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Re: '96 252 454 Magnum performance benchmark
Posted: Tue May 26, 2020 11:28 pm
by akorcovelos
cmattj wrote: Mon May 25, 2020 10:48 pm
Yeah great nasty idle. Letโs make a hit!!
You have no idea how bad I want the lakes to open!

Re: '96 252 454 Magnum performance benchmark
Posted: Wed Jun 10, 2020 10:08 pm
by xlint89
Suspense is killing me. Any word on when she'll be in the water?
Re: '96 252 454 Magnum performance benchmark
Posted: Thu Jun 11, 2020 2:10 am
by akorcovelos
We had it out last weekend, but the lakes were absolutely insane, so couldnโt really push the boat without pummeling my family.
I did get it up to 60 gps on a short hit, it had more but I ran out of clean water. Not bad considering my previous best was 60 on fumes with no gear, and this time it easily pulled to 60 with 73 gallons of fuel, both built in coolers full, and all the junk we drag along, like 3 big bags. I think it will hit 62-63 empty in good conditions.
I still havenโt checked timing yet either, and it feels like it needs another degree or two of base timing.
Honestly the best thing about all that work is how easy this thing fires up now. I literally tap the key without touching the throttle and it jumps into a nice steady idle, and I can hold any rpm without surging. Runs like a new boat, and those manifolds make the swim deck a nice foot massager, lol. Much deeper rumble you can feel in your chest.
I had the sea pump belt start slipping towards the end of the weekend, I didnโt put enough tension on the belt. I have all new v-belts coming Saturday. Still need to install the new exhaust flappers too.
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Re: '96 252 454 Magnum performance benchmark
Posted: Thu Jun 11, 2020 6:21 am
by Big Block Power
Re: '96 252 454 Magnum performance benchmark
Posted: Thu Jun 11, 2020 7:15 am
by cmattj
Haaa. Yes we look at the term clean water as not dodging clumps of muck
That is so awesome AK. That a real world test right there!! Awesome job pal

Re: '96 252 454 Magnum performance benchmark
Posted: Thu Jun 11, 2020 9:43 am
by akorcovelos
Haha, yeah different kind of clean, as in this only brown:

Re: '96 252 454 Magnum performance benchmark
Posted: Thu Jun 11, 2020 8:55 pm
by AsLan7
.
Yes,great job akor.

. Your hard work is paying off buddy.
.
Re: '96 252 454 Magnum performance benchmark
Posted: Thu Jun 11, 2020 10:51 pm
by xlint89
Nice. Thanks for the follow up. Can't wait to here the new top speed.
Re: '96 252 454 Magnum performance benchmark
Posted: Sat Jun 27, 2020 8:39 pm
by akorcovelos
Well, PSA for today is donโt reuse those old rubber exhaust couplers...
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Couple hard pulls and smelled burning rubber. Checked the bilge and saw water coming in from the exhaust somewhere. Tore it down today and found that.
I should have replaced all the rubber exhaust hose when I swapped manifolds. I have 4โ of 4โ Shields wet exhaust hose to replace everything but the transom couplers which are in great shape.
Re: '96 252 454 Magnum performance benchmark
Posted: Sat Jun 27, 2020 10:25 pm
by xlint89
Interesting. I wonder why you're getting so much heat concentrated in one spot?
Re: '96 252 454 Magnum performance benchmark
Posted: Sun Jun 28, 2020 6:45 am
by akorcovelos
xlint89 wrote: Sat Jun 27, 2020 10:25 pm
Interesting. I wonder why you're getting so much heat concentrated in one spot?
When I looked close it seems the angle of the exhaust hose was making the hose contact the flair at the end of the exhaust trumpet. Thatโs also right where the upper water exit is , so Iโm guessing it was restricting water flow at the top and the exhaust gas was un-cooled at the upper trumpet exit. Iโm going to cut an inch off the end removing that flair, should do the trick. Also going to the heavier steel wound reinforced rubber exhaust hose will help as it has a higher temp rating. I should point out the risers themselves never got hot. Even after extended WOT runs I can comfortably rest my hands on both risers.
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Re: '96 252 454 Magnum performance benchmark
Posted: Sun Jun 28, 2020 8:21 am
by Big Block Power
akorcovelos wrote: Sun Jun 28, 2020 6:45 am
xlint89 wrote: Sat Jun 27, 2020 10:25 pm
Interesting. I wonder why you're getting so much heat concentrated in one spot?
When I looked close it seems the angle of the exhaust hose was making the hose contact the flair at the end of the exhaust trumpet. Thatโs also right where the upper water exit is , so Iโm guessing it was restricting water flow at the top and the exhaust gas was un-cooled at the upper trumpet exit. Iโm going to cut an inch off the end removing that flair, should do the trick. Also going to the heavier steel wound reinforced rubber exhaust hose will help as it has a higher temp rating. I should point out the risers themselves never got hot. Even after extended WOT runs I can comfortably rest my hands on both risers.
F478E94D-2A71-4DF0-9220-2389573CEFAF.jpeg
01386C56-7497-4DDD-916D-2CA08D0226FD.jpeg
Buy the looks of that you are going to have bigger problems.
Why did you cut the manifolds in half? Now your going to have water and exhaust fumes all over the place. Buy some JB Weld quick


Re: '96 252 454 Magnum performance benchmark
Posted: Sun Jun 28, 2020 10:17 am
by akorcovelos
Big Block Power wrote: Sun Jun 28, 2020 8:21 am
akorcovelos wrote: Sun Jun 28, 2020 6:45 am
xlint89 wrote: Sat Jun 27, 2020 10:25 pm
Interesting. I wonder why you're getting so much heat concentrated in one spot?
When I looked close it seems the angle of the exhaust hose was making the hose contact the flair at the end of the exhaust trumpet. Thatโs also right where the upper water exit is , so Iโm guessing it was restricting water flow at the top and the exhaust gas was un-cooled at the upper trumpet exit. Iโm going to cut an inch off the end removing that flair, should do the trick. Also going to the heavier steel wound reinforced rubber exhaust hose will help as it has a higher temp rating. I should point out the risers themselves never got hot. Even after extended WOT runs I can comfortably rest my hands on both risers.
F478E94D-2A71-4DF0-9220-2389573CEFAF.jpeg
01386C56-7497-4DDD-916D-2CA08D0226FD.jpeg
Buy the looks of that you are going to have bigger problems.
Why did you cut the manifolds in half? Now your going to have water and exhaust fumes all over the place. Buy some JB Weld quick

Light weight though!
Re: '96 252 454 Magnum performance benchmark
Posted: Sun Jun 28, 2020 9:03 pm
by Bleil05
Hi Akor
Impressive numbers on the boat
One lesson I learned from my local speed shop is to put an oil temp gage on these motors when you modify them
Once the oil gets over a certain temp it fails even though the motor temp is within specs
I would hate to see it scatter over oil failures
Re: '96 252 454 Magnum performance benchmark
Posted: Sun Jun 28, 2020 9:22 pm
by Big Block Power
Bleil05 wrote: Sun Jun 28, 2020 9:03 pm
Hi Akor
Impressive numbers on the boat
One lesson I learned from my local speed shop is to put an oil temp gage on these motors when you modify them
Once the oil gets over a certain temp it fails even though the motor temp is within specs
I would hate to see it scatter over oil failures
Another reason I use BGMOA additive.