I have been reading Chucks notes again and reviewing Wargasms single turbo write up.

Wargasm recommends these numbers:

0 psi- 12 AFR
5 psi- 11.7
10psi - 11.5 AFR
15 psi- 11 AFR
20psi- 10.5


I have my recent map tuned to be 13.8/14.1 AFR at 0 psi. Cars seems very responsive but i am concerned that that may be too lean and cause EGT's to go up. I do not have an EGT gauge FYI.

I am just curious to see what some of you guys have for 0 psi to maybe 5 psi for AFR. My WOT AFR at 15 psi is about 10.9/11 so that is in check.

S4 13BT streetported, 62-1, 3inch TB exh. FYI again

 

I run mine high 12's at 0 psi, taper to high 11's up to 10 psi then low 11's up to 15 psi. I would think your afr's are alright at 0 psi considering 0 psi would be like a naturally aspirated engine. 12:1 is prob about the safe limit up to 10 psi and 11.5 at 15 psi. But it all will depend on the quality of the fuel, the air temps going into the engine, how restrictive your exhaust system from the manifold back is, the heat range of the plugs, your ignition map, if ai is being used... Pretty much the whole combination will determine what is safe for your engine.

 

I used to run mid 13's AFR on my s4 n/a, made 172rwhp all motor. that was on 87 octane and 9.4:1 rotors

 

I dont think I am going any higher then 11.0 AFR at 15psi due to 91 octane WITH ethonal up here in Montana. And the fact that I have a S4 block with the weak rear iron

My leading timing at 7K & 15psi is 11*, actually 10* on map but it should be 11 since the PFC adds 1 degree of timing from N10-N17. Pretty safe I think.

 

is your knock sensor working right? what knock count are you getting?

 

I would richen the low PSI part of the map, ~13:1 would be as lean as I would go. Remember that at 0psi the turbo is still moving a fair amount of air, and at this point your really setting the car up to transition into high load so why start with a ragged mixture. I think you would be setting up an area that could create some knock, If anything I would advance timing to make power in that area.

 

My knock is great. Highest value so far has been 44 at about 4K in the p14 area which IN FACT is too lean(hit about 14.31 AFR there).

At redline, my knock is around from 12 to 8. 18 being the highest knock recorded @ 15psi and 7K, that was also a AFR of 11.8. I ended up adding full there.

 

sounds like you're making a lot of progress, keep up the good work.

 

Thanks man. I am happy I relocated my knock sensor to my rear rotor housing. I did not like the location on the intermediate housing. PLUS i read that S4 have a tendancy to loose the rear rotor the most often, so it is right at home.

 

do you have s5 housings? how/where did you relocate it if you have s4? I've got my motor together, about to drop back in, and I just put the knock sensor back in the intermediate housing. It was really noisy/useless before but I have s4 rotor housings with no hole for a knock sensor. I would regularly get knock readings in the 70s, sometimes without even boosting. But I think my motor mounts were loose too...

i also purchased the dual digital EGT setup for the new engine. have you read about that? https://www.rx7club.com/3rd-generation-specific-1993-2002-16/dual-digital-egts-612960/ it's going to be sweet... now i can finally get my timing dialed in right.

 

this thread has me worried, i recently installed a wideband into my car at at 1/4 throttle i notice the AFR's at approx 14.5:1 sometime's leaner at 0psi, if i get onto boost it does taper down to 10.8:1 AFR, however my knock is the exact same weither i have a free rev. or wrap the tach through 3gears, it hits 105 at most....

at a few psi say, 4psi i do notice the car a little possibly leaner then it should be, anything over 1/2 throttle at whatever RPM the AFR goes to 11.5:1 or richer atleast....

thoughts?...

 

Don't worry too much about it. I wouldn't through any worth to tuning with a factory knock sensor anyways. Seeing knock of 100 isn't uncommon.

 

lol that makes me feel better then....

it hit 103 tonight from a free rev in neutral, i've hit lower at full boost going through gears....

:P

 

I hit 150 on cruice on my car.
If i i boost, It drops down to 0-1.

Maped my car couple of weeks ago, and no knock at all.( Max boost at 20 PSI)
Using diff braze and engine braze, really move all noise to the knock sensor.

 

In my car the intercooler piping rattles like crazy, that and there is some binding and rubbing in the front end

 

also, would it matter weither it's an FC or FD in regards to the knock count?, i'm driving an FC....

 

The s5 knock sensor is in the same location as the FD.

 

ahh, so in other words the knock sensor is pathetically inaccurate, lol....

 

Need a sanity check

16 psi - 11.0
17 psi - 10.9
18 psi - 10.8