Now that I've finished tuning WOT AFR's, it's time to take a look at my cruising cells.

Specific cells I'm looking to tune would be:

N05 - N10 / P01 - P09

How high an AFR (14, 15, 18?) can I use to maximize cruising MPG. I think the 8 MPG (w/out boosting) I'm getting now can be improved on at least a little.

Maybe someone with a less modified car using stock injectors and a closer to stock map can post their cruising AFR's? (maybe I'll cross-post this to the 3rd gen section)

K

 

I'm being told by Checkpoint to use 14.5 ~14.7 for cruising in the N/A area, and then set your accelerator enrichment values such that you run ~ 13.5 in the N/A areas under acceleration. That give you safety, smoothness, and decent mpg. You could run leaner, but is it really worth it?

I use a set of custom t-60 trim twins running parallel, so I'm kinda like a single. Still have my smog pump, too. The numbers above assume you smog pump is not engaged.

Beast

 

This is dangerous. When cruising there's nothing wrong wtih a 16:1 AF, but problems can occur on initial throttle tip in.

I experemented with leaning out the cruising cells to compensate for no O2 sensor feedback. It worked, but when on the track when off throttle through corners, then ON the gas there was a really lean condition that would occur at about 2PSI of boost. I didn't think it would hurt anything since it was plenty rich at 5PSI & above.

Well, the brief lean condition during spool must have caused hot spots which led to the fatal pop! Lesson learned.

 

Currently I'm seeing:

average AFR's in the 11 - 13 range and minimum AFR's in the 9.5 - 10 range. I'll make sure tip-in stays richer, but will probably lean out vacuum > 5 into the 14's and see what it gets me in MPG. A 20% decrease in fuel dumping there should yeild me an acceptable (and safe) 10 - 12 cruising MPG.

K

 

ES -

You're right about tip-in, but you can compensate for that with the PFC using accelerator enrichment and tps vs. injector ratios. I'm assuming nocab72 is using the PFC since he's using PFC nomenclature to refer to the map x/y axis.

I'm running 14.5 across the board from p1 to p8, then I go to 13.5 at p9 and 10 (just before boost) and then follow the usuall 13 --> 12.5 --> 11 --> 10.5:1 as you move up in boost. I run 13.5 in the n/a area on throttle tip-in by messing with enrichment and tps % settings using datalogit software and DIY NTK wideband. No knock, super smooth, decent crusing milage, power up the yingus. I'm still running under 10:1 at p19 ... working up to 10.5 in that row very carefully (one click at a time). Ran 330bhp at the wheels under these rich conditions with some boost leaks. Big single guys will do even better

 

Hey Beast,

I ran stock base map to 337RWHP @ .83bar, this was in 10.5's, stock fuel, block, turbos.

I am tuned to 11.5s, up to P19xN19. Running stronger then ever now. Dyno event will tell what ~1bar will give me.

Nocab72 is tuned to 11.5s as well. His IS a beast.

I am running about the same strategy from P1-P9, but transition to 11.5s, later on.

Use that "tip toe" strategy on the timing too. Keep you from poppin'!

 

My car is tuned for 14.0 at little to no load (cruising).

You might want to go just a little richer due to the tip-in phenomenon mentioned eariler... I have no experience with that issue.

 

Beast, if you don't mind would you PM or post your exact settings for TPS/Inj & accel enrich? It would be helpfull.

Also, what's the difference between the TPS/Inj setting and the PIM voltages other than one being the throttle pos in % with a multiplier on top of it, and the other being throttle position sensor voltage with a percentage of add/subtracted fuel?

 

Here's my latest settings file (I changed it to a .txt so that it would upload to the site - you'll need to rename it to a .dat file), based on the following relevent mods:

full intake, i/c, exhaust (dp, mp, catback)
Nippo fuel pump, 1300cc secondaries
Custom parallel twins (two t-60s, kind flows like a small t04 type turbo) in rewelded stock manifold
PFC (duh)
Twin Power ignition
Stock port

I have a bunch of suspension and stuff that is unrelated to AFR type stuff.

Use this as you will. I think my accel enrichment is a bit too much - I've begun to back off the decay rates and ms settings as I get closer to the afr's I want under cruise, light load, and mash your foot on the floor:-)

As far as tps/inj and PIM, I think you summed it up. The computer somehow chooses between the two depending upon conditions. I guess they have some sort of fuzzy logic that blends the info together to come up with what the injectors should do.

Beast

 

thanks beast.

I see you have O2 feedback enabled. IMHO this makes a big difference in cruising MPG & the switch to open loop rich A/Fs at WOT.

Once my piece gets back together I plan on running O2 feedback again.

 

One thing to mention - you'll notice that my higher rpm cells in the n/a area (N>11, P<10) are corrected WAY lower than the base map. This is due to the fact that I have the 1300cc secondaries. They kick in heavy in that area. I have the PFC set for 1300cc secondaries, but they really flow 1350cc per RC Engineering, so they are flowing a bit more than what the PFC thinks. That means I have to correct as much as 12% downwards to get afr's in the 13's. So, anyone using these settings with 850cc secondaries is going to run lean. Bottom line - DON'T EVER USE ANYONE'S MAPS UNLESS YOU HAVE A WIDEBAND TO EVALUATE THEM, and don't just 'go for it' using new settings. Baby steps are the key here.

Beast

 

Why not adjust the secondary injector size to 1350?

 

I know that my injectors will slowly start to flow less as time goes by, so I just left them alone and adjusted the maps in the ultra-rich areas. At some point as they get dirty/worn I will have to begin bringing the maps back up.

Your approach works, too - six of one/half-dozen of the other. We can also leave the correction factor at 100 for all cells and just adjust the base maps (but I'd rather leave the base maps alone). That's the beauty of datalogit and the pfc

 

 

Beast,

Did that map start life or was it touched by XS? It has alot of negative split in it:
P4,N18
P6,N18
P6,N17
P6,N16
P8,N11
P8,N9
P7,N9
P7,N10

I am no expert, but I feel that negative split is a BAD thing.

 

Wow - I just downloaded version 1.07 and hadn't even noticed this. Been concentrating on fuel instead of timing right now, given that I was pig rich. Good pickup! I'll fix that tonight when I pick up the car. I'll just retard the trailing rather than bump up advance on leading for safety.

My maps started out from Ray at SR, not XS.

Thanks again - this might explain why the car isn't as smooth as it should be in the p6 high rev line.

Beast

 

You bet. Yup, adjust by trailing only.

 

nocab,

You should be able to get 20 mpg or better when cruising.

 

Tuned cruising cells to 14.0 using the OZ-DIY WB. MPG is much, much better than before. No hard numbers because I can't seem to keep my foot out of boost... I just notice the gauge not moving quite as quickly toward E.

K

 

Not only should your mpg improve - your car should feel much, much smoother in the n/a area....... it will feel like a new car :-)

Beast

 

while N/A and > 3000rpm can I safely tune in and keep the 13.5 - 14.0 AFR's? I assume so since there would be very little load on the engine if revving that high but staying N/A...

k

 

In the n/a area you can tune right at stoich. I run 14.2~14.5 under no load in the p<9 area, and bring it up to 13.0 as it crosses into p>10. You just need to do two types of logging in the n/a area - one where you are on the highway just cruising to get your no-load numbers (just shift gears between 3rd, 4th, and fifth to get to the different cells), and another where you are pulling the car under light load (say driving around town on on a road that has lots of speed limit changes - just keep your foot out of it so you don't go into boost). It just takes a bit of time to get it dialed 'just right'. Use your acceleration enrichment to richen up the maps - se the map values based on no-load, then increase your ms duration for acceleration so that those values get richened a bit when you have part-throttle.

Beast.

PS - all of this assumes you are using a wideband, of course. Also, watch for your air pump turning on and off - it will throw off your numbers.... if they suddenly jump to ~18:1 chances are your air pump is kicking in. I disconnect mine when tuning n/a....

 

My airpump is on the floor in my garage, I don't think it will be kicking on unexpectedly?

Thanks for the pointers Beast!

k