Dyno Results - Stock vs Bolt On vs Tune (Karcepts)

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04-05-2017, 09:10 AM

#11

s2000Junky

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Quote:

Originally Posted by Slowcrash_101

Gotta tune, we don't have MAF sensors that can compensate for things that affect air flow, or fuel. Because our cars have MAP sensors, the computer relies on pre-programmed maps for various engine conditions, if you start changing things(bolt-ons) then the way the engine breathes changes, but the maps stay the same. When one tunes, they are essentially tweaking the engine maps to suit the new characteristics of the engine.

If we had combination MAF and MAP sensors tuning would be much easier, the ECM would compensate for any small changes in A/F ratio etc. You would only need to tweak fuel tables when you upgrade injectors, and play with ignition timing advance to control knock. With our cars, we have to tune everything just bolting on an intake and test pipe.

Yes and no. We do have a smart ucu which does self correct at idle and up to 35% throttle opening roughly (called closed loop) which reads and compensates to keep the afr on target. When you get into open loop operation of the ecu 35%/WOT, that's when you need to monitor your afr if you start getting into breathing mods that are improving airflow to the point of being too lean. Depending on the MY S2k, this will fluctuate, but generally an Intake and cat back or test pipe will still improve flow to safe levels without needing to add fuel, because the stock fuel curve is on the rich side to be optimum, especially evident in the early 00-01 ecu, progressively getting leaner and more dialed in with each new series 02-03/ 04-05 etc. The 00-01 ecu runs so rich in fact, ive never seen any bolt ons exceed an optimum afr, even lowering vtec and running primary cam ecu fuel in vtec gets to dangerous levels. That is different on 02+ however. Should always be running a wideband when doing bolts ons to monitor anyway so you know exactly where you are at.

Last edited by s2000Junky; 04-05-2017 at 09:15 AM.

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08-04-2017, 08:09 AM

#12

Dwnfrce

Join Date: Mar 2017

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I've been looking at this package as well since I'm already in STR w/o a tune and it seems i'm at a huge disadvantage. But big issue is i'm in Oklahoma with no easy access to 93 octane. What's the impact to using 91 octane on the tune?