thanks turbite...I am going to fiddle and try to tune it on sat.....

 

ttt

 

I've found that a leaner low-end 2500-3500rpm of around 13.0:1 gives about 5hp more than a richer 12.0:1 mixture. You're probably leaving 7-8hp on the table in the low-end due to the rich mixture. A leaner mixture would also reduce turbo-lag by quite a bit.

Would also be a good idea to remove that rich-dip at 4000rpm. It causes a dip in your torque curve as well. This could be caused by the Weltmeister chip-mappings for the stock turbo which has less lag than your current turbo. But from the linear rising air-fuel curve afterwards, I would surmize that the rich dip is caused by signal-massaging (increasing AFM voltage) in an attempt at getting more fuel in the high-end. However it's futile because the injectors at already at 100%, no matter how much you increase AFM voltage, you'll still get that rising air-fuel ratio towards lean. Increading AFM voltage just lowers the RPM where that rich-dip occurs, and the linear air-fuel ratio towards lean will still appear.

Then in the high-end, I prefer no leaner than 12.0:1. Take a look at this 3-way comparison on the same dyno (fuel adjustments were made in the MASTER-AFM setting on the MAP computer):



Note that low-end torque is hurt most by a rich mixture (green curve). While in the high-end, HP is identical with either a 12.0:1 or super-rich 10.0:1 mixture. But the lean 13.5:1 mixture (blue) hurts the HP the most. So the answer to your question is that there is no ideal air-fuel ratio, it has to do with the RPM range of your engine.

As for fuel-requirements, you're probably at the limit of your injectors. If you had a duty-cycle gauge, like on the AVC-R, you can graph the injector duty-cycle with RPM. While it's true that highest fuel-volume per stroke is required at the torque-peak when the engine is at its best VE, fuel requirements continue to increase with RPM. So even though VE at 6000rpm may have dropped to only 80% of what it is at 4000rpm, you still have 1.5 engine-strokes at 6000rpm compared to 4000rpm. That would mean that you need 0.8*1.5 = 1.2x = 20% more fuel at 6000rpm as at 4000rpm (you would need 50% more fuel is VE was constant)..

For 350rwhp, you can use either 55# injectors or 65# injectors. The max-duty cycle would be about 90% on the 55# and 70% on the 65# injectors. If you do a lot of full-throttle application, like track-racing, I'd recommend the 65# to keep the injectors and DME cool. The GURU chips allow you to flip between 35/55/65/75# injector settings without any interception or massaging of the air-flow signal to fool the computer. All the same look-up points for fuel and ignition are used for optimal power

On the oil-pan gasket, there been numerous people who've had to re-do their gaskets several times. I've posted a procedure that will work the very first time around, it's NOT the official one you see in the manual, there are a tonne of extra steps that's required. Such as throughly cleaning the mating surfaces with acetone, even wiping up the inside of the block as far as you can. And certain sealants are needed as well. Finally, you cannot do the torque sequence in 3 passes, it's best with 4-5 passes to apply even pressure on the gasket and sealant. This procedure works 100% of the time, I've even used it to re-install a used oil-pan gasket on my car after the new one on my new engine blew out on the opening stage of the OTC this year (because engine-builder used the wrong sealant) .

EDIT: Ok, I searched and found my oil-pan gasket procedure:

OIL-PAN GASKET REPLACEMENT

REMOVAL

To remove the pan-gasket, you need to support the engine from above before dropping the crossmember. Then the heat-shield under the turbo prevents access to the oil-pan bolts. Using a LARGE screwdriver, or motorcycle tyre-irons, pry the bottom edge of the heat-shield outwards to that it's vertical. This will allow you to access the bolts.

Also would be a good idea to remove the air-con compressor belt and push that to the outside of the car as far as possible (tighten down pivot bolts afterwards to hold in place). There's two bolts in front that can't be reached easily with the compressor in place.

Then unbolt the oil-pan, to remove it without getting caught up on the pickup, lower just the driver's side of the pan, keep the passenger side about 1" from the block. When the driver side of the pan is about 10" down (mating surface is 45-degrees), pull the oil-pan sideways towards the passenger side to pull the baffle past the pickup tube. Remove pan and R&R the rod-bearings.

INSTALLATION

One of the hardest parts is to ensure that the mating surfaces stay perfect clean at all times when installing he oil-pan gasket. Oil tend to drop down from the block and sit on the gasket surface. So you have to wipe it down with acetone and reach up into the block as far as possible.

Then you also have to scrape off all emnants of the old gasket with a razor blade on both surfaces. WIpe down again with acetone. Wipe off the oil-pick up tube as well.

Duct tape four bolts near the center of each side of the pan so they point up (keep the tap on the bottom side only, so that the bolts don't fall out). Position the bolts about 7" apart, so they split the sides into thirds.

On the oil-pan surface, apply an even 0.5mm bead of gasket-sealant like Yamabond-4 or 3M Fastak Weatherstripping adhesive (#08031 or #08011 should be fine). This is super-strenght contact cement also known as "elephant snot" by DanD. I used it to glue on my 125psi sew-up tyres onto my tubular rims when I was bike-racing. I doubt there'd be any kinds of pressure like that in a crankcase.

Then lay down the oil-pan gasket on the pan, being careful not to disturb the bead of sealant you laid down. The four bolts you taped earlier helps hold the floppy sides of the gasket in place. Gently wiggle the gasket to line up all the other holes with the pan.

Now, lay down another 0.5mm bead of gasket sealant onto of the gasket. During this time, make sure you do not touch the gasket to anything but the oil-pan when positiioning it.

Trick to getting the baffle past the pickup tube is to hold the pan angled down on the driver's side, about 40-50 degrees. Move it up on the passenger side of the car, about 6" to the side of the block, such that the top of the pan is about 0.5" lower than the block. Slide the pan sideways until it's underneath the block, the pickup will go into the baffle. Then raise the driver's side into position underneath the block. Install two center bolts to hold the pan in place.

Then gently install the rest of the bolts (and MySwiss guards) and torque gently by hand such that all the bolts are even. Then tighten by hand just enough such that you see little ***** of sealant barely oozing out. Stop, let the car sit for 6-hours or overnight for the sealant to set and cure.

Come back in the morning and make 3 more gentle passes at the oil-pan bolts to fully tighten them to spec. Reinstall crossmember and that's it.

 

Thanks Danno...... can your Guru chips fix that?

 

anyone have any experience with tuning the Apexi S-AFC II? I know there aren't a lot of 951's with them, mostly Japanese imports....

 

John...fast951.....what size injectors do you have available....

 

55# and 72# Best to email me directly...

 

you have mail....