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!

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.

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

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.

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.

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.

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.

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

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.

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?