Im looking for any extra advice on promoting spool, I'm using an ATP 3076R setup and a modded JDM RS mivec map, ive spent several hours re-working the timing table to make as much off turbo power as i can right now im netting about 23-25 psi right at 4k and i cant seem to get it to spool any better. Car feels great, but im looking improve upon great, thanks for reading heres my current mod list ,
Hard pipe kit
Stock intercooler
Gsc S1
megan coated manifold
turbo using small tial wastegate
and v-band outlet
That should be all the neccesary mod info you guys will need thanks in advance for any help

 

Set AFR to 14-13.5 during spool and it will spool up better.

 

There are two broad schools of thought:

1. Retard timing and run lean to produce high EGT to help spool the turbo.

2. Advance timing and run good AFR for normally aspirated torque to spool the turbo.

The downside to 1 is that you can spool the turbo earlier, but the extra boost might not do you any favors in actually making extra torque because of all your timing retard. I go for 2, but others think differently.

With MIVEC and your particular cams, I would try anywhere from 14 to 28 degree of MIVEC advance in the spool area and picked the best one.

I'd say your spool sounds quite good already though.

 

Thank-you im Already there ,,
Today one of my friends introduced a new theory to me by retarding the timing a lot your actually firing the exaust gases inside the turbo just about ,, but it decreases the power the engine makes but thechnically quickens spool does anyone have proof to support this or to somehow negate the power loss

 

Whoops posted at the same time jcs ,,, with that retarded timing a lot of off turbo power would be lost correct???

And the way mine is right now is like your 2nd suggestion

My mivec is set to 28 in the entire spool up area in a 4th gear pull it hits full boost directly at 4k no matter what rpm i start the run from (2-3500rpm)

 

I tried it on a Subaru engine, and I didn't like the feel or sound of it, boost came in earlier but it didn't feel worthwhile. My Evo came alive for torque with MIVEC and timing advance, it seems to accept a wide range of AFR though, but I'm talking stock turbo here. The main thing to avoid with your cams might be excessive MIVEC, as you might end up with too much overlap, but as you say you've been there already.

I think your spool sounds good for 4th gear on a 3076. My EJ257 would spool a 0.82AR 3076 at about 3500 RPM, but it didn't have VVT and had many feet of exhaust manifold, but still it had a lower rev limit than the 4G63 and ridiculously short gearing meant I was changing gear twice just to go around a bus I think you'll have a nice power band with what you have, full boost just after half of red line RPM isn't at all bad IMHO.

 

in my mivec map, I have from 2000 - 3500, 28.8 from like 100 load.

I tried this last weekend... I was/and now am again, running an AFR of 13.0 - 12.0 during spool up w/ my timing @ 17 at 2000/100 load, 15/12 @ 2500/120-140load, 10, 8, 6 @ 3000/ 160-200 load and I spool ~34xx-3500. I have seen ppl spooling around 3300, so I was trying to hit around there...

So what I did was lean it out to 13.5 - 12.5 during spool up and w/ a new timing profile (for spool) 12, 10/9, 7/5/4 in the same cells, and this did nothing but lose me power, and did not promote any better spool up... IDK, maybe I needed to lean it out even more, but wasnt gonna chance it. The power loss was substantial enough for me to ****can that idea.

 

If you retard the timing you also decrease cylinder pressure (and torque therefore) so in so doing you are not only not gaining spool its probably hurting it. High advance on the MIVEC and 12.5-12.8 AFRs (which requires lean spool to be off and then manually set the curve) will promote the best results. Run the timing as high as you can for your boost spike, but at some point you end up having to keep the timing down anyway.

All in all I agree with John and opt for choice 2.

On the bigger turbos I have been able to increase spool a few hundred but nothing really crazy. For instance we were comparing a very similarly equipped build (cams were different) and I noticed it seems like mine was anywhere from 200-400 rpm sooner on a IX. On an VIII on pumpgas I would assume this would be a little more exaggerated but even then I have seen the smaller turbos light off at 4100 or so. Cam selection makes a big difference in what you are able to do with the MIVEC and spool characteristics as well.

Aaron

 

Thanks to all for the info it seems im on the right path ill keep tweaking keep in mind all the above suggestions and see where i end up ,, bradley when you say hi advance on the mivec do you mean maxed out or have you seen better results at say 20 versus 28???

 

I found good results with 24* mivec and high timing advance 23*-19* during spool with 13.5 afr, this was with hks 272 cams.

Will soon test it on a gt35.

 

Im netting very similar timing numbers im going to try a lower mivec advance and see if it changes anything

 

28.8* is the max stock amount you can run. Thats what I mean as has been pointed out. set the max value before the RPM its likely to light off native and then work to see how much lower you can get it. Rescaling the rpm and load to make this happen and then tapering it off after it comes on will work best I feel.

 

I suggest full advance to 5000-5500 rpm, tapering to zero by 7000-7500 rpm

 

im using full advance to 4500 now tapering to 6 at 6000 rpm then 0 from 6500 on this has givin me the best results with spool so far hope this helps someone else out there

 

If by spool up you mean misfire I agree.