nzjetboating Web Board.

nzjetboating.com Forums => Tech Library => Topic started by: belmont on January 16, 2015, 20:54:09 PM

Title: Engine, unit set up advice please
Post by: belmont on January 16, 2015, 20:54:09 PM
Hi guys

I have recently brought a 4.1 alloy boat running a carb sr20, dominator intake and Colorado single stage. 110mm nozzle and bullet impeller (18deg?)...  boat goes really well with two people, but struggles to get on the plane with 4.  Any advice on how to make it go better??   Do I need more hp? different unit setup?
Title: Re: Engine, unit set up advice please
Post by: ntimz on January 16, 2015, 20:59:08 PM
probably more HP. Sounds about right for blade/nozzle. Is the unit slipping? I had the same setup in my Jet 20. Fantastic for a small boat but 4 people in a 4m boat is getting up there in my experience  2c
Title: Re: Engine, unit set up advice please
Post by: rogee on January 16, 2015, 21:11:45 PM
Should easily do it with 4 people if the engines running right. Lots of variables though. Boat weight would be a major factor  what rpm is it pulling?. Got pics or vid of your setup? Good power upgrade would be to fit a factory sr20det turbo setup and get rid of carb and go back to efi

Title: Re: Engine, unit set up advice please
Post by: belmont on January 16, 2015, 21:14:54 PM
Hi the impeller is pretty much new, so no problem there.. more hp? what engine would you recommend? and would I need to change the unit if I was going for a bigger engine?
Title: Re: Engine, unit set up advice please
Post by: ntimz on January 16, 2015, 21:18:56 PM
Its a bit of a tricky one with the single stage, generally speaking going turbo or to a v6, the unit will struggle trying to deliver the power without slipping. Others on here will know what works. Going to a modern blade has big gains from what i have experienced over the standard bronze blades.
Title: Re: Engine, unit set up advice please
Post by: belmont on January 16, 2015, 21:19:54 PM
rogee

it pulls about 4500-5000, I have been told the boat would be about 400KG.. its a Rakaia 410 hull. I have been told turbos can be expensive to get set up? I will post some photos over the weekend  cheers
Title: Re: Engine, unit set up advice please
Post by: rogee on January 16, 2015, 21:26:58 PM
They are a light enough hull. Somethings cocked up and it should go fine with 4 people if the setup is right. No big deal to do a turbo upgrade but it does add up . Still a better option than a motor swap though unless you dont like turbos .
Title: Re: Engine, unit set up advice please
Post by: rogee on January 16, 2015, 21:31:03 PM
With an 18 scott or whatever bullet and 110 noz you should be at5500 rpm . Your way off the mark so id be checking what imp you actually have then look at the engine for lack of power issues. 2c
Title: Re: Engine, unit set up advice please
Post by: belmont on January 16, 2015, 21:33:41 PM
Would the hp be down because it is carbed?
Title: Re: Engine, unit set up advice please
Post by: rogee on January 16, 2015, 21:38:00 PM
Maybe but a carb will make as much or more hp than efi if done right. That said theres alot of half arsed carb conversions out there primarily because whoever did them was trying to save $$$ not make power....
Title: Re: Engine, unit set up advice please
Post by: lachlan on January 18, 2015, 09:40:00 AM
is it just a standard 100 hp blade ? you need to smack it up a bit finer .

a decent 3 blade will put up with a early subaru turbo engine so it would put up with a sr20de + t aswell

you can +  a sr20 really easily . all the oem stuff bolts on and the market is flooded with it .
hardest part is ecu and someone to tune it

what carb is on it and what does it look like ?
or is it all oem carb stuff from an old primera motor etc ? they are pretty gutless
Title: Re: Engine, unit set up advice please
Post by: belmont on January 30, 2015, 16:24:16 PM
Hi this is my carb set up. Think it's off a 3l ford Essex
Title: Re: Engine, unit set up advice please
Post by: belmont on January 30, 2015, 16:53:49 PM
how would a 3l Nissan vg30de go in my boat? there is one on trade me ready to go..
Title: Re: Engine, unit set up advice please
Post by: dannyb on January 30, 2015, 17:29:11 PM
how would a 3l Nissan vg30de go in my boat? there is one on trade me ready to go..
I saw one in a 3.5 m boat the other day, it was insane  *-)
Title: Re: Engine, unit set up advice please
Post by: lachlan on January 30, 2015, 17:43:29 PM
was that a vG30 or a vQ30 .
the vg30e ( single cam , which that one on TM is )  is a bit of and old dog and prolly not much better than a essex v6 and below a comme v6
that carb setup if a joke . like a lawnmower intake has more potential

Title: Re: Engine, unit set up advice please
Post by: dannyb on January 30, 2015, 18:00:55 PM
was that a vG30 or a vQ30 .
the vg30e ( single cam , which that one on TM is )  is a bit of and old dog and prolly not much better than a essex v6 and below a comme v6
that carb setup if a joke . like a lawnmower intake has more potential
umm not sure didn't ask, but in that tiny 3.5 boat it was , more than enough. The hole shot was impressive practically leapt out of the water  B))T
Title: Re: Engine, unit set up advice please
Post by: belmont on January 30, 2015, 18:22:16 PM
how much better would my sr20 go if I was to get rid of the carb and inject it?
Title: Re: Engine, unit set up advice please
Post by: rogee on January 30, 2015, 20:03:22 PM
was that a vG30 or a vQ30 .
the vg30e ( single cam , which that one on TM is )  is a bit of and old dog and prolly not much better than a essex v6 and below a comme v6
that carb setup if a joke . like a lawnmower intake has more potential

The vg30 engines go really well,  not even that heavy either, done a few and they are much better performers than the ford v6,  for a budget concious build they can be a very good option if you find a low K tidy one , would be well worth considering the TM one as its all there and ready to go for less than the price of a new link atom ecu alone? 
Title: Re: Engine, unit set up advice please
Post by: Karl on January 30, 2015, 22:08:18 PM
Have always run a 16 deg 3 bladed scott impeller and a 115 to 118 nozzle on a SR20. That carb is a a joke.  Get one off a 2L toyota or similar. Given the carb is dodgey what does the distributor look like and what timing are you running.
Title: Re: Engine, unit set up advice please
Post by: belmont on January 31, 2015, 12:11:58 PM
If I was to go for the vg30de engine setup, would it be too much for my unit to handle? Would I need to go to a two stage?
Title: Re: Engine, unit set up advice please
Post by: rogee on January 31, 2015, 12:29:56 PM
No. With the blade and noz you have itl be pretty close   already.
Title: Re: Engine, unit set up advice please
Post by: Karl on January 31, 2015, 17:05:26 PM
If I was to go for the vg30de engine setup, would it be too much for my unit to handle? Would I need to go to a two stage?
VN V6 commadore would be a better option.
Title: Re: Engine, unit set up advice please
Post by: mohawk on January 31, 2015, 21:48:39 PM
+ 1 for the commodore , but budget on a 2 stage pump aswell.
Title: Re: Engine, unit set up advice please
Post by: belmont on February 03, 2015, 21:18:12 PM
Hi guys

Had the boat out tonight. Normally it goes pretty good. But tonight it ran rough. Only got to 4000rpm and sounded rough. A small amount of smoke was coming out of the pipe at the back of the block (see photo) what is the pipe for? And should it be smoking?
Title: Re: Engine, unit set up advice please
Post by: ntimz on February 03, 2015, 21:28:36 PM
That looks like a breather for your rocker cover. usually they are plumbed via a catch can back into the vacuum side
of your intake where it sucks any oil vapour etc and re burns it in the cylinders. Has it always been open and only just started smoking?

Title: Re: Engine, unit set up advice please
Post by: belmont on February 03, 2015, 21:39:56 PM
Always been open like that. And just started smoking
Title: Re: Engine, unit set up advice please
Post by: ntimz on February 03, 2015, 21:45:54 PM
oil pressure, level, temperature all normal?
Title: Re: Engine, unit set up advice please
Post by: belmont on February 03, 2015, 21:51:14 PM
Yeah the temp and oil pressure stayed normal. It has been using a bit of oil. I was only out for maybe ten minutes run time tonight. I will check oil levels tomorrow. Cheers
Title: Re: Engine, unit set up advice please
Post by: rogee on February 04, 2015, 10:11:59 AM
That fitting should would normally be plumbed to the air filter, pcv valve on lower right should go to inlet manifold, we normally just put a small breather filter on the rear fitting ,was it smoke or condensation/steam? if waters got down that open fitting it there will be steam for ages 2c
Title: Re: Engine, unit set up advice please
Post by: belmont on February 05, 2015, 16:50:51 PM
Hi guys I did a compression test today. 1 cylinder was at 105 and another was at 120.... Pretty sure it's time for a new motor... Anyone got anything suitable for sale? thinking the 3.8 v6 and a 2 stage unit.
Title: Re: Engine, unit set up advice please
Post by: lachlan on February 05, 2015, 22:00:28 PM
 . thats only just over 10% variance . the tolerance on a sr20 is 1 atmosphere
was that engine hot or cold ? and was that with the throttle wide open ?

of course smoke comes out the breather hole . half it was prolly steam and other contaminants burning off . or just oil mist from it getting whipped and pumped around

im surprised that carb can spin a jet unit to 4k to be honest
Title: Re: Engine, unit set up advice please
Post by: belmont on February 05, 2015, 22:07:40 PM
Engine was cold. 1 and 4 cylinder was at 150. 2nd was 125 3rd was 105. I did not know to open the throttle?
Title: Re: Engine, unit set up advice please
Post by: garth44 on February 15, 2015, 08:51:19 AM
That's a massive difference between cylinders. She's shot.  There's been a few cheap tidy marinised engines on trade me lately.  A good vh on there at the moment all ready to go.
Title: Re: Engine, unit set up advice please
Post by: belmont on February 15, 2015, 09:02:23 AM
Hi garth44

I have got another sr20 gong inn the boat this week this time running injected. Easy fast way to get back on the water.  I a keen to put a v6 in it over winter. Can you send me the trade me link for the vh?
Title: Re: Engine, unit set up advice please
Post by: rogee on February 15, 2015, 20:45:53 PM
http://www.trademe.co.nz/motors/car-parts-accessories/nissan/engines/auction-845509185.htm




could this be it???