Re: RTECH Supercharger on 502 MPI
 

The first step in making the new oil line from filter to cooler is to find this rare adapter that goes from inverted flare to AN-8. The rest of the line uses AN-8 because that's what the oil filter head has on the out line. The in line however was inverted flare, that's why we reused the stock steel lines. The last shot shows the new oil lines bundled with the fuel return line from the cooler. There's even a hose under there someplace that connects the PCV from this valve cover to the other side's valve cover.

Re: RTECH Supercharger on 502 MPI
 

Hi Marty:

Thanks for the help. I can see what you did.

The inside cavity of the '96 Merc fuel rail is big enough for all, but it is fed from one end through a short section of 3/8 line. I could tee after the red fuel filter and feed both ends pretty easily. I don't think I would have to remove the rail mounted AZS&M regulator.

I have been following AZS&M's instructions. They said to retain the small supply and return lines because of the difficulty of machining the stock fuel rail for say AN-8 fittings. Vortech does not provide anything for this situation because their basic kit is only for 570 HP. I figure if the 3/8 line is a restriction, we will see it on the fuel pressure gauge, because the rail will be under-supplied. This would likely affect all injectors drawing off that large cavity in the rail.

This is why all the other lines in the supply are either -10 or -8, with the return line being -8 as well to avoid any over pressure problems at idle with the big Aeromotive pump.

Here's a picture of the headers. On one of them the water inlet bung for the elbow, which isn't used anyway, was cut off and welded, then polished. You have to look close to notice it. The last picture shows why this cutting and welding must be done.

I have done everything I can do; now the engines are in the hands of the shop doing the install. The boat is also getting new XR drives at the same time. The dyno shop let us down and put us off after 3 weeks of saying they would get to it. Try getting dyno time at the last minute anywhere else at this time of year. Anyway, we will find out if everything is OK out on the water. Isn't that what Captain Ron says?

Seriously though, this fuel pump/injector/ECU configuration has been done before many times by Vortech and AZS&M. We aren't expecting to do much more than adjust the IAC counts and tweak the fuel pressure.

Re: RTECH Supercharger on 502 MPI
 

We test fired one of the engines today. Idled fine, good fuel pressure, no fuel or oil leaks. Left the intercoolers off until the engines are installed. Fuel pump to be attached to the stringer just in front of the engine on starboard side.

Re: RTECH Supercharger on 502 MPI
 

Tomcat,
Finally got my boat back today. They also found 4 loose valve seats. Ended up replacing all of them. Replaced all the exhaust valves with Inconel, Intakes with Severe duty Stainless, new valve springs, FelPro gaskets, new head bolts, valve guides, seals, and I also had them install a water pressure gauge. Hopefully no more problems. I've been out of the country for a while and I see you are making some good headway on those engines. Hope they perform well for you. Keep us informed.

Tom

Re: RTECH Supercharger on 502 MPI
 

The water pressure gauge is a good idea. Where do you pick up the water for the intercooler? Nordic Heat had a problem with head gasket/detonation and he suspected that part of the problem was the intercooler was not getting enough water. It wouldn't hurt to flush out the intercooler core while you're at it. You can do it just by reversing the water lines in/out on the intercooler for a while.

I noticed in Miami that Stainless Marine introduced a separate intercooler strainer at the boat show. It had a fine mesh bag that took out smaller particles that would pass through a regular strainer; particles that wouldn't hurt the engine but might clog the water passages in an intercooler. I don't have any experience with the piece but it makes you wonder how many supercharged engines are running around with partially clogged intercoolers.

This is where an intake air temperature probe would be good. The aftermarket EFI systems can data log this so you can see any reduction in intercooler performance. When Vortech sells a reprogrammed ECU it will go into limp home mode if intake air temperature goes above 140F, indicating an intercooling problem.

Good luck for the rest of the summer.

Re: RTECH Supercharger on 502 MPI
 

We have one of the engines in the boat now, almost everything hooked up. It's close but the intercooler does fit under the hatch. We had to rearrange a few things like drive reservoirs and Latham reservoir but no big deal.

Re: RTECH Supercharger on 502 MPI
 

Both Aeromotive fuel pumps are through bolted on the same four bolts through the center stringer. We ended up using Mercury trim pump relays to trigger these pumps. It's a proven waterproof harness. This is the final view of the lines on the stbd side of the engine. Everything fits in a tight but logical arrangement. This closeup of the front of the engine shows the fuel supply and return lines for the EFI and the small, tasteful Rtech supercooler engraving. :rolleyes: :D

Re: RTECH Supercharger on 502 MPI
 

The other fuel pump and the Mercury relay and harness. The EFI wiring harness has two wires that were originally used to run the VST electric pump. These two wires are used to trigger the relay. This is neat because the ECU will energize these wires for 5 seconds and then turn off if no RPM is sensed. This is a good safety feature.

Re: RTECH Supercharger on 502 MPI
 

The second engine is leak tested and run to check for oil leaks, adjust base fuel pressure, idle quality. Tomorrow this engine goes in the boat.

The first engine is completely installed and all sub systems for the second engine completed (fuel pump, relay harness, intercooler hose and thru hull fittings, moved drive reservoirs, hydraulic steering) and last but not least the XR drive. Hope to be in the water on Friday!

Re: RTECH Supercharger on 502 MPI
 

Second (stbd) engine going in the boat. You do as much little stuff as you can before this, because after the second engine goes in that isn't much room to work.

Re: RTECH Supercharger on 502 MPI
 

With the second engine in place you can see the clearance between the port intercooler and the stbd flame arrester and blower. That's me pretending I did all the work without getting my white shirt dirty. And the third picture shows what it's really like. Be nice to your qualified marine mechanic!

Re: RTECH Supercharger on 502 MPI
 

You can see the clearance between the stbd intercooler and the side of the engine compartment opening. It's about 1/2", so the intercooler just slides down onto the support bracket and bolts on. It wasn't like this the first time we tried to install it. I had to mill the housing 1/2" shorter to get this clearance. The intercooler core doesn't change. All the housings will be built shorter to avoid this problem in the future. It will also give extra clearance between the port intercooler and the stbd blower, which is only about 3/4" now. This will keep the intercooler within the confines of the CMI header width, which is what I should have done in the first place!

This is what it looks like behind the intercooler. A lot going on here. Shifter bracket and linkage clearance, water fittings clearance, throttle linkage clearance, and access to the bottom two bolts that hold the intercooler housing to the transition plate. Everything fits and nothing is hard to install.

We're almost there now. Hookup a couple fuel lines on the stbd engine, intercooler lines, install engine hatches, reconnect the hydraulic steering lines etc. The boat already has fuel pressure gauges, needs boost gauges.

Re: RTECH Supercharger on 502 MPI
 

TC

Water for the intercooler is picked up at the inlet hose just before the cross-over at the front of the engine. A T was installed there.
The limp home ECU is a darn good idea but I'm not sure if Dustin at Whipple added that to mine.
I discussed another water pump and sea strainer with my rebuild guys and they felt I didn't need it as I only boat in fresh water and it's mostly debris free. I will have to watch the water pressure gauge tho. A second water system is not cheap either. I will be back flushing the intercooler each season too. That's easy and not very costly.
Anxious to hear how your engines ran.
Good luck.

Tom

Re: RTECH Supercharger on 502 MPI
 

hotlavey: I've been thinking about where to pick up intercooler water. Right after the pump, or in the case discussed in this thread after the fuel cooler, gets you lake water temp. This should be the coldest water and the best for intercooler performance. But if you are passing fuel the intercooler, maybe you don't want the water to be too cold, because it might cause fuel to condense. Maybe that's why they pick up the water after the oil coolers, if I understand what you described. I've never measured the water temperature after the oil cooler at speed. Does anyone know how hot it gets?

I've been thinking about this because several of my customers have commented on seeing condensation inside the carb box when using cold intercooler water. This is because warm, humid air is being cooled below it's dewpoint when it hits the cold intercooler fins. This is only going to happen while you're idling around. When you're under power, air temperatures will be in the 90-100F range depending on ambient temperature and boost levels. I guess the cure would be a separate pickup for the intercooler, which wouldn't move much water at idle speed. This is usually the setup on Roots blowers where you don't want condensed fuel causing problems as the throttles are opened after a long period of idling.

Re: RTECH Supercharger on 502 MPI
 

The first report came in on the boat's performance. Not fully instrumented and not with good gas, so WOT was not attempted.

First a bit of background. This boat had stock Bravos with 1.5 ratio and 30 Bravo props. With this setup it turned over 5000 RPM and ran in the upper 80s. At the same time as the supercharger installation, the shop installed Bravo XRs with 2" shorter sportmaster gearcases AND 1.26 RATIO!

Usually you build up the engine then find the right props. In this case the owner liked the 30 Bravos, which were labbed by Merc, and and the shop picked the ratio so that the boat should theoretically go 105 mph spinning the same RPM as before. So the supercharger installation has to hit that mark. Tough audience.

I was frankly concerned that the steep gear ratio would make the boat struggle getting on plane, and I had visions of the shorter gearcase making the props blowout just as the boost came in.

Well, the boat practically jumps onto plane. At first we tried planing with drives and tabs fully in, gave it some throttle and we were on plane in no time. So we tried it with no tabs; same thing. The shop did call the Fountain factory before purchasing the 2" shorties for a 1996 single step 35 Fountain. The factory said "You're going to love them". I guess they were right. The boat idles and shifts fine. That's as much as we could do before we had to load the boat for delivery to the owner's cottage.

After a good cleaning and some tuning we will make more serious runs with a careful eye on fuel pressure and plugs. Hope to post some more numbers and pictures tomorrow.

Re: RTECH Supercharger on 502 MPI
 

TC

I am running basicly the same set up: 1.5 RH XZ drive, 30 re-worked Bravo 1(not labbed by merc) and only turned 86 GPS at 5000. The engine would not pull any more r's, however we were on glassy water and that may have slowed us down some. Boat is a 2750 Lavey 2 step ventilated hull. Actually 28' 6" long. It's the same hull Lavey is racing in Factory 1. I was hoping to run 90 mph at 5300. Next time I'll try running down hill.

Re: RTECH Supercharger on 502 MPI
 

I wasn't there for the speed runs last year but your numbers are very similar so I tend to believe them. They said they did reach 5300 in the cool spring air and saw 88 mph. Summer RPM was more like 5100. But that was all on the stock Bravo drive.

I wish we had a baseline for the normally aspirated engine with the 2" shorty XRs. Treadwell Motorsports on this board says the XRs are 2 mph slower due to the heavier gears. Others say no difference. We really want to see over 100 mph. A 15+ mph gain will take a real 200+ HP increase. We shall see.

We do have places to boat downhill here; they're called locks. Can't go very fast through them though. :D

Re: RTECH Supercharger on 502 MPI
 

Tom cat why not use a system like the drab boats use to supply the water to the intercooler? You have a water pick up at the back of the boat that has no imellor or anything, the water just gets rammed in there as the boat goes faster.... Or I think that Biggus has a water preasure set up that as his RPM's increase then it starts to let the water through his intercoolers.

Jon

Re: RTECH Supercharger on 502 MPI
 

I was told the same thing re: XR vs XZ. Kevin(throttle man on the Lavey Race Boat) said XR is stronger, XZ is a touch faster. I only picked up about 5-6 mph after the Whipple and felt it should have been more. Guess I'll have to do a little more dialing in. Kevin's going to drive my boat this coming Wednesday. Should be interesting.

Re: RTECH Supercharger on 502 MPI
 

While he is driving, try to make note of the max RPM and boost. Your speed increase should be more; that kit should be adding 200 HP. Unless there is some major hull/prop efficiency problem you should have gained at least 13 mph. Keep us posted!

The reason I ask about the boost is that one marine mechanic I talked to recently told me that he always puts a bigger pulley on when he does a Whipple install. He won't deliver it with full boost unless the customer insists. He says he does this to avoid drive problems coming back to him. Is it possible that your mechanic did this?

Re: RTECH Supercharger on 502 MPI
 

I'm running 6 lbs of boost according to the boost gauge and to the installer. I am wondering if the 4 loose valve seats could have been a factor and also if the blown head gasket occured prior to making itself known. Could I have been down in power due to those things? I'll let you know Wednesday.
Thanks for the interest.

Tom

Re: RTECH Supercharger on 502 MPI
 

It could definitely have been down on power due to those problems. But it could also have been down on power due to the thing that caused those problems. Is there a knock sensor in the system and could it have been pulling out timing? Detonation is not good, but retarded timing will reduce power and increase heat.

How did the boat run before? Did you have great midrange, then flatten out? Did the last 1/4 throttle do anything? What RPM were you getting to?

The reason I am asking is we are fine tuning the Fountain now. It idles and shifts well, although one engine needs a little more air at idle; it stalls sometimes going into gear. I was worried about getting on plane. When the shop delivered the boat to the customer, they filled the fuel tanks to the top, put 5 big guys on the boat and expected to go 100 mph. Amazingly the boat still jumped onto plane with no blowout at any point. This is with the 1.26 ratio in the 2" shorter XRs. That was a relief.

Midrange acceleration was great with WOT applied. Then when they got to 4500 RPM it stopped accelerating. The throttle went "soggy" and when you backed off to about 3/4 throttle it would accelerate again but only to about 4600-4700 RPM. At this RPM the boat was going 90 mph on GPS. We get exactly this sensation on carb systems when the secondary jetting is too rich. After leaning the secondaries we get better midrange and all the throttle with no stumbling or sogginess.

I suspect that the computer was set up to be safely over rich; I know that's what I would do if I was Arizona Speed & Marine. I told them that I expected the supercooler to deliver more boost than the stock Vortech system. The other possibility is that the knock sensor is pulling timing out. The heads were milled on these engines to get a true 9:1 C.R. and there was some old gas in the tanks. Fuel pressure was right were Vortech says to run it: 50 psi.

I will be calling Vortech and AZS&M on Monday, then going back to the boat on Tuesday or Wednesday with the shop owner. They didn't have any boost gauges yesterday and didn't take the scanner.

Good luck with your testing. We will compare notes on Wednesday!

Re: RTECH Supercharger on 502 MPI
 

hotlavey, you need to run the boat with a scanner hooked up to it. That's the only way you're going to see if everything is ok. With the scanner you can see if you're getting any knock, which would be pulling timing which would greatly effect performance. Actually excessive knock would have caused your blown head gasket. Any merc mechanic who is capable of working on efi engines will have one...if not, find another mechanic.

Re: RTECH Supercharger on 502 MPI
 

Please put an O2 sensor on one of those engines. Without one you have no idea where you are, and where you're going.

Re: RTECH Supercharger on 502 MPI
 

Chase,

After the Whipple was installed we put the boat in the water with the scanner hooked up. We ran it for about an hour; slow, mid, and WOT. Bernie(installer) made a few minor adjustments and we were good to go. I am very sure everything was adjusted and checked that could have been. I don't believe the loose valve seats were caused by the Whippple or by any misadjustments. The problem is that there are so many variables here that it is hard to pinpoint the problem. Water pressure(too little or too much?)is one. Now I have a pressure gauge. There is a knock sensor in the system so??? Could have been a weak gasket from the get go- who knows? I'll know a little more after Wednesday.

Re: RTECH Supercharger on 502 MPI
 

TC,

Ran the boat today. We could only pull 5K with a stock 30 Bravo 1. Water pressure was way low at 10 lbs and we should have 20-30 lbs. 8 of the 16 side inlets are plugged so we have to experiment with both removing some or adding some more. I was told to consider enlarging the nose holes a bit to allow more water. May do that after trying the side inlet plugs. Engine water temp stayed right around 120-130 but the engine builder says I must have more flow. Speed was only 81GPS and the water was oily smooth(bad). Air temp in the 80's. We were on a small lake so we did not even have chop.

Re: RTECH Supercharger on 502 MPI
 

You should just add an offshore pickup and be done. Dustin had told me in the past that only the Merc low water Bravo drive, the Performance Bravo 1, would have enough water flow, otherwise install an offshore water pickup. Without enough water pressure, flow through the intercooler, you're not getting the cooling of the intake charge which will result in greater chance for knock, which the engine will then start pulling timing...(which you will see in a performance loss)...to protect itself from destruction. This could be seen with the scanner hooked up and set to view knock. That's what you should be looking at while running. For tuning, the only thing you can do and use the scanner for is setting idle, by viewing the tps voltage, and setting the base timing. BTW, your suppose to check water pressure first before install to make sure its ok.
Again, everything is ok when you can run WOT with NO KNOCK registering on the scanner....don't go by feel or speedo/tach....hook up the scanner.
I'm convinced excessive knock caused your head gasket problem, especially now that we know you have inadequate water pressure.

Re: RTECH Supercharger on 502 MPI
 

Chase910: Thanks for the advice on the use of the scanner. I also understand that if pulling timing doesn't stop the knocking, the ECU starts dumping in more fuel.

It is a good question "How much water flow do you need through your intercooler and what pressure do you need to get it?" When we tested the supercooler (for carbs) on the dyno I measured just over 5 usgpm with an inlet pressure of 10 psi. Vortech says that their intercooler needs 5 usgpm. Since we use a Vortech intercooler water tee is installed just after the sea water pump. I figure there is much more than 10 psi there.

The Fountain goes back in the water tomorrow. Didn't go today because the boost gauges arrived and were being installed.

Re: RTECH Supercharger on 502 MPI
 

Yes, tomcat I believe that is correct, if timing pull doesn't stop it tries more fuel. The scanner can view knock and timing and you will see timing being pulled as knock increases.

With the water pressure, I only checked at the block, but Whippled needed more than 10 at WOT measured at the block, heck 10psi was at idle. The question is, What flow through the intercooler is needed to keep the intake charge temp low enough to prevent knock at WOT, with pump gas, and normal summer lake temps.? So, if you're saying you only need 5 usgpm flow through your intercooler to keep temps down and increasing the flow doesn't lower the intake charge temps, then you're ok at 10 psi.

Re: RTECH Supercharger on 502 MPI
 

I’m also curious how your getting 10 lbs of water at idle.
I use a 5 lb check valve on the outlet of my IC just to keep pressure around 3 lbs at idle???

Hey HotLavey,
My water pressure problem cost me dearly last season over heating and destroying the back four pistons and some chambers. I was using a transom mount water pick up for the engine and the standard outdrive pick up for the IC. The stepped hull gave me fits using the transom mount and when she burnt down I had 3-5 lbs of water pressure. I had fought this all year. Pressure would change with weight load, attitude, etc… I should have seen it coming.
My flow out the IC was marginal at best using the outdrive. I could see this by looking at my dump out the starboard side when up and running.
A couple of things; the dual pick up drives are not suited well if your X dimension is high at all. If you lower your drive when on the trailer, look and see where your upper intakes are in relation to the bottom of the V (hull). All my holes were above this imaginary line. All this does is allow water to be pounded into the nose and right out the upper holes; whatever’s left, your motor and IC can have :( There is a Merc bulletin regarding this problem.
I have done away with the transom mount pickup completely. I plugged all of my upper holes and enlarged the lower nose holes to 5/16” which equals the one 5/8 hole found in the nose of IMCOs and such. I also added a sea strainer. I plumbed my IC in right after the sea pump with 5/8” barb fittings. First time out I could bury the pressure gauge at 50+ lbs at only 4000 rpm. That was easy to fix with a Merc relief valve and one inch hose that dumps on top of my outdrive. My pressure now stay perfectly steady at 25lbs at WOT. I didn’t have good pressure at idle so I added a 5 lb check valve to the outlet of my IC. This in turn kept my pressure at 3+ lbs at idle and allows no flow thru the IC at idle.
In my case the now low water pick up supplies more than enough water for the motor and IC with 5/8” hose..
You may not need a pressure relief if you don’t run a thermostat. I have to run a 120 deg thermo for our icy cold spring waters, but that’s a whole different story. Whipple and GT Marine suggest a 5/8-3/4 restrictor in place of the thermo in non-thermostat applications to keep pressure up but that again will depend on your source of water ingestion.
Bottom line is, there’s plenty of water to be had and controlled. This is just how I did mine after a very costly experience.
My temps hold steady at 120 deg and pressure at 25 lbs when running hard with this thermostatically controlled setup. All systems go!
Fix the problem before your right back where you started.
Hope that helps.
Sorry Tom, kind of got off subject a bit…
Dave

Re: RTECH Supercharger on 502 MPI
 

Hey Dave:

No problem; I learned something. I assume you installed the relief valve after the oil cooler :rolleyes: and I like the idea of the check valve after the intercooler. I think this would prevent the condensation we find in the carb box under certain weather conditions. Do you have any idea how many usgpm are going through the intercooler?

I am talking to a guy who has the Vortech system on an HP500EFI in a 28 Heat. When he first installed the system he went 81 mph. Then he put on a smaller pulley and went 88 mph. But he has also been playing with extension box and spacers to get there. He's chasing me down for a supercooler.

Re: RTECH Supercharger on 502 MPI
 

Dave,

Thanks for the input. I checked the side inlets on the trailer. In the full down position 4 of the eight holes on the drive were above the keel line of the V. Those 4 (8 if you count both sides) have been plugged since the get go. I think my next step will be to drill out the holes on the front of the drive as you suggested. I will also tap the remaining holes on the sides and carry some extra plugs to use in case the larger holes are not enough. I don't have a thermostat as a cross-over was also installed. My IC dump is on the transom under the swim step so I can't monitor the flow from in the boat. I do know that when it is running in neutral and I am standing behind the boat that the flow is pretty strong, both from the IC and also from the heads(2 different outlets) My idle pressure was 4 lbs.
Good to hear from you again.

Tom

Re: RTECH Supercharger on 502 MPI
 

Funny you ask Tom :)
When I first installed it I had it before the cooler because it was right near the transom. You know, the asthetic thing :)
I quickly changed it when I discovered hot hot my oil cooler (and oil) was getting :)
I'd like to chat with the Heat guy; 88 is a really, really good number for that setup.
Email me if that's a possibility.

HL Tom,
sounds like your headed in the right direction. Just monitor things :)
Later,
Dave

Re: RTECH Supercharger on 502 MPI
 

Sorry guys, I should've looked at my notes from the install before I quoted numbers.
502mag bravo1 performance drive, stock cooling, 3-4psi idle...not 10.

2 ways to reduce knock, reduce intake temps or raise octane of fuel. With the supercooler on the Vortech you should be able to raise the boost without incurring knock if it is indeed cooling the intake charge better than the stock system.
Also you will see that as the water temps drop there is a decrease in the knock value. There is a noticeable difference in running a whippled boat in 50 degree water vs 80 degree water....

Re: RTECH Supercharger on 502 MPI
 

We ran the Fountain again today and got some answers. With the base fuel pressure set at 50 psi the boat ran the same as before. No signal from the knock sensor but only 3.5 psi of boost at 4500 RPM. So we dropped the fuel pressure to 45 psi and some of the throttle sogginess disappeared. Dropped the fuel pressure again to 40 psi and got all the throttles back. Still no signal from the knock sensor and total timing was about 30 degrees. Too many gauges to watch when you're hanging on, but I did think to check intake air temp at one point and it was only 78F. Air and water temperature today was only 70F due to a cold front passing through.

Re: RTECH Supercharger on 502 MPI
 

The result was 94 mph on GPS at 4900 RPM with only 4 psi boost. Slip was a bit high at 15%, but that's the 2" shorter drives. It was a rough day on the bay; we could only take short runs in protected coves and speed was still climbing slowly; the GPS was still climbing when we would run out of room.

But there is no way we are going to get to 100 mph with only 4900 RPM and 4 psi boost. That's only ~625 HP, and the 1.26 ratio is a steep hilll. We have two choices: put on 28 Bravos or put on smaller pulleys. With the 28s we would have to run the engines at 5600 RPM to go 100 mph. That would bring the boost up to 5+ psi which would make about 675 HP, enough to do the job.

With the next size smaller pulley we could make 6+ psi at about 5200 RPM, making about 725 HP and definitely do the job. We can crank the fuel pressure back up to go with the extra air. Decisions, decisions.

Re: RTECH Supercharger on 502 MPI
 

Wow, impressive numbers on the intercooler temps...the supercooler is doing its job. After reading this whole post...their was no doubt that you were running too rich. Boost should be a stock level as the intercooler addition certainly wouldn't raise the boost level, yet ASM had programed a fuel curve for higher boost as I understand it.
Seeing there is no knock...I would just keep raising boost until knock occurs, then try adjusting it out with fuel pressure and you should find the point of max safe boost and fuel pressure. With this supercooler you should be able to run more boost than the stock Vortech setup without knock and see some great gains. Great Stuff.

Re: RTECH Supercharger on 502 MPI
 

Chase910: I have talked to a few other guys who have installed stock Vortech systems and 4-4.5 psi is the norm. This is one reason why the intake air temps are low. I have ordered the next size smaller pulley already. I want to see what the intake air temp is with 6+ psi before I make any statements about the supercooler.

I am not sure why we were so rich; coudn't talk to Jim today. Whatever was prorammed for higher boost levels we didn't get it because we were only 4 psi. It's almost as though the richness was programmed in at a certain TPS position. You could almost get away with that on a centrifugally supercharged marine engine since boost and load increase pretty linear with RPM.

Further testing with props and pulleys next week.

Re: RTECH Supercharger on 502 MPI
 

looks like I dont have the forward clearance in my boat, what do you think Tom?

Re: RTECH Supercharger on 502 MPI
 

It doesn't look like you have the forward clearance. Do you have some headroom? What size intercooler do you have, 324 or 504? Since it is single engine, you may have some room on the stbd side for something better. Can you post a picture taken from the other side of the engine?