Spark vs boost

[StealBlueSHO]

Has anyone done an in depth comparison on our motors concerning running more boost with less spark vs more spark with less boost?

I.e. Say running 3-5 more degrees of spark with 1.5lbs of less boost.

Granted tuning both ways until you see knock?

Not including E blends.

 

[derfdog15]

Has anyone done an in depth comparison on our motors concerning running more boost with less spark vs more spark with less boost?

I.e. Say running 3-5 more degrees of spark with 1.5lbs of less boost.

Granted tuning both ways until you see knock?

Not including E blends.

Not an in-depth comparison, but comparing AJPTurbos car when he dyno'd vs. mine when I just dynoed, he had less spark and more boost, and his car made more peak horsepower and torque. I will try and get his run files/ask him to overlay his files vs. mine to see how it looks through the rev range though.

Maybe he can post that up here?

 

[8nutz8]

Has anyone done an in depth comparison on our motors concerning running more boost with less spark vs more spark with less boost?

I.e. Say running 3-5 more degrees of spark with 1.5lbs of less boost.

Granted tuning both ways until you see knock?

Not including E blends.

i've been really curious about this as well and may be employing brads expertise to test out a low boost/high timing 91 octane tune to see how it feels compared to my current tune. this is of particular concern for me because of the altitude my car is performing in. . it really taxes the turbos to get desired tip where it needs to be. my WGDC is always 90%+ through entire pulls and i'm wondering if the car wouldn't make more power if the turbos we're closer to their efficiency range and not just pumping hot air. any loss in boost can of course be added in timing and brad quotes ~7 hp per degree of timing(which is a little higher than what i'm used to hearing but who knows).
from what i've seen lms goes the low boost/high timing route, and from what i've seen of bcb they do the same and both vendors have some fast cars out there.
on that note i wouldn't mind hearing some other people post their commanded boost/WGDC and timing #s.

i'm on 91 oct-15.5lbs w/90-97% duty cycle and 15-19* spark


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[MiWiAu]

I'm by no means an expert, but I did stay at a Holiday Inn Express last night.

It's a tricky question to answer, as a lot of variables come into play.

At a high level, it's my understanding that if you have to choose between boost and timing, more boost will generally make more power vs adding more timing, but more boost requires less advance and will create more heat.

I'm sure one of the experts will correct me, if my synopsis is incorrect.

How I see it, you might tune differently depending on your application (drag racing, road racing, reckless commuter), so you can optimize how/when you make your power for your desired application, which seems like it makes it difficult to answer a generic question of which is better.

An "in depth" study (as you mention) with some tradeoff curves would be awesome to see, so you can understand the relationship between various parameters (like power vs advance, power vs boost, egt vs advance, egt vs boost, etc).




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[djxfactor]

Grabbing my popcorn for the discussion. Definitely a great topic.

opcornandbeer

 

[StealBlueSHO]

Unfortunately, I believe the only people are who going to be able to really talk knowledgeably about it for our particular platform are tuners who have had the time to dyno/track the differences...that would be companies or guys like Brad, Torrie, LMS, BCB, etc...

Which gets interesting because like what was already posted... some of those tuners lean on the turbos for power and some lean on spark to produce the power...

Brads tune I was running ~210kpa at the manifold and 18.5 of spark in third gear in a multigear run from 0 - 100
LMS tune I was running ~187kpa at the manifold and 23 degrees of spark in third gear in a multigear run from 0 - 100
Torries tune I was running ~201kpa at the manifold and 13 degrees of spark in third gear in a multigear run from 0 - 100

In a non-multigear run, just a straight third gear pull after the car has cooled down Brads tune I get ~210kpa and around 20.5 of spark.

The other tuners wont lock the gears in manual mode like Brad... so I cannot compare....

All that being said.... it just shows different tuners approach it differently..

I just realized this quickly can become a which tuner is better discussion which I don't want to engage in, more along the lines, of given all the different way to tune our cars, what are the benefits/trade offs of spark vs boost...

 

[bpd1151]

Objective, fact laden, well articulated post there StealBlueSHO.

And I agree, ultimately left to each vendor to answer (if they so choose) & unfortunately a discussion that could/will, lilely transcend into an unproductive debate.

I applaud your research and posting of your own personal experiences therein.

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[StealBlueSHO]

If this degrades into a pissing match I will just ask one of the moderators to lock the thread.


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[8nutz8]

If this degrades into a pissing match I will just ask one of the moderators to lock the thread.

Well i think we cross that bridge when we come to it but in my short time on this forum i've witnessed a decently high level of maturity(at least for internet standards) amongst different discussions and would hope we would all be collectively above that.
I would love for some vendors to chime in on the subject. My intention in asking others boost/timing levels was more to develop a rough idea of what certain tuners styles are Example:LMS may lean toward low boost/high spark while Unleashed high boost/low spark etc. This way if someone has a certain preference or style they want to stick to they have a bit of a guideline or idea of what tuner to use.(granted LMS is more of a one size fits all and Unleashed is potentially more "custom")
Not too long ago i reached out to a certain vendor/tuner with these and other questions and their response left much to be desired.
Also i'm mostly interested in peoples WGDC at different boost levels to find out if there's somewhat of a "sweet spot" that's best not to shoot past.

 

[StealBlueSHO]

If this degrades into a pissing match I will just ask one of the moderators to lock the thread.

Well i think we cross that bridge when we come to it but in my short time on this forum i've witnessed a decently high level of maturity(at least for internet standards) amongst different discussions and would hope we would all be collectively above that.
I would love for some vendors to chime in on the subject. My intention in asking others boost/timing levels was more to develop a rough idea of what certain tuners styles are Example:LMS may lean toward low boost/high spark while Unleashed high boost/low spark etc. This way if someone has a certain preference or style they want to stick to they have a bit of a guideline or idea of what tuner to use.(granted LMS is more of a one size fits all and Unleashed is potentially more "custom")
Not too long ago i reached out to a certain vendor/tuner with these and other questions and their response left much to be desired.
Also i'm mostly interested in peoples WGDC at different boost levels to find out if there's somewhat of a "sweet spot" that's best not to shoot past.

LMS as you would suspect is fairly low on my car as far as the WGDC... in the low 60's through out the gears... no curve, just flat...

AJPTurbo was similarly flat however was in the low 80's for WGDC... that's with his boost regulator modification.  I will caveats this by saying that Brad was not exactly thrilled with the WGDC being that high, however, we discussed it, and with my SHO being a weekend only car, it was acceptable. I wanted a specific boost setting.

Unleashed was all over the place, not quite sure how Torrie managed it, but the WGDC would vary quite largely during the same run by 20% or more.

That being said, I'm sure the extra heat being put back into the engine from the turbos running that hot has some effect on spark tables as the IATs climb... but the does the extra boost offset the lower spark due to heat?

Maybe on a dyno that can produce some really fantastic numbers cause your not red lining every gear to get to 3rd for a dyno... thus the effects of an elevated IAT is not realized?

Where as on a 1/4 mile run, where you are red lining the gears, really making those turbos work for longer periods, that elevated IAT hurts you because it scales back the timing?

I could be completely off base, still curious however how the tuners on our platform view this...


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[derfdog15]

If this degrades into a pissing match I will just ask one of the moderators to lock the thread.

Well i think we cross that bridge when we come to it but in my short time on this forum i've witnessed a decently high level of maturity(at least for internet standards) amongst different discussions and would hope we would all be collectively above that.
I would love for some vendors to chime in on the subject. My intention in asking others boost/timing levels was more to develop a rough idea of what certain tuners styles are Example:LMS may lean toward low boost/high spark while Unleashed high boost/low spark etc. This way if someone has a certain preference or style they want to stick to they have a bit of a guideline or idea of what tuner to use.(granted LMS is more of a one size fits all and Unleashed is potentially more "custom")
Not too long ago i reached out to a certain vendor/tuner with these and other questions and their response left much to be desired.
Also i'm mostly interested in peoples WGDC at different boost levels to find out if there's somewhat of a "sweet spot" that's best not to shoot past.

My car stock, WGDC was around 40-50% on pulls. (maximum %, it was lower at points as well)

@ 15 PSI at the dragstrip, in ~50 degree weather, it was closer to 65-70% maximum(on a 93 octane tune, stock spark advance)

@15PSI on E20, it was ~ the same as above.

On the current 15-16PSI, E20, with wastegate mod, it goes around 80% at maximum, but generally stays in the same 50-65% range.

Logs attached. Stock is my stock pulls, Rev5 is the drag strip 93 octane, Rev15 is my last major E20 tune revision before wastegate mod, rev21 is current wastegate mod tune that I dyno'd on.

I have also attached the dyno pull log, since the intake wastegate(MV-S wastegate mod) was open the full pull, and the dyno put a lot more load on the car, you can see that WGDC is much higher


I also included Revs 1-4, and some extra drag strip logs, and my stock dyno log. The First few revs incremented boost, by 1 psi at a time if I recall correctly so should show a few varying WGDC. They are all on 93. Rev 5 drag logs should have about 15 to 20 runs down the track, worst being a 13.4 and best being a 12.87 with most at the 12.9-13.1 range. 93 octane on the drag logs. "stock" dyno pull shows the load that was on the car even with the wategate mod not being used, that is with the stock stragie but optimized for E20, rear O2s set properly for catless downpipes, stock BOV set properly for TiAL bov and stock deleted, thermostat settings for my 170.Essentially the stock dyno pull is on a tune, which is optimized for my mods, but has no increased boost or spark, and keeps all stock ford strategies in place (including closing the throttle on shift)

Hopefully these will help you/others. I had to do a .zip because some of the logs are massive (IDK how AJPTurbo put up with my logs in the past)

 

[FoMoCoSHO]

If this degrades into a pissing match I will just ask one of the moderators to lock the thread.


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It really shouldn't, I believe with most anything, there is more than one way to skin a cat.

It doesn't mean one is right or wrong.

17-18+ psi is fun but the fun is very short loved due to the IAT2 compensations.

I prefer my car with less boost and lots of spark advance. (25+)

I can't put my finger on it but it feels better to me.

It Seems like everything happens faster and the car doesn't feel weak at High RPMs.

 

[8nutz8]

Great info StealBlue and Derf!! Those are good comparisons for me. I've attached my stock log for comparison as well- take note of the quite literally "elevated" WGDC my altitude causes even at stock boost levels. And thanks for the wealth of logs Derf- I feel like i'm about to go cross-eyed from looking at logs for too long some nights. Have no clue how Brad keeps his sanity. You can see i hide certain columns and highlight others to make it easier on the eyes.

 

[StealBlueSHO]

If this degrades into a pissing match I will just ask one of the moderators to lock the thread.


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It really shouldn't, I believe with most anything, there is more than one way to skin a cat.

It doesn't mean one is right or wrong.

17-18+ psi is fun but the fun is very short loved due to the IAT2 compensations.

I prefer my car with less boost and lots of spark advance. (25+)

I can't put my finger on it but it feels better to me.

It Seems like everything happens faster and the car doesn't feel weak at High RPMs.

From personal testing and driving I tend to agree with you. The bigger boost tunes will give you more torque especially low end torque around 3K rpms. Where I feel like the high spark tunes tends to like you said, give you more power at the upper rpm's.

You can look at logs all day, lord knows I have 100+ datalogs of various tunes on my car, and I have analyzed to the best of my ability all of them.

Ideally, besides having one our esteemed vendors and tuners maybe explain the pros and cons to both, getting some track time to compare the time differences would be good. The high boost application getting a lot of get up and go off the line but I believe start to peeter out towards to the top end due to IAT's/Knock limitations... vs the lower boost higher spark applications that may not have the lowend torque but because they run cooler IAT's pull more consistently through the gears.

 

[derfdog15]

Once tracks open up in march/april and I get my wastegate spring testing done on current tune, I will be glad to pester AJPTurbo for lower boost/higher spark and see how the times compare

 

[SHOwoosh]

Would it be possible to have both? Request more boost/reduced timing at lower/mid rpm and reduced boost advanced timing at higher rpms? Seems plausible but then I really don't know anything anyway.

 

[StealBlueSHO]

Would it be possible to have both? Request more boost/reduced timing at lower/mid rpm and reduced boost advanced timing at higher rpms? Seems plausible but then I really don't know anything anyway.

LMS has a way to curb the boost spike in first gear only which helps with traction off the line... not sure if that level of granularity can be continued... if needed..


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[ajpturbo]

Would it be possible to have both? Request more boost/reduced timing at lower/mid rpm and reduced boost advanced timing at higher rpms? Seems plausible but then I really don't know anything anyway.

LMS has a way to curb the boost spike in first gear only which helps with traction off the line... not sure if that level of granularity can be continued... if needed..


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I've seen boost spikes are much more manageable and easily mitigated when desired boost is less than 190 kpa....In fact when the desired TIP is in the high 180's I don't even see boost spikes that would require a 3 bar map sensor. And you don't even run lean when you get a boost spike over what the map sensor can read because the 02 sensors would just add the fuel....It's not what you want but but that's what would happen so the idea that you automatically go lean if you exceed the map sensors range is wrong.

 

[ajpturbo]

Would it be possible to have both? Request more boost/reduced timing at lower/mid rpm and reduced boost advanced timing at higher rpms? Seems plausible but then I really don't know anything anyway.

I would never increase boost and reduce timing....Boost and spark are meant to increase cylinder pressure which is what makes power.....Sometimes on big turbos in low rpm you might reduced spark to get the turbos to spool but that's not needed with the baby turbos the SHO's have.

Spark follows load tables with the ecoboost. So yea you can command any spark at various loads at various RPM

 

[ajpturbo]

When I dynoed from stock boost to 18.5 psi I ran the max spark that the fuel could tolerate and made more power at each boost level until about 18.5 psi....18.5 psi was only a few hp more than 17.5 so it wasn't really worth it.

I don't really think that less boost and more spark is necessarily a tactic for max power but rather a guarantee that you can rest easy knowing that people won't have inadequate fuel pressure and less problems and complaints coming back to your company since data logging is not required which is smart in my book. Because strangely enough not all SHO's have the same fuel delivery capabilities.

I've seen some SHO's look fine at 16 psi and some borderline at 13-14 psi.

When operating in an efficient zone of a given turbo, I've never seen a car make more power at lower boost compared to a higher boost when both are running max spark the fuel can handle

I would never send a tune without datalogging and run more than 13 psi.....Of course if I was only running 13 psi I wouldn't even run a 3 bar, there is just no need.

Stealblue on your car if we lowered boost the tables would've commanded more spark but since I'd say we were within the efficiency of the turbos we were moving more air at the higher boost and that coupled with running max spark is why I think it ran well

I think that sums up my take for now until I am provoked by the forum which happens a lot which is why I enjoy the forum lol