cobra marty

Good job guys. Get a 30" prop. Keep it comming!

HPJunkie

Wow thats awesome. Accolades to the tomcat! Am I reading you right...no pulley change? do you have a photo of the stock procharger setup? Thanks Greg

Biggus

iTrader: (1)

Thats right, no pulley change, just a more efficient and less restrictive path to the carb.

HPJunkie

you guys done or what? Im dying to hear the progress. This stuff is huge. greg

Biggus

iTrader: (1)

Yes, we had some fun!!!

next step is to contact Nickerson Perf in the morning for some carb tuning.

the results so far were just incredible!

Gained @4 lbs boost just bolting the intercooler/box (no pulley change)

Reduced the intake temps by 30*

We are now running @8 lbs boost and intake temps are 86*

Pretty impressive! (we were running 4.5 lbs and 109* intake temps with the stock Procharger box)

The R-Tech Supercooler will increase boost and drastically reduce intake temps WITHOUT spinning the blower faster!!!!

What do you think of that????

Kurt

HPJunkie

Well Kurt, I think its great so what happened? Is 85 it or what? are plug readings the problem? They are for me. do you use new plugs or slightly used or colored or what? So you have EGTs or not? What does dean need to do ? Is tomcat going home with his box? Greg

tomcat

Hi guys:

Just got home from Maine. Here's the scoop so far.

We increased boost and lowered temps more than I thought we would. Based on our measurements we have increased air density to the carb by 20% without spinning the blower any faster. Our baseline with the 28 Bravo was 5000 RPM. With the supercooler we blew by that mark with tremendous midrange stopping at 5400-5500 with a couple inches of throttle left. We are going to need a 30 Bravo.

The reason we stopped testing was when we tried to use the remaining throttle the engine started surging. We couldn't hold the boat at a steady RPM to let the speed climb up the last few mph. Even so we saw an extra 5 mph on the GPS.

We don't have near enough jet. A 20% increase in air density is huge and we weren't prepared for that. We didn't have big enough secondary jets to provide that much extra fuel, and you can't just throw huge jets in the primaries without midrange problems. We know that Nickerson modifies the metering blocks to provide the extra fuel so we decided to stop chasing it until we talked with Dean on Monday.

When the carb gets sorted out I think 85 mph is quite possible against a baseline of 77. The reason these numbers are on the low side is we took out the rear seat and hatch for ease of access during testing. We also decided not to play with the trim to squeeze out the last mph, so the drive is tucked in more than normal. Both of these things increased wetted surface. As a result the boat is about 4 mph slower than normal on the baseline.

When we put the weight back into the stern of the boat and play with the trim the speed will go up, but I'm just interested in the back to back comparison. If we can get the fuel to go with the 20% more air we will be adding about 100 HP and I would expect about 7-8 mph over the baseline.

Biggus

iTrader: (1)

The Supercooler was bought by board member Neverenuff, the owner of the test boat.

But don`t you worry, the R Tech Supercooler is in production as we speak.

Kurt

tomcat

We don't have any dyno numbers on this particular engine, but when we dyno tested the prototype on the 454 Magnum that used to be in the boat we produced 650 HP with the Procharger and 740 HP with the Rtech/Procharger. This was on an engine that made maybe 425 HP with GM heads, a mild cam and the dyno headers. I would expect similar numbers from a 502 with the same heads and cam, maybe at a lower rpm.

The Rtech added 2 psi in that test and did not lower temps since the prototype core was the same size as the Procharger core. The production unit in the boat test added 3 psi and lowered temps due to the large 468 in3 core.

tomcat

I wouldn't say that the 502 engine in the boat now was built differently to handle the Procharger and it certainly wasn't modified to suit the Rtech in any way. It is an 8.75:1 engine with iron Merlin heads. The cam has longer duration than the 454 Magnum than we dyno tested. The larger displacement, better flowing heads and bigger cam reduced the boost level from 6 to 4.5 psi when the procharger was reinstalled. That was our baseline.

To duplicate the boost level we achieved with the Rtech you would have to go up 1 or 2 pulley sizes, and you wouldn't make the same power due to hotter air temperatures and the power lost to spin the blower faster. Then there are all the reliability issues that go with spinning the blower faster.

Thanks to Paul for once again providing his boat for this R&D. Thanks to Kurt for opening his house and dock to us. Check out this mini marina!