'96 252 454 Magnum performance benchmark

akorcovelos · Post by **akorcovelos** » Sun Apr 21, 2019 8:45 am

Easter stuff with family today so no lake time, but next weekend for sure.

akorcovelos · Post by **akorcovelos** » Sun Apr 28, 2019 6:37 pm

Out with the old, in with the new!

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And a little custom touch to let people know this isn’t your average 454.

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Big Block Power · Post by **Big Block Power** » Sun Apr 28, 2019 8:12 pm

Well can't wait to hear about the difference it will make. I have no base line other than my butt. So can't wait either. Im just going for 3mph out of both props and ecu. 63 is my target.
Good luck man.

akorcovelos · Post by **akorcovelos** » Sun Apr 28, 2019 8:19 pm

I’ll be ecstatic if I get 63, but that would be 4mph more with the tune, 6mph total with the props. That’s seems unrealistic, but we’ll see next weekend.

cmattj · Post by **cmattj** » Sun Apr 28, 2019 8:38 pm

akorcovelos wrote: Sun Apr 28, 2019 8:19 pm I’ll be ecstatic if I get 63, but that would be 4mph more with the tune, 6mph total with the props. That’s seems unrealistic, but we’ll see next weekend.

Get ready to be ecstatic pal. All she needs to do is 5200 rpm or higher to get there. Since the 4900 limiter has been overwritten..... May see 64 if the DA stays good!

Im betting 64mph

akorcovelos · Post by **akorcovelos** » Sun Apr 28, 2019 9:18 pm

Well, at 59mph it was pinned at the 5k limiter, and the new tune gives me another 400rpm, I just hope she cat turn that high. The only good thing about this crappy spring is I’ll have consistent conditions for both trials this year which match the benchmark last fall. Fingers crossed, but 63+ and I’ll be doing a happy dance!

akorcovelos · Post by **akorcovelos** » Sat May 04, 2019 5:02 pm

Well, today was a full fail. ECU is going back to Whipple, I assume they just plane screwed up the tune. Wouldn't idle, it was set at like 450rpm, and even when I nursed it out to open water I lost 500rpm and 7mph top end...looked to be pig rich too as it left a fuel slick on the water when I fired it up.

To top it off I checked the waterway app and saw they put the lakes to no wake during the 20 min I was testing. So, old ecu is back in the boat, and it will likely be memorial day before the lakes open up as the forecast is rain all 5 days next week...

Big Block Power · Post by **Big Block Power** » Sat May 04, 2019 5:45 pm

akorcovelos wrote: Sat May 04, 2019 5:02 pm Well, today was a full fail. ECU is going back to Whipple, I assume they just plane screwed up the tune. Wouldn't idle, it was set at like 450rpm, and even when I nursed it out to open water I lost 500rpm and 7mph top end...looked to be pig rich too as it left a fuel slick on the water when I fired it up.

To top it off I checked the waterway app and saw they put the lakes to no wake during the 20 min I was testing. So, old ecu is back in the boat, and it will likely be memorial day before the lakes open up as the forecast is rain all 5 days next week...

Well that just sucks man. Mine didn't idle till I got his fuel to it from changing the fuel filter than the iac had to catch up. Smelled a bit rich to. At least you had a spare I don't so cross my fingers.

cmattj · Post by **cmattj** » Sat May 04, 2019 7:30 pm

Damn. Well at least it brought you back. Did the idle ever relearn? Looking forward to hearing what their thoughts are.

akorcovelos · Post by **akorcovelos** » Sat May 04, 2019 9:10 pm

When the engine was fully warm is would barely stay running in neutral. Even then it was a major turd, hoping they just flashed the wrong tune on it or something simple, like for the non-mag 7.4 or something...I’ll get it shipped back next week, maybe they can turn it around before the holiday. Curious to hear what they say as well.

tgrace98 · Post by **tgrace98** » Sat May 04, 2019 9:16 pm

Ugh that sucks man! Idk what would be worse, the bad tune or no lake time till Memorial Day. Hopefully they can turn it around quickly

cmattj · Post by **cmattj** » Sat May 04, 2019 10:20 pm

akorcovelos wrote: Sat May 04, 2019 9:10 pm When the engine was fully warm is would barely stay running in neutral. Even then it was a major turd, hoping they just flashed the wrong tune on it or something simple, like for the non-mag 7.4 or something...I’ll get it shipped back next week, maybe they can turn it around before the holiday. Curious to hear what they say as well.

I’m Wondering as on one of the tabs on the ecm seems different then your OEM one as well. Maybe just the angle? Could that be off internally as possible your timing is suddenly retarted and your total timing could be 20 degre ish??

akorcovelos · Post by **akorcovelos** » Sat May 04, 2019 11:18 pm

The whole footprint of the ecu is bigger, but Mercruiser put mounting holes for both so it fit no problem, pins are the same on both sides. According to Whipple, and several threads on OSO both ecus are interchangeable by serial number. The symptoms certainly reflect retarded timing, but I doubt it’s due to the physical components, rather the timing map they loaded on it.

I didn’t think to bring my timing light, should have. Injector PWM and cold start enrichment is suspect too as it was running very rich. The rev limiter is also in question as it consistently would hit 4500 and hit a wall no matter trim or throttle input, exactly 500 rpm less than the stock ecu. Many questions, for now I can only guess until I talk to Whipple.

Big Block Power · Post by **Big Block Power** » Sun May 05, 2019 6:32 am

Is that a mefi1 2 3 or 4? It looks totally diff then my mefi4. I'm guessing 2 or 3 because it's much easier than mine. When you found it I thought it was the same part number. I know the mefi4 is used in a ton of fuel injection options.

Ytmsn · Post by **Ytmsn** » Sun May 05, 2019 6:44 am

That too bad Akor, I feel bad for you as I know you had high hope's and expectations. But I suspect you'll get it sorted out and come roaring back!

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