502 HO MAG 430 HP Upgrades

[Captainervin]

Has anyone done any upgrades to the exhaust or Computer?

 

[jack14r]

Has anyone done any upgrades to the exhaust or Computer?

I did the Whipple stage 2 on a 380 hp motor and removed the catalyst,it is much better out of the hole pulling skiers and is about 4-5 mph faster.I have a bravo 3 drive on a Cobalt A25 and a 3 different prop sets with a 22.5 lead prop and a 24 rear prop is what I use for skiing it will turn 5300 rpm at 58.5 mph,with a set of 24s it will turn about 5200 and with a set of 26s it will turn 5000 at 60 mph.This motor had some flat spots in it before the mod and now it is perfect.

 

[BHC Vic]

I did the Whipple stage 2 on a 380 hp motor and removed the catalyst,it is much better out of the hole pulling skiers and is about 4-5 mph faster.I have a bravo 3 drive on a Cobalt A25 and a 3 different prop sets with a 22.5 lead prop and a 24 rear prop is what I use for skiing it will turn 5300 rpm at 58.5 mph,with a set of 24s it will turn about 5200 and with a set of 26s it will turn 5000 at 60 mph.This motor had some flat spots in it before the mod and now it is perfect.

What exhaust did you go with? I'm still considering his just a little scared I guess

 

[Captainervin]

What exhaust did you go with? I'm still considering his just a little scared I guess

I just got off the phone with CMI they have the headers for my application

 

[BHC Vic]

I just got off the phone with CMI they have the headers for my application

I heard headers where 5k which is money I'd rather keep. Wonder if u could do the tune and leave the cats

 

[jack14r]

What exhaust did you go with? I'm still considering his just a little scared I guess

Just took cats out and stayed with the stock cast exhaust.

 

[Captainervin]

Just took cats out and stayed with the stock cast exhaust.

Did you do the deletion kit ?
What improvements did you see?

Does it sound any different?

Thanks again!!!

 

[BHC Vic]

Just took cats out and stayed with the stock cast exhaust.

How hard it is to pull them?

 

[Bigbore500r]

ATTENTION FEDERAL GOVERNMENT ATTENTION FEDERAL GOVERNMENT

 

[Miss Venomous]

Federal Government, I would never personally bring my cats on the boat....

 

[Singleton]

What exhaust did you go with? I'm still considering his just a little scared I guess

Wait until the engine and drive warranty has expired then do it. You can do the ECU flash (Whipple stage 1 or 2) without messing with the cats and exhaust.

 

[BHC Vic]

Wait until the engine and drive warranty has expired then do it. You can do the ECU flash (Whipple stage 1 or 2) without messing with the cats and exhaust.

Thank you that's what I've been wondering [emoji106] I believe warranty is up I will check though. Vacation check is going into the boat [emoji4]

 

[pronstar]

I really wonder how much of a gain you'll get ditching cats. Modern cats have very high flow and oftentimes, removing them might net a single-digit HP increase on a stock-hardware N/A motor, and you'd never feel it if that's the case.

 

[BHC Vic]

I really wonder how much of a gain you'll get ditching cats. Modern cats have very high flow and oftentimes, removing them might net a single-digit HP increase on a stock-hardware N/A motor, and you'd never feel it if that's the case.

I was just considering because they weigh a lot but I don't want to buy a new exhaust system. If I can just do the tune and get the 80hp I'd be stoked. I know it's not a ton of gain but for 1500 bucks why not

 

[BHC Vic]

Also I wonder how that will effect my prob

 

[pronstar]

If a tune & no cats truly nets 80hp, the cat alone is likely a very small percentage of the gain.

If removing a cat(s) nets you a huge gain on its own, then the cat(s) have problems and aren't functioning right.

 

[Singleton]

Also I wonder how that will effect my prob

You will move up in prop. 24 to 26, or 26 to 28.

 

[Ultra247]

I'd start by going to Boostpower for a reflash on the ECU. That usually helps quite a bit. I went to powerflow manifolds on a 7.4 LX and it made a big difference in sound and about 2-3 mph. Hole shot was better. The modern exhausts that come from the factory are pretty good so most of the shops have told me not to waste the money on an exhaust upgrade.http://www.riverdavesplace.com/forums/images/smilies/yikesj.gif

 

[BHC Vic]

Anyone know if b&d does the flash? His shop isn't too far

 

[Bigbore500r]

I was just considering because they weigh a lot but I don't want to buy a new exhaust system. If I can just do the tune and get the 80hp I'd be stoked. I know it's not a ton of gain but for 1500 bucks why not

80hp from tune-only is a massive gain on a 430hp motor. Unless it is purposefully de-tuned from the factory to a much lower power level, i would be surprised to see 80hp without supporting exhaust mods. If that were the case Mercruiser needs to fire their tuner lol

 

[Singleton]

Anyone know if b&d does the flash? His shop isn't too far

Unplug ECU, ship to Whipple. Wait about a week it gets shipped back. Don't think anyone else can do it, has to be shipped to Whipple

 

[Ultra247]

Boostpower is up in the valley. Alexi will do it at his shop. I just had mine done a couple of months ago.

 

[BHC Vic]

80hp from tune-only is a massive gain on a 430hp motor. Unless it is purposefully de-tuned from the factory to a much lower power level, i would be surprised to see 80hp without supporting exhaust mods. If that were the case Mercruiser needs to fire their tuner lol

I'm no mechanic but from what I understand (which isn't much [emoji12]) the mag is a de tuned ho. Basically it's the throttle mapping that is different. So in lame mans terms. The tune makes the mag the ho... Basically. I'm sure someone can explain it wayyyyy better

 

[Shortdeck]

I'm no mechanic but from what I understand (which isn't much [emoji12]) the mag is a de tuned ho. Basically it's the throttle mapping that is different. So in lame mans terms. The tune makes the mag the ho... Basically. I'm sure someone can explain it wayyyyy better

The Mag has a resistor plate behind the air cleaner.

With the tune and new(or machined) inlet they say you can net power similar to the HO motor.

 

[BHC Vic]

The Mag has a resistor plate behind the air cleaner.
View attachment 487354
With the tune and new(or machined) inlet they say you can net power similar to the HO motor.

View attachment 487361

I heard better power but similar works for me [emoji4]

 

[Singleton]

I heard better power but similar works for me [emoji4]

Increase in octane as well. You start pumping 91

 

[BHC Vic]

Increase in octane as well. You start pumping 91

Yup that's only downside I see but not really a huge deal. Would be cool if I could break 70 on a gps speedo [emoji4]

 

[Singleton]

Yup that's only downside I see but not really a huge deal. Would be cool if I could break 70 on a gps speedo [emoji4]

The other thing your not told before the tune. After it is done you are running richer then before at max rpm levels so you will end up changing your engine oil more often. I am changing mine every 25-30 hours now.

 

[BHC Vic]

The other thing your not told before the tune. After it is done you are running richer then before at max rpm levels so you will end up changing your engine oil more often. I am changing mine every 25-30 hours now.

Good to know. I'm going to have to find s place in bhc or havasu that's a long frequent tow to cobra [emoji16]

 

[Singleton]

Good to know. I'm going to have to find s place in bhc or havasu that's a long frequent tow to cobra [emoji16]

Changing oil is easy. Saturday night I punch hole in filter and drain oil out into 5 gallon bucket. Sunday am, take off old filter, install new one add oil and off we go. Filter and oil get dropped Monday am at a shop

 

[HBCraig]

Can Boostpower and/or Whipple do the same ECU upgrades to 496HO's?

 

[Bigbore500r]

The Mag has a resistor plate behind the air cleaner.
View attachment 487354
With the tune and new(or machined) inlet they say you can net power similar to the HO motor.

View attachment 487361

Holy restrictor plate batman.....

That would do it! Ok 80hp from removing THAT and a tune is totally plausable. Rip that shit out ASAP!

 

[BHC Vic]

Holy restrictor plate batman.....

That would do it! Ok 80hp from removing THAT and a tune is totally plausable. Rip that shit out ASAP!

Can I get that thing out or a shop or...?

 

[Bigbore500r]

Can I get that thing out or a shop or...?

Looks pretty easy, but not sure if you need a replacement inlet piece or if just removing the restrictor leaves you with a finished inlet. If it did , then you would just bolt the TB back on and have it flashed. Ive never done it......looks like Shortdeck has

 

[hvnfun]

I did the Whipple stage 2 on a 380 hp motor and removed the catalyst,it is much better out of the hole pulling skiers and is about 4-5 mph faster.I have a bravo 3 drive on a Cobalt A25 and a 3 different prop sets with a 22.5 lead prop and a 24 rear prop is what I use for skiing it will turn 5300 rpm at 58.5 mph,with a set of 24s it will turn about 5200 and with a set of 26s it will turn 5000 at 60 mph.This motor had some flat spots in it before the mod and now it is perfect.

What did it cost you to do the upgrade?

 

[LargeOrangeFont]

The other thing your not told before the tune. After it is done you are running richer then before at max rpm levels so you will end up changing your engine oil more often. I am changing mine every 25-30 hours now.

Does not compute... More fuel in the oil is a different problem. Or are they wanting you to change it for a different reason?

 

[LargeOrangeFont]

Changing oil is easy. Saturday night I punch hole in filter and drain oil out into 5 gallon bucket. Sunday am, take off old filter, install new one add oil and off we go. Filter and oil get dropped Monday am at a shop

Yep.

I bought a $18 12V oil pump from Amazon. You just have to go to Home Depot before you use it and buy some 1/4 hard plastic tubing to make a longer run down the dipstick tube. I'd buy a 5 gallon bucket and lid while you are there to store used oil, unless you have a large container for it. After a day on the boat, hook the pump to the battery and it will suck the warm oil out of the pan in about 5 minutes. Then just swap the filter, fill with oil and you are done. You just have to do it while the oil is warm.

http://www.amazon.com/gp/product/B0..._m=ATVPDKIKX0DER&pf_rd_r=18AX4BBZ92PC211QAYHX

 

[CoolCruzin]

Those cat manifold weigh a lot from what I was told .Just removing them and running CMI or imco alum. would be a plus.
A shop told me to have some one help removing them cause they are heavy .

 

[Miss Venomous]

Yep.

I bought a $18 12V oil pump from Amazon. You just have to go to Home Depot before you use it and buy some 1/4 hard plastic tubing to make a longer run down the dipstick tube. I'd buy a 5 gallon bucket and lid while you are there to store used oil, unless you have a large container for it. After a day on the boat, hook the pump to the battery and it will suck the warm oil out of the pan in about 5 minutes. Then just swap the filter, fill with oil and you are done. You just have to do it while the oil is warm.

http://www.amazon.com/gp/product/B0..._m=ATVPDKIKX0DER&pf_rd_r=18AX4BBZ92PC211QAYHX
View attachment 487418

I have been using the old style hand pump type to create vacuum & watch it dribble out! :thumbsup

 

[LargeOrangeFont]

I have been using the old style hand pump type to create vacuum & watch it dribble out! :thumbsup

For $18 I'd buy a new one of these every year if I had to, but this one worked fine. I assume it will last at least a couple more years. The key is having the oil warm when you suck it out. The time consuming part is setting up your longer sucking tube the first time, and figuring out how to orient the pump, discharge tube and canister.

 

[BHC Vic]

Well it sounded easy at first [emoji12]

 

[BoostPower]

Boostpower is up in the valley. Alexi will do it at his shop. I just had mine done a couple of months ago.

Yes we do reflashing in house and 1 day turnaround[emoji1303]

 

[curtiej10]

Just did the whipple stage 2 up grade and removed the cats. I gained about 300 rpms and 3 mph top end. Not sure how much torque but they say 200. The boat did plane much quicker. Over all for $900 and change not bad. By changing the stock cast exhaust to CMI headers you'll prob lose about 200 lbs, just the section that held the cats was about 50 lbs. I will look to do that upgrade next.

 

[BoostPower]

Just did the whipple stage 2 up grade and removed the cats. I gained about 300 rpms and 3 mph top end. Not sure how much torque but they say 200. The boat did plane much quicker. Over all for $900 and change not bad. By changing the stock cast exhaust to CMI headers you'll prob lose about 200 lbs, just the section that held the cats was about 50 lbs. I will look to do that upgrade next.

[emoji1303][emoji1303]

 

[Runs2rch]

Just did the whipple stage 2 up grade and removed the cats. I gained about 300 rpms and 3 mph top end. Not sure how much torque but they say 200. The boat did plane much quicker. Over all for $900 and change not bad. By changing the stock cast exhaust to CMI headers you'll prob lose about 200 lbs, just the section that held the cats was about 50 lbs. I will look to do that upgrade next.

900 for 3mph. Running 91 now also?

 

[LargeOrangeFont]

900 for 3mph. Running 91 now also?

I'll bet it picked up more than that in the midrange.

Stop asking him questions. He needs to work on my boat today

 

[Runs2rch]

I'll bet it picked up more than that in the midrange.

Stop asking him questions. He needs to work on my boat today

Eh maybe. The tuned 496's seem to run the same.

Noted! No more questions!

 

[LargeOrangeFont]

Eh maybe. The tuned 496's seem to run the same.

Noted! No more questions!

Yea I'd bet both are very similar. I think the move is to buy the regular 8.2 and flash it when the warranty is up. Then you are talking $700 for 75 HP.

 

[Runs2rch]

Yea I'd bet both are very similar. I think the move is to buy the regular 8.2 and flash it when the warranty is up. Then you are talking $700 for 75 HP.

This makes the most sense, but the availability of 91 on the water is not always there.

 

[LargeOrangeFont]

This makes the most sense, but the availability of 91 on the water is not always there.

I'm sure boostpower can do the same thing, but Whipple lists a couple stages of tunes for the big blocks so you are not locked into 91 unless you go to stage"2" or whatever.

I always put 91 in the boat anyway but for my 6.2 the only Whipple tune offered needs 91. It is supposed to be a 20 HP bump or so.