Stingray 230 LX Engine Swap & Whipple
 

Hi all,

Just wanted to share details of a project that I have been working on with my 2007 Stingray 230 LX Bowrider. Two winters ago I had a boat with a dead 350 mag mpi and elected to move forward with a new engine in the existing boat. I swapped the old engine for a new Mercury Remanufactured 385 performance tuned with headers. The engine is rated 350hp stock and 370hp with headers. I also have captains choice exhaust. Over the last two summers I put about 80 hours on the new engine and found that it improved my top speed by about 5mph. I swapped the original speedo for a GPS so it is hard to get exact improvement numbers but that is about right. The old speedo was more than 10% high based on rpm - WOW. I can now hit 60 on GPS with a light load and some light chop and 57 or 58 regularly.

Now that we are broken in it is time to take advantage of the beefed up internals in this engine. This winter I am adding a whipple supercharger, dual hydraulic steering and trim tabs. I am also swapping the drive for a Bravo XR since my steering was shot and my old drive was approaching 500 hrs and had some wear. I went Bravo XR and not a shortie after all of the good advice I got on this forum and some other searches. The boat is just not fast enough to really benefit from the shortie and planing and turning will be too compromised for the small added benefit. And ... my kids are going to be driving this thing in a few years. My marina found me a refurbished for close to 1/2 price so easy choice.

I have thought a lot about swapping to a different cam but want to run it for a summer and see what it is like first. I also love the sound of this engine and am reluctant to change it too much. That being said, the Seven Marine supercharged 627hp outboards use the LS9 cam and from what I hear they sound very good. It is 211/230/122 vs the stock one in the 385pt which I believe is more like 214/218. With the supercharger the additional exhaust duration should be very meaningful and the 122 LSA would hopefully keep idle reasonable. Any thoughts on cam are welcome as it may be next winter's project. I will also have to get my ECM custom tuned too which I know is riskier than the proven Whipple tune I am getting now. Lots to think about.

Thanks to everyone for posting so much great info on this board. Will post speed and driving characteristics when I get it in the water.

Hi all,

The supercharger is now installed but we are running into what appear to be fuel issues. Huge thanks to Whipple and BBlades who have been great to work with along the way. After installing the supercharger we could not start the motor at all. Turned over but would not catch. With 10 degrees of mechanical advance it fired up but would only get to 3,000 rpm or so before losing fuel pressure. With some tweaking on advance and fuel pressure we were able to get it to 4,000 but same thing. Then we changed the pickup from the tank and hardwired the low pressure pump. We have reached 5,000 rpm but only with 26gpm fuel burn and with speed of 64mph vs. 60mph pre-supercharger. I have not driven it yet to see firsthand and confirm tach/burn numbers but hope to later today. Has anyone had any fuel issues like this when adding a supercharger to an EFI motor?

Some additional data points:
1) the prop slip seems way too high here so I wonder if the marina had it trimmed too high. The 21 mirage plus I used to run went 60 at 5000 rpm same GPS speedo. Now I am running a 4 blade 24 pitch BBlades. Should go at least 69 with same slip and it feels like it hooks up better than the Mirage did.
2) The 385 performance tuned with the whipple is supposed to be 515hp. With my headers/thru hull exhaust it could be slightly higher as the motor is rated at 370 with headers by Mercury. 515hp should be around 40gph. Much higher than 26.
3) Based on speeds and associated hp from other Stingray bowrider owners 64mph is probably achieved with 400 - 425hp - although an 8.2 burns over 30gph at 425hp so that is a headscratcher too.

Any thoughts or advice are welcome. Hope to have more info to add here in a day or two.

Hi all,

Update that the boat has spent the winter in the highly competent hands of Saris Racing for some additional engine work and tuning. New higher CFM heads with larger chambers to reduce compression to about 8:1, cam, intake, ECM, higher boost pulley (targeting 8psi), and a few other things. The boat ran between 66-68 mph GPS last summer with a high of a hair over 70 on a sub 40F morning in September exhaust closed - too early to make that kind of noise. I tried a number of props from Bblades who was also great to work with. The 4 blade OB/FX labbed to reduce diameter was probably my favorite prop although I have not yet labbed the Mirage 25 which was about the same speed stock with more bow lift. Both props would cause chining if over trimmed but reducing the diameter of the Bblades prop reduced the stern lift and helped tremendously. The boat was definitely running a little rich with the tune so I enthusiastically am taking Jason's recommendation to change and custom tune it. CID will be slightly higher with the new heads - 391 now I believe. Objective is to see what the potential horsepower is here without going so far as to require mid-summer adjustments of valves or making the idle too choppy with too much cam.

Will post more when the ice thaws and I can try it out :)

Just trying to follow along.
This is the engine ?
C&M Marine Distributing - Remanufactured 385 Performance Tune Engine 8M0064807

If so, not sure why reference on LS9 cam. Totally different engine. Most regular sbc use a 112-114 lsa cam when supercharged.

Engine displacement being calculated with chamber volume as a factor is a new one to me.
I guess technically, but I've never seen it done customarily.

Yes, it started with the 385 PT from Merc Reman. I got the idea for the LS9 cam from the Seven Marine 627 outboard which is a 9psi supercharged similarly sized engine. A friend of mine has 3 of them on his boat and raves about the performance and idle quality. You are right about the LSA - super high

I think you are right Cheech and I misspoke there. Displacement is borexstroke so head volume is not in the calc. I was factoring the increase in total volume with the new 72cc heads necessary to get from a 9:1 closer to an 8:1. Going aluminum on the heads to squeeze a bit more PSI in there and lose a little weight.

Okay. On same page now. That LS9 cam is quite unique, Nothing i’ve ever remotely seen on normal 23 degree small block.

Your in good hands at Saris’s shop.

Did you figure out your fuel supply issue or waiting for lake to be usable until you know ?

Fuel issue is solved with an upgrade and definitely ahead of water test. Not sure exactly what Saris is doing but I know it needs attention. I definitely feel in good hands. This is my first custom engine build so I don't have a lot to compare with but I could not feel more comfortable.

I think I was running closer to 470hp based on calculating horsepower and speed from the original engine (300hp/~56mph), New 385pt (350hp/~60mph), Others experience with the 425hp in a 230sx (65ish mph) Whipple added (?hp/68 - 69mph). I cannot really count the 70 because it was in the 30s and super dry. These are ideal condition speeds all around. The shorter intake manifold that comes with the Whipple is great for fit and is very compatible with the tune but it compromises evenness of air/fuel distribution. By replacing with a taller one with better mixing they can custom tune a leaner mix adding power.

If it is of any help, I had a 496 Mag (375HP) 230SX closed deck, with a 25"P Mirage prop and it ran around 67 mph GPS, I think if i kept trying and was in the boat alone I could coax 68 mph out of it. I had that 25P Mirage labbed by BBlades and it ran the exact same mph but with a bit more bow lift. I sold the boat due to the poor performance, but the boat itself was fine. From reading the internet it appears the same boat with a 496 HO ran more like 70 - 72 mph.

Thanks for the info kornegle. The SX and LX were not too dissimilar in weight and design. If I recall Stingray would post speeds about 1-2mph higher with the 230 SX set up the same way on their claimed performance. I am boating on Newfound Lake in NH which is 600feet and is humid more often than not and have never come close to their speed. I think they claimed the stock 230lx with 300mpi was 60-61mph and I never saw more than 57 gps and usually ran closer to 54. I was running a 21 laser too which is about 1mph faster than the mirage on my boat having run both. You are definitely getting more speed with 375hp than I would. I forgot to add that my 385PT has headers and captains call exhaust which supposedly makes it closer to 375hp pre-whipple and I think I saw 62 once. 58-60 was more like it.

Did you get more chine walking with the additional bow lift? Now that I am running high 60s that is my limiting factor. Particularly when there is a small chop which used to be my best top speed conditions.

If it's any help, 2001 230LX
Stock 5.7TBI B3, 26p - 56gps
383 - 480hp B1 (corrected, Kodiak Exh Dyno),mirage 21p - 70gps.
413 - 440hp, B1 (corrected, EMI), Offshore 21p - 68gps
413 - 620hp Procharger, B1 (corrected, dyno headers), B1XS 24p - 80gps, P5X 25p - 80gps

Well, horsepower wise, I had a 496 Mag (375 HP rating) in a 230SX Stingray. I think the hull bottom on the 230SX and yours is the same (I might be wrong). The 375 HP with a 25P Mirage Plus prop pushed mine to about 67 mph at 4600 rpm (about 8.4% slip) with my wife and me and a bit less than 1/2 tank of fuel. Your small block is lighter, even with the blower so I would expect it to be at least as fast with the same HP. If it has 515 HP, I would think it would run closer to 74 mph?

05 stingray 230sx 8.1 /496
 

Hey Guys, new to the forum. I'm purchasing a 05 230sx with the 8.1/496 ..


Can anyone tell me the realistic top speed please?

Here or dm is fine!

Mine 230SX ran about 67 mph at 800 ft elevation and mine was a 375 HP Mag not the 425HP Mag HO. The 425 HO should run at least 71 - 72 mph. The Stingray website said mine should run 68 - 69 mph but I never hit that. Perhaps in colder weather with less than 1/4 tank and me in it alone it would have hit 68 mph? Running the Silent Choice exhaust open or closed made no difference in top speed on mine. It was a good comfortable boat, on smoother water. I sold it and bought a new 2400 Checkmate Pulsare with a 300R, and it has only run 76 mph so it was not that much faster.

Any idea why this one is hitting 58? The wake tower shouldn't make it drop 12 mmp should it? In order to hit the 70s should he have to trim out or no?

Trim- Yes
Trim setting is a constantly moving target. Depends on load, speed, water conditions.
At WOT bump your trim up while watching speed. When speed/RPM stops increasing stop increasing trim.
(RPM can increase without an increase in speed, that means you are trimmed out to much.)

First an update. After a winter with Jason Saris the 385PT has really woken up. Dyno sheet attached. I ran it for a few weeks and realized that the air vents on the side were too small. Took me a while to figure this out. Jason hit 76mph GPS on Lake George where he is with no engine cover in hot and humid conditions. With the cover on I saw 72-73mph in the early summer humidity. I found a set of vents that are slightly more than double the size of the old ones and with those I hit 75mph @5300 rpm with my labbed four blade Bblades OBFX (14 inch diameter, 25 pitch). I had 5 people in the boat, half a tank and it was 80s and humid. Unfortunately after that I had an electrical issue with my fuel system and decided instead of troubleshooting it I would take it back to Jason for an upgraded system with a single pump. He is so good I think it is a confidence thing to bring it back rather than risk someone else now. He also tweaked my fuel map a little bit but it ran really well with his first custom program. I am excited to try it again next summer. Given that the extremes of hot and humid vs. cool and dry were worth about 4mph the summer before I think it may be possible to see 80 @5,600. I am taking Jason's advice and propping for 5,600 max.

One thing I realized about this boat now is that it takes a lot longer to get to top speed. It will very quickly get to what appears to be a steady level and will consistently rise about 1mph or 2mph over the next couple of minutes. A little bit of that is coaxing it with trim until it chines but I think it is mainly from the smaller diameter prop getting full grip and losing its slip.

To speculate on speed of the 230sx mentioned above, here is my speed history based on the most optimal conditions I could find:

Stock 300hp - 57mph
385PT stock + headers - 350hp (said 370 w/headers) 62mph
Whipple added 5lbs boost and XR drive - HP unknown but speculate 470 - 70-71mph
Now - 561hp (@5300) - 75mph with my boat loaded - I think 588hp @5,600 rpm and 80mph possible in very ideal conditions


https://cimg3.ibsrv.net/gimg/www.off...3ffb6ebe9e.jpg

I was thinking about it this morning and realized I should have added the realistic speeds for my Stingray in addition to the fastest. I would say realistic means 1/2+ tank of gas, a few people in boat and weather where you want to be on the water so 75+F. See below:

Stock 300hp - 57mph; realistically 52-53mph
385PT stock + headers - 350hp (said 370 w/headers) 62mph; realistically 57-59mph
Whipple added 5lbs boost and XR drive - HP unknown but speculate 470 - 70-71mph; realistically 66mph - 68mph
Now - 561hp (@5300) - 75mph with my boat loaded - I think 588hp @5,600 rpm and 80mph possible in very ideal conditions; in this case the 75mph was the realistic speed.

One other observation on these boats is that weight definitely impacts speed more when my hp was lower particularly weight in the bow. With the higher hp weight is less of a factor than it was before and weather seems more of a determinant. I remember when I was running the 350/370hp I had two ~180lb boys in the bow and three adults in the back on a hot day. Boat ran 53mph with the boys in the bow and just having them move to the bench seat in the back made it accelerate to 56mph.

On top speed and trim when I was lower hp I could get a little bit of porpoise by overtrimming and could rev up too. Once the boat got over 66mph overtrimming would cause chine walking before I got the rev increase or porpoise from over trimming. Also, at 60mph or less my fastest speeds were in about 1'-2' chop with following wake. Now I need closer to calm to really trim it up without chine walking.

My 230SX only ran about 67 mph so it was too slow to chine walk. Perhaps that heavy big block kept the stern planted and reduced the chine walk? I could trim it to the stops and it would not really chine walk/

Kornegle,

That makes total sense. When I first got my Bblades OB/FX Four blade it was a 15.25" diameter. With that amount of blade area it was VERY stern lifting and it would start chining in as low as 60. Another reason we labbed it down to 14" diameter. It is also driven by conditions. More waves and particularly angled set it off. Feels amazing to drive it when it is so light on the water though.

I am thinking I am going to lab my 25" Mirage Plus this winter. Would love to try it at 14" diameter and with sharpened blades. That should give me a little more speed than the 4 blade. At this point though I think I am about done with speed upgrades both because the amount of time you can be in conditions to drive above 80mph is low and pushing my current block any harder will be diminishing returns with the reliability cost.

One of my favorite props was the 23p Offshore or Vensura 4 blade. Smaller diameter and that extra blade held the load real nice. The P5X-25 was still the best in overall holding and keeping it from rocking side to side. I'm getting less interested in ringing out every last MPH (getting old). I redid my procharger with a better impeller and am getting more boost than I have my motor mapped for. I really need to put my 66lb injectors back in and rescale the fuel table for the added boost if I want to go faster, but I think I just going to put the bigger injectors back in and put a bigger pulley on the blower to slow it down. I'm OK with 76-78. Now if I can get may hands on a -2 imco, whooweee, crank that boost and see what's in her! I think 85 with the p5x and 11-12 lbs of boost is totally doable. But is my ass if I pop the motor again. (Though it last popped when cruising and coming off plane). Be sure to keep an eye on your plugs when running hard on boost.

Don't you have an intercooler on that Whipple? Temp really doesn't matter to my setup, I make my own nice weather.

"Stock 300hp - 57mph
385PT stock + headers - 350hp (said 370 w/headers) 62mph
Whipple added 5lbs boost and XR drive - HP unknown but speculate 470 - 70-71mph
Now - 561hp (@5300) - 75mph with my boat loaded - I think 588hp @5,600 rpm and 80mph possible in very ideal conditions"

You know there is no cure for this, right? :eek:

I ran 67 mph with a 25P Mirage Plus that was labbed. It had more bow lift after labbing but it did not gain any speed. It held the bow higher and porpoised a bit less and drove a bit better but no faster.

I do have an intercooler. Did you custom tune your EFI? My setup has some conservatism in it. With the exhaust open it runs right around 8.5psi at full throttle and 5600rpm. Whipple said 10psi is the absolute limit with my compression and running pump gas. I have been running 93 in it. They also put a different manifold on it than what came with Whipple so that my fuel/air mix is more consistent across all cylinders.

What grenaded your engine? Was it a bad plug or were you too lean with the high boost? 11-12psi is a lot. Your compression must be in the low 7s?

I have an Acell DFI7 setup and tuned it myself. I wouldn't say I lean burnt it. I think I was running too hot of a plug and it melted and caused some pre-ignition which caused the top ring on my tightest piston to butt and pop the top off after crusing at about 45 and coming off plane. Motor locked up with hard parts obstruction. Fortunately the only damage was the piston and a bunch of valves. I had about 7-8 lbs of boost at thay time and now is over 10, but I haven't datalogged to see what it goes to because my injectors are too small. I have 8.4:1 compression

Ugh. Losing an engine over a plug. Are you running 11-12PSI on 8.4:1? I have 8.0:1 and Whipple says no more than 10psi on pump gas. Are you retarding timing or making the mixture rich at high boost?

Kudos to you for self tuning. I got a lesson from Jason's team on how to do it but still have not dug in. So far his tune is very good.

Out of curiosity, how much does your boost drop when you open your exhaust? I have seen my boost gauge move noticeably downward even at levels like 3psi around 50mph when I open the exhaust.

I have my timing map set to pull a few degrees when boost gets to the higher levels. Fueling is around 12:1 at Wot, maybe high 11's if I pay attention to the Wide Band under way. I cruise in the low 13's. I don't run switchable exhaust, not legal in MN and has no buisness on engines set up like ours. I feel pretty safe running 10-11psi with premium. When I switch over to my Holley Dominator EFI setup, I'll have knock sensors as well.

ACrooks69 - how much speed do you lose with the P5x - 25 compared to a four blade?

I didn't, it's my fastest prop. I just like the Bravo XS better all around. Great hole shot, good holding, just doesn't hold it as solid at WOT.

Is your P5x - 25 labbed? I have found that reducing diameter on my 4 blade OB/FX from 15.25 to 14 made the boat more stable. Less stern lift. Curious if you are running the stock 15" diameter of the P5x. I have read a lot of great things about this prop from other boaters too.

I believe it is untouched. I bought it second hand. Doesn't lift the stern too much, just has a real good iron grip on the water. Unlike my XS, that one you have to drive and trim, but still feels good, the p5x is a lot more predictable.

If I didn't say it before, the XS is better all around. The hole shot is amazing for a 4 blade, very little bow lift, can hold plane down to 20.3. Thebp5x is more of a lumber wagon out of the hole. Not a ton of bow lift, just not as fun. Of course my procharger help getting that nose down quick too. I imagine if I vented the p5x like the xs is, it would come out of the hole better. No exhaust, but it still pulls air through the passage. I have the exhaust bellows removed to make sure air can get sucked out freely.