550s and AFR settings

[XakEp]

I know that if you have the 450 injectors you should set your tuning at all Zeros to start and work from there. What should I set my baseline at to start tuning with 550 injectors? According to the math these things should flow about 19% more than the stockers, so does that mean I set it to -19% across the board and tune from there?

I have the Wahlbro 255lph HP fuel pump and the HKS S-AFR with a 16G and the large hahn SMIC. 19% seems a little excessive to me, but what do you guys think?

When I do hard 3rd gear pull my EGTs dont break 1300 and my timing hits 20.5 with the psi at 15... O2s are pretty steady but I dont remember what the exact numbers were.

[Hal]

Actually, 18% is closer... so - 18% gets you 450cc offsets.

Now, in addition to that, when you go WOT... the ECU will target 9.9:1 afr, so you can then tune from there.

Taking out an additional 10% will give you about 10.5:1, and 15% will be 11:1.

Hal

[john]

But please either verify the settings with a dyno/wideband O2 combo, or an incar wideband.

[XakEp]

Ok, heres what I did... I took Hal's advice and leaned my car out to 10% across the board, and then took the amounts that I leaned out and divided them by half (for shits and giggles... It seemed right) and added the totals... The car pulled hella hard and topped out at 1500 degrees EGT. I backed off a little and richened the mix at 7k and 6500 and leaned out the low and mid bands a little more until the car stopped pulling hard, and backed off a bit. I'll post my numbers but I think that with 104 gas, an added 3-5 psi on the MBC and careful driving, I could hit low 13s. At any rate, the car is pulling like a banshee, and I'd like to thank this club for helping me!

And yes, as soon as I get some money saved i'm going to the dyno. Who's with me?

[XakEp]

Hrmmm... Heres an idea... SInce the AWD helps with the launch, I dont think I have to lean out the lower band any m ore, I'll richen it a bit and lean out the mid and high bands more since I need more power to compensate for the AWD chassis... what di you guys think?

[DlandryTSI]

I would still do the whole map. Otherwise the car will be completely flooded with fuel on the bottom end. Of course thats me and my big turbo's opinion :)

--Dave

[john]

Get it on the dyno, or beg/borrow/buy an in car wideband. Just guessing at numbers will work up to a point, but to get it really and truely tuned a wideband is necessary.

IMNSHO.

[XakEp]

I dont hknow anyone who has a wideband or I would most certainly use it... THe dyno I want to go to doesnt have a wideband yet either... But either way, youre absolutely right, I have to get one to tune this thing RIGHT...

[john]

If the car is AWD, then Autosport Werks in Broomfield can help. If it's FWD, go see Bear at Dyno Pro.

In car widebands are starting to show up in the area.