GM turbo Diesel 6.5 V8

Silversurfer · 01-09-2005, 10:39 AM

GM turbo Diesel 6.5 V8

Maybe one for Fuller this!

Anyone know what the fuel consumption on one of these engines would be in a boat? Rough MPG figures would be great thanks!

Jon Fuller · 01-09-2005, 10:46 AM

It rather depends on the hp.

My 325's burn 15 imperial gallons/hour flat out, each.

In normal 'cruise/blast/idle/blast/criuse etc' use, I expect to use between 10-15 galls and hour (combined).

My last boat, (26 extreme) had a single 230-ish hp 6.5 gm, turbo, no intercooler, it probably used IRO 9 galls/hour flat out, but across the season, it averaged 2.8 galls/hour, or back then £2.50/hour.

Silversurfer · 01-09-2005, 11:00 AM

Thanks - HP is 220 and there are two engines boat runs at 50knots.

Captain Chaos · 01-09-2005, 11:37 AM

what boat mate? anything interesting?

Silversurfer · 01-09-2005, 11:49 AM

It’s a secret and only a though at the moment, but going to have a look at a boat next week - Phantom may be up for sale soon. Baby forces sale!

glen76 · 01-09-2005, 05:44 PM

jf are your gmcs raw water cooled?? excuse my ignorance but saw ur smokey arse at cowes week and when i saw all the water runnin out the zorsts it got me thinking. Are ur gmcs marine engines or marinised engines?? if u marinise em is ok to chuck all the green through em or best to use a closed cooling system?

many more qs to follow

Jon Fuller · 01-09-2005, 07:03 PM

My GM's are the lower compression version of the AM General V8 as built and used in the military 'Hummer'

The Automotive version is basically the same, except it has a 21.3:1 CR, and mine are 18:1, to allow higher boost pressure to be used.

I bought them as long motors from Peninsular marine engines(blocks, cranks, rods, pistons etc) and marinised them myself, but of course Peninsular market them as complete motors, either on transmissions (for shaft drive), or hooked up to a Bravo1.

And no, they are not raw water cooled, closed circuit with 50% of the finest.

Diesels like to run at a happy 80deg C, most raw water setups run down around 60C, plus, I couldn't bare all that salt munching away at my motors.

Jon Fuller · 01-09-2005, 07:05 PM

Quote:

Originally posted by Silversurfer
It’s a secret and only a though at the moment, but going to have a look at a boat next week - Phantom may be up for sale soon. Baby forces sale!

50 knts! how big is this boat?

glen76 · 01-09-2005, 09:41 PM

so hows ur cooling system work jf? i presume its pumped up leg into an exchanger then back out the zorsts.. if so what marinising is there to do to an engine that running on a closed fresh system? isnt it similar to a car system then.. how many water pumps you got? oh yeah and what do the gmcs rev too?

Jon Fuller · 01-09-2005, 10:10 PM

Ok, sea water is picked up by scoops in hull, from there it goes to the sea strainers, then the raw water pumps (rubber impellor/Jabsco) then to the engine oil coolers, from there it goes through the Chargecoolers (intercoolers), then on to the heat exchangers (equivalent to car radiator), then it's dumped into the wet bend (exhaust/water injection point) and out the arse.

there is also a conventional water circulating pumps on the motors to move the 50/50 coolant mix around the blocks, just like a car system.

my motors have a max rpm of 3600, but mine are propped to rev just over that (about 37-3800)

Matt · 01-09-2005, 11:21 PM

41'

Quote:

Originally posted by Jon Fuller
50 knts! how big is this boat?

Silversurfer · 02-09-2005, 09:28 AM

Went to see the boat last night its runs a "closed fresh system" the boat is 37 feet long and is of Italian dersign and build.

Looks greats will consider a sea trial after me wedding! ( Stag do this weekend - gone surfing!)

Jon Fuller · 02-09-2005, 09:32 AM

just out of interest, are the motors from Samurai engineering, down in the west country?

a 37 footer with 440hp is very unlikely to do 50 knts

Silversurfer · 02-09-2005, 10:50 AM

Not sure havnt been out in it yet the advert says cruise @ 40 knots flat out 50 knots you know what sellers are like will pm you the advert.

glen76 · 03-09-2005, 09:51 AM

what bout the holes usually used in the leg, do u just block em some how or havent you got em?? is it not possible to pump the water up through them and save on having lumps in your hull or could it only be a direct route to engine through the leg.. got any diagrams?

glen76 · 05-09-2005, 01:47 PM

its ok sportsboat just explaine it all to me in an article, clear as mud now!

Scand · 13-09-2005, 06:01 PM

Quote:

Originally posted by Jon Fuller
It rather depends on the hp.

My 325's burn 15 imperial gallons/hour flat out, each.

In normal 'cruise/blast/idle/blast/criuse etc' use, I expect to use between 10-15 galls and hour (combined).

My last boat, (26 extreme) had a single 230-ish hp 6.5 gm, turbo, no intercooler, it probably used IRO 9 galls/hour flat out, but across the season, it averaged 2.8 galls/hour, or back then £2.50/hour.

Are you running two of these in the Phantom?
May I be as bold as to ask how much these cost to build?
I was wondering about replacing my twin 5.7 MFI V8 petrol’s with something that’s a bit cheaper to run.

verytricky · 13-09-2005, 06:48 PM

Quote:

Originally posted by Jon Fuller
a 37 footer with 440hp is very unlikely to do 50 knts

I had a sunseeker with tripple KAD42's at 47 foot, could touch 44 knots, 48mph.

Silversurfer · 13-09-2005, 07:36 PM

Seen something else now along the lines of the sunseeker hawk range

Admiral P. Brain · 14-09-2005, 08:10 AM

our sunseeker tomahawk mk2, twin kad42, total 460hp, runs 42-44mph.