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Ok - so this afternoon I am attempting to Upsize the injectors to Supra 315cc.

Never done this before.

So after an hour, I have the manifold off.
And can see oily/fuely/caramalised coating under gasket.
Is this normal? Or is it a problem?
Small amount of oil in upper part of manifold. Car doesn't us oil.



Stu

Yeah that's the oil vapour from the PCV valve. It only gets let in under vac so when the engine isn't under load.

Yup, problem, your car is fooked. I'll do you a favour and buy it from you for $5K

That's normal. Very rare that an inlet is spotless.
Due to emissions that any oil vapours are fed back into the inlet to be burnt by motor (ie. a closed system). That's why catch cans (to catch the vapour) are illegal.

MINX wrote:


Stu

The truth is revealed why SE's are so wheezy, check out the bore size on those cylinders

Hey Spy - keep your SuPerfluous opinions to yourself.

315 Supra Green Top injectors in for nearly 3 weeks now.
Opinion - Not Sure.
I am not excited about them.
They definitely add 'power' in mid to high range (above 3500) with boost at 10-11 - providing really strong pulling power right up to redline with no pinging.
No noticeable loss of fuel economy.

However, they do take a while to warm up.
Not just getting the gauge upto normal, but it takes between 5 - 10 minutes to get the temp enough to really get them running smoothly. Until then, there is a bit of stodgyness on light throttle applications and changing gear, a little delay(overfueling?) before power comes on. So trying to simply drive smoothly upto 60 isnt as smooth and effortless as before.
Once they are hot though, very nice.

PS Also changed the PCV Valve to a 323 GTX Turbo Valve. (dunno if it made and diff)

Does anyone on here know the fuel rail pressure is for the SE? My Workshop manual says 53/61 psi but it covers the NA as well & I'd have thought they would be different.

THE REAL BORIS wrote:Does anyone on here know the fuel rail pressure is for the SE? My Workshop manual says 53/61 psi but it covers the NA as well & I'd have thought they would be different.

Hey Boris,

NB's have 60 odd psi of fuel pressure, as far as im aware this did not change for the SP or SE...

Thanks sprx3,
I am trying to use the RC Engineering formula to get the injector horsepower potential. The problem is ...... FM reckon the stock injectors are at their limit at 200 rwhp. (or 230 fwhp for their calcs.).
We have found by experience that the stock ecu will only idle properly on 320's or so. But, even at 100% duty cycle the RC formula limit is 200 fwhp NOT rwhp & that's with a 61psi fuel pressure & 0.6 BSFC.
Puting this thread on 320's into the same equation we get 240fwhp or about 205rwhp.
BUT my own car only has RC310's producing 205rwhp (from two entirely different dynos.) & yet a 10.5:1 a/f ratio at maximum flow??.
I cannot make sense of it but worried that our 'upgraded' injectors are still very much at the limit.

I have found that not all injectors are flowed at the same pressure, which can give a large difference in flow rate.
Also don't get to concerned about the US dyno figures, All the engines we have imported from the states ( N/A methonal burnning chev based) have been at least 10 - 20% down on the HP figure when dynoed in Aus, and on different dynos too. It is well know the the US has HP in the air.
Brett

bretauto wrote:I have found that not all injectors are flowed at the same pressure, which can give a large difference in flow rate.
Also don't get to concerned about the US dyno figures, All the engines we have imported from the states ( N/A methonal burnning chev based) have been at least 10 - 20% down on the HP figure when dynoed in Aus, and on different dynos too. It is well know the the US has HP in the air.
Brett

OK thanks, so the real stock injector limit probably is 200 fwhp then. I thought all injectors were flowed at the same industry standard pressure of 43.5psig & the (RC) calculation takes that into account?

Davex3 wrote:10.5:1 is very rich. Generally with a turbo you want to aim for about 12:1.

I'm still on the stock SE ecu so it's Mazda covering their butt with that ratio.

I think the 310's are at their limit now with 205rwhp (10.5psi @ 18C) and, with the freezing weather here, it's probably more like 220rwhp with the 12# boost pressure as well. Cannot do much about it because of the creep. Have to change up earlier!

All very helpful, thanks guys.