mt_goat

I think what is happening is the ECU thinks and reports via the software the timing as being there, but because the piggy back is down line of the ECU it doesn't know its really been delayed. My knocking was worse before I pulled timing.

Texas_Ace

No you misread it, i was saying that was a good thing, it means that the ECU is not detecting knock and added the lost timing back in.

The stock ECU is always listening for knock above 3k rpm's. It is always advancing the timing till it hears knock and then retarding it, then doing that over and over hundreds of times a second.

So you are always at the knock limit no matter what you input into the URD.

In the above example it was around 20 degrees of peak timing but with 3 degrees removed it was up to 23 degrees of peak timing on the OBD. Which once you remove the 3 degrees retard it doesn't know about it right back at the starting point of 20 degrees.

Under 3k rpm's the knock sensor is turned off so in that area yes the URD would effect timing and thus knocking a lot. I have an auto but still even when i boost it in low RPM's i can't hear any knock at all.

Gadget and speedy both have some good reading on this as well but what it means is that the URD timing adjustment function is unless with my meth injection and not needed. So i have no qualms about getting rid of it.

Texas_Ace

True i was more thinking about how this thread has a lot of different points so this new meth setup could easily get lost in the rest of this maybe a new thread would be best so that system could be kept together.

Once it comes in I just might do that, not gonna be much progress on it till then anyways.

mt_goat

Yeah its below 3000 rpms that I have had heard the knocking. I'm probably driving below 3000 about 90% of the time. I also have an auto.

Texas_Ace

Yep, in that area you could have some knocking, i had some every now and then on hot days till i got the meth injection, have not heard it since.

Texas_Ace

Well, just got finished with V1 of my idler pulley setup. Looks like it is going to work quite well, really adding a lot of contact area for the belt and more tension.

Only problem with V1 design is the sheet metal i found is only 16 gauge (thickest i could find at home depot) and it is bending under the strain. So i need some thicker metal and i need to figure out a way to reinforce it. Got some ideas just got to find a place i can reinforce it too.

I have very high hopes for this setup working to totally stop my belt slip, it will be doing a lot of things all at once to add more grip.

vital22re

iTrader: (2)

pics or it didn't happen

aa1911

iTrader: (1)

^^ heh heh

Thanks for the pics/comparison of those tensioners TA...

I think your writeup on the meth kit might entice more folks to go with the blower, it is nice to have options for optimum power... i know some of my buddies don't want to SC just because of the additional fuel upgrade (cost) but with a good meth kit this puts the final cost a bit lower now.

Sweet to see your above 10psi now! Keep it coming TA

Texas_Ace

LOL, don't worry i always take pics of stuff, V1 was not finished though. Finished V2 today and tested it out earlier today.




As you can see this adds a lot of contact patch for the belt to the pulley. It also adds tension to the belt since it makes it act like a smaller belt. It then finally adds more force/friction to the pulley as well since that side of the belt is the side that gets pulled tight and with this new angle it adds a lot of force to the pulley.

Gonna cut off some of the extra metal and paint it at some point but it is working fine for now.

Tested it out and it does indeed work although not as well as i had hoped. Gained around .5psi or a little more. Belt is still dusting although not as fast and boost still drops on the top end. So still got belt slip but it is getting better.

For $20 in parts though it was a worthwhile investment. Real simple too if anyone wanted to make one themselves. I just used the old idler pulley from my old tensioner that i replaced., got a 12"x12" sheet of 10 gauge steel and a few bolts and washers is all you need.

Oh and a drill and grinder then an hour or so of time.

I am thinking about updating it a little more to possible give some more tension but not sure if it would actually help much. We will see. I think i have another problem beyond just belt slip, i should be around 13psi so I am still a fair amount low.

Thats what i am hoping, i love finding better and cheaper ways to do things.

If it works like i hope, it should allow for the $600 for the meth kit be all you need after the supercharger itself vs the $1300 for URD stuff that doesn't really add power just makes it safe to drive. The meth kit will also add a lot of power.

mt_goat

My first SC belt only lasted 3000 miles, so I must have had a slipping problem too. Of course it broke 500 miles from home in the middle of no where.

Texas_Ace

Sounds like fun, which belt did you use? how much boost did you get from your setup then and now?

I have heard that it takes a little bit for the belt to break in, not sure how true that is.

It also hit me last night another possibility for the loss of boost that makes more and more sense the more i think about it.

You know earlier when i was talking about how water can boil in the SC and displace a lot of air? I am wondering if this is happening to me.

At one point i ran out of meth last night so i came back and refilled, i used more water this time because my ARF's were a little rich and went back out. I noticed that my boost dropped ever so slightly after going back out from 10 mins earlier when i was using more meth and running richer (running too rich will also cause a loss of boost).

I am thinking maybe the water is boiling and causing some of my problems. It would also explain why the boost keeps dropping more and more the closer the redline it gets.

The faster the engine is spinning the faster the SC is spinning. The faster the SC spins the more heat it makes. The more heat it makes the more of a chance the water would boil and cause a loss of boost/power.

It has got me thinking to say the least. I have heard people say they can have intake temps in the 300 degree range with a 2.0 pulley which is obviously PLENTY to boil water. Now the water will cool that down a lot but it is possible it is still hot enough to boil the water.

The new meth setup will allow me to run pure meth which should help this a lot if this theory is right, might also play around with a pull or 2 with the meth turned off and put the 7th injector tune back in there to see what happens.

Like usual will keep you updated.

mt_goat

It was a new SC, so it was the factory belt that came with it. I have consistently gotten 10.5 psi of boost from day one (2.1" pulley). I've always run 50/50 water/meth (aquamist)

Texas_Ace

That is just very strange, my headers should lower my boost a little but not 2-3psi.

What belt are you using now? toyota or the gates?

mt_goat

I got all my belts from a dealer, not sure the labeling. Next time I have the hood open I'll look. Definitely carry an extra one and the tools to change it. Its a PITA to do on the side of the road so I inspect mine for wear often.

How many miles are on your SC? I see its one of the old ones, maybe that's the problem?

Texas_Ace

If you got it from the dealer then it is a dayco belt, same thing i used before. Very strange.

The SC has around 80k miles on it but i had it rebuilt before installing it 10k ago.

Maybe it is the old SC design that is to blame somehow. No clue how though.

I did some interesting testing today with some interesting results.

Decided to do some data logging both to try to figure out my boost problems and to see if my theory of the water being part of the problem and to see if i see any issues removing the URD system for my new meth setup.

In a nut shell, my hunch on the water being at least partly at fault seems to be on the money and i do not see any issues removing the URD system.

So lets start off with the boost issues. Did some data logging, all in 2nd gear mind you, to see what my boost looked like. Got consistent results.

Here is a screen shot of my boost plot on a 2nd gear pull with the 2.0 pulley and 9gph of 50/50 meth spraying.



Boost peaks at around 9.7psi and then tapers off to 8.4psi at redline.

I then turned the meth off and turned the 7th injector back on, tune was not perfect, it was a little rich (low 11's) but good enough for what i needed.

It led to this:



Boost peaking at 9.1psi but holding basically flat across the board.

I then looked back over my logs from when i had the 2.2 pulley and no meth to compare it. Here is what i found:



Boost once again holds flat across the board and doesn't drop up top that much. Peak boost is 8.5psi which means i am only gaining .6psi by going from a 2.2" pulley to a 2.0" pulley. Something is wrong obviously.

So from this i learned a few things, First off the meth injection is adding some boost and it is also causing me to lose boost on the top end, which makes perfect sense.

Redline is where the temps are highest and the chance of boiling is highest. it also drops boost up there with the water injection on, to below the boost with it off. So my theory that the water is boiling and displacing air seems to have been right.

It explains the top end boost loss. So still need to figure out where the rest of my lost boost is going. Hoping going to pure meth with the new kit will help this, we will see.

Now to the second part of this, meth injection vs 7th injector.

I also data logged my timing under these tests to see what kind of advance I was getting. Along with a few other tests.

First off i got a baseline timing with my 2.0 and 9gph of 50/50 mix, first number is timing, second is RPM it was at:

16 3364
14 3538
15 3794
15 3990
16 4208
18 4424
20 4629
21 4873
19 5076
16 5268

That is basically a stock timing map! not bad at ALL for a supercharged truck running a 2.0 pulley on pump gas with meth injection. This is with zero timing correction on the URD.

After this i then decided to try leaning it out to see if leaning it out would change the knock threshold.

So i then turned off the 7th injector to lean it out, this caused the AFR's to lean out to around 13.5:1 by redline.

Here is the timing map from this run:

14 3551
15 3740
15 3924
15 4105
17 4314
18 4500
20 4686
21 4859
20 5005
17 5165
16 5319

The timing is basically unchanged from the first run showing that even with it leaning it out there is not more knock, the water and meth do a GREAT job of stopping knock. Oddly i noticed slightly more boost on this leaner run.

So lastly here is a comparison of the meth pulls vs the pulls i turned the meth kit off and just used the 7th injector, I had 5 degrees removed from the whole map on these pulls but i went ahead and subtracted it out of the numbers to avoid confusion. So these are the actual timing numbers followed by RPM.

11 3123
8 3287
9 3486
9 3671
10 3864
10 4029
11 4198
12 4363
14 4545
14 4694
15 4859
15 4990
13 5123
11 5241
12 5010

Wow, it is WAY more knock prone without the meth! those are the kind of numbers i would expect with a supercharger, at least 5 degrees retard everywhere. These pulls are also pretty rich since i didn't want to take the time to get it perfect, so it is less knock prone then it would be at 11.8:1 AFR's leaned out i expect at least another degree or 2 of retard. The meth is doing it's job and doing it very well!

Oh, and after doing some pulls back to back with and without the meth i can safely say that it makes a HUGE difference in power! at LEAST 20-25rwhp. It is a completely different truck with the meth injection! not to mention safer!

Can't wait to see what happens with my new meth kit. Hopefully someone finds this info worthwhile.

mkzg

how long did that take you to add the supercharger?

mt_goat

Wow, that is a drastic drop off in boost. I don't know anything about it, but is it possible it could have something to do with the SC bypass valve operation.

I did a quick search for some info and only found this by Gadget:

Texas_Ace

Talking about actual install time? Not sure, maybe an afternoon. The hard part was research and finding good deals on all the parts to make it work right.

the install itself is easy.

Yeah it is a lot of drop off. But like I showed in the next plots without the water injection boost held basically flat to redline so I am almost positive that the water is boiling and causing the high RPM drop.

I am still low on boost but that is across the board, the bypass valve is possible and i am looking into it. It is opening/closing fine, that much i know, what i am not sure about is if it is sealing properly inside.

I can move the butterfly in and out some which says that it is not sealed to me. It is a PAIN to remove though and even if it is not working right not sure what i can do to fit it.

mt_goat

Oh ok, that wasn't clear to me. So on the next plot is the drop off at the end just you letting off the gas pedal or hitting the rev limit or something?

Texas_Ace

The second plot doesn't drop hardly at all, just spikes in the middle a little. The 3rd plot does drop off some up top but it is from 2 years ago so not sure what i was doing, other plots from the same time held basically flat, that was just the first one i found to get a screen shot of.