Turbocharging a lawn mower

[bertsmobile1]

torque x RPM / 5251.1 =HP
In order to add a turbo you would need to also add some sort of pressurized oiling system. I am guessing that the kits you showed are for larger engines.

Yes I forgot to add the fudge factor because I was not trying to put in an equation, just to show that you can drastically increase theHp simply by making the engine run faster
The down side is a governed mower should be running just past the peak torque revs , thus as you load the engine the torque ( which is what does the work ) comes into play to help the engine recover .
Go too far past peak torque and the curve flattens out so not much extra torque to help it recover.
Japanese buzz boxes are the perfect example where you need to change back all the time in order to accelerate under load .

 

[wineman]

I haven't been here in years and haven't played w/ turbo cars for a long time but when I got the email notification about this thread I had to read it. I figured it would be entertaining and it was. Also sometimes hilarious. Kudos to the posters who mentioned the necessity of pressurized oil and increased fuel flow.
OP: No oil pump = no turbocharger. Other posts made great points such as increasing the fuel capacity to match air flow. FYI, forced induction works by increasing intake air charge i.e. exhaust spins one side of the turbo so that the other side... the compressor side, compresses air going into the intake) and on a carbed engine that's tricky business. EFI engines of course can vary the amount of gas easily bc they have computerized engine managment... along with a fuel pump and fuel injectors and several sensors providing feedback to the ECU (the computer mentioned earlier) so that it can match fuel pressure to intake air, among other things. BTW there is no $75 turbocharger. The last turbo I bought circa 2008 cost about $800 and was not considered particularly expensive at that time. I do remember ebay turbochargers (and devices to make a car sound like it had a turbocharger) available from China which weren't real turbochargers at all but they sold like hotcakes to all the Honda fanboys. Some good folks on here have told you this is a terrible idea. Trust them on this. But part of me hopes you do try this. The results should be entertaining.

Well, I got everything together this morning. It took 4 hours to do. I was told that I may have to use some starter fluid first, but did not and it started right up. This is the sequence of what happened.
It started with a much louder engine and then some alternating low and very high pitched sounds. The mower was shaking violently and the blade seemed to be running a much higher rpm. Then all of a sudden the engine seemed to surge even more (it would not not turn off no matter what I did) and I heard a bang. It stopped running and blue smoke cam out along with it dumping of oil and then I smelled gas and went to the other side of the house for safety reasons, heard another loud pop and the entire mower was covered in gas and flames. I got the fire put out and figured it probably would not run again. It blew pieces of the engine out a few feet and 2 of the bolts that hold the engine in had been broken.

Do any of you have a suggestion as to what I might have done wrong in the assembly.

 

[wineman]

It's absolutely silly and absurd for anyone to be interested in this kind of thing for a lawn mower that's actually used to cut grass.
Even the current horsepower ratings we have, even though they're kind of a joke and erroneously high, still have far more power than we need to cut our lawns!

The only thing I can see this being worthwhile for are the play toys and race or pulling mowers people do.
This is not some makeshift play around kit but a real turbocharger and would certainly give huge power increases but it also would come with other complications with tuning and then with exhaust etc but I'm assuming anyone wanting to build this kind of power for pulling purposes etc is using a custom exhaust of a very large size or rather a dump and using the size to help tune exhaust scavenging etc.

Now in the play around version of Turbo charging lawn mower I've done that several times just for fun.

The quickest and easiest way has always been with a leaf blower but you can also use anything where you have a controlled or consistent flow of air like a shop vac exhaust or compressed air etc.
All you have to do is add an extra fuel source

So you take your handheld leaf blower whether it be gasoline or a battery powered one and then you drill you a hole somewhere around 8 in from the end of they discharged tube there where the air comes out and you pipe you a little hose brass fitting spray tip nozzle etc into there.
You need Subway to control the size of the bottom like a fixed orifice etc but many things can be adapted.
Then you run you a piece of tubing, preferably clear so you can see the fuel flow to a fuel tank source and when you blow the air out the blower it will suck the fuel out and you can adjust everything just right with your speed and with the orifice size so you're blowing a gasoline enriched mixture of air coming out of the end.
Now of course you can take this makeshift design a little further and turn it into a flamethrower too but none of it is very safe.

So you just pipe the leaf blower into the intake with various plastic hose and adapter assemblies like PVC or Shop-Vac accessories.
You can even get creative and make a little box with a rubber flap that falls down and is open when the engine is running and no air coming from the leaf blower so it sucks air not through the tubing and not through the leaf blower but in reality that's not really a problem because most leaf blowers will flow just fine and don't restrict the flow at all.
This way though when you pressurize the air filter intake and stuff with the leaf blower it will soft close the little box flap so the only air coming through is coming from the leaf blower with the gasoline mixture.

The problem is you really can't give it that much volume until you get up to pretty high engine speeds but if you had a situation where you kept the engine at constant RPMs or even if you eliminated the governor like many race engines do you could get it adjusted pretty decently.

Well, I got everything together this morning. It took 4 hours to do. I was told that I may have to use some starter fluid first, but did not and it started right up. This is the sequence of what happened.
It started with a much louder engine and then some alternating low and very high pitched sounds. The mower was shaking violently and the blade seemed to be running a much higher rpm. Then all of a sudden the engine seemed to surge even more (it would not not turn off no matter what I did) and I heard a bang. It stopped running and blue smoke cam out along with it dumping of oil and then I smelled gas and went to the other side of the house for safety reasons, heard another loud pop and the entire mower was covered in gas and flames. I got the fire put out and figured it probably would not run again. It blew pieces of the engine out a few feet and 2 of the bolts that hold the engine in had been broken.

Do any of you have a suggestion as to what I might have done wrong in the assembly.

 

[Mike88se]

I am going to work on it today and will report back.

Okay, should be interesting.

They said that using an octane booster will also be part of the deal.

Might be best to just buy some race gas. I say you still need an oil pump. Among other things I looked at your link. Uness I missed seeing it, the site doesn't give any specs on the turbo except "100hp" so you really don't know what you're getting in terms of compressor size, wastegate (the thing that controls when to dump boost to prevent your piston(s) from becoming missiles) setting etc.
So add a manual boost controller and boost gauge to your parts list just in case you do get enough exhaust to move the turbine. Which I don't think you will bc that turbocharger is just too damned big for your lawn mower. I don't recall you posting the displacement or air volumetrics (is that a word?) but I do recall you saying it's a Murray so at least you won't be blowing up a good mower. J/K

They said to use 90W differential oil and everything would be fine.

Ok (altho 90w oil sounds crazy) but where are you running the oil supply & return lines? To the crankcase obviously but the question is how are you going to get oil to flow through the supply line to the turbo? I see they have banjo fittings and oil feed flanges for sale but gravity is not your friend here.Oil is not going to voluntarily run up the supply line to the turbo bearings. There's so many problems with this idea that I don't even know where to go next so I'll just recommend you read the second review at the link on that site to Amazon. That is what is going to happen with a $140 turbocharger in a best case scenario. It seems like nitrous oxide would be easier and more likely to work but you'd still need more fuel. NOS got a bad rep from people who didn't know how to use it plus those silly Fast & Furious movies. It's actually good when used properly.
At any rate I'll say good luck and hope to get email notifications of the results.

 

[wineman]

Okay, should be interesting.


Might be best to just buy some race gas. I say you still need an oil pump. Among other things I looked at your link. Uness I missed seeing it, the site doesn't give any specs on the turbo except "100hp" so you really don't know what you're getting in terms of compressor size, wastegate (the thing that controls when to dump boost to prevent your piston(s) from becoming missiles) setting etc.
So add a manual boost controller and boost gauge to your parts list just in case you do get enough exhaust to move the turbine. Which I don't think you will bc that turbocharger is just too damned big for your lawn mower. I don't recall you posting the displacement or air volumetrics (is that a word?) but I do recall you saying it's a Murray so at least you won't be blowing up a good mower. J/K

Ok (altho 90w oil sounds crazy) but where are you running the oil supply & return lines? To the crankcase obviously but the question is how are you going to get oil to flow through the supply line to the turbo? I see they have banjo fittings and oil feed flanges for sale but gravity is not your friend here.Oil is not going to voluntarily run up the supply line to the turbo bearings. There's so many problems with this idea that I don't even know where to go next so I'll just recommend you read the second review at the link on that site to Amazon. That is what is going to happen with a $140 turbocharger in a best case scenario. It seems like nitrous oxide would be easier and more likely to work but you'd still need more fuel. NOS got a bad rep from people who didn't know how to use it plus those silly Fast & Furious movies. It's actually good when used properly.
At any rate I'll say good luck and hope to get email notifications of the results.

Well, I got everything together this morning. It took 4 hours to do. I was told that I may have to use some starter fluid first, but did not and it started right up. This is the sequence of what happened.
It started with a much louder engine and then some alternating low and very high pitched sounds. The mower was shaking violently and the blade seemed to be running a much higher rpm. Then all of a sudden the engine seemed to surge even more (it would not not turn off no matter what I did) and I heard a bang. It stopped running and blue smoke cam out along with it dumping of oil and then I smelled gas and went to the other side of the house for safety reasons, heard another loud pop and the entire mower was covered in gas and flames. I got the fire put out and figured it probably would not run again. It blew pieces of the engine out a few feet and 2 of the bolts that hold the engine in had been broken.

Do any of you have a suggestion as to what I might have done wrong in the assembly.

 

[CraigH]

Well, I got everything together this morning. It took 4 hours to do. I was told that I may have to use some starter fluid first, but did not and it started right up. This is the sequence of what happened.
It started with a much louder engine and then some alternating low and very high pitched sounds. The mower was shaking violently and the blade seemed to be running a much higher rpm. Then all of a sudden the engine seemed to surge even more (it would not not turn off no matter what I did) and I heard a bang. It stopped running and blue smoke cam out along with it dumping of oil and then I smelled gas and went to the other side of the house for safety reasons, heard another loud pop and the entire mower was covered in gas and flames. I got the fire put out and figured it probably would not run again. It blew pieces of the engine out a few feet and 2 of the bolts that hold the engine in had been broken.

Do any of you have a suggestion as to what I might have done wrong in the assembly.

That has to be one of the best posts of the year right there!

@wineman have you got any pics of the setup at all? Or any info on the parts used?

 

[Mike88se]

Well, I got everything together this morning. It took 4 hours to do. I was told that I may have to use some starter fluid first, but did not and it started right up. This is the sequence of what happened.
It started with a much louder engine and then some alternating low and very high pitched sounds. The mower was shaking violently and the blade seemed to be running a much higher rpm. Then all of a sudden the engine seemed to surge even more (it would not not turn off no matter what I did) and I heard a bang. It stopped running and blue smoke cam out along with it dumping of oil and then I smelled gas and went to the other side of the house for safety reasons, heard another loud pop and the entire mower was covered in gas and flames. I got the fire put out and figured it probably would not run again. It blew pieces of the engine out a few feet and 2 of the bolts that hold the engine in had been broken.

Do any of you have a suggestion as to what I might have done wrong in the assembly.

much louder engine: no muffler
Turbos make high pitched sounds... maybe you actually got it to spool up
The oil? Where was it coming from?
The gasoline... if the turbo spooled high enough then it got very very hot. I've seen them get glowing red hot. Might have melted the gas tank if it was plastic... or maybe the fuel hose. If it's any consolation your project was more successful than I expected... sort of.
I imagine you had a lot of predetonation... piston is probably toast
Mostly it sounds like what people here expected to happen... happened. Now you can get a better lawn mower I'd recommend a used Honda. They're usually reliable but parts are cheap, they're easy to work on, and it's a good time of year to find a deal on one, unless there's a lot of trees in your area in which case people may be using them to bag leaves which is something they're very good at.

This>>>>

have you got any pics of the setup at all?

 

[ToniG]

Do any of you have a suggestion as to what I might have done wrong in the assembly

Not having a kill switch/fuel shutoff (or an inlet strangle). I do hope there is a video, it could be useful.
As you learned, Don't have much fuel in the tank.
To have any chance of success( just getting it to run ok) in this type of experiment you need to do a lot of thinking, research & learning. Listen to advice from the experienced.
Analise results of the failure, one obvious point being over-speed = bang. (wasn't that advised...)

If you did get to the stage where you had usable control of the engine with increased RPM/power it will be short lived. Maybe should wear motocross boots.
Most modern mower engines are the opposite to "bullet proof", there is little or no headroom for "increased power & reliability". You can't have both in this situation.
So good on you for doing something interesting but do expect to fail in the original goal to cut Harder-Longer.
I have fails in my experiments & its part of the learning.
At least you can fallback to a bit bigger engine after the smoke settles, this has a good chance of success.

I had an old 8hp B&S powered walk behind mower that was bogging down with tall seteria grass, I made a longer exhaust pipe with a free-flow silencer (perf-tube with glass fiber packing), re-tuned & the mid RPM power increase was now adequate for the job.

 

[Hammermechanicman]

Need a pic of the engine with the turbo on it and a link to where you bought it from.

 

[bertsmobile1]

I expect when he has a good look the rod will be poking out through a nice new window in the crankcase
Would not turn off is most likely because the spark plug was now red hot which allowed the engine to continue running but way out of time because the charge would detonate as soon as it got to a combustable Air:Fuel: compression ratio
next time take a video and put it on You Tube people like to see engines blowing up and who knows you might even make $ 4.95 in royalties .
We did try to warn you .