32 Skater with supercharged Rtech 800EFIs
 

Here is a photo journal of the supercharger installation, dyno testing and engine installation. This is a late model 32 Skater that ran ~110 mph with stock HP500EFIs and Bravo drives. Victory Marine in Texas is handling the installation. Engines were freshened using Cometic head gaskets, ARP rod bolts and better bearings; stock heads, cam and exhaust.

Re: 32 Skater with supercharged Rtech 800EFIs
 

Supercharger installation is straightforward. Vortech blower, mounting brackets and drive assembly are used. Fuel system is different from stock; we uses bigger rails plumbed in parallel and an Aeromotive regulator with 50 lb injectors. The injectors are good to 800 HP, the rails and plumbing are good for more. Large intake mounted intercooler and upper plenum reduce restrictions to air flow and increase cooling effectiveness versus typical remote mounted intercoolers.

Re: 32 Skater with supercharged Rtech 800EFIs
 

One of the engines was taken to Precision Marine for dyno testing and three days of ECU calibration. Although readings of 830-840 HP were measured, the 50 lb injectors were really done at 800 HP. Since this was our target anyway, fuel and spark maps were set up accordingly. Manifold air temperature was 73F using 60F city water. Engine was held at 5200 RPM for six minutes on one run to allow observation of temperatures under steady load.

Re: 32 Skater with supercharged Rtech 800EFIs
 

This is Victory's closed cooling system, nice addition to a salt water boat. The extra size and capacity of this system will be mandatory when we start supercharging 525EFIs. First engine going in the boat. Two engines installed waiting for exhaust system. Using the air filter assembly shown requires that the water inlet on one of the elbow tops be modified. These particular headers were also modified to take a wide band O2 sensor for further testing. Boat should be in the water on Saturday for prop testing. Results to come...

Re: 32 Skater with supercharged Rtech 800EFIs
 

Nice looking project. Did you ever flow that intake?

Re: 32 Skater with supercharged Rtech 800EFIs
 

Hi Gary:

We didn't flow the intake and I don't know at what RPM/CID it becomes a bottleneck. I did talk to Jim at AS&M and others about it, and decided that the long runners were good for this application with the stock cam. We want to maintain as much low RPM grunt as possible on the engine alone and let blower's linear boost curve do the work on the top end.

This is a conservative approach that works well in big boats. With a big engine in a smaller boat you can build the engine for higher RPM and make much more horsepower, but I don't have to tell you that. :cool:

Re: 32 Skater with supercharged Rtech 800EFIs
 

Nice job Tom. You've been busy. What were the boost numbers at each rpm? Does that skater have Stelling boxes?

Re: 32 Skater with supercharged Rtech 800EFIs
 

TC, I was just wondering how your manifold compared to a reworked 502 EFI manifold.

Re: 32 Skater with supercharged Rtech 800EFIs
 

Hi Marty: The boost numbers are typical centrifugal. As far as I know it's a Bravo transom assembly with Imco drives.

RPM - Boost
3000 - 2.25
3500 - 3.00
4000 - 3.93
4500 - 4.46
5000 - 5.57
5500 - 7.01

Hi Bill: The heads and cam are stock. Victory Marine has a bunch of these 500EFI engines that are takeouts and/or Mercury service returns. When they asked what to do with them to prepare for the the Rtech kit I just said use Cometic gaskets. But I think they do make a little more power because air enters the upper intake manifold through a big hole in the top, after passing through a perfect diffuser (the intercooler). This has to improve air flow into the ports compared to having high velocity air entering that plenum through a relatively small throttle body at one end. I don't really have a "back to back" way of testing this theory, but the overall improvements of the intercooler plumbing and air flow into the intake manifold contribute to the high HP numbers for relatively low boost.

Hi Gary: If you tell me exactly how you flowed your intake I will try to duplicate the test procedure with the next intake we do. It would be good to know. I have heard of people extrude honing the lower intake.

Thanks,

Tom Robinson
www.rtechperformance.com
(416) 709 - 8714

Re: 32 Skater with supercharged Rtech 800EFIs
 

The boost curve just about looks almost just like the HP curve. Can you plot those boost numbers on the graph above?

Re: 32 Skater with supercharged Rtech 800EFIs
 

Hi Marty: I don't have the datalog file yet to make a different graph but I plotted the points roughly. Although I just drew a line through the points there is actually a dip in the boost curve coninciding with the torque peak where the heads and cam are most efficient. You can tell by looking at the graph that if this engine had a better valvetrain, we could let it rev higher and the boost and HP would keep increase accordingly.

For boats like this Skater it is possible to run out of pitch with available/desirable gear ratios. To reach top speed you may then have to increase engine RPM.

Re: 32 Skater with supercharged Rtech 800EFIs
 

Hey Tom,

Great numbers!!!

Who's going to be the throttle man? :eek: :D

Kurt

Re: 32 Skater with supercharged Rtech 800EFIs
 

Bill of Victory Marine will likely be on the throttles. Discussed gear ratios and props with Bill last night. The boat originally had 1.26 ratio Bravos and they went to 1.34 with the Imco because it's easier on the lower gear set and propshaft. This means a big jump in pitch. My prop software says 38" :eek: First numbers should be in this weekend.

Re: 32 Skater with supercharged Rtech 800EFIs
 

Installation completed, headers installed. Ummm...Shiny parts... :cool:

Re: 32 Skater with supercharged Rtech 800EFIs
 

Hey Tom!

How'd she run yesterday???

We're anxious to hear the results! :evilb: :D

Kurt

Re: 32 Skater with supercharged Rtech 800EFIs
 

Good luck with the drives.

CM

Re: 32 Skater with supercharged Rtech 800EFIs
 

Kurt: Weather permitting the testing will be done this afternoon(Sunday). Yahoo, I see that you live close by; worried about shrapnel from the drives? :D

Re: 32 Skater with supercharged Rtech 800EFIs
 

Not worried about shrapnel, you will be way out in front of me. It just gets old idling in all the time.

Been there done that.

Curtis

Re: 32 Skater with supercharged Rtech 800EFIs
 

Fred:

I don't know the history of the boat at all, but it is a beauty. They are out on the water right now. It's windy on Galveston Bay today so they started with 34" props which will limit the speed with a 5600 rev limiter. They want to get used to the boat above 120 first and won't be trying for any big numbers until all is in order. I can't agree more with the safe approach.

Thanks,

Tom

Re: 32 Skater with supercharged Rtech 800EFIs
 

Just curious who's boat is it ?

Curtis

Re: 32 Skater with supercharged Rtech 800EFIs
 

Well, the report from Texas is as follows:

As expected the 34 Bravo props are too small and they hit the 5600 rev limiters in very short order, limiting speed to 120 mph. Brutal acceleration but obviously more pitch is required. No hint of knock, O2 readings and manifold air temperatures all good. Winds and limited daylight prevented more testing today.

The owner would like to remain nameless at this time, but he is very happy. Maybe he has a surprise planned for someone. :D More results to come this week as more pitch is tested.

Re: 32 Skater with supercharged Rtech 800EFIs
 

What was the top speed with the stock 500 EFI's? What prop, pitch,rpm, drive ratio?

Re: 32 Skater with supercharged Rtech 800EFIs
 

Hows the water temp with Victory's closed cooling system any info on there setup
Thanks

Re: 32 Skater with supercharged Rtech 800EFIs
 

mtm: I didn't think to ask about the closed cooling system but you can probably learn more at

www.govictorymarine.com

Marty: I sent you a PM

Test crew leaving for three hour tour

Re: 32 Skater with supercharged Rtech 800EFIs
 

Thanks Tomcat

Re: 32 Skater with supercharged Rtech 800EFIs
 

Any more testing ?

Re: 32 Skater with supercharged Rtech 800EFIs
 

Further testing to be done sometime this week. We are arranging for some helicopter shots during the next run. Weather is not cooperating though, too windy. I'll keep you posted.

Re: 32 Skater with supercharged Rtech 800EFIs
 

I love that TQ curve from 4000 to 5500 is completely flat! Imangine with extrude honed lowerintake manifold and ported heads you could extrapolate the curves out to 6000rpm and see 8.5 boost , 900HP and 800+TQ. Now you would have a 2,000rpm spread, perfect.

Re: 32 Skater with supercharged Rtech 800EFIs
 

Marty: I know but where do you stop? You'd need better injectors, lifters, springs, rods, aftermarket block etc.

The boat is going out again tomorrow with 37 Bravos (36 repitched). We'll see if it will hit the rev limiters with those.

Re: 32 Skater with supercharged Rtech 800EFIs
 

it is a really nice boat, with great engines
could have picked up a ton of horsepower with new heads and cam
but for the stock stuff, just awesome results, i hope it does well today

Re: 32 Skater with supercharged Rtech 800EFIs
 

Any results ?

Re: 32 Skater with supercharged Rtech 800EFIs
 

Here's the progress report:

The boat went out this afternoon with 37 Bravos. These are repitched 36 Bravos but we had no previous experience with them. Acceleration was still great, but at WOT the engines hit the rev limiters with maximum speed not increasing very much over the 34 Bravos. If these props really are 37 pitch, then they are slipping ~20%. Because they are reworked props you always wonder if they are right. In hindsight a set of box stock Merc 36 Bravos would have been a good trial. Victory Marine is thinking that the boat needs five blades.

We will have more results when we get some other props to try.

Re: 32 Skater with supercharged Rtech 800EFIs
 

You should probably try herrings, they will help the drives last longer.

Tell Little bill I said Hi,

Curtis

Re: 32 Skater with supercharged Rtech 800EFIs
 

Victory Marine talked to Mercury and they suggested a pair of 34" Maximus five blades. If they arrive today the boat will go out for another run.

Re: 32 Skater with supercharged Rtech 800EFIs
 

I think they may have to go back to the 1:26 RATIO

Re: 32 Skater with supercharged Rtech 800EFIs
 

The progress report for today:

The five blade props arrived today and if acceleration with the four blades was brutal, you'd have to call it vicious with the five blades! :evilb:

Conditions on the test area were rough and windy, so they could not do a top speed run. But they were able to exceed 120 mph in less distance than it took the four blades to get there, and they did not hit the rev limiter. Now we're getting somewhere. :D

Re: 32 Skater with supercharged Rtech 800EFIs
 

At the TOPPS 20th anniversary party.

Re: 32 Skater with supercharged Rtech 800EFIs
 

Do the air intakes stick out the engine hatch ?

Re: 32 Skater with supercharged Rtech 800EFIs
 

Not much. The upper plenum is 1" above the top of the hatch and could have been covered with a small raised section, but the hood scoops looked better.

Re: 32 Skater with supercharged Rtech 800EFIs
 

Dont waste any time getting a rear facing scoop installed.

One good wave or rooster tail and you will hydralic the the motor.

And it will happen, its happened to me on every skater ive owned 36ft thru 46ft.

CM