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Re-Installing My Supercharger

Gadget

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You are going to piss off your stock cooling system and the way the thermostat works. If the engine needs more cooling the thermostat adjusts for that. You do what you described the thermostat will close down.
 

Gadget

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Also, sending 200* water through your intercooler radiator and then to the intercooler core is not going to cool the induction air any better. Likely going to heat it up a bit.
 

iniazy

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Also, sending 200* water through your intercooler radiator and then to the intercooler core is not going to cool the induction air any better. Likely going to heat it up a bit.
Hmm. Good points, just not sure the water exiting the oil cooler gets that hot.

Just something I was thinking about, probably not a great idea.
 

Gadget

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Yea, it gets that hot. It is like 190 going into the cooler and it is hotter than that coming out as it is taking heat out of the engine oil.
 

iniazy

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I've discovered an AFR sensor problem in my Fortuner, that explains why for so long I've felt the car getting sluggish when driving for a while in the extreme heat.

A couple months ago I had done very precise fine-tuning on closed-loop operation, to get it just right. After I felt very satisfied, and got most closed-loop AFR above 12:1 AFR, I went on a road-trip. While going on the trip this is what showed up in my AFR gauge:


I was shocked, why is it getting so rich? I just finished getting closed loop done properly? So I thought there must be something wrong. I pulled out my OBDII scanner, started up my tablet, and got connected to my ECU, to find this:


My right bank sensor was giving a wrong reading, and the right bank fuel trims are going haywire. Left bank is doing ok. So I knew this is either a bad AFR calibrator, a bad AFR sensor, or a bad harness. This problem only appears after driving for a while in the hot weather. Doesn't appear in the winter.

When I got home, I swapped the yellow and blue wires in the AFR calibrator to see if the problem moves to the other side. It didn't, which clears the calibrator from any faults. So now it is down to the right-hand-side sensor or the harness. I replaced the right sensor with one old sensor I had in my stash, and I have not tested the car yet. If the sensor turns out to be cleared, then it is down to the harness, which is what I am suspecting.

The harness I have was a used one I bought a couple of years ago when I was trying to get the UCON EMS working, and after installing it found that the right hand sensor wires were cut and then reattached by twisting them together, without crimping or soldiering. So I fixed that by soldering them properly a couple of years ago. I think the soldiering that was done is causing some current to escape some how, causing the AFR reading to get thrown off, when the heat is cranked up and the wires/soldering expand. Some how. This explains the high heat sluggishness, when the right bank goes down to 10.5-11:1 AFR at partial throttle, the engine will definitely lose a lot of power. Now whenever I start feeling it getting sluggish, I look down to the AFR gauge and find that the problem is happening again.

I am now certain my car was built by Murphy.

On a different front, I came to the conclusion that there's no way I can make the boost I want using a Supercharger. I'm spinning my Rotrex at it's maximum factory limits when at WOT, and still barely able to touch 10 PSI in good conditions. And I'm using the largest Rotrex supercharger there is, the C38-91. Now how can I push it to 15-20 PSI? Nothing but a Turbo can do that. A single Rotrex supercharger is just not cutting it for me.

I think the reason why I'm not making as much boost as I used to before the engine build is because the engine now is slightly larger in displacement, with lower compression, so this means more vacuum which offsets the boost. I think that's the reason. There is no other reason, given I have no vacuum leaks. In that case, I can either find a way to fit another Rotrex supercharger in series to make significantly more boost, or use a Turbo.

I don't think I'll do that with my current vehicle, but it is something I learned. With a built engine, a single Supercharger will not give the engine its maximum potential. I'm certain my engine can easily handle another 5-10 PSI of boost without breaking a sweat.
 
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Torspd

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Oh, it definitely can handle the extra boost. Fab up that turbo kit!!! A man of your skills could have it done fairly easily.

I am curious what you find with swapping in your old sensor, or swapping the sensors side to side.

Keep us posted.
 

iniazy

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Oh, it definitely can handle the extra boost. Fab up that turbo kit!!! A man of your skills could have it done fairly easily.

I am curious what you find with swapping in your old sensor, or swapping the sensors side to side.

Keep us posted.
You overestimate my skills. I have zero welding skills. I'll need turbo yoda. Maybe I'll do a turbo kit someday. I'm thinking of doing it on a straight engine, either four cylinder (hilux wink wink) or a 1fz Land cruiser six cylinder. A V engine adds significant complication to the process.

I'll find out soon if replacing my AFR sensor fixed it. I'm traveling now and left my pride and joy at home.
 
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Redlantern

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What about twin charging it? Running the rotrex with a turbo would be pretty awesome.
 

Torspd

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I run urd s/c. C38-92 blower. 70mm pulley. 16 to18 psi of boost. Sounds like I'm safe from knock then. That's good for me, I like to abuse mine.

How is his C38-92 making that boost pressure, without over spinning his charger, while yours is only making 10 psi? Which size pulley is yours again, and is the difference due to yours being a 91 and his being a 92?
 

iniazy

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How is his C38-92 making that boost pressure, without over spinning his charger, while yours is only making 10 psi? Which size pulley is yours again, and is the difference due to yours being a 91 and his being a 92?

C38-91 and 92 are exactly the same except for the inlet, which is 3.5 inches in the 92 as opposed to 3 inches in the 91. They should make the same amount of boost given the same conditions. Why are they different is a puzzle. Maybe ambient temperatures has something to do with it. Unless I somehow got a smaller supercharger. I didn't verify the model of my supercharger when I first received it.

I'm using 80 mm pulley but my crank pulley is much larger than the stock crank pulley, so we're probably spinning the units in very comparable speeds. I've done the calculations and found that going lower than 80 will overspin the supercharger beyond factory limits.

Also a factor could be my lower compression pistons, which could offset the boost with more vacuum. Whatever it is, I couldn't get mine to make any more boost. I would love to get my hands on a URD filter housing to see if that helps any. Maybe my air filter is too small and restricting air flow.
 

Torspd

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@Gadget thoughts?

Can you not just do a test drive without the filter and see how it performs?
 

Gadget

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Odd. I have 91 on mine, 80mm pulley, stock crank pulley, uncorked the safeties and put down 540 RWHP on 93 octane.
 

shane881510

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Odd. I have 91 on mine, 80mm pulley, stock crank pulley, uncorked the safeties and put down 540 RWHP on 93 octane.
Humm I have 70mm pulley 6400rpm but on stock bore an stroke. Wonder how much hp I make compared to u.
 

Gadget

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Yea, that is a complete mystery since you keep refusing my offer to come to URD to find out.....
 

shane881510

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Yea I see that, I'm not refusing the offer just can't make it to his shop. Neither time or financially will allow me to go to it or I'd be there all the time.
 

Torspd

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Business right off, for Gadget, in the name of testing. Ship your truck. ;)

Where are you iniazy???
 

30Birdy

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I'll take off work and volunteer to drive it there. I'll just a plane ticket and gas money :)
 
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