I am working on fine tuning my new setup, and one of the many details I have come across is that besides opening up the top end and breathing better, I want to improve low end or low rpm low load drivability. At normal accel from a stop light I effectively have to rev up to avoid a bog situation. This has been the case with my evo before mods, and many others I have driven.

For me this is in many ways a reason why many stock clutches don't last as long as people think they should. Its because they are revving up to have brisk take offs, but the low end torque is missing and without the rev will stall or buck.

I want to improve this characteristic, and was trying to figure out if adding timing in the low rpm and low load cells just before boost would kick in is the best way to do this. Or is it fuel. In some threads I have read that richening up the mix will provide more torque, but in others I see a lean mixture (like lean spool) will provide the extra power.

What are the recommendations and reasons for what you believe is the best way to tune to give more accel power (twist, torque) on brisk take off from a stop?

 

https://www.evolutionm.net/forums/ec...ter-spool.html

But in short, you cant usually have the best of both. The IM and head work typically will sacrifice low end to gain top end. But the cliff notes in the 1st post of the linked thread are a very good place to start.

 

I remember that thread from appauldd. I will give it a reread. So is faster spool and off boost torque analogous. So that tuning for one is the same as the other. I didn't think about it that way.

I was trying to find a way to get some pop just in the initial take off. My evo has always required revving and then slipping in the clutch to make it go. Very unlike my old WRX, which popped very well off the line.

I comprehend your comments on the two different goals, because no matter how big the turbo the rex always ran out of air quickly it seemed. My current setup on the evo doesn't seem like it ever does. It pulls weirdly all the way until 7500rpm when I chicken out and get off of it.

Now after reading the million page "show us your timing" thread I wanted to see if bumping the timing would be the right approach. In your link I see that opposite of reduce timing for spool.

I pasted in my timing map in case I am generate a discussion off of that. I would be interested to see anyone else's timing map with cams and any rationale behind. This is my own hack job, so take it easy.

 

Your timing table looks pretty decent,you could start by adding more timing at idle and right off of idle to help you get going,start at like 10 degrees instead of 7and go from there,good luck

 

I havent really messed with <100 load timing too much. Mostly just pulling timing from 100 to peak load until VD stops showing increase in tq. I figure with how quick you go from vacuum to 100 load (0 psi), there wasnt a whole lot to gain there. And my only changes there were to smooth the transitions into the >100 load timing cells.

You may also want to look into some of the accel enrich settings. "Asynch vs TPS delta" & there is an RPM dependent table there too.

btw...you have a ton of resolution in between 0-2500 rpm.

 

If you tune for best power, you will get the best "spool." It might not look like it on a dynochart, but if you look at torque vs. time, the best power setup wins every time.

On my setup, I found I could run suprisingly aggressive on even 91 octane up to about 12 psi. I think I was up around the 12.5:1 AFR range and still reaching MBT. I turn the boost down as far as it will go and fully tune it at that level. It gives you a good idea of where timing and fuel should be at the lower loads.

I also run "lean spool" with different maps then stock and it makes 1st and 2nd gear really snappy.

 

I wish I had the comprehension to run lean Spool. I think I saw a write up you did a while back..

 

same here. Ive disabled it long ago. Now wondering if it may be worth revisting since Im actively autocrossing again.

 

one thing i found made a noticeable difference on my car was coming up with a good mivec map. (i believe the op has a 9 also)

 

Yup, I have a 9 and the Mivec is also unchanged since I did it years ago for the previous setup. I believe its essentially the mix of the JDM RS and "how to tune evo" thread, but I don't recall exactly. I messed with it a lot when tuning essentially a stock 9 with very good results. Now with the 272 Cams I don't really know what the approach on that should be , so I have left it alone, focusing on the timing map. I'll post it here if it helps the discussions.



@charlie.tunah - Yup I should get rid of the 1250 and 1750 rows to make room for more up top. I the past I have chicken'd out when it comes to changing map resolution.

@03whitegsr - Do you 'run aggressive' up to 12psi by adding lots timing or was that just an AFR comment? I still have lean spool enabled, but have not changed anything related to it.

Am I dense or are some of the comments saying to richen up for more power on the low load columns and the others saying to lean out for more power (lean spool)?

I love this stuff!

 

No. Your reading it right. Im confused as well. And now doubting whether or not Im tricking myself. Im reading the same discrepancies with timing..some seem to be doing better with as much timing as it will take, others say pull timing so spool is quicker (due to higher egts).

I pulled timing and tried to maintain 12.5 afr until 15 or so psi. I was hitting 20 psi by 3000 rpm starting the pull at 2000. This past weekend I fixed some MAJOR boost leaks, but now my laptop is giving me issues and dont have any data since then. But it seemed like I was getting to full boost quicker, the tq curve seemed to change accordingly, but this is also VD...

 

Same here! I've been researching this too.

I tried different timing and AFR. I also am in open loop full time. I lowered the knock warning light to signal at 30 load and on.

It drove me crazy seeing all the perceived knock below 100 load. I don't know if this was phantom knock, but it was more severe when I had high timing below 100 load. I did this per the timing and MPG thread. I meant to get knock cans to determine if it was real, but I decided to trust the knock sensor and I pulled timing and raised the knock light signal to 100 load and up.

I felt like with the higher timing and leaner AFR it had more torque. Also, like VIIIdriver, I had the my idle loads at 11* due to the S2 cams. I definitely liked how much snappier it felt. I go back and forth between this and 9*, I kind of like the lope sound.

 

Play arround with more timing in the area 80-120 load x 500-2500 rpm.
Dont get too ambitious but the Evo will respond to timing there.

Setting all those 7* cells at idle to 10* will assist as you have bigger cams fitted.

As 03whitegsr says, there are benefits to revising the Lean-spool tables.
For example, set start to 2250 rpm and End to 3500 rpm and reduce the enleanment to about a half AFR.

 

Thanks merlin.oz. I will give some more timing a try at the range you noted to see how it takes it and report back.

I used to have 10 in the idle, but like 10isace, when I got the cams I wanted some burble to show for the engine work. Time for that fun but gimmick to go.

I also lowered boost back to my original map of max at 25-26 (stock 9mr turbo). Once beyond that I had to pull timing to not knock on 91. I have modded all this engine breathing stuff, but haven't been able to modify the tuning because everything I tweak induces knock it seems.

My lean spool end table is set to 7000rpm? Is everyone's like that? I was trying to figure out the condition that would stop lean spool in those high rpms, since that seems weird. I also couldn't figure out where to reduce the 'enleanment', what table?

For the sake of this discussion, this path is on the more timing and leaner ARF camp. How about some comments from the make it richer or retard timing for higher EGT guys.

 

the enleanment is the 'Lean Spool AFR Mapping' table

cheers