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backtobirds
05-18-2009, 02:05 AM
After the rebuild, diagnosing what turned out to be a bad crank sensor mount, and exploding the trans on the test drive around the block I have the car back together and driveable. Also got a Moates Quarterhorse for tuning. Props to those guys, that is probably the best EEC-IV tuning product I have ever used. Plenty of fun to drive and it sounds like a big block, but I can't get any boost out of it.

A little background, new block, rotating assembly, SSM heads, ported intake, MPX case and plenum, 10% crank pulley, 10% jackshaft, 10% blower pulley, cam, and long tube headers. So I would expect some boost but it barely creeps to maybe half a pound. So, for what it might be:

Head gaskets are of course new, ARP head studs, 99 block so the threads are countersunk an extra inch for better gasket retention. No evidence at all of gasket failure, and it showed 160 to 170 psi on a compression tester.

Intake-torqued, retorqued, dry and thread-locked.

I am using teflon gaskets on the blower outlet, return plenum-to-intake manifold, and return tube-to-return plenum. Turbonetics silicone couplings for the FMIC piping.

Put the blower together with anarobic gasket maker and torqued everything. I had a problem with the bypass plate sticking, so I sent it back to Charles and he opened it up a little to free it.

Still no boost. The car pulls 18-20 inHg at idle and I sprayed all the connections and gasket areas with brake cleaner, as well as the intercooler. I even did all this with the bypass manually closed as well, but came up with nothing. Just to double check my butt dyno and boost gauge I took a datalog. The MAF follows the throttle position sensor just fine until the TP is opened up, but then it only shows the engines natural air capacity and no more. Score one for the butt dyno I guess. Anybody have an idea what might be going on?

Here is the datalog if anybody wants to see.
http://www.mediafire.com/?xciiygy1wyl

David Neibert
05-18-2009, 11:26 AM
If you have already ruled out the bypass valve, then I'm betting it's something with the rotor pack or blower drive shaft. See this thread.

http://www.sccoa.com/forums/showthread.php?t=106201&highlight=boost

David

backtobirds
05-18-2009, 03:51 PM
I took a look at that thread. I hope that isn't the problem, as I can stick my finger between the rotors to hold them and twist on the pulley, but it isn't slipping doing that.

David Neibert
05-18-2009, 04:49 PM
Do you have the boost gauge hooked up to the return plenum, because if hooked to the inlet plenum, it will only read vacuum. Are you certian that the boost gauge is working ? It is possibly that it will only read vacuum if gauge gets clogged up with gunk...had it happen to mine from using nitrous. It's easy to test the boost gauge using an air compressor with pressure regulator turned down to about 10 psi...just supply the compressed air to the gauge hose.

I'm asking about the boost gauge, because if it runs like a big block, then it has to be making boost. Without boost a low compression 3.8 will barely get out of it's own way.

David

backtobirds
05-18-2009, 06:03 PM
Do you have the boost gauge hooked up to the return plenum, because if hooked to the inlet plenum, it will only read vacuum. Are you certian that the boost gauge is working ? It is possibly that it will only read vacuum if gauge gets clogged up with gunk...had it happen to mine from using nitrous. It's easy to test the boost gauge using an air compressor with pressure regulator turned down to about 10 psi...just supply the compressed air to the gauge hose.

I'm asking about the boost gauge, because if it runs like a big block, then it has to be making boost. Without boost a low compression 3.8 will barely get out of it's own way.

David

No, it just sounds like a big block. Actually louder than a 5.0 Mustang I had. The gauge is hooked up to the stock location. I checked the gauge as well as the airflow (the datalog). When the bypass closes nothing happens.
The blower hub doesn't seem to be slipping on the shaft, but I don't know how much force is put on it under boost. I would imagine however that if I can hold the rotors and turn the pulley and it doesn't slip that would be good enough. I also wonder if the rotors and MPX housing aren't sealing, but Charles said that's not possible...... Just more down time I guess.

fturner
05-18-2009, 06:34 PM
Make sure the spout jumper is plugged in. It almost sounds like the car isn't making any timing and is stuck at 10 degrees, which would make it choke on itself going into boost.

Datalog spark, rpm and vmaf and see what your getting commanded wise for spark.

Fraser

backtobirds
05-18-2009, 07:26 PM
Make sure the spout jumper is plugged in. It almost sounds like the car isn't making any timing and is stuck at 10 degrees, which would make it choke on itself going into boost.

Datalog spark, rpm and vmaf and see what your getting commanded wise for spark.

Fraser

I was having a problem with the spark where at initial throttle it would pull around 40 degrees. i traced it down to torque limiting. i don't know how it works, but i set some spark tables to zero to make it driveable. The spark would recover instantly, but still no boost.

fturner
05-18-2009, 08:33 PM
What year is your car and what is the catch code for the EEC?

And just what tables did you zero out?

Fraser

backtobirds
05-19-2009, 12:46 AM
What year is your car and what is the catch code for the EEC?

And just what tables did you zero out?

Fraser

It is a 95. Catch code is P5X0, strategy is CBAZ0. BE is the only program that supports CBAZ0 that I know of, but you can still view the strategy and bin without registering. I zeroed the "Spark Torque Limiting for Torque Ratio" table, it was the one going WAY negative. I don't intend to leave it that way, but it is a temporary fix until I figure out how that torque limiting process works.

backtobirds
05-19-2009, 01:46 AM
i just realized... when I get on it people can hear it whine 300 yards away, so the hub can't be slipping.

KMT
05-19-2009, 10:19 AM
i just realized... when I get on it people can hear it whine 300 yards away, so the hub can't be slipping.

How does the car perform without the sc belt?

fturner
05-19-2009, 12:38 PM
What did you do to your tune to take into account a blown setup instead of a N/A setup?

Not saying you haven't done anything but just curious.

Fraser

backtobirds
05-19-2009, 12:52 PM
So far I have just made the changes for the hardware. Injector settings, injector timing from the cam, MAF transfer, etc. As for the rest, I am going to use my wideband and knock sensor to get everything close before putting it on a dyno. But I can't do any of that until I get the boost problem fixed. Are you thinking they are related?

fturner
05-19-2009, 02:26 PM
The stock N/A tune is set up for a motor that will probably never see more than 70% load at WOT, so all the fuel enrichment and spark tables are set up accordingly.

Add a blower, and now your seeing about 120% to 130% load (super coupe setup) almost the second you put your foot down, meanwhile the spark isn't there to support it and neither is the fueling, which by the way may be to lean for a boosted setup as we typically target 11.7.

Was the car originally a n/a 3.8 with a distributor?

Fraser

backtobirds
05-19-2009, 03:33 PM
The stock N/A tune is set up for a motor that will probably never see more than 70% load at WOT, so all the fuel enrichment and spark tables are set up accordingly.

Add a blower, and now your seeing about 120% to 130% load (super coupe setup) almost the second you put your foot down, meanwhile the spark isn't there to support it and neither is the fueling, which by the way may be to lean for a boosted setup as we typically target 11.7.

Was the car originally a n/a 3.8 with a distributor?

Fraser

It sure was n/a with a distributor. i can datalog commanded a/f and load. can also try it without the belt. i might have to play with load scaling. but i should note that it doesnt fall on its face, just doesnt make boost. i would think that at 4000 rpm with the throttle open and bypass closed it should make boost regardless of what the tune is doing. but hopefully i can datalog tomorrow. forgot i have a project due at the end of the week.

bigpoppa822
05-19-2009, 03:55 PM
If people can hear you whining from far away, then how is it not making boost? :confused:

backtobirds
05-19-2009, 04:17 PM
If people can hear you whining from far away, then how is it not making boost? :confused:

that would be my dilemma
actually, it may be making boost but not getting anywhere. I cant find any leaks though. and i haven't considered that the intercooler may be clogged. i should check on that.

Surgin
05-19-2009, 05:42 PM
I had the same problem, errrrrr from the blower, just no boost on the gauge. So i pulled it and resealed everything. Cranked it up, lower idle and less vacuum. I didnt drive though, burning fuses, crushed wires, etc.....

Justin

fturner
05-19-2009, 07:12 PM
The tune is WAY off and doesn't support a boosted setup. If the timing isn't right as well as fuel demand, it will not make boost much over "0" because it'll fall flat on its face before boost has a chance to build up.

It would help to tell everyone exactly what car that motor is running in and what it was originally.

Have fun working out the problem ;).

laters
Fraser

backtobirds
05-19-2009, 10:13 PM
The tune is WAY off and doesn't support a boosted setup. If the timing isn't right as well as fuel demand, it will not make boost much over "0" because it'll fall flat on its face before boost has a chance to build up.

It would help to tell everyone exactly what car that motor is running in and what it was originally.

Have fun working out the problem ;).

laters
Fraser

The car is a 95 LX 3.8 with a SC based engine. when i get home i will put up a link to the datalog, as well as compare my tune to a SC tune. you sound like you have been inside the eec before, any pointers?

fturner
05-19-2009, 11:24 PM
Inside the EEC........

Its cramped in there.

Fraser

Young-SC-Owner
05-19-2009, 11:49 PM
Inside the EEC........

Its cramped in there.

Fraser

Mighty warm over them Canadian summers eh scotsman

backtobirds
05-20-2009, 12:28 AM
Here is a graph from the datalog.
http://www.mediafire.com/?t0qnmynwyi0
The tune isn't perfect, but not far from decent condition IMHO. When the TP opens, the spark drops (still working on that one), but recovers. I didn't log commanded A/F, but the fuel pulsewidth jumps.

Here is the datalog CSV.
http://www.mediafire.com/?mqygojvdmdf

I KNOW the tune isn't perfect, I did just get the car back together over the weekend and don't even have the wideband in yet. My first goal is to get it to a good running condition and get the lambdas tied to the MAF. Then dyno time.
Either way, if anybody sees anything constructive that jumps out at them, lemme know. I might even put the old SC housing back on just to rule that out. Or find out the MPX housing isn't right. Don't really know anymore. Gonna watch some Aqua Teen for now.

fturner
05-20-2009, 10:17 AM
Look at the load scaler functions and you'll see how different those are. I'd start by comparing the SC base tune and update the LX ones to match and that should get you fairly close.

The spark pull your seeing may have something to do with the tip-in spark.

Fraser

backtobirds
05-20-2009, 12:56 PM
Look at the load scaler functions and you'll see how different those are. I'd start by comparing the SC base tune and update the LX ones to match and that should get you fairly close.

The spark pull your seeing may have something to do with the tip-in spark.

Fraser

Rght on the money, Mr. Fraser. I spent some hours last night looking through EECTuning.org's threads, as well as comparing my datalogs and binaries to other vehicles. In the first datalog, the torque truncation and torque control (the automatic-equipped cars' version of tip-in) was pulling all that spark out. Once I zeroed the torque control table, I still initially lost spark, but not nearly as much and not enough to stall the car anymore. On the second datalog, the spark was pulling from the borderline table, and the lack of advance I was seeing matched up to the BDLN table. I took a look at some other tunes, and the 94/95 4R70W SC's had -11 degrees at high load low throttle, while the 95 Cobra got around 9 degrees advance. I am using those cars to compare against, since the 94/95 Mustangs used CBAZA and are very close to my CBAZ0 strategy, while the 94/95 SCs are blower tuned, but still use the later generation of EEC-IV strategies.

I am happy with not using torque truncation anymore since I rebuild my 4R70w and turned it into a monster in the process. I do however think there is still some tip-in going on somewhere, since the spark does recover after the initial retard, and I would like to get an understanding of that. It is still a little too much retard for my liking.

I agree with you on the load scaling not being correct. I have updated the tune with my new injector and MAF specs, but I have not yet datalogged the load% to see if the changes stuck. My load tables only go to 80 or 90 depending on the table, while the SC gets 130, and as far as I know that is burned into the PCM and not adjustable. Hopefully the PCM pulls fuel and timing from the load%. How would I adjust the load scalars to account for my new load range? The spark and fuel tables have load vs. RPM or temp or whatever the particular table uses, and I'm not clear as to where the scalar tables come in to play.

fturner
05-20-2009, 02:08 PM
I'm not sure if the normalizer functions are available for you in the CBAZ0 strategy in BE as I don't think that def file is fully developed. In all the SC defs, the functions for scaling are there for you to change so you can rescale your load values.

The RPM and Load values you see in the spark and load tables come from Scalar values that can be edited, and in BE, you can click right on the link on that axis and it should take you direct to that scalar.

I wonder what it would take for you to swap out to the 94/95 SC EEC which for the auto would be the W4D2 calibration. You may be in luck that all the wiring is the same between the 2.

Might be something for you to consider?

Fraser

backtobirds
05-20-2009, 02:31 PM
There is a function called "Spark Scaler for Load," that has load in one column and row in the other. So the spark table sees a load, looks to that function, then goes to the selected row back in the spark table? If that is correct then it would make sense. I was thing the spark tables were just like a normal xy graph. If this is the case, how would I scale it? Is it just a matter of new load divided by old load times the row in the scalar function? If that is how it is done I would think the eec would be looking at, for example, the 80 load row, but that would actually equal 130 load. Makes sense to me if that is how it's done.

fturner
05-20-2009, 02:42 PM
There is a function called "Spark Scaler for Load," that has load in one column and row in the other. So the spark table sees a load, looks to that function, then goes to the selected row back in the spark table? If that is correct then it would make sense. I was thing the spark tables were just like a normal xy graph. If this is the case, how would I scale it? Is it just a matter of new load divided by old load times the row in the scalar function? If that is how it is done I would think the eec would be looking at, for example, the 80 load row, but that would actually equal 130 load. Makes sense to me if that is how it's done.

Thats pretty much how it works, and its extrapolated between those values. So you'd go in on the load side and increase the second to the top row to say 105 then the top row would be 200.

There's a caveat.... your strategy actually uses 2 different load values, one is used for fueling (I believe) and the other is used for everything else. The one value will never go over 100%, and 100% is considered to be say 70% of the other load value. There is a sealevel load to load percent function that determines this. The table was built from testing at Ford and is an actual representation of VE the motor is capable of. So this table would say that at 70% VE, the motor is running at 100% load (max load)

The supercoupes have this function disabled, so Load and Load% are always the same.

There's a good document out there that explains this really well.

Fraser

backtobirds
05-20-2009, 02:52 PM
Thats pretty much how it works, and its extrapolated between those values. So you'd go in on the load side and increase the second to the top row to say 105 then the top row would be 200.

There's a caveat.... your strategy actually uses 2 different load values, one is used for fueling (I believe) and the other is used for everything else. The one value will never go over 100%, and 100% is considered to be say 70% of the other load value. There is a sealevel load to load percent function that determines this. The table was built from testing at Ford and is an actual representation of VE the motor is capable of. So this table would say that at 70% VE, the motor is running at 100% load (max load)

The supercoupes have this function disabled, so Load and Load% are always the same.

There's a good document out there that explains this really well.

Fraser

I think I got it now. I think I saw that article. And the load is the actual VE of the engine so it can go above %100, but the load% would be the percent of load. So if the engine sees %150 VE that is 150 load. Then at 100 load the load% would be 66. I assume the number for scaling it are not arbitrary, and I would set the second to highest row to whatever my max load is from datalogging.

fturner
05-20-2009, 02:58 PM
There is a scalar that you can turn that mode off and it ignores the Table I mentioned above. There's 2 fields of thought on that, and personally I'd just turn it off and only have to worry about one load value for everything, then you don't have to worry about remapping the sea level load function I mentioned above which as you mentioned would require a few datalogs to map out the new loading the motor can produce.

Go with the numbers that you see in CZAW0 and that should get you going pretty good. Normally we don't change the load scaling it has unless the motor is extreme. Then set up the spark tables and fueling tables like CZAW0.

Fraser

backtobirds
05-20-2009, 03:22 PM
There is a scalar that you can turn that mode off and it ignores the Table I mentioned above. There's 2 fields of thought on that, and personally I'd just turn it off and only have to worry about one load value for everything, then you don't have to worry about remapping the sea level load function I mentioned above which as you mentioned would require a few datalogs to map out the new loading the motor can produce.

Go with the numbers that you see in CZAW0 and that should get you going pretty good. Normally we don't change the load scaling it has unless the motor is extreme. Then set up the spark tables and fueling tables like CZAW0.

Fraser

I think I know waht you are referring to. CWAZ0 has a scalar called "Air - Load Scaling Switch (Percent Load)" It's options are calculate load or absolute load, and it is set on absolute. My CBZA0 has a scalar called "Percent Load Switch," and it's options are load/peak load, load, or inferred load. It is originally set to inferred load. I can do that, but I may change it back to inferred load later to get better resolution on my tables.

fturner
05-20-2009, 04:03 PM
Out of curiosity, why do you think you need better resolution in the tables?

Fraser

backtobirds
05-20-2009, 04:13 PM
Out of curiosity, why do you think you need better resolution in the tables?

Fraser

Don't need, just want. But that's a good point. By the time I get to a load point over the 80 my tables are set up for, I'll pretty much be at WOT anyway so it probably won't matter.

XR7 Dave
05-20-2009, 05:07 PM
I think you guys are way overcomplicating this. :p

XxSlowpokexX
05-20-2009, 05:19 PM
I'm with Dave on this one

fturner
05-20-2009, 05:36 PM
Ok, so you both are suggesting that the tune settings and load ranges for an n/a 3.8l motor is sufficient to run a sc'd 3.8l motor with no changes.

Back to the books for me I guess.

Fraser

backtobirds
05-20-2009, 05:37 PM
I think you guys are way overcomplicating this. :p

True, but it's keeping me out of trouble :) I'm gonna stop thinking about it until I go drive around some more. And get more datalogs. And see if I left a rag in the intercooler, lol.

fturner
05-21-2009, 09:56 PM
I am so very confused now.....

Everything I read says that if you take an N/A setup to a boosted setup you have to compensate in the tune accordingly because of the increased load etc, otherwise you have a crap running motor. This is something that has to be done.....

Yet your guys are saying that doesn't have to be done.......... the stock n/a load settings should be good enough to run a motor with 14 pounds of boost.

Back to the drawing board for me I guess, and everything I've said just made me look like a complete fool.... which is nothing new :D.

Fraser

XR7 Dave
05-21-2009, 10:41 PM
No, I just said you guys were over complicating it.

Not being able to make boost is a mechanical problem. Regardless of the tune, the blower should build boost.

David Neibert
05-22-2009, 03:16 PM
No, I just said you guys were over complicating it.

Not being able to make boost is a mechanical problem. Regardless of the tune, the blower should build boost.

And then it should fall on it's face.

David

backtobirds
05-22-2009, 05:54 PM
I blew into the intercooler tube and didn't get any resistance, so I'll go ahead and rule out a rag forgotten in it. I just finished putting the M90 housing back on, and I'm putting up some pictures while the gasket maker stuff cures. I think I'll give it an hour. Here are some pics of the M90 and MPX.

First up is the coupler hub. It looks hideous. I for the life of me could not get it to slip, but I marked it anyway so I can double check it later
http://www.mediafire.com/?t5wi3zombk3

Rotor pack.
http://www.mediafire.com/?jzokn4mmzqy

Old M90 case.
http://www.mediafire.com/?jzokn4mmzqy
Some scoring on the walls. I don't know if that is normal, it was like that when I got the car. The tips of the rotors are the same way.
http://www.mediafire.com/?ym4wtwtmmdj

The MPX.
http://www.mediafire.com/?mdamqo0zzdm
See the different color/texture part in the lower corner? I don't remember if it was that way when I got it, but that part doesn't feel any different.
http://www.mediafire.com/?lhytjwzdy1w

I should also note that at first, I could get it to 5 give or take 1 psi of boost at maybe %75 throttle. That was as far as I dared take it without a tune. And now it does nothing. I will try it with the M90 and post back after that.

backtobirds
05-22-2009, 08:02 PM
I went out and drove it, no change. From the datalogs, MAF kg/hr peaks around 390 at 3500 RPM. HEGO averages .39v. I think that is a little lean, I don't remember. And I don't have my wideband installed yet. Moving on. Load never goes over 85. Ever. And I did change my load switch from inferred (scaled) load to actual load, like the SC tunes. I'm leaning away from the problem being the blower since I have the same symptom on the MPX and now the M90. I don't want to distract anybody if they have thoughts, but how can I check for belt slip? The MAF reading doesn't suggest any extra air coming in to account for the blower. I am using the Magnum Powers tensioner, but who knows.

As a sidenote, I added 8 degrees to my low RPM blocks in the borderline spark table, and that seems to have taken care of my off-idle stumble. Once I get the knock sensor hooked up I can fine-tune it. Here is my datalog if anybody is curious about it.

http://www.mediafire.com/?wyz2amde2uo

XR7 Dave
05-22-2009, 09:30 PM
KG/hr means little because if your curve is wrong then the Kg/hr values are wrong.

.39v is extremely lean. A narrow band O2 should read about .8v or higher under high load. Sounds like you have it so lean it simply can't run. What MAF curve are you running? Sounds like it's not even close to right.

PS. media fire sucks. If you want people to see your stuff attach it to your post. I'm not even going to follow those links.

backtobirds
05-22-2009, 09:43 PM
KG/hr means little because if your curve is wrong then the Kg/hr values are wrong.

.39v is extremely lean. A narrow band O2 should read about .8v or higher under high load. Sounds like you have it so lean it simply can't run. What MAF curve are you running? Sounds like it's not even close to right.

PS. media fire sucks. If you want people to see your stuff attach it to your post. I'm not even going to follow those links.

The MAF is the C&L tuner MAF. So you're right, it's probably nowhere near right lol. From what I hear in the tuning community. And I agree on mediafire. Forgot I could do uploads here, got my boards mixed up. Lemme try it.

Got it. I had to delete some data and zip it for the forum to accept it, but the gist is there.

backtobirds
05-22-2009, 10:13 PM
oops, forgot the pics.

XR7 Dave
05-22-2009, 10:22 PM
According to that log you have .8v at high load. Time for a wideband. Seriously, I have no doubt that the whole thing should run fine with the proper settings but it may be a little much too think you can just jump into it and go. I've done plenty of NA to blown conversions but I can't really follow everything you are trying to do or needing to do via the internet. I'd have to see it hands on and I still think you have some sort of mechanical problem like maybe a huge boost leak.

backtobirds
05-23-2009, 02:09 AM
According to that log you have .8v at high load. Time for a wideband. Seriously, I have no doubt that the whole thing should run fine with the proper settings but it may be a little much too think you can just jump into it and go. I've done plenty of NA to blown conversions but I can't really follow everything you are trying to do or needing to do via the internet. I'd have to see it hands on and I still think you have some sort of mechanical problem like maybe a huge boost leak.

.8 Hego? I haven't looked TOO closely at that datalog, just wanted to see if anything changed with the stock M90 back on it. I want to get the mechanicals right before I dive into the tune. But, I can put the wideband in Saturday and force open loop for the time being. Which reminds me, I can't think of anything I have to do this coming Friday, so I can come up to see you if I don't work it out by then. This is ironically the one weekend my cousin in Cleveland is out of town, but I can stay Friday night with the aunt and uncle if necessary. I will be coming from Columbus, but let me know what time to show up and I can leave from here accordingly.

And NO!!! diagnose it over the internet! NOW!!! Just kidding. I know exactly how you feel. I have plenty of friends who say "my car makes a noise, what is it?" Usually the answer is "rotary girder," lol.

backtobirds
05-24-2009, 07:33 PM
Got it. Sean and Shane came over and we messed with it. When I locked it into 2nd gear and revved it against the brakes to get some load, they watched the motor and the bypass didn't always close. I have the vacuum line for my bypass going to the inlet plenum, so the blower and bypass were keeping each other in equilibrium.

Par two is we zip-tied the bypass shut. As soon as the boost got to 15 psi, it would flutter between 15 and 10 very fast, and the motor made a screech. I guess I now have belt slip. I'll research it and try to take care of it tomorrow, I am sick of looking at it tonight. Thanks to everyone who got in on this board, I learned a lot from it.

19TbirdSC91
05-24-2009, 07:57 PM
Got it. Sean and Shane came over and we messed with it. When I locked it into 2nd gear and revved it against the brakes to get some load, they watched the motor and the bypass didn't always close. I have the vacuum line for my bypass going to the inlet plenum, so the blower and bypass were keeping each other in equilibrium.

Par two is we zip-tied the bypass shut. As soon as the boost got to 15 psi, it would flutter between 15 and 10 very fast, and the motor made a screech. I guess I now have belt slip. I'll research it and try to take care of it tomorrow, I am sick of looking at it tonight. Thanks to everyone who got in on this board, I learned a lot from it.

Yeah, I had a good time over there, sorry i wasn't a whole lotta help lol. Once you get the bypass vacuum line going to the right location, I wonder if you will still have the "par" two issues, maybe its just cracked out cuz of the bypass. Definetly pumped to get mine running this week.

Sean

XR7 Dave
05-24-2009, 08:45 PM
I have the vacuum line for my bypass going to the inlet plenum, so the blower and bypass were keeping each other in equilibrium.


The bypass valve is supposed to go the inlet plenum. Therefore if it's not working right when connected that way then you still have issues to straighten out. You can route it to the return plenum side if you want, but that will cause the transition from vacuum to boost to become abrupt. Some people don't mind this condition, but that's what you'll get anyway. Either way it will work.

backtobirds
05-24-2009, 09:41 PM
The bypass valve is supposed to go the inlet plenum. Therefore if it's not working right when connected that way then you still have issues to straighten out. You can route it to the return plenum side if you want, but that will cause the transition from vacuum to boost to become abrupt. Some people don't mind this condition, but that's what you'll get anyway. Either way it will work.

Dave I agree, and that is what motivated me to do it that way. But we put a vacuum tee in the line to the bypass actuator and hooked it to a gauge. The tool kind, not the in-car kind. The gauge reading at the bypass (vacuum signal from inlet plenum) matched the gauge at the factory location on the return plenum at closed and part throttle. But at open throttle/no vacuum on the post-blower gauge, there was vacuum on the bypass/pre-blower gauge. Seemed that the blower was pulling vacuum which made the bypass want to hang in limbo or open back up. With the bypass zip tied open it worked fine.

Ideally, I would like to use an electronic actuator for the bypass fed by the throttle sensor. Then I could put a potentiometer inline to add or remove bias, or even override the input signal altogether. But first things first.

quick35th
05-25-2009, 02:10 AM
Jonathan,

It was funny standing around watching you get frustrated with your SC, and you blame me for loosing all of your tools and parts in your pile of goodness. I agree that the bypass line needs to be plugged into the location on the return plenum like we talked about. Its cool that we figured out what was wrong with it before you had to spend all that money to tow it up north. Be sure to give me a call here soon so we can get all the bugs worked out.

As for you Sean, your car is long.overdue for needing to get finished, it bess get done this week. The force must be strong LOL!

Shane
Glynn Motorsports

19TbirdSC91
05-25-2009, 03:15 AM
The force must be strong LOL!

Shane


"My balls are tingling..."

Surgin
05-25-2009, 08:08 AM
I had the same problem with mine, the plenum to lower manifold was leaking. Pulled it and resealed it, same problem 2lbs of boost. I had the bypass hooked to the two line plug on the return plenum, by the cross-talk on a 90 SC, and the bypass would not close fully. I relocated the hose it to the drivers side and "T"ed it into the main line and capped the other line. No problems anymore.

Just my 2 cents......


Justin

XR7 Dave
05-25-2009, 09:02 AM
Dave I agree, and that is what motivated me to do it that way. But we put a vacuum tee in the line to the bypass actuator and hooked it to a gauge. The tool kind, not the in-car kind. The gauge reading at the bypass (vacuum signal from inlet plenum) matched the gauge at the factory location on the return plenum at closed and part throttle. But at open throttle/no vacuum on the post-blower gauge, there was vacuum on the bypass/pre-blower gauge. Seemed that the blower was pulling vacuum which made the bypass want to hang in limbo or open back up. With the bypass zip tied open it worked fine.

You can rig it or you can fix it. The bypass is not supposed to see boost, it is supposed to see 0 when the car is in boost. What you described to me is correct operation. Make sure that when the bypass is closed it is actually putting a little pressure on the "stop". If the bypass is not set properly it will not work right. Many people do not get the bypass set correctly (so that it is putting some tension on the stop screw) when closed thus creating a problem.


Ideally, I would like to use an electronic actuator for the bypass fed by the throttle sensor. Then I could put a potentiometer inline to add or remove bias, or even override the input signal altogether. But first things first.
While that might sound cool it would be a nightmare setting it up to work correctly. Ford/Eaton knew what they were doing when they designed the stock bypass. It works fine on all applications from mild to wild. If yours isn't working right it's because you have something wrong and need to fix it.

When you remove vacuum from the bypass vacuum line the bypass WILL stay closed unless you have either a bad bypass valve or it is misadjusted.

quick35th
05-25-2009, 11:08 AM
"My balls are tingling..."

"The force is really strong, he must be working on his SC."

Shane
Glynn Motorsports

quick35th
05-25-2009, 11:15 AM
Dave,

How do you adjust the bypass? Do you just adjust the amount of vacuum it sees? Its not like you twist it or can adjust a bolt on it to adjust it. It is pretty much a sealed unit so idk how you could get it out of adjustment inless you hooked up the vacuum line going to it in the wrong location. On sean's SC the line for the bypass goes to a tree on the driverside firewall, the tree gets it's vacuum from the return plenum near the downward bend facing the firewall. So shouldn't it work if properly if he hooked it up like that?

Shane
Glynn Motorsports

backtobirds
05-25-2009, 11:40 AM
When you remove vacuum from the bypass vacuum line the bypass WILL stay closed unless you have either a bad bypass valve or it is misadjusted.

I have a pump on that vacuum tester. The bypass is fully open by 15 inHg, and holds with no leakage. I need to mess with it some more. I just need to figure out why I am making so much vacuum with the throttle open. I am using an 85mm C&L maf, the MP 80mm throttle body, and the MP chrome tube with that steel divider box and the monster air filter Charles Warner has in his cold air kit. Actually I think it is the cold air kit. So with all that, the only thing I can come up with is that my %30 overdrive requires a lot more throttle to reduce vacuum on the inlet side. The blower spins faster so it requires a lot more air, so the restriction from the throttle plate is magnified. That make sense to anybody?

If that is the case, then my tune may be affecting it. I wasn't ready to go fully WOT. The car was running perfectly (except for boost) Friday, but my tune got corrupted. Now that my wideband is in I need to go get the MAF straightened out so I can go WOT.

XR7 Dave
05-25-2009, 11:54 AM
I have a pump on that vacuum tester. The bypass is fully open by 15 inHg, and holds with no leakage. I need to mess with it some more. I just need to figure out why I am making so much vacuum with the throttle open. I am using an 85mm C&L maf, the MP 80mm throttle body, and the MP chrome tube with that steel divider box and the monster air filter Charles Warner has in his cold air kit. Actually I think it is the cold air kit. So with all that, the only thing I can come up with is that my %30 overdrive requires a lot more throttle to reduce vacuum on the inlet side. The blower spins faster so it requires a lot more air, so the restriction from the throttle plate is magnified. That make sense to anybody?


In a word, no. You are not making any sense. You aren't the first person to run 30% OD. OD has nothing to do with it. You verified that the bypass actuator works fine (I suspected that it would), now just set it properly and connect the vacuum line to the proper source (directly to the inlet plenum).

quick35th
05-25-2009, 12:10 PM
You verified that the bypass actuator works fine (I suspected that it would), now just set it properly and connect the vacuum line to the proper source (directly to the inlet plenum).

Dave,

Pretty sure the vacuum line for the bypass valve is already hooked directly to the inlet plenum.

Shane
Glynn Motorsports

backtobirds
05-25-2009, 12:43 PM
Yes, it is already on the inlet side. To boil down my post up above, with the bypass closed there is enough vacuum on the inlet side to allow the bypass to open back up. At least partway. I am going back over now to play with it. Somehow, some scalars in my tune got themselves set to values that don't make any sense, so I corrected them.

XR7 Dave
05-25-2009, 12:53 PM
Yes, it is already on the inlet side. To boil down my post up above, with the bypass closed there is enough vacuum on the inlet side to allow the bypass to open back up. At least partway.

I give. :o

quick35th
05-25-2009, 12:58 PM
Doesn't the inlet plenum and everything before it stay at vacuum even under boost so wouldn't it make sence that even under boost the bypass would stay open because the pressence of vacuum? I really think he should connect the bypass to the return plenum, fix his tune, take care of his belt slip then see how the car runs. Though jonathan I would take care of the belt slip before 100 percent tuning it because its not going to make full boost.

Shane
Glynn Motorsports

KMT
05-25-2009, 01:21 PM
with the bypass closed there is enough vacuum on the inlet side to allow the bypass to open back up.

A closed bypass indicates vacuum not happening...

If the engine is capable of generating 'enough' vacuum to operate the bypass properly, there is no chance of a simultaneously occurring overriding condition. You can't have both (when the controller is ok and properly connected), sorry.

quick35th
05-25-2009, 01:38 PM
I think Jonathan might not be explaining this correctly so I will explain what I saw. Like normal when he starts his car vacuum plus his bypass valve closed, but when jonathan stabs the gas to make boost the bypass valve does not close or it moves just slightly but no where near what it should. At idle he is getting 16 inches of vacuum.

Shane
Glynn Motorsports

KMT
05-25-2009, 01:55 PM
>when jonathan stabs the gas to make boost the bypass valve does not close or it moves just slightly

Does that really make sense (meaning you really think it's hooked up properly) to both of you guys?

Forget engine operating the bypass controller and check how much vacuum it takes to work the bypass controller via a test (vacuum/pressure) hand pump.

Compare his to another car.

Then correct the vacuum supply issue and be done :)

quick35th
05-25-2009, 05:20 PM
No I am not saying it is hooked up right at all right now. I am only saying what it is currently doing. To hold the valve open using a hand pump it takes around 15 inches to hold open and it will not leak. The problem, as I saw it, is that under load vacuum is not being taken away from the bypass valve.

Shane
Glynn Motorsports

backtobirds
05-25-2009, 11:37 PM
I should jump in. Would have sooner, but I played with the car long enough to almost be late for work. So I said it was on the inlet side. Well, it WAS. It was on the vacuum distribution block per the vacuum diagram posted in here somewhere. Anyway it was hooked up to the inlet side. Well somewhere along the way when I put it together a year ago that block ended up on the return side. So I have to redo my vacuum again. Anyway, I moved it to the inlet side, and all good now. Dave, I don't like it on the return side :). Anyway I have to redo my vacuum. Anybody know what thread Charles uses on the fitting ports on the MPX inlet plenum? I measured one at 3/8-27. The fittings with barb ends or vacuum ends at Advance all have pipe thread. And I have never seen anything with 27 thread count. That is acurate, btw, I checked it with a thread gauge. There is a plug there that I want a fitting for for the bypass tube.

KMT
05-26-2009, 12:16 AM
>Well somewhere along the way when I put it together a year ago that block ended up on the return side. Anyway, I moved it to the inlet side, and all good now.

Hey, that's good news...thanks for the report and good luck w/the rest of your fun :)

backtobirds
05-26-2009, 12:44 AM
>Well somewhere along the way when I put it together a year ago that block ended up on the return side. Anyway, I moved it to the inlet side, and all good now.

Hey, that's good news...thanks for the report and good luck w/the rest of your fun :)

Thanks man. I've gotten so frustrate with it I've been eyeing that quarry not far from me. Wouldn't start, turned out I made a bracket for the crank pickup out of steel. The crank pickup is Hall-effect, so magnetic. Got it running, and my new used "worked fine" trans gave out. Rebuild the trans (that was actually fun), then ran into this. But now I am down to normal problems at least .

Speaking of, I got the belt slippage toned down. Used a powerstroke steel pulley. I had to kiss the tensioner with a die grinder to make it fit, but its on there now. Now the boost just hangs at 15 psi, or goes back down, but no more fluttering.

I know there were posts about this before, but I searched belt slip and got a bunch of results. Haven't been able to get through all of them. I will try smaller belts, but I don't know how the sizing affects the fit on this belt system. I might even need to mess with the jackshaft system, but I don't know if I can stuff the powerstroke pulley into there. Anyone remember where that thread is, or have experience on where to go next?

nickleman60
05-26-2009, 06:29 AM
Ever thought just trying a different vacuum bypass diapham just to eliminate a source? I know you said it seemed to work and closed with 15 psi of vacuum but I would still change it and hook it to the inlet plenum side.

fturner
05-26-2009, 07:21 PM
Glad you found your problem, now get that damn thing tuned in properly :rolleyes:.

I was wrong which is nothing new, but I would focus on getting the tune setup close to reality before running the car so it would eliminate it being the problem... different school, different thoughts I guess.

Have fun.
Fraser

backtobirds
05-27-2009, 05:21 PM
I understand how the tune affecting it could make sense. Either way, you're right, I need to get it tuned. I just got my wideband put together, so I can start from there.

backtobirds
06-28-2009, 04:41 PM
Well good news, I got it on the dyno. Got absolutely nothing accomplished, though. We commanded 11:1 AFR, for %70 absolute load on up, but the PCM absolutely refused to go below 11.6-ish. And I couldn't get the rev limiter to go away. And it poured about a gallon of coolant out the back at the end of the very last pull. The good news is it made 22 psi, 300hp and 350lb/ft on mostly 12.8 AFR from the wideband without a hint of knock. If I can find these lambse and rev limit problems those number should go up significantly I would think.