted. I’ll try again. I thought the instruction book that came with the wideband said it was 17mm??? I’ll have to check, most likely a memory data error, faulty hardware J

From: jif [mailto:horsepower@mx5forum.co.nz]
Sent: Friday, 17 November 2006 11:05 a.m.
To: horsepower@mx5forum.co.nz
Subject: [MX5Power] Re: VIKING tuning

The AFPR works by blocking some of the fuel return to raise the pressure in the fuel rail. Without a fuel return (NB mx5's) this isn't possible, altho they say you can convert it easily enough. The pressure is only raised when it senses boost and it raises it by some ratio - eg 6:1 ratio means 43psi base pressure + 6x (5psi manifold ) = 73psi.

Correct me if I'm wrong

The wideband bung takes standrard sparkplug threads, exhaust places should have these? Found something here:
------------
The 02 thread size is 18 mm x 1.5.
Stephanie

Stephanie Turner
Office Manager
BEGi / Bell Engineering
phone: 830-438-2890
fax: 830-438-8361
www.bellengineering.net
------------

[Posted via External Email]

VIKING RACING · Post by **VIKING RACING** » Sun Nov 19, 2006 10:05 am

Got the WOF yesterday and went for a short drive(2 years since last time and it felt great!!

)
Did some testruns and the diagnosis of not enough petrol seems right. 5psi at 2500rpm but no increased power, at 4000rpm kick in the butt(always thought it was turbolag).
Will start by installing a fuelpressure gauge and the AFP...
2: this Oxclamp thing sound intresting, will recearch more.
but as usually lack of time is the main enemy.
Any of you guys going to the club thing next sun 25/11?

poison · Post by **poison** » Fri Nov 24, 2006 1:25 pm

Viking Said “Any of you guys going to the club thing next sun 25/11?”

I’m going, and keen to look at your car too, it will be interesting to see if our set-ups are the same. Hope it doesn’t rain, the weather does not look today. I think it should be the 26th as today (Friday is the 24th)

I’m hoping that Miatamad has his car up and running too.

[Posted via External Email]

Growler · Post by **Growler** » Fri Nov 24, 2006 4:44 pm

I'm going too...as well as MXMike. It would be good to see some of the other turbo cars.

Growler.

VIKING tuning

VIKING tuning

VIKING tuning

VIKING tuning

VIKING tuning

VIKING tuning

VIKING tuning

VIKING tuning

Lack of fuel!!

VIKING tuning

Who is online