I need advice on fuel type for DASA motor

[catfish4767]

I recently purchased a ski with a DASA 850cc in it. The motor has 185PSI in each hole, was told it was a 4mm stroker. I know nothing about these motors, so I was reaching out to see if anyone could advise me on what fuel to get based on motor specs. My local dealer said 110 would be too high for it but the previous owner said he wouldn’t run anything except 110 in it. Said he previously ran 91 octane in it and blew the motor. He had it rebuilt and then swore by 110. Any advice you can give me? I would like to get to a lower octane; preferably 93 since a local station sells it at their no ethanol pumps.

Thanks

 

[Mdavies_02]

I cannot speak for your engine, however in my similar PHP898 +4mm stroker with 185psi I run 91/93/94 depending where I am. Ethanol free if its within a half hour drive. Best of luck.

 

[catfish4767]

That gives me a starting point. I just couldn’t see why the need for running 110 but also don’t want to blow a motor. So to see you have a similar set up and running 91-94 makes me think a lesser is fine. I’ll keep searching around. Thanks!

 

[Quinc]

Are you brapping around or holding full throttle chasing boats?

 

[catfish4767]

Are you brapping around or holding full throttle chasing boats?

Mixture of both? My lake is 600 acres and I like to cruise around to different areas but will also brag around, then move on to the next. So not constant ripping but some here and there

 

[catfish4767]

Are you brapping around or holding full throttle chasing boats?

Just trying to get comfortable on this ski so we can do another video

 

[Quinc]

I would start with mixing your 93 4:1 with the 110 just to be on the safe side and go from there.

 

[catfish4767]

Depends on the Ignition Timing too...not just Stroke and Compression; also Port Timing and Impeller Load. The Exhaust Pipe too

For an Apples to Apples comparison, Stroke and Compression are only "half the Apple."

Contact DASA via Email. Kyle(?) will give you the correct answer.

I sent Kevin an email this morning. I will see if he responds in a few days then email Kyle. This has a MSD TL system with a laydown pipe. 148mm set back pump - unsure on prop (got two different answers), no idea on timing.

 

[kevbo]

Start with an ignition timing and fuel mixture setting that will allow for full throttle runs on pump gas and see if you have enough power. Remember that performance will rise right up to the piston sticking. Higher octane keeps the piston from sticking. Your engines octane requirement revolves around ignition timing and full throttle fuel mixture.

 

[Sparkplug]

Ran my dasa 1100 on 91 all last yr. Like 50 hours ish. Don't remember. I switched from red line, to super tec half way through. For the corrosion protection. I mostly blip around but I did at least 20 percent wide open throttle fast runs covering distance on the river. I regularly ride straight down to the launch. It's about 3/4 Mille and that's a pinned shot.

Wear was less or same as a buddy with less hours. Running that fancy gas and fancy mix.

I have easy access to leaded aviation fuel. I swear it ran worse on that stuff.

I'm bumping to 220psi this season. I'll run the avgas. It'd easier to get for me. I was on 185 last season

Billet air compressors that squish a little more than others is all these things are

Sent from my SM-G970U using Tapatalk

 

[DylanS]

Depends on your curve and several other factors but I’d be willing to bet my left nut you don’t need to run strait 110 at 185psi even if it was set for 28deg total advance.

 

[generaldisarray]

lake lotawana! I used to live there!
Is that you in that Jeff Needles video? Thats a great video!

The Lees Summit airport sells 100LL. Just walk up to the pump and act like you know what your doing. Dont carry the can in the FBO. They get super pissed.

 

[catfish4767]

lake lotawana! I used to live there!
Is that you in that Jeff Needles video? Thats a great video!

The Lees Summit airport sells 100LL. Just walk up to the pump and act like you know what your doing. Dont carry the can in the FBO. They get super pissed.

Ha! Yeah thats me (Jeff) and my brother Tommy on the red ski. When did you live at Lotawana?

I knew LS Airport sold some sort of higher octane fuel. I will have to ask one of my buddies who flies out of there how he transports fuel from there back to his shop.

 

[bored&stroked]

Ride style has everything to do with octane needed from my experience. I run like 210psi and a few degrees advanced stator on about 93 octane [3 gallons 91 to 1 gallon of 100LL] for years now without issues. Head comes off every season to inspect. But I don't hold it wide open any longer then 10 seconds at a time. I basically just chase boat wakes or cruise with friends, no racing for me. At 185psi I'd be running strait 91 octane but everyone is different.

 

[catfish4767]

. But I don't hold it wide open any longer then 10 seconds at a time.

I have a superjet that I will use for ripping around and holding wide open. I will probably chase a few boats with this ski but nothing crazy. The boat traffic is pretty high so I don't have to chase too many as another one is usually shortly behind

 

[generaldisarray]

I lived there from 90 to maybe 03. in Y block. My mom sold the house maybe in 08ish. She sure regrets it.

Yeah we ate at the Marina end of last year around October. The number of boats on the water on a Saturday afternoon was insane. Totally not how it was back in the day.

When I buy 100LL at Lees Summit, I just use a regular gas can.

 

[catfish4767]

As a rough reference, have a DASA 850 PV STOCK Stroke in my 2013 SuperJet with B Mod Pipe, MSD Enhancer, Dual 46mm Mikunis, Stock Pump with 10/18 Skat Trak Impeller for a Buoy Chaser and Kyle strongly recommended 93 Octane Gasoline for the Stock Stroke. All good running 93 with the STOCK Stroke for several years now.

Kyle also said I could run up to 28 degrees of Ignition Timing Advance.

TIP: Going to a "Colder" Spark Plug (e.g. #8 to a #9) can help cool the Piston some and very SLIGHTLY lower the Octane requirement. Just adds another small degree of protection. NOT a way to go from 110 to 93 Octane though...

When you talked with Kyle, was this over the phone or by email? It's only been a day but I haven't heard back from either Kyle or Kevin. I'm not expecting an instant response, but curious the best way to contact them.

 

[catfish4767]

I just found out my local booze store sells race gas 98 through 118 octane. Could I take the 118 and mix it with 93 and be good? It was about $100 for 5 gallons of sunoco 118

 

[DylanS]

I just found out my local booze store sells race gas 98 through 118 octane. Could I take the 118 and mix it with 93 and be good? It was about $100 for 5 gallons of sunoco 118

Yes you can mix fuels to get your desired octane. Just google “octane calculator” and it s pretty strait forward

 

[Harbor]

I just found out my local booze store sells race gas 98 through 118 octane. Could I take the 118 and mix it with 93 and be good? It was about $100 for 5 gallons of sunoco 118

I just went thru this… . Each of the fuels ABOVE the SS 100 unleaded have different stoichiometric fuel ratios and slightly different specific gravity’s and can require jetting/mixture changes…

Stoichiometric fuel ratios are as follows
Pump gas with 10% ethanol is around 14.1
Didn’t look up pump with 0 ethanol
SS 100 unleaded is around 14.2
110 is around 14.9
112 is 15.1
114 is 14.9
116 I forget but around 14.9

I mistakenly bought the 112, thought I was pumping 110…. then went for a Sunday ride and brought some along to add when I was getting low…. Well my ski ran like poop….down 50% on power and won’t rev out. Then i wondered if it could be the fuel… looked up the stoichiometric ratio and specific gravity and found it different than the pump gas I used when I tuned my ski…. Switched back to pump gas and resolved the issue… called Sunoco tech and confirmed my findings…

The SS 100 unleaded is the closest stoichiometric ratio to pump gas. If you already tuned your ski mixing the SS100 would require almost no tune changes..

When I added the 112 I was roughly 50/50 race and pump.. or 60/40 race/pump and it ran like crap as far as power goes…

If you get anything other than the SS 100 unleaded.. retune your ski to your new fuel mix…

My ski is a Lamey 8 mil stoker on 200 psi, Msd enhancer, RRP pipe, 148 pump 23 deg timing…I run 91 pump gas in it, it’s a surf rec boat. I don’t hold it pinned, usually cruise 30 mph max, sometimes I’ll take it up to 40 mph briefly… I should be running higher octane as well… you should too, especially since you have a lay down pipe and Msd total loss..

SS 100 and pump 93 mixed 50/50 would be around 96.5 ?