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Hi guys,

Back on May 5th I brought my car down to Matt & Bobby at Jailbreak Tuning to do some software tuning on the dyno. Previously my car had the Dinan stage two software (along with their intake, exhaust and 3.45 rear differential, all of which it still has). Check out the video:


The first three runs we did were with the Dinan software still intact, to get a baseline. Run three was the strongest of them, with peak horsepower at 327.46 and peak torque at 314.79. (note: these are all SAE corrected numbers) Matt pointed out to me how rich the mixture was above 5250rpm and how "wavy" the lines are, which Matt says is indicative of the knock sensor kicking in all the time. Luckily these are both things that can be fixed with software to produce more power. Then Matt downloaded the Jailbreak software to my ECU and we did some more runs. The horsepower and torque curves immediately jumped up, and the A/F ratio stayed much closer to 13.0. So already a great improvement. But Matt saw some things that could be improved upon - a small change in fueling here, a timing adjustment there, etc. We did a run or two with the MAFs disconnected - made virtually no difference at all. After eleven runs in total we were done.

The results:

Peak horsepower: 327.46 to 342.82
Gain: 15.36

Horsepower @ 6000rpm: 311.06 to 333.11
Gain: 22.05

Peak torque: 314.79 to 330.63
Gain: 15.84

Torque @ 4500rpm: 311.55 to 330.59
Gain: 19.04

Again, all numbers are SAE corrected. Oh, this was with 91 octane (CA) pump gas, by the way. Don't be overly concerned with the absolute numbers - it's more about the differential, as the car wasn't moved from the time the Dinan stage 2 was on there until the Jailbreak tune, using the same dyno on the same day, same outside temperature, etc. It was around 75 degrees F, by the way. Also, the car's air conditioning was on, which could account for a little bit of power loss.

You can see the "waviness" in the run 3 curves, and how much flatter the curves got with the changes (run 11). The air/fuel ratio improvements are also very visible. Just look at that flat torque curve!

Now that I've had this tune in place for a few weeks I can give some overall impressions. The car is just as driveable as before, but it seems more "eager". Just a bit more juice. The idle is smooth. No CES light or codes. And sport mode stays on! I'm a fan.

Matt & Bobby are super nice guys that know what they're doing. I'd definitely recommend their products. Here's their site: Jailbreak Tuning If you're in southern California they may be able to do custom tuning on the dyno for your car like they did for mine, so definitely ask them.

I hope this has been helpful!

Brian
 

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Those are great results. I have the JB tune and I really like it, especially since they managed to fix a severe case of kangaroo effect on hard acceleration.

Many dyno runs on here have shown the AFR doing that same dive into the mid-11's at high rpm, which always puzzled me since the conventional wisdom for modern engines is to aim for around 13:1. So it is a weight off my mind now your post has confirmed that is what JB aim for. :)

So why do stock cars go so pig-rich at high rpm? I think it must be to provide detonation margin for cheapskate owners running 87 octane gas.
 

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Thanks for posting this! Concensus around here and the E60 group is that the Dinan tune is conservative. Will be interesting how much more power Matt can extract from the Unicorn.


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Very nice results and well documented!
 

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I too have the Jailbreak Tune, and while I have not had the opportunity to dyno the car and have them tweak it, the Kangaroo effect is eliminated. It is smoother, more responsive, and much more driveable.
 

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I was trying to find info on their LA shop but couldn't find any, do you have their location or did I just miss it on their site? Great results though! I'm definitely considering them.
 

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Those are great results. I have the JB tune and I really like it, especially since they managed to fix a severe case of kangaroo effect on hard acceleration.

Many dyno runs on here have shown the AFR doing that same dive into the mid-11's at high rpm, which always puzzled me since the conventional wisdom for modern engines is to aim for around 13:1. So it is a weight off my mind now your post has confirmed that is what JB aim for. :)

So why do stock cars go so pig-rich at high rpm? I think it must be to provide detonation margin for cheapskate owners running 87 octane gas.
They run richer than LBT (leanest best torque) to hold the exhaust gas temps down to protect the head, the valves, the exhaust manifold and the cats. Advancing the timing will also drop EGT.

It is unlikely that the engine would pass an OEM durability sign-off with an AFR of 13:1!
 

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They run richer than LBT (leanest best torque) to hold the exhaust gas temps down to protect the head, the valves, the exhaust manifold and the cats. Advancing the timing will also drop EGT.

It is unlikely that the engine would pass an OEM durability sign-off with an AFR of 13:1!
I know you know your stuff, Sub8, but even in the bad old days of domestic, cast-iron, wedge-shaped, two-valve, offset spark plug, low squish combustion chambers, the optimum AFR for power was considered to be 12.5:1. With modern aluminum, 4-valve, centre-plug, CFD-designed, ITP-fed, fuel-injected, knock-sensed combustion chambers, surely 11.5:1 is a bit rich?
 

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Nice. I already have their out of the box tune and will head down to the shop to dyno-tune after I get my Evolve headers and CAI installed.
 

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Hey 68, you are completely correct! Maximum torque is almost always around 13:1.

However at that AFR at high RPM and particularly at sustained high RPM your EGT is going to be way above the benchmark of around 900 - 950C. With high EGT you have a simple material durability issue; typically the maximum valve bridge temperature a modern head can support is around the 250 - 280C mark (steady state), max exhaust manifold temp around the 950C mark and cat entry around 900C. However at higher EGT you also have the potential to create hot spots on exhaust valve edges, spark plug end threads and on piston contour lines (valve cutouts) etc. These can act as a precursor for det and in extreme cases for pre-ignition. Therefore running a little richer than LBT while hurting power in isolation gains you in the ability to hold a bit more spark without it knocking.

The extra fuel is used purely to cool the various components in the firing line.

I`m not slaggin the tuners in any way, i'm just saying that for OEM durability not many engines, even the very latest designs can hold the optimum AFR for maximum performance when running at high (>5000) rpm.

OEM have to take account of the spread in engine hardware and sensors and component ageing.

Getting more spark advance into the engine is where the real performance increase comes from, while still holding good durability, cylinder pressure issues aside.

Anything that drops exhaust back pressure will also help EGT and hence allow a leaner running engine safely. On this engine its no surprise that decent headers make such a difference, you can cram extra spark in and drop the enrichment - win / win!

Cheers.
 
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