Data Logging with the LM-1 and LM-3

[hitz]

Sum,

  You've started another good thread!

  When John Woody suggested 50/50 methanol along with the water did he mean 50% alcohol /50% nitro ? Sounded scary but I've only been around straight methanol with one bike years ago. I'm in the dark about running any fuel but gas and diesel. Seems like I spend a lot of time in the dark. 8-[

  Harv

[Dynoroom]

Sum, more than one person has run a system like you have in this car, I would look for whats wrong and and save all the "tricks" for later. I know when you have a problem it can be tempting to bolt on an easy fix but if somethings wrong that doesn't go away. So remember it should work with what you have...why won't it?
Mike

[Salty Blaster]

Hi Hitz

It's water injection under boost in the gas class which is legal if you do not add any power enhancers to the water. What I meant by methanol is 50% alcohol and 50% water mixed and injected together in the gas. That is a very small amount and acts as an evaporation accelerator and the water cools the air charge and to a small degree aids cylinder head cooling. Once you monkey with the gas it puts you in the fuel class. 100% H2o and your a gasser.

JW

[Sumner]

Sum, more than one person has run a system like you have in this car, I would look for whats wrong and and save all the "tricks" for later. I know when you have a problem it can be tempting to bolt on an easy fix but if somethings wrong that doesn't go away. So remember it should work with what you have...why won't it?
Mike

Mike thanks, you are entirely right.  If we use the water injection it will be to give us a little insurance and hopefully to be able to run a little more boost safely.

We do need to get the air/fuel and corresponding EGT figured out.  Hooley e-mailed me the data for the 2 graphs I put up with this post.  Yesterday I got the data from the chassis dyno shop in the mail.  Looking at it and with help from Tom B. it looks like we weren't totally off the barrel valve and on the "pill" alone.  So we need to work on the secondary (enderle calls it the "idle check valve") fuel supply spring and/or shims to help richen it up at the part throttle setting.

Our TPS was not working right.  I can see when Hooley was applying the throttle, but not the percent of throttle.  We will get that fixed so we can see how far we are in or off the barrel valve.  We also need to get the RPM hooked up and logging so we can see if we are at a steady state RPM or if it is rising.

The dyno shop's computer failed to record the first run where the boost was up about 12 lbs., but they got the second run.  That run was really low hp/torque and the boost was only 7 lbs. or so.  The rpm at the beginning of boost was 3700 and only climbed to 5800 at the end of 10 seconds, so I'm sure he was probably on the pill very little on that run.  They didn't record EGT, but their air/fuel was with in a tenth or two of ours.  We were in cylinder/pipe 4 and they were in #6.

We didn't get much done at the dyno, but the experience along with the data has hopefully given us a direction to go in and we are a little smarter today than a week ago or looking at it another way we are starting to realize how dumb we really are at this point .

c ya, Sum

[Rex Schimmer]

Sum,
I think that most guys that can make a roots blown engine work and live probably have a pile of broken parts that taught them. Actually that is probaby true for any form of engine that make real "on the edge" horsepower, blown, turboed or naturally aspirated. Going with a roots blown gas combo has to be one of the most difficult as gas is so unforegiving.

As I always say: "When you learn by experience the test comes first and the lesson comes afterward."

Rex

[ddahlgren]

Until you have rpm and fuel pressure I don't think you will find the solution.. You never did say what rate of change in rpm was programmed on the dyno as well. It might be a matter of changing pump drive ratios and nozzle sizes along with the usual secondary bypass drill of springs and jet sizes under boost.
Dave

[Sumner]

Until you have rpm and fuel pressure I don't think you will find the solution.. You never did say what rate of change in rpm was programmed on the dyno as well. It might be a matter of changing pump drive ratios and nozzle sizes along with the usual secondary bypass drill of springs and jet sizes under boost.
Dave

The dyno was so screwed up we didn't really get enough of a base line to figure much out and Hooley wasn't able to look at the graphs (above) until he got home.  We only have one graph from them and it was the second lower boost run as the first run kicked off their computer.

I looked at our graph and theirs for the second run and during the period of low boost the rpm went from 3700 to 5800 in 10 sec.  We are not setup at the moment to data log fuel pressure.  That might be a good thing for us to think about.  There is still one input (we could disable the acceleration) that we could use for that.  We didn't think of that, thanks.

If we have time/money before August Hooley would like to go back to a better dyno in Tulsa that has more experience with race motors.  Looking over everything, we need to work on the secondary circuit like you said.  We do have different springs/shims to do that.

We will have RPM and better TPS readings at that point.  The TPS readings along with flowing the barrel valve (in the shop with air) should help us to know in the future if we are on the barrel valve or only on the pill at different throttle settings.

The plan before the next run is to try and richen the secondary and pill for safety and also change the pulleys and lower the boost.  I feel we need to get the air/fuel in the low 12's maximum under boost and see if we can get the EGT to level off as on the other two runs it was still climbing at the end of the short pulls.

So are you saying we can change the drive ratios of the 80A pump also??

What kind of parameters are we looking for with the fuel pressure if we can log that??

Thanks and c ya,

Sum

[Hellfirejim]

I don't have any experience with the LSR side of racing [ not yet anyway] but I do have a fair amount of experience with that type of fuel system working with a roots type blower.

You are running against a series of issues.  The first and main issue is you don't know the relationship between engine rpm and fuel pressure.  Since this is a positive displacement pump, you are right in assuming as the rpm goes up so does the fuel delivery.  You can start cheaply enough by teeing in a fuel pressure gauge to the output of the pump to watch it manually.  Seems crude but it does work.  BTW: I used a 300psi gauge to start  with until I knew what pressure I was running.  You can then size to match.  got it out of McMaster Carr cataloge. Of course a recording device is best.

I am not a chevy guy by experience but I understand that there are cylinders that run hotter than the other cylinders.  I don't remember which ones but I am sure someone here can tell you.  If you are only going to use one EGT it needs to go there.  At least if that is the hottest cylinder you can jet for that.

Question: what size is your motor and what size is your blower with what overdrive.  The reason I asked is it seems the nozzles seem a bit small to me.  I could be wrong, just seems that way.  

If it would be possible it would really benenfit you to have a split system meaning some in the hat and some in the manifold.  Why? because it would allow you to balance out your motor under power.  When you crank up that blower it changes where all the air and fuel goes in the manifold.  If you had some nozzles in the manifold you could increase or decrease to match the needs of that particulary cylinder.  BTW: as a byproduct you could also set up the hat to balance the motor at idle.

One other final thought. I remember talking with a guy who was running a blown gas big block in drag racing and he had all kinds of problems but eventually sorted it out.  It seems he reduced his compression some and increased the boost.  He said it was more controllable and tunable.

If I can help in anyway just ask.
jim

[Sumner]

.........................
You are running against a series of issues.  The first and main issue is you don't know the relationship between engine rpm and fuel pressure.  Since this is a positive displacement pump, you are right in assuming as the rpm goes up so does the fuel delivery.  You can start cheaply enough by teeing in a fuel pressure gauge to the output of the pump to watch it manually.  Seems crude but it does work.  BTW: I used a 300psi gauge to start  with until I knew what pressure I was running.  You can then size to match.  got it out of McMaster Carr cataloge. Of course a recording device is best......jim

We can get a pressure transducer?? and log the fuel pressure with the LM-1, but we don't know how to use that data at this point .

........................
I am not a chevy guy by experience but I understand that there are cylinders that run hotter than the other cylinders.  I don't remember which ones but I am sure someone here can tell you.  If you are only going to use one EGT it needs to go there.  At least if that is the hottest cylinder you can jet for that........
jim

I can't remember for sure, but I think the EGT probe is in #7, if not #8, which we think is the leanest cyl..  We are now running 2 probes in the same cylinder.  I just got him one with a gauge that is on the dash in front of him and the other goes to the LM-1 to data log.  The next time he fires the motor we will also be able to see if they are the same.  Right now the LM-1 one reads 200*F when the temp is about 90, but they say it is hard to calibrate it on the low end.  If we find out it is off at higher temps we will be sending it in for re-calibration in the next week or so...

...............
Question: what size is your motor and what size is your blower with what overdrive.  The reason I asked is it seems the nozzles seem a bit small to me.  I could be wrong, just seems that way. .....

It is a 406 with an 8-71 and we were running 10% over on the run in the graphs.  Hooley is changing it to 10% under driven and that is how we will start on the salt.  We feel we will be able to build enough boost to accomplish what we need to running like that.  The nozzles were what Enderle recommended for our combination.

.........................
If it would be possible it would really benefit you to have a split system meaning some in the hat and some in the manifold.  Why? because it would allow you to balance out your motor under power.  When you crank up that blower it changes where all the air and fuel goes in the manifold.  If you had some nozzles in the manifold you could increase or decrease to match the needs of that particularly cylinder.  BTW: as a byproduct you could also set up the hat to balance the motor at idle.

One other final thought. I remember talking with a guy who was running a blown gas big block in drag racing and he had all kinds of problems but eventually sorted it out.  It seems he reduced his compression some and increased the boost.  He said it was more controllable and tunable.

If I can help in anyway just ask.
jim

With the split system I think we would need to be running two circuits out of the barrel valve.  We might look into that later if needed, but for now we'll work with what we have.

I think we are fine now with the compression we have and the low boost and race gas.

Thanks for the comments.  Gives us more to consider.

c ya, Sum

[Hellfirejim]

The way to use your fuel pressure data is to align it with engine rpm.  This will tell you what pressure you are running and when.  It will also tell you when any poppet opens up and so forth.  

With this information, you can see if what you are doing to control the flow of fuel is working as you expected it to.  The last part of the sentence is important.  For example, if your "hi-speed" is not set correctly then it acts like a pump sizer verses a hi-speed bleed off.  It is very interesting to actually see what is happening with your fuel system verses just guessing at it.

Good luck and like i said if i can help any way please just ask.  this means bouncing ideas of each other.

jim