supercharging 496 non ho

[turbo mach1]

im looking for feedback, im looking to supercharge my 01 27' conv. and was tossed between the whipple, and procharger, install on the whipple has to be easier, but im looking for help on the overall project

[turbo mach1]

im looking for feedback, im looking to supercharge my 01 27' conv. and was tossed between the whipple, and procharger, install on the whipple has to be easier, but im looking for help on the overall project

[persuaderkurt]

I too am considering supercharging my boat. I have a 5.7LX carb. I have been reading quite a bit about the ProChargers and have kind of zero'd in on them. I like their centrifugal intercooling. I am not looking to beat my engine to death and would be happy with an extra 10 mph. Keep me posted on your project maybe we can learn from eachother. My personal email address is kurt2@nelaser.com

[Blizz]

Remember roots and Lysholme style blowers take alot of power to run em centrificals aren't as bad on power.

[JW]

ALSO remember that both the 496 motors, AND a standard 350 (non-Mag) have cast pistons/rods instead of forged, so be light on the boost............

[happy]

our shop has whippled the 496 (both versions) and 502's.. with no problem.. (at least with the lower ends holding up) you'll see maybe 5lbs boost max.. its your outdrive you need to worry about most.. if you want your set up to look pro out be prepared to spend some money and time making brackets... and use #8 fuel LINE MINUMUM.. if you don't you'll mess up your fuel pump and run lean.

[vinny p.]

I tossed the idea around of Whipple a while ago. Then I decided that it would not be cost effective for me. I am someone who does not believe that you can simply bolt on a kit and gain 50% more horsepower. It doesn't sit well with me. I have been doing this for a long time and nothing has ever come that easy. Sure you can bolt it on and if the programming is right, you will get the advertised power, BUT for how long. How long will it take to obliterate those stock junk Mercruiser head gaskets and valves? How about that cast bottom end you have in that non-ho 496? What do you do if the mapping of the ECU is wrong? How do you fix the fuel curve? To me, it just seems to complicated. Too many variables that I cant control. These are some of the reasons I opted to build a N.A. 540. I picked every part myself. I assembled everything. I put in the best parts available. The end result was 680 hp @ 5800 rpm, 660 torque @ 4500 rpm. Which got me 80 + mph and a real big kick in the seat when you drop the throttle at cruise speed. The best part is, I CAN TUNE IT MYSELF. I dont have to screw around with sending my ECU across the country when it is running bad. Oh, the next best part is that I still have a great stock complete 454 Magnum in my garage to sell or keep for whatever reason.

[panther150]

You've all made good points,supercharging can easily give you large gains in hp and more importantly, torque. You're cast bottom end will be ok with the 5 psi or so you will be able to run on pump fuel.I got 100hp. and 100ft. lbs of torque on my 5.7 smallblock surburban with just under six lbs of boost on the stock cast bottom end. You have to be careful not to run them lean though,any detonation could mean by by pistons!My tow vechicle combo would barely run on premium "pump" gas.The thing I really like about supercharging is the massive amount of low end touque you get on a otherwise stock shortblock.Vinny is right though, there is " no replacement for displacement", and with a large motor you can build yourself well over 500 hp.on even regular pump gas.With both supercharger kits, and 540's being very expencive, you have to figure how much power you need, what the premium fuel availability is on the water in you're area, and figure out the best bang for you're buck.I would give the people over at Comp Cams a call and discuss a cam,injectors,modified or larger throttle body combo, possibly with some mild head porting. I think you will be really surprised on how much power you can get with some easy bolt ons.

[vinny p.]

Panther,
As I am sure you know but just wanted to make a point... There are vast differences between supercharging a truck and a boat. The constant load put on a boat motor being the main difference.
Merc makes a hell of a good motor. But, we have to understand that they are in this business to make money. They use the best parts that they HAVE to. When we attempt to modify it, those original parts may not be good enough.

[happy]

there is no substitute for cubic inches... http://checkmate-boats.com/graemlins/lol.gif

[panther150]

I meant no offense , I was agreeing with all of you're points, what I was saying was that with the five or so psi of boost the stock cast bottom would be ok.With modest rpm's and good octane,a mild supercharged setup will live, I did'nt mean to insinuate that it was a better combo than you're 540, or would produce awayway near the same hp.

[mkhammer]

I beleave a pro charger is a good way to go. With a 5 psi kit your engine will last along time. With a procharger it builds boost with rpm, witch is easier on your drive and engine, has a cooler air intake than a roots or whipple.
I know several people that procharged thier 496 with a standard bravo drive with no problems.
Its a good economical and reliable way to gain hp on a stock engine. For modified engines they all work when setup correctly

[vinny p.]

Panther,

No offense taken here. I am merely trying to convey my opinion. I am not saying one is right or wrong, it is all up to your personal preference and ability. My opinion is obvious, but doesnt mean it is right for you. We are all here to share experiences and knowledge. Everyone here has learned something.

[persuaderkurt]

mkhammer,

That is exactly why I am choosing a pro charger. They build boost as rpm's go up. They are much easier on the engine and drive then a roots or twin screw. I like the idea of building boost as rpms go up. This is important to me since I have a 350 small block and an Alpha drive. I have been nervous about supercharging my set up until I researched the pro chargers. I rarely go flat out or rarely use the full accerlation of the motor. I am more doing this as a learning project. I must admit I am a little eager to see what it does to my top speed and to here the pro charger noise.

I have made a contact with a guy in New Jersey that has put a number of pro chargers on small block checkmates, bajas and fountains. He said none of his customers have had problems and would be glad to let me talk to them to see how their set ups are working.

I plan on starting out with just 3psi of boost just to be safe. I will see how things go and maybe increase it from there.

[Blizz]

Prochargers are easier on yoour motor but most people like the low end grunt when used in a boat app thats why merc still uses roots/twin screw type blowers with low boost levels. But if you wait long enough someone is testing a four speed centrifical that will let you keep your boost up at idle and slow down as your rpm's rise so you don't overboost.

[happy]

when installed right, the pro charger and whipple both run fine.. and after your mechanic gets all the bugs worked out of em.. and you learn to watch your guages, and know what they mean.. you'll run fine.. the next is your drives.. drive right and they will live... otherwise, you'll be going thru em left and right..

[mkhammer]

Persuaderkurt
I run a m3 procharger at 9 lbs boost on my modified hp 500 I have had no problems so far it runs good. Mine is a carb and I like it. I can tune it myself. You should add a couple gages. a pyrometer, fuel preasure, and boost gage. you could do without the boost gage on a low boost setup. tune it by your pyrometer. 1200 deg. at full primary. look at your carb butterfly when you move your linkage, mark your throttle when your at full primary before your secoundaries open up. then at w.o.t. jet your carb so the pyrometer runs 1400 to 1450 deg. max and your engine will live. you will have to start with about one size larger on the primary jets and 8 to 10 sizes larger on the secoundary jets and may have to go up or down. If you have a efi. you have to get recalibrated from Arizona speed and marine.
If you have any question fell free to ask

MK HAMMER

[panther150]

If you're running a holley double pumper, I think you need to reference the secondary power valve to you're boost pressure by way of a small tube going that carries boost pressure to the secondary power valve,it is a simple procedure ,any good engine shop who has done these type of combos will do it cheaply for you.Again check this out , but I think this applys to marine applications as well.Good luck.

[panther150]

What it is is a small (one eith dia. rubber tube going from a fitting on you're manifold to a fitting the shop will install on you're carb. so you're secondary power valve see's boost pressure.

[persuaderkurt]

MKHAMMER,

Thanks for the advice. I am going to make this a winter project. That way I will have plenty of time to install it and do all the running around I know I will have to do for a project like this. I love gauges, that way I know what is going on and will likely install the gauges you mentioned. Don't be surprised to see a post asking you for help/advice. Thanks for the encouragement. My engine is a carbed 5.7.

[mkhammer]

Persuaderkurt
The procharger kits are good. They give you step by step instructions and everything you need for installation. except: you have to run a holly dbl pumper carb w/ mechanical secoundaries. they supply everything you need to convert your carb and fuel boost referance line. They don't tell you how to jet. you will have to reprop your boat to stay at manufactures rpm limit. You may have to mount the inner cooler remotely. you should run a sea strainer so junk doesn't go into you inner cooler. You need about 12" of clearance in front your harmonic balancer and up for your new pullys and belts 10" will work but its tight Just wanted to let you know some of the things it intells before you get into it.

MK HAMMER

[persuaderkurt]

MKHAMMER,

Thanks for the info. I have a question for you. I noticed in the Pro Charger technical literature it stated that thru-transom exhaust is not required for 3.5 psi boost but it is for 5 psi boost. I currently have a Corsa Silent choice system and am planning on the 3.5 boost. The silent choice is important to the wife. Will I be able to switch back and forth between thru-transom and thru-prop or will I have trouble?

I have saved a lot of your postings for future reference. Your knowledge of engines is quite notable.

[happy]

i have to admit the step by step instruction are cool.. but both companys need to go back and write in the fuel line size correctly so you dont waste a fuel pump under boost and lean out your engine.. whipple a 496 and change a serpentine belt.. (not the blower belt) see how much is comming apart.. ask them both where your going to bolt on your extra items and make it extreemly sanitary... its alot of work..

both systems run quiet well.. but set up is extreemly important.. most important is the person behind the wheel know what the guages mean.. and know when to get out of boost before the get into rebuilding/buying another engine.

ooohhh yeah.. they have to watch the guages too.. no bikini distractions!!!

[mkhammer]

Persuaderkurt
Glad I could be of some help.
With the 3.5 psi switching to thru-prop may kill some performance but won't kill your engine
if you watch your pyrometer. If it starts to get hot(and it may not) back out of it and cruise. that will lower your boost. with any kind of forced induction it will raise your exhaust temp and head temp. induction. thats why they use econel exhaust valves so they can withstand higher temp. and headers so exhaust gases escape easier to keep head temp down. You will only Know for sure what kind of exhaust temp your dealing with after you install your prcharger. Thats why a pyrometer is a very impotant gage. if you don't have a bung for it on your exhaust you will have to remove your exhaust and drill and weld one in #6 near the flange. so it can be welded inside and out. if you don't weld have a pro do it.
Sounds like a good winter project.

MK HAMMER

[Craig]

Just wanted to clarify, the 496HO has:

-Camshaft-steel
-Rods-forged steel
-Pistons-cast aluminum

Vinny I always think your posts are very informative and I can tell you know your ****. But, why do you think the bottom end is so crappy? In early models, 2001 and before, the crankshafts were forged steel. Then GM came up with some new way to cast it and that's what they stuck with. "Nodular" iron or something like that?? They claim just as strong. I know, i know, Merc marketing, but I've never heard of any troubles that guys are having.

I'm no mechanic by trade, but in my opinion the 496 is a very stong motor especially on the bottom. I think the 496 internals are very impressive, (maybe not quite totally to hi-perf par, but close.) I always thought that the poor attributes of this motor is the top half: cast iron heads, and poor intake. Though the cam is strong, it's obviously suited for those heads and intake. More of a midrange cruising motor, but it sure runs good in my 270 Convincor...

Anyone ever consider the heads, intake and cam developed by Raylar? Expensive, ($5,300) but I've heard nothing but praise.

-Craig

[bowtie]

<BLOCKQUOTE class="ip-ubbcode-quote"><div class="ip-ubbcode-quote-title">quote:</div><div class="ip-ubbcode-quote-content">Originally posted by panther150:
If you're running a holley double pumper, I think you need to reference the secondary power valve to you're boost pressure by way of a small tube going that carries boost pressure to the secondary power valve,it is a simple procedure ,any good engine shop who has done these type of combos will do it cheaply for you.Again check this out , but I think this applys to marine applications as well.Good luck. </div></BLOCKQUOTE>
First off let me say that I know nothing about running a blow through carbed setup, so this may be way off; but, I have never seen the sense in running a power valve on the secondary side of a double pumper anyway. First off, almost if not all of the D/P have progressive linkage, and the power valves are intended to allow a leaner part throttle situation while providing extra enrichment under heavier loads (aka more throttle). Well if the secondaries do not start to open until 1/2 throttle then as soon as they start to open the manifold vacuum should have fallen below the P/V open point anyway so basically they are open the whole time the secondaries are. IMO, all secondary power valves should be plugged and the carb jetted accordingly. FWIW.

[panther150]

I always ran mine plugged as well Bowtie,but there are guys running this combo with blow through setups.I'm sure procharger will include specific instructions for their marine application.On my 1050 dominator on the last combo in my drag GTO I ran the primary and secondary valves plugged, and it worked great(it was strictly a race car) One of my buddies ran a similar combo (wilder high rpm roller) built by a well known engine builder with the same 1050 with power valves in both primary and secondary , I told him to "lose them" but he tried them anaway on the builders advice and they worked great too! My point is, sometimes you never know until you try if you're setup is going to work for you or not.I'm looking forward to learing to set up my Panther next year.

[mkhammer]

The boost referance line runs from the carb box to the fuel pressure regulator to increase fuel pressure with boost so your engine doesn't lean out. For every lb. of boost you have to have a lb. increase in fuel pressure.Example if you have 7 lb fuel pressure at idle and at W.O.T. you have 5 lbs of boost you need 12 lbs of fuel pressure at W.O.T or your fry your engine. if it went to the power valve you couldn't monitor it with a gage. There is no power valve on the secoundary. The line to the power valve is something differant it regulates the power valve under boost or load and it is on the primary side only

[panther150]

The reference line I was referring to was'nt meant to have a guage, it went to the backside of the secondary power valve( only Holley double pumpers have them)and it was one way of richening the fuel mixture when the boost went up.I'm not familiar with the marine combo's out there,does you're combo have have a second regulor before the carb? I would think 12 psi at the carb would be too much for you're needle/seat assy.Again I hav'nt seen a marine blower setup or enen a marine carb close up, if you could sometime post some pic's i'd be very interested to see them.

[mkhammer]

Panther150

I run an areomotive electric fuel pump and a single regulator before the carb that is supplied in the procharger kit from ATI. The regulator comes with a fitting on it for the boost refferance line they also include a needle and seat and new floats. a secondary power valve is not needed and would be a unreliable way to have correct fuel mixture. You must jet by means of a pyrometer and plug reading to be correct anything else is a guess. ATI also warns you in the step by step instruction manual more than once if boost refferance and jetting is no done properly it can cause severe engine damage. You may be in doubt but this is they way it is on a marine engine. As far as pictures go my checkmate is stored at my home in Lake Havasu AZ. my primary residence is in Califonia so when I get a chance I will take some pics. sorry I won't be able to give exploded views inside my carb.

MK HAMMER

[panther150]

Thanks for the info, I did,nt mean to come off like I was douting you,just the gearhead in me being curios.I'm trying to learn more on how marine combo's are set up.The secondary power valve setup i described was just one of many different combo's used for street supercharging, the power valve ritchens the mixture as the boost goes up,this combo is used be Kens speed and machine ,a popular pontiac engine builder in the states.More fuel pressure means more volume,my holley race pumps were 19 psi instead of 9.5 psi and delivered thirty to fourty percent more volume,I was just surprised that you're needle and seat would take 12 psi,I have alot to learn about marine combos,and that if what makes this website so much fun!

[mkhammer]

No problem, a street engine is alot differant than a marine engine. a marine engine's tallorances are set up alot closer than a car engine if its machined right and don't run at a 180 to 230 deg. like a street engine. Thats over heating in a marine engine, most marine engines run at 140 deg. gaskets, cams, exhaust systems, brass freeze plugs are differant just to name a few. you run a boat over miles of water at 5000 rpm. a street engine gets trottled up and down all the time. If you were cruiseing in you car at 5000 rpm you would want to grab another gear. I run a M3 procharger at 9 psi of boost my fuel presure at 5300 rpm is 16 psi I don't think the needle has time to shut off at higher rpm. when the rpm goes down so does the fuel presure at idle am back at around 7 psi. The boost refferance line runs from the carb box to the regulator. The boost pressure that runs through the line puts the same boost pressure to the regulator as produced from the procharger to open it up. If there wasn't a boost refferance line the the boost pressure in the carb box could actualy put pressure back through your jets and at boost and you would have negative fuel pressure less than you have at idle and fry your engine. so I don't think the needle & seats ever see the fuel pressure that is read at the regulator. remember the whole carb is inclosed and under pressure. I hope I could shed some light on this subject. I don't mean to ramble

MK HAMMER

[panther150]

Not at all,thanks alot for the info!

[Craig]

<BLOCKQUOTE class="ip-ubbcode-quote"><div class="ip-ubbcode-quote-title">quote:</div><div class="ip-ubbcode-quote-content">Originally posted by mkhammer:
No problem, a street engine is alot differant than a marine engine. a marine engine's tallorances are set up alot closer than a car engine if its machined right and don't run at a 180 to 230 deg. like a street engine. Thats over heating in a marine engine, most marine engines run at 140 deg. gaskets, cams, exhaust systems, brass freeze plugs are differant just to name a few. you run a boat over miles of water at 5000 rpm. a street engine gets trottled up and down all the time. If you were cruiseing in you car at 5000 rpm you would want to grab another gear. I run a M3 procharger at 9 psi of boost my fuel presure at 5300 rpm is 16 psi I don't think the needle has time to shut off at higher rpm. when the rpm goes down so does the fuel presure at idle am back at around 7 psi. The boost refferance line runs from the carb box to the regulator. The boost pressure that runs through the line puts the same boost pressure to the regulator as produced from the procharger to open it up. If there wasn't a boost refferance line the the boost pressure in the carb box could actualy put pressure back through your jets and at boost and you would have negative fuel pressure less than you have at idle and fry your engine. so I don't think the needle & seats ever see the fuel pressure that is read at the regulator. remember the whole carb is inclosed and under pressure. I hope I could shed some light on this subject. I don't mean to ramble

MK HAMMER </div></BLOCKQUOTE>

Actually a marine engine has INCREASED piston to bore clearance, not tighter. Also, a marine motor shouldn't be running quite that cool (unless that is what a blown motor needs to be run at?) Most big block marine motors (454 and 502) run at about 180. The new 496's actually being the coolest at around 170...

Neither marine nor auto motors should be run up past 190, let alone 230.

-Craig

[mkhammer]

I never said tighter I said closer tallorance. witch means blue printing. Mercruiser does not run thier engines at 180 deg. its 140 on the carb models. a 496 ho runs a 160. the cooler thermostats and water cooled exhaust manifolds keep engine compartment temperatures down. try running a car that is supercharged in a 120 deg. heat at 5000 rpm for seven miles straight then stop and sit on the hood I bet engine temp is over 180 deg. And some car engines are known to run as high as 230 deg. I didn't say it was a good thing. But you can run what ever you want buddy.

[mkhammer]

Before I start a pissing match. The fact is every year stock engine from every manufacture has thier own recommended specs for thermostats and every thing else about thier engines. mine is 140 deg. and most carb models are. efi engines run a little higher temp. As for modified engines its up to the builder to run what that person feels is right for thier application. the average heat of the day in the summer here is 118 deg. I have assembled many engines auto and marine. so I know what works here. One of my 2005 work trucks has a 190 thermostat in it and its all stock. when I pull a heavy load with it up a grade the temp rises to 220 deg It doesn't have cool fresh water coming into it like my boat. As far as piston clearance goes forged pistons have a much higher expansion and contraction rate than a cast piston. so skirt to cylinder wall clearances have to be set up differant. .005 to .007 is not uncommon for forged pistons in a marine engine. I personally wouldn't set one up over .005 but some hardcore race guys I know do. I would never use cast pistons in a marine engine myself. And what I mean close tallorance is, the cylinders should be bored within .007" of the final dimension. the machinist should measure each piston add the measurement to the correct piston to wall clearances that you provide and use that dimension to to hone each cylinder out for the piston that goes in that bore. pistons can very. most car engine builders won't do that. They just pick a number and make them all the same this is just one reason its more expensive to build a marine engine properly.

[Craig]

Hey buddy, no pissing match here. I know what t-stats merc uses in their motors. We were just talking about this in the shop the other day... That's what caught my attention in your post. They run at a higher temp then the t-stat. Why? I have no idea. Older motors seem to run 180, later models like mine with closed cooling seem to be at 170. Called Merc with concerns, they said that's fine. Regardless, all I was saying is that 230 is overheating in any engine, not just a marine engine.

Re: tolerances: Your first post was ambiguous, I knew what you were saying, I was just clarifying, never disagreed with you. Important topic that many guys are interested in.

-Craig

[mkhammer]

If your such a expert why did you have to call mercury marine, why didn't you just look up your application. and your wrong the 88 to 92 454 & 502 mag raw water system came with 140 deg thermostats. a 496 mag 2001 & up with closed cooling comes stock with a 160 deg. a 454/502 mpi comes with a 160. a 1977 to 1981 330 hp 454 carb comes with a 140 deg. any marine shop that has merc net can look this up. I don't know what kind of shop you work in but it sounds like automotive. I don't know where you get your info from its incorrect.
I agree 230 deg. is too hot for any engine but I see automotive engines get there all the time with a 190 stat. my boat has never seen 160 it runs at 140 where ite supossed to but thats my application. So who's ambiguous