turbo outboard???

[ct20sutphen]

Everybody seems to forget about the member here who built this one:

God damn thats like SEX for me!!!

I love turbos and I run a T88 on my pontiac but thats a dream sitting right there.LOL

You guys are gonna make me build two of these damn engines for the sutphen.

I make 878 HP with my pontiac and I only shift it at 5800 RPM.
I only put 11 psi boost to it .
Lots more ower left in it. I am going Gen 7 DFI this year.
Otherwise Id seriously be looking into boosting my twin 2.5 mercs.

This thread has me all worked up.

[ct20sutphen]

I have seen pics of this boat. I always thought it was a Honda motor on that 12" mid.

Heard from a good source that guy is having trouble getting it to run, make power and stay together.

I priced out doing a project like this on one of Wayne Taylors 12" mids last winter. You are looking at big bucks to "try" something that you dont even know will work. One of the biggest cost is the dry sump oil system.

I would think you would be better off starting with a existing 4 stroke outboard and have heard work done to it and bolt the turbo up to that.

Anyone know the weight of the new verado 350 powerhead only?? That is a 2.6 liter inline 6 with a double overhead cam and 4 valves per cylinder. That is what is needed. This thing puts out 350hp STOCK and meant to run for 100's of hours, I cant see it being that far out there to get another 150hp out by pumping the boost up for a race motor.

theoretically, 1 bar or 15 psi boost, would DOUBLE the HP output of the engine assuming that it will flow the air needed and all in the same RPM range.

[STV_Keith]

One question mark is will the gearcase handle it?

[JrCRXHF]

theoretically, 1 bar or 15 psi boost, would DOUBLE the HP output of the engine assuming that it will flow the air needed and all in the same RPM range.

Umm i have never seen it work that way.

So many other things effect power output besides just boost.

more power yes if you have all the other bases like fuel spark and so on covered. What the turbo will do if sized right is up the VE of the motor to give it more power.

[Mark75H]

What the turbo will do if sized right is up the VE of the motor to give it more power.

A turbo does a lot more than increase the volumetric efficiency, it increases the cylinder pressure beyond what volumetric efficiency can.

If all a correctly sized turbo did was improve VE, the maximum power increase would only be the 15% to 20% ... getting up to 100% VE.

[ct20sutphen]

On every engine I have turbocharged The rule of 1 bar 15 psi = twice the Hp is just about right on the money.
Case in point my 455 .030 in my pontiac.

It was a 350 HP engine at best with 8.2 to 1 compression with out the turbo. At 11 psi it made 878 HP and ran 9.70 @145
It had previously run an 11.50 with 10.0 to 1 compression and a bigger cam

As long as you dont out flow the heads and the intake theoretically 1 bar will bring in double the air and double the fuel over a N/A set up.
Theoretically is the key word.

Your basically taking a 455 CID engine and tricking it into being a 900 CID engine.
Now thats over simplified but thats the way any boosted application works
The engine is just a big air pump.
More air in, more air out = more Hp and torque.
Pretty simple really

S/C and Nitrous work on the same principal.

yes fuel and ignition need to be adressed as well especially since a pump that produces 100 GPH at 5 psi will drop off considerably at 20 psi which is 1 bar added to the 5 psi which is what is needed at 15 psi. On a race car we use a boost referenced regulator to keep things even with boost pressure referenced off thecarb hat compressor inlet tube area.

I also would like to add that boost is not a measure of air flow but rather a measure of restriction in the intake tract.
So a 455 with better head and intake flow may move more air at 15 psi boost than the same 455 engine at 15 psi boost with lesser flowing heads and intake.

same psi less CFM

This is all 4 stroke stuff but I would imagine 2 stroke would follow.

[40hpmariner]

Everybody seems to forget about the member here who built this one:

for this guy obviously money is no option :P

[ct20sutphen]

what ever happened with this one?

[STV_Keith]

Opposite to 40hpmariners thoughts, I believe Gary ran out of funds on the project and had to sideline it.

[ct20sutphen]

Maybe we can get gary to update us on how far along he got?
This ones very interesting to me.

whats his screen name on here?

[G Rowe]

Yeah its collecting dust in a box at the moment, cashed up and went to europe for a few years !
Had it running, but as STV said the turbos were too small and I was only running a stock 280 ECU - the computer was freaking out an dumping fuel in etc etc - still managed to blow up the dyno though. After I built this I got hold of a guy who develops turbo snow ski's and was also on the team that developed the land and sea kits, was a wealth of information and if people say it cant be done - there wrong! just time and money : )

[mrcrsr]

it seems to that packaging constraints(getting it to fit under a factory cowling) would be a big problem as well. as stated earlier, efi would be the only way to go. i just got my 3 litre running well w/ a wolf ecu, that can be set up for boosted applications, so that wouldn't be a problem, i just don't see how to get it under a cowling, at least w/ a 3 litre. i guess if you were using a 2.5 you could run a 3 litre alien cowling/pan w/ a custom sst baseplate to adapt the 3 litre cowl to the 2.5. as far as asequencing turbos man diesel does it , they shut off one turbo at lo speed to enhance spool up time, but 2 turbos would make the setup more complex

[Dd24skater]

Here is the picture I think your looking for

[STV_Keith]

it seems to that packaging constraints(getting it to fit under a factory cowling) would be a big problem as well.

You would have to build a completely different cowling. It won't fit under anything stock. Think about the piping routing...probably has to go up and over the cylinder head on one side beside the flywheel, like the old L&S did. EFI would be key to making it live. Easy enough these days though.

You would likely need something significantly larger...like...

[BC Black Max]

This can work. Plugging my 3.4L cowl currently, custom plate for the pan and you would just have a decoy 3.4L.

It can still be exhausted under water, one more hole to cut, Twister log style . Brucato ignition or MAD EFI can handle this..gimme a O2 sensor and EGT meters.

Who ever is plugging this later style cowl ...this is cool.

You would have to build a completely different cowling. It won't fit under anything stock. Think about the piping routing...probably has to go up and over the cylinder head on one side beside the flywheel, like the old L&S did. EFI would be key to making it live. Easy enough these days though.

You would likely need something significantly larger...like...