|By cdm (cdm) on Sunday, October 19, 2003 - 6:06 pm:
|Is it possible to upgrade/ modify my engine to produce more HP? Its a MC - MCX 350 HP. I already have a ACME 13.5 * 16 prop. Any suggestions..|
|By cdm (cdm) on Monday, October 20, 2003 - 11:05 am:
|Come on people, throw me a bone here! Any suggestions would be appreciated!|
|Try replacing your sparkplugs with Platinum + 3 Splitfires. They are about 8 dollars each, but they'll add about 10Hp and a lot more throttle response. I assume you have a fuel injected engine, so unless you want to do some serious modifications, the only other way to really add some HP would be to play with the Throttle body. You can re-jet the throttle body ( or have them bored out) to pick up some additional power, but you should find a VERY qualified mechanic before embarking on this project. Also adding a K&N air filter package will improve your air intake and add about 6-8 HP. I have done all of these things with my Porsche engine and they worked out very well. Nothing too different with the boat. |
|cdm, is the 350hp not enough for the x-star? I'm thinking about getting one with the same engine. What's a good price to pay for an '04 X-star?|
|Hmmmmmmmmmmmm, not to be a jerk but nothing listed will really work for you here except for the K&N possibly, though I think the MCX already has a Conical high flow filter on it. As for the spark plugs other than maby lasting longer or a little bump in fuel economy yourt not going to see much difference. As for the TB mods i'm not sure what you thinking here, the MCX is a "Multi Port Injected" engine meaning that the TB has nothing to do with introducing fuel to the motor (i.e. jetting?) and will hardly be worth you time to polish let alone run the risk of boring it and going through some of that thin metal. As far as I know it's more hassle than it's worth for the power even to use old tricks like porting & polishing and even Extrude Hone processes. It seems that Indmar has done a lot of the tricks a normal tuner would have done in the first place. The only thing I think would be logical was a different computer tune via flash or chip, but even then it would be a pain to properly tune and though you might pick up slightly more power the curves set by Indmar are set that way for a reason. Not to rain on your idea or anything I would love to see some viable way of this happening, but I would be damn sure to take my boat to someone with a VERY good reputation before they got in to my 6-15K motor!!! Finally sorry Will but what Porsche do you have that all this worked on, seeing that to my knowledge no Porsche was ever TB injected....Either this is BS or it's time for a new, honest mechanic.........Matt|
|What do you need more horsepower for? |
If it is to improve hole shot, there isn't a lot that you can do to the engine. You could switch to a lower pitch prop so that the engine turned faster and thus generated more horsepower during the hole shot, but that would impact your cruising speed and economy.
If your hole shot is OK and you want more top end (i.e., you want the engine to turn faster) then the generally accepted approach is to make the engine breath easier. Sometimes you can buy a new EFI electronics module that will improve top end. You can upgrade the intake manifold and fuel injection system. Upgrading the exhaust system can also help. On the more extreme end would be replacing the camshaft, increasing compression, and various other hot rod tricks.
Increasing the compression will require using high octane gas.
Changing the camshaft could result in a rough and/or faster idle, harder starting and possibly worse bottem end.
Changing the exhaust would increase the noise.
All the above will take $$$$
|Don't do the airfilter on your boat. What's on there now is designed to prevent an explosion...called a flame arrestor. A K&N filter is not going to provide that for you. Flowing heads and cam's are maybe your best bet. I would have to guess that they would void any warranty. |
|I agree with Matt, this is a very tuned engine for its size and to mess with it would be trouble specially with a computer that is tuned for the engine the way it is. The only thing that could be done is some kind of trader for an upgrade engine maybe. Talk to your dealer. |
K&N makes Flame Arrestors specifically for marine applications.
|That sounds like a good suggestion then and what could it hurt putting in nice spark plugs too. |
|If you got the money, maybe a centrifugal supercharger, but now that I think about it, probably not. I have the same engine and it needs 89 octane which means the compression is already higher than normal. An engine which a supercharger usually has a lower compression ratio like 8:1 I believe. I wouldn't waste my money on the plugs. |
Matt, I don't know what type of Fuel injection system the indmar engines use, so you're probably right about the Throttle body. But as far as Porsches go, I have owned and operated 5 911's 1978, 83 85, 92 and finally a 02- all except the last model utilize a throttle body for fuel management into to tuned ports. My 85 is a race ready Carrera with Bored out jets, Polished ports, K&N filter system, has headers, a light weight flywheel and newer pistons with higher compression. It is a 3.2 Litre engine that puts out 285 HP , and in a 2000lb car, it's a rocket.
When you get out of school, you can buy a porsche and join your local PCA chapter and learn all about the heritage of the Porsche engines.
|Matt, that object in the center of the picture is called a throttle body- this was the '85 before the overhaul. |
|Let's try again.. |
|MCX comes standard with the K&N air filter |
|By cdm (cdm) on Monday, October 20, 2003 - 4:07 pm:
|Hey guys, |
Thanks for the information, keep it coming! I spoke with my dealer, he said that he was happy I didn't go with the LQ-9 385HP. He said the LQ-9 is slow out of the hole and not a good match for the New X-Star. I have already switched my prop to a 13.5 * 16 ACME 4 blade prop. Its great! He said the best thing I could do is to have a supercharger installed. It would add 100 HP = 450HP. Only one problem.... its $6000.00 for a supercharger!! You think spark plugs would do anything?
|By cdm (cdm) on Monday, October 20, 2003 - 4:09 pm:
|Does anyone know.... Is the MC LQ-9 385 HP supercharged? I don't think so but....|
|By gvb (gvb) on Monday, October 20, 2003 - 4:56 pm:
|Spark plugs aren't going to make a difference... just buy the cheapo's. |
|$6000.00 for a supercharger is insane, look elsewhere if you want a supercharger. Hell maybe $1000.00 if you install it yourself, say goodbye to any engine warranty though.|
|Cool Will my last post was in no way ment to dis you or anything to that effect, I simply wasn't familiar odviously with some of the earlier offerings which I assumed were mechanical injection, after looking this link caught my eye, correct me if i'm wrong but the injectors are directly opp. the cylinder...http://www.e-toolbox.com/application/8852/8852CH15_BOSCH_CONTINUOUS_INJECTION_SYST.htm if this link is to be trusted from 78-83 this is the system used..... Therefore I see no way to increase fuel delivery via jets as the injectors were responsible for this....that is unless the MCX uses Bosch continous injection systems.....so true using what i was tought in school I spent 5 min on Google to figure this out, this is the education I do hope one day to use in purchasing such fine automobiles. |
as for the LQ9 it moves our porker X-30 pretty good as is, but if you are looking at supercharging the only drawback would be how to mount the unit, as well as the required additional fuel pressure needed while under boost. This would also mean updated computer programs to deal with more air and fuel in the eng.
Again cheers, and i'm off to the bar to make the best of my school days while they are still here. Check back later, Matt
|The CIS system has a fuel management (throttle body ) in front of the fuel injectors themselves- which are directly opposite the cylinders. I think they call it a Fuel distributor- different language but the same thing. In 1984, Porsche went to a newer injection system which is more dependable with less moving parts. I believe this is very similar to what many engine manufacturers in the marine business are using today, which is why I even raised the subject. I own a Tige 2100V with a Mercruiser 350 MPI engine and for the life of me I couldn't tell you how it works, because it's under warranty and I wouldn't even think of screwing around with the motor until the warranty period is up. Even then, I wouldn't. these motors are so highly refined and well tuned that if sucking a couple more HP out of them were possible and adviseable, then It would have already been done at the factory. |
PS- the plugs WILL give you more throttle response. they burn the fuel more cleanly and thoroughly and the motor seems to run better. Higher octoane fuel helps too. I have run both in My Tige since I bought it in '01.
|Spark plugs will not provide a horsepower increase. |
The job of the spark plug is very simple, it ignites the air/fuel mixture. The ideal situation is to have a slow, controlled burn of the fuel rather than an instantaneous explosion (often referred to as detonation), so the idea that a hot spark or more spark area etc. is going to do anything for you is just not true.
What a spark plug can do for you is provide easier starting, or or avoid missing at very high RPMs, or be more foul resistant, etc. If your engine isn't running right, then changing plugs might do something for you. If your engine is running right and tuned properly, spark plugs will do nothing.
|Sorry to say, but spark plugs will NEVER give you a 10 hp boost. A K&N spark arrestor may help the engine breath better, but the improvment will probably not be noticable. Run the fuel octane recommended by the manufacturer. If it runs properly on regular pump gas, putting premium in it is a waste of money. |
For a big increase in hp on a smallblock chevy you can throw alot of money at it with a whipple supercharger kit ($5999.95 plus installation), marine exhaust headers ($1500.00-$2000.00 plus install).
What will you have? A boatload of money in an boat that will only be a couple of mph faster, although it will probably be able to pull trees out of the ground on the bank.
Big power can only do so much for a ski or wakeboard boat. You have no adjustable trim, so that's not going to help, and the hull design will only go so fast and that's it.
Sorry for the rant. If you want to go fast buy a Cigarette or a big cat.
|Craig, I agree with you totally. |
However, I think the original poster wants to increase power because his boat is sluggish pulling up a boarder when it is heavily weighted.
Paying $8 for a gimmicky spark plug is proof positive that there are marketing geniuses in the world. Sorry Will but you got took if you bought those high dollar plugs.
|I have tried the platinum 3s on both my 88 and just for the heck of it on my 90 Ruf. They caused all kinds of problems. Higher octane fuel burns at a slower rate and will decrease hp unless the engine requires high octane due to increased compression. Maybe if advance timing, could use higher octane. Not sure, but generally, higher octane will impair performance unless you engine requires it. 93 is good enough.|
|I don't know how robust the bottom end (crank and rods) of this particular motor is, but you may want to research that before supercharging. I know that the LQ9 would have no problem with the extra power. Porting and polishing the heads would be a good start, anything you can do to improve the air flow in and out of the intake and exhaust respectively will help. I don't know how tuneable the Fuel systems are but you could look at timing and air/fuel ratios. Porting a throttle body on a multi-point fuel injection system can be worth some power as the throttle body introduces air into the system (air and fuel are required for combustion). It was worth a few horsepower (3-5)in my car, but it's doubtful you will feel a few horsepower in a weighted boat.|
|By the way, when I went to the Masters earlier this year, there were two Nautiques that were used for the ski fly competition, both supercharged PCM's that were putting out 500 plus Horsepower, very impressive.|
|A "supercharger" generally refers to a belt driven blower. These are rather expensive to add and dramatically increase the space required for the engine, as the engine gets a lot taller (blower sits on top of the intake manifold) and longer (it is a very wide belt on the front). These are usually used only for the serious go-fast applications. |
A "turbo-charger" is a device that uses waste engergy in the exhaust to spin the blower. They are generally much cheaper to install as they don't require quite as much engine modification. They are also much more reliable.
The down side of the turbo charger, when used in a boat, would be the need to have hot exhaust between the engine and turbo. The standard marine engine has a water jacketed exhaust manifold, which would not be useable with the turbo. Again, you would have a space problem in a boat that was not designed for it. An even greater issue is that you will have some lenght of VERY hot exhaust pipes running to the turbo, which will require significant spacing to the engine cover and other components to avoid heat/fire issues.
Neither the Supercharger or Turbo charger is going to make a dramatic difference at the low end, they really don't provide much boost till the higher RPMs. They will make your boat a lot faster, but it won't give you that much harder of a pull.
For bottom end, stump pulling Horsepower, there is no substitute for cubic inches!
|Rod- Todays "superchargers" do not need to sit on top of the motor. Vortec etc.. are a belt driven unit that runs off of a belt that is the same size as the serp belt and mount like a second alt. or other belt driven acc. they take up very little space and do make a fair amount of low end boost |
|By cdm (cdm) on Thursday, October 23, 2003 - 12:25 pm:
|There is more than enough room in the engine compartment, thats not a problem. When weighted my rpms are in the 3000 + range out of the hole and am running at ~ 3800 - 3850 rpms at wakeboard speeds (~ 24 mph). Don't you think the 3000 rpm range is enough to produce low end "supercharged" power increases out of the hole. Your "Stump Pulling Horsepower," if you will! What is considered low end then? Thanks|
|By cdm (cdm) on Thursday, October 23, 2003 - 1:04 pm:
|I have researched Superchargers online too, but have not found anything specific to my application. 350 HP MCX Vortec 5.7. Am I missing something here? The above post seems to be specific to existing 500 HP engines!|
|Contact the manufactures Iím sure that you could get something custom made for your application. May be more expensive but I feel the few extra hundred dollars is worth knowing that your system is the best for what you want, and not just throwin together from 3 or 4 different kits.|
|Rod, you may want to go educate yourself on modern supercharging. Your comments above are outdated and completely inaccurate. |
Either a turbo or supercharger will have a dramatic effect on low end boost if designed properly for the application.
Also, generally turbocharger systems are substantially more complicated and more expensive than supercharger applications.
The biggest issue with a marine application is being able to tune the EFI system for the increased air and fuel flow. The marine systems do not usually use a mass air meter and can't use 02 sensors in the exhaust. That means the cpu's are fairly limited in what adjustments they can make beyond the factory programming.
|I agree with Greg, turbocharging is very expensive. The ATI Procharger (supercharger) is also a good system, and they make marine applications, it is doubtful that you will find anything specific to your engine since it usually takes these companies some time to get a product to the market. Where is the throttle body positioned on your engine? Is it attached to the front of the engine, or does it sit on top like a carburetor. Either way, you might have to have some new intake pipes fabricated, but a kit for a 350 Chevy engine should have the proper brackets for mounting the supercharger. http://www.procharger.com/M_engine.shtml|