Jump to content
GPI Racing

We need something new to talk about.

Recommended Posts

We need something to liven this place up. Here is a link to the newest engine in my quest. It is called the RST V8. The original was based on 2 Yamaha R1 engines but they have just run a 2.4 litre version that made 400hp. The engine weighs 163lbs. It runs 12000 rpm all day and has been tested to 15000rpm. It is a little more favorable than my initial packaging with the Powertec V8. I will be mating it to an Alpha 1 SS drive so I can use the coned sportmaster housing and gearsets. 2:1 gears to start. I will try to get this project done by Jasper so I can show the performance boat world how it goes. With Mercury taking a stand that they will keep raising prices and forcing big heavy engines on us this may get a different avenue going on hi-perf boating. Any bets on how a 600lb rocket runs with 400hp? Anybody want a ride?

Link to the original 2 litre spec: www.mountune.com\files\newsfiles\RSTV8.pdf

Randy

post-639-1135046347.jpg

Edited by GPI Racing

Share this post


Link to post
Share on other sites

No I don't want a ride, but feel free to throw me the keys. :D

The plan is to make Jasper next year.

This is a cool project but it would sure take getting use to turning around and not seeing an outboard.

Good luck with the project. If this works, how about we put one in my 22ft toon? :o I need something to go after Iverson with! LOL

B-RAD

Share this post


Link to post
Share on other sites

Looks Cool Randy. Whats the deal with Merc? Are you saying that they are going to raise prices on the 2.5 stuff untill we dont buy it anymore.. If so. That is BS...

Share this post


Link to post
Share on other sites

Wow, this looks like it could be really cool, possibly revolutionize our sport. I can't wait to see how it turns out Randy.

fish

Share this post


Link to post
Share on other sites

A little more info.

The engines have run for HUNDREDS of hours. (try that with a merc) The rebuild interval is going to be in years not months. This figuring how many hours we boat. In the cars they look inside after about 10000 miles. The boat will be wore out by then.

Mercury has just raised prices again. Nice. How's $500 for the bracket that holds the throttle and shift cable on a 2.5.(the list goes on) They are not interested in our business. They are treating us like the "poker run" crowd who have unlimited bucks.

I will have an engine that doesn't break and is faster than anything they have ever built. And for a cost not much different than a 2.5 drag.

Low end torque is very flat. 160ish ftlbs. Very similar to a 2.5.

Share this post


Link to post
Share on other sites

Aweseome Randy...good on ya...keep us posted :)

Share this post


Link to post
Share on other sites

Randy,

could you not make it even lighter and stronger using a direct drive with a hydraulic clutch and a rudder box built off the transom. Just think about how much prop you could turn in the quarter mile if you could roll in with your revs at over 10,000 and drop the clutch?

VERY neat project....good luck

Any chance of fitting one on top of a 12" or 15" mid section, a stock 2.5 power head weights in at over 180 lbs I beleive this thing is only 163??

Share this post


Link to post
Share on other sites

Randy do you think the Alpha SS uppers are gonna hold?......... I suppose as they don't have to withstand the torque, and the boat is light.

I have an SS, need another if you know where you can source them.

RT

Share this post


Link to post
Share on other sites

I think that a surface drive would be the way to go, something like an Arnarson.

Share this post


Link to post
Share on other sites

A few years back, about 1986, a guy that boated with us took a Youngblood TX19 jet boat, scrapped the 455 Olds/Berkley jet drive and put an 350 Chevy and an Arneson drive in it. It was a regular lake boat, I would guess the bare hull weighed in the 1100 pound range.

He had no transmission, but did have a clutch in it. The clutch was 2 disc Crowerglide centrifugal like some drag cars use. It had a clutch pedal you could over ride it with. At idle, the boat would just sit there, you didnt even have to step on the clutch. For normal takeoffs, just tap the throttle and go. For a bad ass holeshot, he could hold the clutch in, rev the motor and either drop it or let it out easily. It worked like a charm.

The 350 Chevy was mild, probably 300-350 horse motor and on motor only, the boat would run in the 105-110 MPH range, about 30 mph faster than the jet drive ran with the bigger motor. He did have a 200 horse nitrous shot that livened things up quite a bit.

The only draw back for some was no reverse, but there are transmissions available now.

Anyway, this boat ran like this for several years with little or no problems. Those Arnesons are a slick, trouble free drive. I would like to have seen that boat with a light weight big block with some serious power.

ER

Share this post


Link to post
Share on other sites

Randy,

If you decide to go with the arneson, I know a guy who put one in an 1975 18' donzi. No transmission like ER was talking about but the boat is on the high side of the 120's mph. That is a heavy hull too. I believe supercharged small block at around 1000hp. He has been doing this as a project for a lot of years and learned a lot of stuff the hard way. I am sure he would be willing to give the benefit of some of his experience with this, just let me know if you would like to pull his ear. BTW, his is one of the feature boats on the arneson page.

Share this post


Link to post
Share on other sites

Here are some pictures of my "other" project. An intake for the 2.5 that gives all the benefits of the Mad efi manifold I worked with and the SVS I've been playing with. But with a twist. Using a single airhorn butterfly to control the air it has a much nicer idle and midrange. The signal to the box is better too. By moving the injectors forward of the reeds we gained a big boost in punch from idle to 7000. The side benefit is now the reeds control the fuel charge timing and the cylinder get the fuel at the proper time. Less chance of a random burndown with the injectors in front. Mercury firing 2 at a time and at no sequenced effect has always been a little odd.

We will be red anodizing the part and providing all the hardware. Fits any motor with the 7 petal front. Carb, 260, 2.4, 280, drag or whatever.

I tried loading ithe pictures but the file's to big.....I'll send it to B-rad..he'll fix it.

Randy

Edited by GPI Racing

Share this post


Link to post
Share on other sites

The Donzi deal sounds cool. A set up like that in a more modern, efficent hull like a STV would scoot. I see where you can build a 450 or so cube all aluminum small block Chevy with off the shelf parts. Probably for about the same price as a 300 Drag.

A motor like that would really have some serious torque and an effiecnt boat along with an Arneson would be interesting.

Randy, I am sure you have a reason for going with a MerCruiser........is it because of the ability to trim?

ER B)

Share this post


Link to post
Share on other sites

randy you can send it to me, I can re size and post it

I always though a direct drive shaft through about where the drain plug is and use the existing transom to build an assembly to hold a rudder. And a small Allison trubine ( 320 hp ) would be slick.

RT

for Randy

post-7-1135115336.jpg

Share this post


Link to post
Share on other sites

ooops, wrong picture! LOL

Looks like RT posting the pics. Your more talented then I thought! :o:P

Not too shabby RP but I'll take "The Girl Next Door" instead!

There, now we have tons to discuss. Gonna be a long winter.

post-70-1135115693.jpg

Share this post


Link to post
Share on other sites

RT, have you ran an intake like that yet?

That style with a slide in front rather than a horn works very well on our OMC's.

I do angle the injector towards the reeds, but I am not sure that is necessary.

ER B)

Share this post


Link to post
Share on other sites

The injectors are angled 15ish degrees. That is what makes the placement of them so tricky. After going through all the design it's easy to see why Mercury put them on the crankcase. To get everything to fit was a big challenge. We also wanted one piece as I ran some protos made from several pieces. The responce and low speed is something that is felt "seat of the pants". Side benefit is the engines start better too.

Thanks rob and B-rad for the picture help.

We will only be making 20 manifolds for the first run. Half are spoken for already. While we did everything to keep the cost down it was quite expensive to have made. The kit with all the pieces and the manifoled anodized will sell for about $750. It took us 2 months to find a shop that could do it and get the price down. I was originally quoted 1 1/2 times that. Then we had toget it plated and buy all the hardware. I think the finished product turned out good though. And it is one thing you can bolt on and get something back for a change. I own every intake for a merc there is. This is something that I originally made for myself, but saw the need for it in the field.

randy

Share this post


Link to post
Share on other sites

Randy, what's the advantage to moving the injectors out in front of the reeds?

Share this post


Link to post
Share on other sites

Basically Mercury chose to fire their injectors 2 at a time. This means when number one is getting fuel (and let's imagine the piston is on it's way up from bottom dead center) Number 2 is getting fuel at the exact same time but it's on it's way down!. Not the best senario. They could have (and so could I) come up with better electronics to fire the injectors sequentially. That would take money and a whole new system. Not in the Mercury scheme of things. By placing the injectors in front, they still squirt at the same time. (2 at a time) but now the fuel can stay in suspension in the manifold for a micro-second. When the time is perfect the reeds open and the fuel/air charge is pulled in, at exactly the perfect time. The reed become the perfect injector timing device. This is why we see such a rush in the lower rpm. At high rpm the air/fuel flow is so quick that it runs very much the same. The mercury injectors are practically firing nonstop at this time. The work I put into the manifold was to get a nice clean running 2.5. You could put an SVS on the front of the manifold and have the advantage of wet reeds fuel timing with Tony's stackable system. Right now with the airhorn it runs as hard as anything we've ever tested. I wanted something flexable so we included the bosses and holes to use it on a carb fronthalf (enabling carb guys to convert to EFI) and the 280. Every 7 petal front will accept it. That's the scoop on it.

Randy

Share this post


Link to post
Share on other sites

RP, that looks REAL good. I made a similar set up for this F-1 V8 Darrell Lane brought me. As soon as I get it put together, I'll post a pic or 2. I was doing the assy and found 2 crank journals spalled, so off to MCC. I also made some replacable chamber heads for it.

ER B)

Share this post


Link to post
Share on other sites

Create an account or sign in to comment

You need to be a member in order to leave a comment

Create an account

Sign up for a new account in our community. It's easy!

Register a new account

Sign in

Already have an account? Sign in here.

Sign In Now

×