After much searching and reading on this forum, it appears to me that there are two different schools of thought on tuning.

One school of thought says that the most power can be achieved by dialing back timing in order to run as much boost as possible.

The other school of thought says dialing back the boost and running as much timing advance as possible is the way to go.

Am I correct in my perception that this is the two underlying approaches to tuning?

If so, has anyone ever tested the two extremes on their car, same day, same dyno, same mods, same fuel, etc., in an attempt to see which angle actually worked best on their car?

I read a post just the other day by someone who insists they make more power by dialing back from stock boost level to 18 psi. This is the first I've heard of anyone actually turning the boost down. Has anyone else tried this?

Thanks,
Jim

 

I am pretty much a noob at this so take my post lightly.

It seems like people shoot for 21-22 psi. Although it seems like the magic numbers arent boost, but timing. From people I have talked to in the dsm community they aim for 16 degrees at redline.

 

Was my question too easy or too difficult?

In any case, here is the question again in its simplest form.

Which usually makes more power additional timing or additional boost?

Assuming that you are at the point where they are mutually exclusive. Meaning that in order to get more boost timing must be pulled. Or, to add more timing boost must be reduced.

Thanks,
Jim

 

Do you have Ecuflash and Evoscan? I suggest you do it yourself. I tried to change timing I get more power than just increase boost, that is just my test.

 

i just tuned my car recently again and tuned for 23 psi pump and increased timing a lot lol and tuned it and managed to get no knock with high psi, high timing...now that is best power!

 

I did quite a bit of testing with various timing, air:fuel and boost on my car and what I found was that for 93 octane raising the boost above 25psi required a few degrees less timing and quite a bit more fuel.. to quell knock, so much that the car started feeling flat. The track agrees, I was consistently 1-2 tenths slower. I pulled the boost back down to 24psi, leaned the fuel back out and added a few degrees of timing and it felt worlds better and I shaved off several tenths.

each car is different but that's how mine responded. Happy tuning.

 

Isn't the stock turbo struggling to keep about 20psi at redline?

 

I allow mine to spike to ~ 24psi which gives me some good torque during the intial hit, the boost will taper off some towards redline. Obviously you have to tune for this but it can be done.

 

Its a good theory I guess.

 

https://www.evolutionm.net/forums/sh...ing+high+boost

The theory has already been experimented with...These are the results.

 

I was very pleased to see 4WheelSlide's tuning experiment. Even though it is only one data point, it does appear that increased boost adds more power than increased timing.

Has anyone else attempted any similar tuning experiments?

 

For the most power you should tune as close to 12.5:1 with no knock since this is where fuel burns the fastest.

However that is not the safest, so you try to give a margin of safety with 11.3:1 or so with little to no knock.

Lots of timing with adding fuel = Rich
Timing with the right amount of fuel = power

 

12.5:1 ? thats what i tune race gas at on the lean side.... are you sure thats what you meant to say?

 

Yes that is waht i meant to say. Fuel burns fastest at that rate 12.5:1. That is unsafe though since alot can go wrong, so we tune to for richer AFR's.

The reason why you tune Race gas Leaner because it has a slower burn rate. So the leaner you go to 12:5:1 the faster it will burn, hence the 12ish AFRs you get tuned for on race gas.

Fuel burns slower after 12.5:1 and before that.

 

Personally I like 11.0-11.5 on pump gas and 11.5 to 12.0 on race gas, it allows a bit more timing and boost and that makes more power than leaning it out.